Vitamin B12 and Human Nutritional Evolution

I once believed and argued that the fact that humans require vitamin B-12 provided substantial support for the idea that humans have a biological requirement for dietary meat.  My reasoning went thus:

Humans require vitamin B-12, and only animal products reliably provide natural bioactive vitamin B-12, therefore we must be adapted to and dependent upon meat-eating.

I have since realized that I made a few mistakes here.  Although we definitely require B-12, animal products are not the only reliable sources of natural bioactive B12, and human B-12 metabolism provides evidence that our ancestors adapted to an environment/diet that had a low availability of B-12 compared to currently recommended daily reference intakes.

Human B-12 Metabolism

Humans have enterohepatic circulation of vitamin B-12.[1 ] As noted by Herbert [2 ], this can allow an initially B-12 replete adult go 20-30 years without vitamin B-12 intake:

“The enterohepatic circulation of vitamin B-12 is very important in vitamin B-12 economy and homeostasis (27). Nonvegetarians normally eat 2-6 mcg of vitamin B-12/d and excrete from their liver into the intestine via their bile 5-10 mcg of vitamin B-12/d. If they have no gastric, pancreatic, or small bowel dysfunction interfering with reabsorption, their bodies reabsorb ~3-5 mcg of bile vitamin B-12/d. Because of this, an efficient enterohepatic circulation keeps the adult vegan, who eats very little vitamin B-12, from developing vitamin B-12 deficiency disease for 20-30 y (27) because even as body stores fall and daily bile vitamin B-12 output falls with body stores to as low as 1 mcg, the percentage of bile vitamin B-12 reabsorbed rises to close to 100%, so that the whole microgram is reabsorbed.”

What kind of environment/diet would naturally favor the survival of humans having such efficient recycling of vitamin B-12 but not of other B-complex vitamins? 

As a general principle, if an organism subsists on a diet with a low availability of a certain essential nutrient, it needs mechanisms for increasing absorption and retention of that nutrient, to prevent deficiency.  On the other hand, if an organism subsists on a diet with a very high availability of a certain essential nutrient, then it needs mechanisms for reducing absorption, detoxifying, and eliminating that nutrient.

Put in natural selection terms, only an ancient environment/diet with a low B-12 availability would have favored the survival and reproduction of humans who could recycle B-12 very efficiently.  An ancient environment/diet with a high B-12 availability would have made such a capacity unnecessary; on the contrary, an environment with a high availability of vitamin B-12 would have favored those who were less efficient at using B-12, or those who deliberately excreted excessive B-12 (in order to prevent B-12 accumulation and toxicity).

Thus, modern human B-12 metabolism suggests that modern humans are adapted to a diet that provides B-12 in less than required amounts on a daily basis, while occasionally providing larger doses in excess of requirements.  

Currently the National Academy of Sciences recommends that adults consume 2.4 mcg of B12 daily.  They calculated that this covers the needs of 98 percent of individuals, but most of us require less than this.  The following table shows the B12 contents of commonly consumed animal products:

Three ounces of beef or salmon provides the recommended intake, and three ounces of shellfish substantially exceeds the recommended 2.4 mcg.  In contrast, one would have to consume 24 ounces of chicken or turkey daily to ingest 2.4 mcg of B12. 

Non-animal B-12 Sources

As I said above, I previously accepted that only animal products reliably provide natural vitamin B-12.  Although this is a common belief, and probably a good general rule in modern industrialized nations, I think we have significant evidence that pre-industrial humans had other significant sources of vitamin B-12.

First, although animal products provide the most common vector for delivery of B-12 in modern industrialized nations, only microbes produce vitamin B-12. [3] Many microbes have the ability to produce B-12, among them the following genera: Aerobacter, Agrobacterium, Alcaligenes, Azotobacter, Bacillus, Clostridium, Corynebacterium, Flavobacterium, Micromonospora, Mycobacterium, Norcardia, Propionibacterium, Protaminobacter, Proteus, Pseudomonas, Rhizobium, Salmonella, Serratia, Streptomyces, Streptococcus and Xanthomonas. 

