Harvard Meat Study

On Monday, March 12, 2012, the Archives of Internal Medicine published online "Red Meat Consumption and Mortality: Results From 2 Prospective Cohort Studies," a study done by researchers from the Harvard School of Public Health.  This study found that eating even one serving daily of red meat increased total mortality and risk of mortality from cardiovascular disease and cancer.

The researchers carefully controlled for intakes of total energy, whole grains, fruits, and vegetables; age; body mass index; race (white or nonwhite); smoking status; alcohol intake; physical activity level; multivitamin use; aspirin use; family history of diabetes mellitus, myocardial infarction, or cancer; and baseline history of diabetes mellitus, hypertension, or hypercholesterolemia. In women, they also adjusted the data for postmenopausal status and menopausal hormone use.

Some in the cattle industry have questioned the validity of the food frequency questionnaires used in this type of study (here).  The authors of the study responded:

"However, all the questionnaires used in this study have been validated against multiple-day food records—at least 14 days during a year—and have been found to be acceptable in terms of validation and reproducibility.

"Second, although there [are individual] day-to-day variations in food consumption, people are generally eating in a pattern that can be captured by the questionnaire. We were interested in between-person variation[s], and we were comparing people who eat a high amount of red meat to those who eat a low amount of red meat. Because we repeated the measurements every four years, the cumulative average used in the analysis represents a long-term dietary pattern. That is a strength of this study, because many other studies may have only a single measure at baseline.

"Last, but most importantly, the measurement error generally tends to attenuate the association, and if we corrected the measurement error using some statistical methods, the associations were much stronger!"  [emphasis added]

Some have responded to this by claiming that "correlation doesn't equal causation" (as if the Harvard researchers don't realize this), or that the results only apply to consumption of conventional meat, not grass-finished.

Such a response ignores two important facts:

1) This study is only one among hundreds finding an association between red meat consumption and increased mortality from heart disease and cancer. 

2) Basic research has shown that these hazards arise from components that occur in meat from grass-fed animals at levels equal to or greater than levels found in meat from grain-fed animals.  


The following provide examples of the large number of studies finding positive associations between consumption of red meat and adverse health outcomes:

Meat consumption and colorectal cancer risk: Dose-response meta-analysis of epidemiological studies

Meat consumption and risk of colorectal cancer:  A meta-analysis of prospective studies 

Processed meat consumption and stomach cancer risk meta-analysis


Meat consumption and the risk of type 2 diabetes meta-analysis


Meat consumption and prostate cancer risk


Thus, this new study is not some isolated, rare, unusual finding.  It resonates with a large body of corroborating epidemiological evidence finding a positive association between red meat consumption and risk of or mortality from disease.  It adds to that growing body of evidence. 


Of course, "correlation does not prove causation," so some scientists have taken the next step required, doing research to find out if there are any plausible mechanisms by which consumption of meat could increase the risk of mortality. 

So far, researchers have found that a number of components of red meat have biological effects providing plausible mechanisms by which diets rich in meat could increase the risk of chronic diseases and mortality.  The suspect components include animal protein, cholesterol, arachidonic acid, heme iron, and Neu5Cg sialic acid, all of which naturally occur in red meat.  Further, the concentration of these components of meat is not markedly affected by feeding or pharmaceutical strategy used in raising the animals; meat from grass-fattened animals has practically the same amount of these components as meat from grain-fattened animals.


Animal Protein


Animal protein typically forms a larger proportion of lean grass-fed than conventional fatty meat, and promotes increases in IGF-1 levels, which appears involved in promotion of breast, colon, and prostate cancers.

High animal protein intake raises serum IGF-1 levels. [Full text]

IGF-1 has roles in growth promotion and carcinogenesis. [Abstract]

Elevated IGF-1 levels were associated with a 49% increased risk of prostate cancer and a 65% increased risk of premenopausal breast cancer.  [Abstract]

Elevated IGF-1 levels are associated with increased risk of prostate cancer, lung cancer, colorectal cancer, and premenopausal breast cancer. [Abstract]  


Dietary Cholesterol

Starting with a zero cholesterol diet, adding small increments of dietary cholesterol raises serum cholesterol levels, in a dose-response fashion.[Full text]

Elevated serum cholesterol increases the risk for cardiovascular disease. [National Cholesterol Education Program]

Elevated serum cholesterol increases risk of ischemic stroke in the general Japanese population.[Abstract]

Mice fed a high fat, high cholesterol diet and showing elevated serum cholesterol have increased mammary tumor growth and metastases compared to controls. [Abstract]


Emerging evidence indicates that oxidized cholesterol plays an important role in the angiogenesis process that supports tumor growth. [Abstract]  

The more unnecessary LDL cholesterol in the blood, the more likely there will be oxidized cholesterol in the blood.

Individuals with elevated serum cholesterol found to have a 35% increased prostate cancer risk.[Abstract]

Cholesterol-depletion of breast and prostate cancer cell lines induces apoptosis  whereas cholesterol-enrichment via elevated serum cholesterol (due to diet) supports tumor growth and progression.[Abstract, Full Text]

Elevated LDL positively correlates with increased risk of advanced stage colon cancer.[Abstract]

Patients with colon adenomas, the precursors of colon cancer, have elevated LDL.[Abstract]

Patients with distant metastases of colorectal cancer have significantly elevated serum cholesterol levels compared to those without metastases. "Elevated serum lipid levels may facilitate the development of distant metastasis in CRC [colorectal cancer] patients."[Abstract] 

Heme Iron, Arachidonic Acid, HCAs, PHAs, and Neu5Gc

Heme iron, a form of iron found at the highest levels in red meats. I discussed some of the evidence linking iron intake and levels to inflammatory diseases (including heart disease and cancer) in this post.


Arachidonic acid, which occurs in meat from grass-fed animals at levels equal to or greater than found in meat from grain-fed animals, and is involved in cancer promotion, which I discussed in this post.

Neu5Gc, a type of sialic acid produced by non-human mammals but not by humans, which enters humans through consumption of mammalian meat and milk, is incorporated into epithelial and endothelial tissues, incites an auto-immune response and inflammation in those tissues, and has been found concentrated in malignant tumors (full text).  

Of interest, this paper on Neu5Gc includes the following passage:

"Although earlier studies claimed the absence of Neu5Gc from normal human tissues, we showed thatit is also present in smaller amounts in normal human epithelial and endothelial cells in vivo (Tangvoranuntakul et al. 2003). Furthermore, we recently demonstrated that mice with a human-likedefect in the CMAH gene had no detectable Neu5Gc (Hedlund et al. 2007), effectively ruling out an alternate mammalian pathway for synthesis. This paradox is explained by our finding that humans can metabolically incorporate Neu5Gc via oral intake (Tangvoranuntakul et al. 2003). We have therefore suggested that the well-known epidemiological association of human cancers with consumption of red meat and milk (which happen to be the richest dietary sources of Neu5Gc) (Rose et al. 1986; Norat et al. 2002; Lewin et al. 2006) might be related to this unusual metabolic accumulation. Here, we have demonstrated another required component for this hypothesis – circulating antibodies that can recognize Neu5Gc on human tissues and can potentially generate chronic inflammation. To our knowledge, this is the first example wherein a nonhuman molecule becomes metabolically and covalently incorporated onto human cell surfaces, even in the face of an immune response against it. Further studies are needed to firmly establish a link between Neu5Gc expression in tumors and anti-Neu5Gc in the pathogenesis of carcinomas."[emphasis added]

This passage illustrates that the epidemiological association of human cancers with consumption of red meat and milk is "well-known" among scientists and that they have moved beyond questioning the association (since it is scientifically well established) to elucidating the mechanisms responsible for this association, in this case Neu5Gc, the first nonhuman molecule proven to become part of human cell surfaces despite an immune response against it.


I first learned about Neu5Gc from this video by Plant Positive:

Cooking meat at high temperatures, particularly over open flames, produces heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) which are carcinogenic.   These will form in meat cooked at high temperatures regardless of how the source animal was fed.    The National Cancer Institute says "numerous epidemiologic studies have used detailed questionnaires to examine participants’ meat consumption and meat cooking methods to estimate HCA and PAH exposures. Researchers found that high consumption of well-done, fried, or barbecued meats was associated with increased risks of colorectal (14), pancreatic (15, 16), and prostate (17, 18) cancer."
Summary

Protein, cholesterol, iron, arachidonic acid, and Neu5Gc all occur naturally in meat, and HCAs and PAHs form in meat cooked at high temperatures, regardless of the feeding or pharmaceutical strategy used to raise the animals from which the meat is taken.  

The studies I cited above only provide a small sampling of the laboratory data providing evidence of plausible mechanisms by which an excessive consumption of meat could increase one's risk of mortality.  Epidemiological research generated both the lipid hypothesis and the hypothesis that red meat increases mortality risk, but we now have much stronger data to support these hypotheses. 

We have evidence for specific mechanisms by which these naturally occuring substances can initiate (HCAs or PAHs) or promote (protein, cholesterol, iron, arachidonic acid, and Neu5Gc) fatal diseases, so only someone ignoring or ignorant of the above data could argue that the association of increased risks of mortality from cancer and heart disease apply only to people eating meat from grain-fed or drug-treated animals, or that the epidemiological associations have no plausible physiological basis.

Conventional Meat May Contain MAR Bacteria: What To Do About It

7/13/11 update:  I decided that I don't want to endorse or appear to endorse the use of any meat produced by conventional methods of feeding the livestock grains, primarily corn and soybeans.  Since animals consume 80% of the grain and soy produced by U.S. agriculture, this system drives the ongoing destruction of our topsoil both through crops and through grazing.  Animal food production consumes 87% of all freshwater used in the U.S. each year, and thus is the primary driver of depletion of water reserves.  This system also produces most of the water pollution occurring in the U.S.  Our conventional livestock production system has enormous costs detailed in this article from Cornell University.  Since I have known of these costs for more than 20 years, I feel embarrassed and remorseful that I wrote this series and other articles that endorsed the use of conventional animal products.
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When I wrote my guides to conventional beef (One, Two, and Three), I  looked at data reporting on residues of hormones, antibiotics, chemicals, and pesticides in conventional beef, but I did not find any information about microbial counts in meat from animals raised in conventional confined animal feeding operations (CAFOs).

Now it looks like I have to add multiple-antibiotic resistant (MAR) bacteria to the list of likely contaminants of conventional supermarket meats.   Reuters reports that researchers have found that conventional grocery meat frequently has significant levels of bacteria resistant to antibiotics. 

The Arizona-based Translational Genomics Research Institute (TGRI) tested 136 meat samples from 26 grocery stores in Illinois, Florida, California, Arizona and Washington D.C..  They found that the meat had high levels of Staphylococcus aureus (S. aureus), and more than half of the bacteria tested had resistance to multiple antibiotics.

"The study found that in 96 percent of the meats with staph bacteria the bacteria were resistant to at least one type of antibiotic, and 52 percent were resistant to three or more types. "

"Of all the types of meats where bacteria was resistant to three or more antibiotics in the study, turkey was the most resistant, followed by pork, beef and then chicken. "

While you can kill these bacteria easily by cooking the meat properly,  you also can spread these bacteria by handling the meat then other foods or objects.  You can prevent the spread of these microbes by washing hands and counters before and after handling meat and keeping other foods away from uncooked meat.

Apparently the FDA knows about this:

A spokeswoman for the Food and Drug Administration said that the agency was aware of the TGRI findings, and similar studies of antibiotic-resistant bacteria in meats, and was working with the U.S. Agriculture Department and Centers for Disease Control and Prevention on the causes and effects.

"FDA has been monitoring the situation. The TGRI study points out that the public health relevance of the findings is unclear. FDA continues to work with CDC and USDA to better understand this issue," the FDA spokeswoman said.

To give the foot-dragging bureaucrats a leg-up on this problem, I can think of two well-documented main sources for these bacteria: 1) treated (drinking) water containing multiple-antibiotic resistant (MAR) bacteria may be used to wash meat products in meat-processing facilities, and 2) confined animal feeding operations.  When you confine animals and hold large numbers in close quarters, while feeding them a grain-based, inappropriate diet, you create a breeding ground for infectious microbes. 

Simply put, we could stop directly or indirectly subsidizing pharmaceutical houses and corn-based animal feeding operations, which would save taxpayers money, reduce federal deficit spending, and make drug-laced CAFOs uneconomical compared to drug-free pasture-based operations.  This would encourage the growth of pasture-based animal operations, which when properly managed can reverse desertification and produce animal products of superior nutritional value in terms of omega-3 fatty acids, vitamins, and minerals.  The land, animals, and people will all be healthier as a result.

While the FDA et al go about taking their time "to better understanding this issue," it appears you can reduce your exposure to these microbes by implementing these strategies:


1.  If eating conventional meats, eat less turkey and pork compared to beef and chicken.  Previously I have recommended pork over chicken because pork has a better fatty acid profile than chicken (less omega-6), but now appears that pork presents a greater microbial hazard.  Hence you may want to choose chicken over pork, and remove the chicken skin to minimize omega-6 intake.
2.  Consider buying meat frozen or freezing it after purchase, because freezing can reduce microbial concentrations by up to 97-99%.
3.  Eat more whole cuts of meat and less ground meat, since ground meats may have bacteria in them whereas whole cuts will generally only have bacteria on the outside surfaces.
4. Wash your hands and counters after handling uncooked conventional meats.
5.  Cook conventional meat adequately.
6.  Whenever possible, get grain-fed meats from animals raised without antibiotics. You can get them from local farmers, butcher shops, and some 'natural' markets.  In Arizona, Sprouts Market and Sunflower Market both sell grain-fed meats from animals raised without antibiotics.  Animals raised without antibiotics very likely have lower counts of antibiotic-resistant microbes. 
7.  When economically practical, buy meat directly from farmers who raise their animals without antibiotics on pasture or species-appropriate diets.   