Bacillus megaterium is a common soil bacteria, not pathogenic to humans, and a producer of vitamin B-12.[4]  According to Patricia Vany of the Department of Biological Sciences at NIU, B. megaterium occurs in human breast milk.[15, third slide] 

Lactobacillus reuturi, a member of the gastrointestinal ecosystems of humans, poultry, swine, and other animals, and present in sourdough culture, produces vitamin B-12. [5]

Albert et al reported “the human small intestine also often harbours a considerable microflora and this is even more extensive in apparently healthy southern Indian subjects. We now show that at least two groups of organisms in the small bowel, Pseudomonas and Klebsiella sp., may synthesize significant amounts of the vitamin.”[6]

In 1995 Suzuki reported that the marine algae, nori, prevented all signs of B12 deficiency symptoms in 6 vegan children he studied:

“A nutritional analysis was conducted on the dietary intake of a group of 6 vegan children aged 7 to 14 who had been living on a vegan diet including brown rice for from 4 to 10
years, and on that of an age-matched control group. In addition, their serum vitamin B12 levels and other data (red blood cell count, hematocrit, hemoglobin, etc.) were determined in the laboratory. In vegans' diets, 2-4 g of nori (dried laver), which contained B12, were consumed daily. Not a single case of symptoms due to B12 deficiency was found. There were no statistically significant differences between the two groups with respect to any of the examination data, including B12 levels (p < 0.05). Therefore, consumption of nori may keep vegans from suffering B12 deficiency.” [7] 

[In 2005 Croft et al reported that algae acquire vitamin B12 through a symbiotic relationship with bacteria. (14) ]

In 2009 Koyyalamudi et al [8] reported that the common white button mushroom can provide vitamin B12 of value equivalent to that found in beef, beef liver, salmon, egg, and milk (not analogues).  Koyyalamudi et al determined that the mushrooms probably absorbed the B12 from bacteria inhabiting their growth medium:

“High concentrations of vitamin B12 were also detected in the flush mushrooms including cups and flats.  HPLC and mass spectrometry showed vitamin B12 retention time and mass spectra identical to those of the standard vitamin B12 and those of food products
including beef, beef liver, salmon, egg, and milk but not of the pseudovitamin B12, an inactive corrinoid in humans. The results suggest that the consumer may benefit from the consumption of mushroom to increase intake of this vitamin in the diet.” [8]

In 1994, Mozafar reported that spinach leaves and barley seeds grown on soil fertilized with organic matter or isolated B12 take up vitamin B12 into their tissues from the soil.  The spinach leaves and barley kernels were thoroughly washed with distilled water before being tested for B12 content, so this was not a case of finding B12 on soiled plants.  Their testing confirmed that these plants contained active B12, not inactive analogues.[9]

In summary, it appears that non-pathogenic soil microbes, human small intestinal bacteria, lactobacilli from fermented foods, some sea algae, common mushrooms, and plants grown on soil fertilized with animal manure can all can provide biologically active B12.   Any of these could have served as ongoing sources of B12 for prehistoric human ancestors, but modern circumstances may make these non-animal sources of B12 unreliable for modern humans.

I think it safe to assume that our prehistoric ancestors had more contact with soil than we do, sitting on it, sleeping on it, digging in it, and drawing water from sources in contact with the soil.  Humans like other primates are apt to touch their own lips from time to time, providing a vector by which soil microbes could enter the human gut.

Humans living in modern industrialized nations typically ingest multiple courses of oral antibiotics over a lifetime, reducing or eliminating the population of B12-producing bacteria residing in the small intestine.   All of our prehistoric ancestors would have been breast fed and probably kissed often, which transmits flora from one generation to another, and this transmission would not have been interrupted by antibiotic treatments.

Fermentation of plant foods, particularly fruits, occurs spontaneously in nature,  providing another route by which our ancestors may have ingested B12-producing lactobacilli.  Our ancestors almost certainly consumed any edible wild mushrooms and all of the plants they ate grew in soils teaming with bacteria and fertilized by fermented organic wastes, providing another B12 source.