High Protein Diets Raise Colon Cancer Risk? No.

In the more bad science department, MSN online published an article today with the title "High-protein diets may raise colon cancer risk."  It reports the results of a study done a team of researchers led by Dr. Harry J. Flint, of the University of Aberdeen and published in the American Journal of Clinical Nutrition.  Here's how the article describes the study:

"The findings are based on 17 obese men who each followed three short-term diets: a one-week menu plan designed to maintain their weight; a four-week high-protein diet with moderate amounts of carbohydrates; and a four-week high-protein diet low in carbs.

The first diet, which allowed about 360 grams of carbs per day, typically offered cereal, eggs and toast for breakfast; a sandwich and salad for lunch; and chicken, fish or soy, along with pasta, for dinner.

The low-carb diet — which allowed just 22 grams of carbs each day — generally consisted of eggs-and-bacon breakfasts, and lunches and dinners heavy in meat, poultry and fish, along with some vegetables and cheese.

The moderate-carbohydrate diet allowed 181 grams of carbs each day. Both high-protein diets contained just less than 140 grams of protein per day.

At the end of each diet period, Flint's team analyzed fecal samples from the men to look at levels of certain metabolic byproducts."

So do you notice anything funky about this description?

How about this:  they fed the men the high carbohydrate diets for only one week, but the lower carbohydrate diets for four weeks, before taking fecal samples.  This falls into the category of not minimizing variables. How does this kind of study get past peer review?

But of course if you want to create a "study" that favors the high carbohydrate diet, you might just fool around like that.

The really valuable paragraph in this report goes like this:

"The study looked only at short-term shifts in certain compounds that are byproducts of metabolism, and not actual disease risk. So it does not show whether high protein diets really raise the risk of any colon diseases."

Which outright contradicts the sensational title. 

If you want to know whether high protein diets increase colon cancer risk, how about studying Eskimos/Inuit?  Eating their native diet consisting almost exclusively of meat and fat, containing little or no fiber, they had no colon cancer.  How about the Masai?  Eating their native diet of meat and milk products, again, no colon cancer. These samples alone disprove the idea that meat causes and fiber prevents cancer as surely as finding one black swan disproves the statement "all swans are white."

Meanwhile, Dr. Oz, poster boy for the "healthy whole grain diet" rich in fiber that supposedly protects against cancer, turns up with colon polyps, possible precursors to colon cancer. 

As the MSN article says, "obesity is thought to be a risk factor for a number of diseases, including colon cancer."

As explained by Loren Cordain and Michael Eades in this article, both obesity and colon cancer arise from excess insulin production, which is driven by carbohydrate ingestion, not meat or protein intake. Colon cancer falls in the category of epithelial cell malignancies.  Cordain and Eades explain how diets high in refined carbohydrates promote hyperinsulinemia, which raises levels of insulin-like growth factors (IGF), reduces IGF binding proteins, and disables the body's natural antitumor system based on vitamin A activation.

Like other cancers, the prevalence of colon cancer has increased in tandem with increases in consumption of carbohydrates, including fiber, not increases in protein or meat consumption. 

Moreover, as I discussed in my article Fiber Fallacies, these researchers could do a little research and find that high fiber diets have been repeatedly shown to produce changes in colon tissue that precede cancer, or in some cases, actually increased the number of cancers relative to a fiber-free diet: 

Many people think eating a high fiber diet will prevent colon cancer; but we not only have no proof or even weak evidence that ingestion of fiber prevents colon cancer, on the contrary we have experimental evidence indicating that diets high in fermentable fibers actually increase colonic cell proliferation of the type that leads to cancer.

Lupton et al reported that a diet high in fermentable fiber increased cecum size and large intestine length, and reduced pH and stimulated cell proliferation, in rat colons. [J. Nutr. 118: 840-845, 1988.]

Jacobs and Lupton found that when they fed rats a high fiber diet based on either oat bran, pectin, or guar, the yield of proximal colonic adenocarcinomas increased by 4.5 to 5 times over the fiber free level. [Cancer Research 46, 1727-1734, April 1986]

Mandir, Englyst, and Goodlad found that when they fed mice fiber in the form of bran or apple pomace, both fibers significantly increased cell proliferation, number of polyps, and tumor burden born by the mice. Both fibers increased polyp diameter, bran by 243% and apple fiber by 150%. [British Journal of Nutrition (2008), 100, 711–721].

Generally, diets high in fiber make the feces softer and looser. A study by Inoue et al found “Soft or loose feces increased the risk for all subsites of colorectal cancer, particularly in female rectum cancer (odds ratio [OR] = 4.5)” [Cancer Causes Control 1995 Jan;6(1):14-22.]. Although epidemiological studies generally don’t carry much weight, when the odds ratio goes above 2.0, the association carries more weight. This finding of a greater than 4 fold increased risk of colorectal cancer in people with soft or loose stools suggests that high intake of fermentable fiber may promote cancer in humans as well as rats. 

Kok-Yang Tan and Francis Seow-Choen dispensed with all the myths of high fiber consumption in their article Fiber and colorectal diseases: Separating fact from fiction published online in the World Journal of Gastroenterology.   I suggest that these physicians take some time to read it instead of wasting their time beating a dead horse.  High protein diets don't cause colon cancer, and high fiber diets don't prevent it.  On the contrary, we have some pretty good reasons to believe that high fiber diets promote colon cancer.  Conventional 'wisdom' dies hard, but it will die. 

Earth Medicine: Operation Hope

7/13/11 update:  Operation Hope is based on the important realization that livestock and grasslands form an integrated ecosystem.  Putting cattle on desert and managing them as if they were wild game animals does help restore the desert to grassland.  Now that we know that, why not go a step further.  The best approach might be to return the wild game to their native lands and forget about managing the cattle as if they were something they are not.  Also allow the natural predators to return (wild cats, wolves).  Then leave those wild animals alone.  DM


 In 2006 the FAO published Livestock's Long Shadow in which they claimed, essentially, that herds of livestock degrade land, destroy ecosystems, pollute water, release greenhouse gases, and reduce biodiversity.   Livestock are essential to the health of the grasslands that overgrazing has gradually converted into deserts.

But this fact remains hidden from 'experts' who make their living by crunching numbers and creating theories in U.N. cubicles without ever having actually thought about how nature works.  Fortunately we have people who learn by studying nature, not just numbers, like Allan Savory.

Allan Savory

Savory won the 2010 Buckminster Fuller Challenge Prize of $100,000 for the Africa Center for Holistic Management (ACHM) in Zimbabwe by demonstrating that by INCREASING the number of livestock on barren land by 400% we can convert it from desert back to productive grassland:

"Desertification is occurring on 25% of the land area of Earth, degrading 73% of the world's rangelands and causing widespread poverty. By reversing desertification, we could create innumerable positive consequences: mitigating climate change, droughts and floods, and reducing poverty, social breakdown, violence and genocide. Yet most attempts to date have not only been ineffective, but have been band-aid solutions that do not address its real "root" causes. Enter Semi-Finalist Allan Savory and his surprising trimtab approach to reversing desertification that he calls "holistic rangeland management." Nearly the exact opposite of prevailing theories that blame desertification on overgrazing, Savory's solution centers on dramatically increased livestock numbers to reverse desertification. The tremendous success of Savory's counter-intuitive solution is evidenced through his work with Operation Hope at the Africa Center for Holistic Management (ACHM) in Zimbabwe. For hundreds of years the 6,500 acres of the ACHM were barren, dry fields until 1992 when Savory increased the livestock by 400% and managed them through holistic, planned grazing. Over time, the barren fields were transformed into green grass and open water, full of water lilies and fish.

Did you get that?  By increasing livestock by 400% and managing their grazing to mimic patterns of wild grazing animals this project turned deserts into grasslands and wetlands.  Look at this transformation; on the left, before the grazing, on the right, after the grazing:

Source: Inhabitat.com

This was accomplished by skillfully using lots of cattle, the very same species that the FAO claims is destroying the planet.

I don't know if Savory has ever read the Tao Te Ching, but his whole project is based on a Taoist sensibility:

In the pursuit of learning, every day something is acquired.
In the pursuit of Tao, every day something is dropped.

Less and less is done
Until non-action is achieved.
When nothing is done, nothing is left undone.

The world is ruled by letting things take their course.
It cannot be ruled by interfering.

Tao Te Ching Chapter 48

Do you think you can take over the universe and improve it?
I do not believe it can be done.

The universe is sacred.
You cannot improve it.
If you try to change it, you will ruin it.
If you try to hold it, you will lose it.

Tao Te Ching, Chapter 29

Instead of doing something based on conventional 'wisdom' that putting animals on a desert will make it worse, Savory just noticed that grasslands need livestock as much as livestock need grasslands and rather than trying to change or interfere with nature, he decided to emulate it:

Operation Hope has successfully reversed desertification on their learning site called the Dimbangombe Ranch in Zimbabwe. The concept is formed around the idea that large herds of animals — which have reduced in numbers over the years — were an essential part of the grasslands ecosystems. The herds have diminished in size and thus ecosystems are faltering. Savory has developed an approach that uses livestock to replace the once ubiquitous herds of grazing animals in order to reboot the ecosystem. Farmers create a plan for livestock grazing in order to make the most of their presence. The livestock’s hooves break up the ground so water can seep through and plants have room in the soil to grow. Their manure fertilizes the ground and increases vegetation. The livestock then graze on the vegetation and keep the grasses at a healthy length and density.

Imagine that.  Nature didn't make a mistake in pairing graziers with grass; the graziers actually help the grass, and the grass holds water in the soil.  So, Savory took a look at land like this:

And realized that to make it more productive he had to put animals on it, not take animals off of it.  He taught a team of people to put animals back on the land, move them around the way native species would migrate, and let nature take its course.

The herds of cattle did what cattle do--express their "boviness," as Joel Salatin would say--and all the people had to do is help the cattle do it while moving about in a pattern like wild graziers.  Pretty soon the land and cattle both started looking pretty lush:

The return of cattle, water, and grass made the people pretty happy:

All of this gives farmers more productive land, allowing a better harvest of crops. Previously, as desertification took hold, communities were moved off their land and violence broke out because of displacement. Savory’s approach to range land management keeps people on their land, sustains communities, improves livelihoods, creates food security and returns ecosystems to their natural state.

I find it so perfect that this project got the Buckminster Fuller prize because Bucky himself ate an animal-based diet.  Ray Audette tells the story in Neanderthin:

"R. Buckminster Fuller is famous for inventing the geodesic dome, but most who know of his work are unaware that he advocated a diet of meat, vegetables, and fruit.  In the 1960's, Bucky found himself very overweight-- at five feet, five inches he weighed 200 pounds.  Concerned about his increasing size he applied his scientific and philosophic genius to the problem.  His solution was, and remains, unique among low-carbohydrate advocates.  

One of the basic tenets of Bucky Fuller's philosophy is that nature is always most efficient in using energy.  The sun is the Earth's main source of energy, and solar energy is directly concentrated in the form of plants throught the process of photosynthesis.  Theorizing that humans should seek the most energy-concentrated (i.e. the most natural) source of protein and calories Bucky concluded that he should eat that meat of animals that eat plants..

By applying the unique idea of "energy accounting" to his weight problem, Bucky lost sixty pounds and greatly increased his energy.  He continued to eat a low-carbohydrate diet for the rest of his life (he died at age 88). "

So, don't believe those ivory tower eggheads who tell you that "livestock's long shadow" is destroying the Earth.  Practice always trumps theory, and practice shows that meat is medicine even for the environment.  It looks like livestock provide the best way to turn deserts back into grasslands.  Let's have a steak to celebrate!

Watch Alan Savory talk about his holistic approach in my post Keeping Cattle: Cause or Cure for Climate Change?

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The Practically Primal Guide to Conventional Beef, Part 3: Nutritional composition

7/13/11 update:  I decided that I don't want to endorse or appear to endorse the use of any meat produced by conventional methods of feeding the livestock grains, primarily corn and soybeans.  Since animals consume 80% of the grain and soy produced by U.S. agriculture, this system drives the ongoing destruction of our topsoil both through crops and through grazing.  Animal food production consumes 87% of all freshwater used in the U.S. each year, and thus is the primary driver of depletion of water reserves.  This system also produces most of the water pollution occurring in the U.S.  Our conventional livestock production system has enormous costs detailed in this article from Cornell University.  Since I have known of these costs for more than 20 years, I feel embarrassed and remorseful that I wrote this series and other articles that endorsed the use of conventional animal products.

To reiterate, in this series of posts I only aim to discuss primarily whether or not conventional meats presents health risks to the consumer, not whether the methods used to raise conventional grain-fed meats produces the best environmental effects.  I have already discussed hormones in part I, and antibiotics and chemicals in part II. 

The next concern is the nutritional composition, including total fat content, fatty acid composition, omega-6 to omega-3 ratio, and vitamin and mineral content. 

Duckett et al compared the effect of grain- or grass- finishing systems on the nutritional composition of beef.  Comparing lean meat from grain- and grass- fed animals, they found that the grass-fed product had:

• Increased moisture content
• Decreased total lipid content by 43%
• 288% greater vitamin E content
• 54% greater b-carotene content
• Twice as much riboflavin
• Three times as much thiamin
• 30% more calcium
• 5% more magnesium
• Roughly the same amount of omega-6 PUFA
• Three times the omega-3 PUFA
• Similar saturated fat content
• 20% lower MUFA

Ducket et al found that grass-finished and grain-finished beef had, respectively, 1.65 and 4.84 times as much omega-6 as omega-3 fat, but, as noted, the absolute amount of omega-6 did not differ significantly between the two finishing strategies.  Thus, grain-feeding does not increase the omega-6 content, it only decreases the omega-3 content, of the meat.  This graph from EatWild.com shows the effect of grain-finishing on omega-3 content of meat from cattle:

Faucitano et al compared the effects of grain- or grass- finishing, either with or without hormonal growth promotants, on beef composition and palatability.  They raised all cattle to the same level of back fat deposition before slaughter, and found:

• Meat from cattle fed grain and growth promotants had a tendency to appear dark in color whereas that from cattle fed grass had a more desired red color.
• Meat from cattle given growth promotants tended to have a tougher texture.
• Meat from grass-finished cattle was just as tender as grain-finished if allowed to grow to the same level of back fat deposition.
• Types of feed did not alter omega-6 levels in meat
• Meat from grass-finished animals given no growth promotants had about 50% more omega-6 fatty acids than animals given growth promotants regardless of feed type.
• The more grain given to animals, the lower their omega-3 content of their meat, in a dose-dependent fashion (same finding as Ducket et al above).
• Meat from exclusively grass-finished animals had 2.5 times as much omega-3 fatty acid as meat given a finishing diet of 70% grain.
• The omega-6 to omega-3 ratio ranged from 1.2 in grass-finished meat to 2.2 in 70% grain-finished meat.
• Meat from grass-finished animals had slightly more CLA than meat from grain-finished animals.

This is the first study that I have seen showing that use of hormones in cattle decreases the amount of omega-6 fat in the meat from these animals. It also contradicted the usual belief that grain-finishing increases tenderness, indicating that if we allow grass-finished animals to accumulate back fat to levels equal to grain-finished animals, meat from these animals will have tenderness equal to meat from grain-finished animals.

Rule et al compared muscle fatty acid profiles of bison (range vs. feedlot), beef (range vs. feedlot), elk (wild), and chicken. They found:

• Generally, range fed beef and bison have higher total amounts of PUFA and a higher PUFA/SFA ratio than feedlot finished, due to higher contents of omega-3 fatty acids.
• Range-fed beef and bison had omega-3 fatty acid levels similar to wild elk and 3 to 4 times that found in feedlot-finished meat.
• Feedlot feeding increased total fat content (g/100g) by 50 to 100%.
• Range-finished beef and bison had total fat contents (g/100g) similar to wild elk and skinless chicken breast.

This graph from EatWild.com depicts the findings of Rule et al:  

Rule et al found the following ratios of omega-6 to omega-3 fatty acids:

• Range-fed bison, 2.09
• Feedlot bison, 7.22
• Range-fed beef, 2.13
• Feedlot beef, 6.28
• Elk, 3.14
• Chicken breast, 18.5

Rule et al concluded:

“Range-fed bison and range-fed beef cows would provide consumers with very lean meat that is comparable to meat from free-ranging elk with respect to fatty acid profiles currently regarded as the most healthful. The feeding regimen for bison production affects the leanness and fatty acid profile of the meat. Range bison production should be emphasized to obtain the leanest bison meat with the lowest cholesterol concentration possible.”

Grass provides greater amounts of selenium than grain, so grass-finished animals have higher levels of these minerals than grains. Marchello and Driskell [Great Plains Research 11 (Spring 2001): 65-82] found that grassfed bison have as much as four times more selenium (an essential trace mineral) than grainfed bison. Eating just three ounces of grassfed bison, for example, supplies more than 100 mcg. of selenium, which is several times the daily minimum requirement.  Selenium plays an important role in thyroid function, protects the body from mercury, and appears to have anticancer and cardioprotective effects.

Obviously, grass-finished meat (lean cut) gives you substantially greater nutritional value than grain-finished meat, particularly for vitamin E complex, B-carotene and mixed carotenoids, riboflavin, niacin, selenium, and omega-3 fats, along with a lower levels of total, saturated, and monounsaturated fat.  

The Omega Issue

A high dietary ratio of omega-6 to omega-3 fatty acids may have adverse effects.  In August 2010, Massiera et al reported results of a study in which they fed mice a diet containing 35% of energy as fat, and 28 times as much omega-6 as omega-3 fat, over successive generations—a situation similar to the typical Western diet.  The results reported in the abstract:

“Offspring showed, over four generations, a gradual enhancement in fat mass due to combined hyperplasia and hypertrophy with no change in food intake. Transgenerational alterations in adipokine levels were accompanied by hyperinsulinemia. Gene expression analyses of the stromal vascular fraction of adipose tissue, over generations, revealed discrete and steady changes in certain important players, such as CSF3 and Nocturnin. Thus, under conditions of genome stability and with no change in the regimen over four generations, we show that a Western-like fat diet induces a gradual fat mass enhancement, in accordance with the increasing prevalence of obesity observed in humans.”

Stephan Guyenet discussed this research in detail here.  Thus, it appears that a high n-6:n-3 ratio may promote obesity and adversely affect gene expression across multiple generations. As Stephan demonstrates in a series of articles on the topic of fats, a high intake of omega-6 oils also appears to promote cardiovascular disease, cancer, osteoporosis, liver disease, and several other diseases of civilization.  However, we should note that in the three studies I have quoted, the ratio of omega-6 to omega-3 in grain-finished beef or bison did not exceed 7.22, a far cry from the 28 to 1 ratio used in this study. In contrast, chicken breast has a ratio of 18.5.

Furthermore, the absolute amount of omega-6 fat in any of these foods is relatively small.  Using the USDA database, we find the following (food, weight, omega-6 mg):

• Grain-finished beef chuck with ¼” fat, 100 g, 218 mg
• Grain-finished beef chuck with ¼” fat, 1 pound, 1 g 
• Game meat, bison, chuck, shoulder clod, separable lean only, raw, 100 g, 114 mg

In cattle and bison, both ruminants, it appears that the microbes in their guts consume or transform most of the omega-6 in feed grains, such that, as noted in the studies cited above, the absolute amount of omega-6 in their tissues remains constant regardless of finishing method.  Their tissues develop a high n-6:n-3 ratio by route of feed grains lacking omega-3s that they would get from grass or other foraged foods. 

Now compare USDA data for lamb and pork:

• Grain-finished lamb, domestic, composite of trimmed retail cuts, separable lean and fat, trimmed to 1/8" fat, choice, raw, 100 g, 1 g  (0.330 g n-3)  
• Grain-finished lamb, domestic, composite of trimmed retail cuts, separable lean and fat, trimmed to 1/8" fat, choice, raw, 1 pound, 5g (1.5 g n-3) 
• Pork, fresh, composite of trimmed retail cuts (leg, loin, shoulder, and spareribs), separable lean and fat, raw, 100 g, 1.3 g (0.09 g n-3)
•  Pork, fresh, composite of trimmed retail cuts (leg, loin, shoulder, and spareribs), separable lean and fat, raw, 1 pound,  6.0 g (0.4 g n-3)

Lamb and pork have about 5 to 6 times as much omega-6 as beef and bison.  Lamb has in its favor a relatively high content of omega-3, with a n-6:n-3 ratio of 3:1.  This makes it a really good choice for a practically paleo diet.  Pork has a less favorable ratio (15:1), so I would suggest keeping pork to a smaller fraction of the total diet.

Now take a look at the omega-6 levels in the following (food, serving,  omega-6):

• Chicken thigh with skin, one pound, 13.6 g
• Chicken thigh without skin, one pound, 9.5 g
• Chicken breast with skin, one pound,  6.4 g
• Chicken breast without skin, one pound,  2.7 g
• Walnuts, 1 ounce (14 halves), 10.8 g
• Walnuts, 100 g, 38 g
• Safflower oil, one teaspoon, 3 g
• Safflower oil, one tablespoon, 10 g. 

Some comparisons:

• Chicken thigh with skin thus has a little more than twice as much omega-6 as lean grain-finished pork, and nearly 14 times as much as fatty grain-finished beef chuck.  
•  Chicken thigh without skin supplies about 50% more omega-6 than grain-finished pork, and 9.5 times as much as fatty grain-finished beef.   
• Chicken breast with skin provides about half as much omega-6 as pork and 6.4 times as much as the fatty chuck.   
• Chicken breast without skin has nearly 3 (2.7) times as much omega-6 as fatty beef on a weight basis.  
•  Just one ounce of walnuts provides six times more omega-6 than a whole pound of pork, and 10.8 times more than a whole pound of fatty grain-fed beef.   
• Just one teaspoon of safflower oil provides nearly twice as much omega-6 as a whole pound of pork shoulder, and 3 times as much as a whole pound of fatty grain-fed beef.

So, if you want to avoid excess omega-6, you should focus on eliminating chicken skins; limiting dark meat poultry, pork and chicken breasts; limiting nuts high in polyunsaturates (most are); and most importantly eliminating all vegetable oils except olive, palm, avocado, and coconut.  If eating grain-finished meats as staples, focus on using beef, bison, and lamb.  Use less of leaner cuts of pork and poultry.

The balancing act

These data make it very clear that the best way to reduce your intake of excessive omega-6 oils lies in restricting intake of chicken and eliminating most tree nuts and vegetable oils from your diet.  If you do this, you can easily attain a healthy total diet ratio of omega-6 to omega-3 even if you eat only grain-finished beef, lamb, pork, and bison, by including some fatty fish like salmon, sardines, or sea bass in your diet. 

As we saw above, a pound of fatty beef has 1.0 g of omega-6.  Assuming that you limit all other significant sources of omega-6 in your diet, if you consume 6 pounds of beef in a week, you will get 6 g of omega-6.  To get an ideal 1:1 ratio of omega-6: omega-3 in your overall diet, you will need to eat something that will provide 5 g of omega-3s with almost no omega-6, such as salmon or sardines.  Take a look at the USDA figures for the amounts of omega-3s in these canned fish:

• Salmon, pink, canned, solids with bone and liquid, 100 g, 1.7 g
• Sardine, Pacific, canned in tomato sauce, drained solids with bone, 100 g, 1.7 g

Thus, 350 g (12 ounces) of either salmon or sardines in the week will give you enough omega-3 to balance out 6 pounds of beef.  So I could eat a pound of beef each day 6 days each week, then have three-quarters of a pound of salmon on the 7^th day, to get the desired ratio.  Alternatively, I could eat my pound of beef daily with a few sardines to achieve the same result.

Now let’s say that you make a mistake that I made, and eat 100 g of walnuts daily.  This would provide you with 266 g of omega-6 each week.  You can see that you would have to eat a ridiculous amount of salmon or sardines – namely,  15 kg/34 lbs – each week to achieve a 1:1 ratio of omega-3 to the omega-6 in those walnuts.

You can also see that you could easily consume excessive amounts of omega-6 eating a diet based on “lean” grain-fed poultry rather than red meat.  A primal dieter gets the best results by basing the diet on meat of ruminants and hindgut fermenters, not poultry.

Eat fish, not fish oils

Some may wonder about using fish oils to achieve the balance of omegas.  I don’t recommend the isolated fish oils, because oils packed removed from fish often go rancid, and research suggests that they may not have the benefits of eating fish, and may increase mortality. In contrast to fish oils, whole fish supply a number of nutrients other than omega-3 fats that may promote health, including vitamin D, magnesium, and selenium.

Summary

• Meat from grass-finished cattle, bison, or other ruminants provides higher amounts of several important vitamins, minerals, CLA, and omega-3 fatty acids than meat from grain-finished animals. 
• Meat from cattle treated with hormones has less omega-6 than meat from cattle not treated with hormones.
• Feeding ruminants (cattle, bison, lamb, etc.) or hindgut fermenters (e.g. pigs) grain instead of grass results in significantly lower levels of omega-3 fats, but has very little effect on the absolute amount of omega-6 in the meat.
• Meat from ruminants finished on grain concentrate has low levels of omega-6 compared to meat from grain-fed poultry, most tree nuts, or nut or seed oils.
• You can easily achieve a desirable omega-6:omega-3 fat ratio while eating large amounts of meat from grain-finished ruminants or hindgut fermenters by consuming reasonable amounts of fatty fish like salmon, sardines, and mackerel.
• The main sources of omega-6 oils in most diets include meat from grain-finished poultry, tree nuts, oil seeds, and nut or seed oils.
• If you include significant servings of any of the items listed in that previous sentence, you will have great difficulty achieving a desirable ratio of omega-6 to omega-3 oils because you will have to consume unrealistic amounts of fish or fish oils.
• Regular intake of fatty fish can easily counterbalance the omega-6 found in grain-finished beef, pork, bison, or lamb, so long as you minimize intake of chicken, temperate tree nuts, oil seeds, and nut or seed oils.

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The Practically Primal Guide to Conventional Beef, Part 2: Antibiotics, Chemicals, and Pesticides

this article from Cornell University.  Since I have known of these costs for more than 20 years, I feel embarrassed and remorseful that I wrote this series and other articles that endorsed or appeared to endorse the use of conventional animal products.
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As an advocate of grass-fed animal products, I have been critical of practices like use of antibiotics in livestock, but not always with adequate information.  Like other people critical of confined animal feeding operations (CAFOs), I started this investigation with the idea that we should raise animals in a manner as close to wild as possible, which would preclude the use of antibiotics.  

People critical of conventional animal products often claim or imply that these products carry harmful residues of antibiotics and other chemicals, particularly pesticides.  I realized that I had accepted these charges without doing investigation myself.   I wanted to find out if this is the case, both to have my facts straight when talking about any possible advantages of grass-fed meats, and to know if I should advise people to avoid these products at all costs, including not eating meat unless you can afford grass-fed animal products. 

Do Livestock Get Overloads of Antibiotics?

Based on data supplied by the FDA, some people have gotten quite upset to find that, by crude weight, 80% of all antibiotics used in the U.S. get used in livestock production, the other 20% getting used in human medicine.  Opponents of antibiotic use claim that this “overuse” of antibiotics in animals constitutes the main cause of antibiotic resistance in bacteria. 

Although I am not a fan of antibiotic use, I find it inappropriate and illogical to evaluate the use of antibiotics on the basis of total tonnage given to either all livestock or all humans in the U.S.  Medical personnel give doses of antibiotics according to weight, not according to head.  In humans, children get smaller doses than adults based on weight.  Pigs, averaging 230 pounds each, would get larger doses than the average 150 pound human, and cattle, averaging 1300 pounds, require even larger doses. 

According to USDA data , in 2008  U.S. livestock included:

• 96, 035, 000 cattle and calves with a live weight of 41 billion pounds.  
• 66, 708, 000 hogs and pigs with a live weight of about 30 billion pounds.   
• 5,950,000 lambs and sheep, weighing 440, 286, 000 pounds.   
• 9, 000, 000 dairy cattle, which would have an average live weight of about 4 billion pounds.   
• 450 million chickens at an average weight of 5 pounds gives 22.5 billion pounds of chickens.   
• 6 billion pounds of turkey   

These numbers have varied only marginally for 10 years spanning 2000-2009.

Using an average weight for humans of 100 pounds (including children), and a U.S. population of 300 million, we can calculate that the total weight of humans in the U.S. comes to about 30 billion pounds.  From the above data, we can see that the weight of livestock in the U.S. is in the range of about 104 billion pounds, about 3.5 times the weight of humans in the U.S..  Adding miscellaneous food animals (bison, ducks, and others) not counted in the USDA data would bring the weight of animals even higher.

Since antibiotics are dosed by body weight, if we used antibiotics in animals at the same rate as in humans, we would expect that we would annually use three to four times as much antibiotics (by gross weight) in treating animals as in treating humans.  The Center for A Livable Future  reports that in 2009 we used about 29 million pounds of antibiotics for food animals, and about 7 million pounds for humans, or just about 4 times as much in food animals in humans.  Calculated by weight, the use of antibiotics in food animals does not vary much from the use in humans; so if we are overusing antibiotics in animals, we’re also overusing them in humans (on a per weight basis).

We don’t administer low doses of antibiotics to children to increase their rate of growth, yet on a weight basis we seem to use nearly as much antibiotics in people as in livestock.  Since it appears that antibiotics get used in food animals at about the same rate per pound that we use them in humans, this should put to rest the Center For A Liveable Future’s speculation that livestock producers “most likely administered them [antibiotics] in continuous low-dosages through feed or water to increase the speed at which their animals grew.”

Antibiotic Resistant Bacteria

I don’t know why veterinarians apparently get most of the heat for supposedly overusing antibiotics in livestock.  As a Chinese medicine provider, I routinely treat people who have received prescriptions for antibiotics from conventional medical doctors for acute upper respiratory conditions without anyone performing cultures to determine whether the infection is bacterial or viral.  The vast majority of such conditions are viral, and viruses are not susceptible to antibiotics. 

I also have many people tell me that their physician prescribed antibiotics for their chronic sinusitis, but Mayo Clinic research suggests that most chronic sinus infections are fungal.  Antibiotics don’t affect fungi, in fact they enhance fungal growth by killing off harmless flora that would otherwise keep fungal infections at bay.  Thus, I would guess that widespread, essentially indiscriminate use of antibiotics in humans is the most likely cause of antibiotic resistant strains of bacteria that commonly infect humans. 

Then, how about people flushing antibiotics and other drugs down their toilets or sinks?  Whether done intentionally (disposal) or by urination and defecation after using the drugs, it contributes to antibiotics and other drugs occurring in tap water.  This direct deposit of drugs into municipal water supplies can in part account for the multiple antibiotic resistant (MAR) bacteria found in drinking water. 

Further, it seems to me that anyone who has the idea that we could prevent bacteria from developing antibiotic resistance has failed to understand the basic biological principle of evolution by natural selection.  If you understand this principle, you will see that any use of antibiotics at all contributes to the development of antibiotic resistant strains, and that it is only a matter of little time before fast-reproducing microbes develop resistance to all of our antibiotics. 

Here’s the view based in understanding of the principle of natural selection:  Antibiotics present a environmental stress to bacteria.  In any bacteria population, there will exist a variation in susceptibility to any one antibiotic.  Some will have little or no resistance, and some will have complete resistance.  Whenever we use an antibiotic, we will kill off the bacteria that have insufficient resistance, and those with resistance will remain to reproduce.  This will happen whether we use the antibiotics on a herd of cattle or a human population, even on one individual. 

In short, the principle of natural selection predicts the eventual failure of antibiotics.  As an alternative, I could suggest that we curtail our use of antibiotics, and instead put attention on fortifying host resistance by hygiene, proper diet (for vitamin A and numerous other nutrients) and sun exposure (for vitamin D), use herbs that contain multiple natural antimicrobials for routine antimicrobial purposes, and leave the high dose antibiotics for a last resort.

However, taking another perspective,  I can’t control the actions of other people, and we will adjust to super microbes as surely as we have adjusted to conventional microbes.  If we exhaust the usefulness of antibiotics, this may indeed serve us better in the long run by forcing us to look for better ways to control infectious disease, like increasing host resistance in the manner I have suggested. 

By the way, although we have a great outcry about the supposed increase of antibiotic resistant microbes in developed nations, I haven’t seen any dramatic increase in infectious disease in these nations.  Infectious disease still wreaks its greatest toll in poorly nourished developing nations. 

Antibiotic and Chemical Residues in Meats and Dairy?

The Food Safety Inspection Service of the USDA performs random tests of animal products for residues of antibiotics and fifteen other chemicals or classes of chemicals, and publishes the findings annually.  Below I have copied the page from the 2008 edition of the FSIS National Residue Program Data (aka “Red Book” ) .

Click for larger version.

According to this data, of 4146 samples tested for antibiotic residues, 276, or about 7%, had antibiotic residues that did not exceed residue limits (i.e. non-violative), and only 2 samples, or 0.05%, had violative residues.  Since the USDA impounds products that violate the residue limits, not allowing their sale, this suggests that 93% of animal products on the market have NO antibiotic residues, and the other 7% have residues that have no health effects because they are not large enough. 

If you survey the rest of the list, the FSIS found violations of residue limits for only 5 other chemicals or classes of chemicals:  arsenic, avermectins,  carbadox, chlorinated hydrocarbons or organophosphates, or sulfonomides.  In each case, the violations occurred in much less than 1% of samples. 

Based on production class (i.e. type of animal) the FSIS found violations occurred in beef cows, boars/stags, bob veal, bulls, goats, heavy calves, heifers, market hogs, non-formula fed veal, roaster pigs, and sows, with the highest numbers of violations occurring in heavy calves—2 violations out of 456 samples, or 0.44 percent.  The following graph depicts the number of samples of each production class (in the hundreds, up to nearly 1500 samples in some classes) along with the percent violations (red dots, all less than half of a percent) in each class :

Click for larger version.

The USDA FSIS page "Beef: Farm to Table" explains the regulation of antibiotic use in livestock:

“Antibiotics may be given to prevent or treat disease in cattle. A "withdrawal" period is required from the time antibiotics are administered until it is legal to slaughter the animal. This is so residues can exit the animal's system. FSIS randomly samples cattle at slaughter and tests for residues. Data from this Monitoring Plan have shown a very low percentage of residue violations. Not all antibiotics are approved for use in all classes of cattle. However, if there is a demonstrated therapeutic need, a veterinarian may prescribe an antibiotic that is approved in other classes for an animal in a non-approved class. In this case, no detectable residues of this drug may be present in the edible tissues of the animal at slaughter.”

This Purdue University video describes what happens when the FSIS discovers that a producer has product that contains violative residues:

In short, producers stand to lose their businesses if they produce animals with antibiotic or chemical residues exceeding USDA limits.

I know some may not trust the USDA, considering it in league with the producers to cover-up their misdemeanors.  I myself fall into that class.  You might want to consider the report of Schnell et al, entitled Pesticide Residues in Beef Tissues from Cattle Fed Fruits, Vegetables and Their By-products, from The Journal of Muscle Foods.  The abstract:

“Muscle, adipose, liver and kidney tissue samples were collected from cattle fed potato processing residue (n=20), apple pomace (n=20), pear pomace (n=10), cannery corn waste (n=20), cotton gin trash (n=20), tomato pomace plus almond hulls (n=16), dried grape solids (n=10) or dried citrus pulp (n=6) as well as from control cattle which were not fed fruits, vegetables or their byproducts (n=21). All adipose tissue samples (n=143), representative samples of the above feeds (n=24) and representative samples of muscle (n=35), liver (n=35) and kidney (n=35) tissues were assayed for acephate, benomyl, captafol, cypermethrin, folpet, azinphos-methyl, captan, chlorothalonil, ethyl parathion, and permethrin. In 2,720 tests for the aforementioned oncogenic pesticides, eight tests were positive, but no residue amount that would be considered violative was detected. The only pesticide detected was benomyl and it was detected at nonviolative levels in the adipose tissue of cattle that had been fed either apple pomace or pear pomace.”

Thus, Schnell et al found pesticide residues in only 8 of 2,720 samples, i.e. 0.29%, from cattle fed several different foods that may have pesticide residues.  This gives some indication of the low levels of residues on these particular crops (apples, pears, corn, cotton, tomato, grape, and citrus), or of the efficiency with which the liver and kidneys of bovines get rid of residues.  Note also that they tested liver samples, confirming my long held belief that liver does not store but transforms and eliminates toxins from the body.

Vazquez-Moreno et al tested for pesticide residues in adipose tissue of beef, pork, and poultry from plants located in northwestern Mexico and published the results in the Journal of Muscle Foods (5 May 2007).  According the the abstract:

“This study involved testing of adipose tissue from beef (208 samples), pork (112 samples) and poultry (39 samples) for pesticide residues, including nine different chlorinated hydrocarbons (CHC) and nine organophosphates (OP). Tissues were collected during a two-year period (1996–1997) from plants located in the Northwestern Mexico, and determinations conducted by gas chromatography under international performance criteria. While none of the pork samples contained CHC residues, 17 (1996) and 11 (1997) beef samples contained either hexacholorobenzene, heptachlor, aldrin or dieldrin. Also, poultry samples (three in one year and four in the other) contained residues of either hexachlorobenzene, heptachlor or dieldrin. None of the tissues tested contained organophosphate residues above the detection limit. CHC incidences and concentrations were lower than those reported for other Mexican and Latin American regions, but higher than reports from the U.S. Based on the Mexican or U.S. tolerances, all concentrations of CHC found were nonviolative.”

In this study, no pork samples, 13% of beef samples, and 18% of poultry samples from Mexican processing plants contained CHC, while none of any samples contained OP, and in no case was the concentration of CHC above limits. 

Compare this to cabbage:  100% of cabbage samples contain at least 49 naturally occurring pesticides. As documented by Bruce Ames (PNAS pdf), 99.99% of the pesticide load consumed by the typical American consists of pesticides that naturally occur in plant foods, which when tested have a toxicity and carcinogenicity similar to synthetic pesticides. This slide from Ames's paper lists 49 pesticides naturally occurring in cabbage (click on image for larger version):

So if you avoid conventional meats in favor of plant foods, you don't avoid pesticides or antibiotics (plants contain natural antibiotics also), and you probably increase your pesticide and antibiotic load.  But when you eat meat, as shown by Schnell et al (above), you have put a filter between yourself and the plant sources of toxins.  Relatively speaking, it appears that fresh conventional meat presents a much lower pesticide and antibiotic load than organically grown cabbage. 

Consider also that antibiotics and  persistent pesticides are ubiquitous hazards these days, and due to their presence in water and soil, may occur in “organic” and grass-fed animal products as well as conventional.  For example, a company producing organic chicken in the UK found residues of nitrofuran, a banned pesticide, in meat from their birds. 

 All in all, although a part of me would prefer to have "pure" animal products without residues of any potentially toxic chemical, the reality is nothing is "pure."  From my perspective, it seems that most conventional animal products have no antibiotic, pesticide, or chemical residues, and in the small percentage (less than 0.5%) that has residues, they occur in amounts that present no hazard to health.

Request for support: I invested more than 8 hours of time in research and writing this article and freely offer it to you.  If you find this information helpful, and want me to continue providing this service, consider using the PayPal Donation Button in the right hand column to donate 25 cents, 50 cents, or one dollar for each article you like, or sign up for  $3.00 per month subscription.  For a very small donation or about the cost of a cup of coffee each month, you can support my continuing to provide this service.  Thanks for reading!