All of this information suggests that modern hygiene, indoor lifestyles, antibiotics, and use of chemical rather than biomass fertilizers in farming have reduced the amount of B12 available to humans in modern urban environments from non-animal sources. 

Thus, the low availability of B12 from non-animal sources in modern urban environments is an artifact not reflective of preindustrial environments, and it appears probable that our prehistoric ancestors had more non-animal sources present in their environment, like the southern Indians studied by Albert et al.[6] 

My Fallacious Appeal to 'Nature'

When I previously argued that meat-eating is the 'natural' way to get B12, I committed the fallacy of appeal to nature. 


The problem here lies in these underlying assumptions:  1) all 'natural' behaviors are 'health-promoting' behaviors for modern urban humans,  and 2)  all 'unnatural' behaviors are unhealthful.

Consider these questions:

 

Is it natural for humans to wear clothing?  Does wearing clothing promote better health in some circumstances?  (Imagine people living in Minnesota rejecting clothing because their African ancestors didn't wear any.)

 

Is it natural for humans to live in igloos in the arctic circle?  Does living in igloos in the arctic circle promote the best of health?

 

Is it natural for humans to live in natural caves?  Do humans have the best possible health when living in natural caves?  Is a natural cave the best possible human shelter?

 

Is it natural for humans to commit homicide, engage in war, or eat human flesh?  Do any of these promote health? 

 

If all you mean by 'natural' is 'spontaneously occurring,' then all human behaviors are 'natural.' 

But is the 'natural' choice of our ancestors the best possible choice for modern humans of the present day?

Simply put, the fact that our ancestors did something then does not tell us that it is the best thing for us to do now.

The fact that our ancestors obtained B12 by a 'natural' route (eating meat) does not tell me that this is the optimal way for me to get B12 in our modern circumstances. 

The Nature of B12 Supplements

Artificial synthesis of B12 requires about 70 synthesis steps, making it impractical as a method for commercial production of B12.  “Therefore, today vitamin B12 is exclusively produced by biosynthetic fermentation processes, using selected and genetically optimized micro-organisms.” [10]

In other words, we cultivate, feed and breed living microbes so that they will produce the nutrient we want.  This practice seems similar to cultivating cattle to produce protein or B12.  If the former is ‘artificial,’ so is the latter.

Tablets of microbially synthesized B12, burgers of ground beef, capsules of vitamin D extracted from sheep’s hair, and tortillas made from corn are all end products of humans processing a raw material into a form that humans can conveniently consume.   If you reject B12 tablets as ‘unnatural,’ you should similarly reject ground beef burgers and vitamin D capsules.

The information above indicates that modern antibiotics and hygiene have reduced or eliminated intestinal flora that would otherwise produce B12 for us, and modern agricultural practices have reduced the B12 content of plant foods.  Similarly, modern indoor lifestyles have reduced our endogenous production of vitamin D.  We can reasonably use supplements to correct for these technology-induced deficiencies.

In short,  B12 supplements are the most reliable source of natural B12 in the modern environment.

Microbial B12 Supplements Recommended To People Past 50 Years Of Age

The Linus Pauling Institute at Oregon State University recommends that all people (including omnivores) over the age of 50 take a B12 supplement:

“Also, individuals over the age of 50 should obtain their vitamin B12 in supplements or fortified foods like fortified cereal because of the increased likelihood of food-bound vitamin B12 malabsorption.”[11]

In the publication Dietary Reference Intakes [12 ], the National Academy of Science Food and Nutrition Board concurs:

So these sources do not consider animal foods to be reliable sources of B12 for those of us more than 50 years of age.

Do we reject this advice because it is not 'natural' to take supplements?

Some B12 Options


Modern humans typically use their minds to identify their requirements for health and comfort, then develop and use appropriate technology to provide those requirements in the most efficient, safest possible way.  

Thanks to microbe-ranching, each modern urban human now has the opportunity to decide which of at least 3 courses s/he would prefer to take to ensure achievement of a healthy B12 status.

Course 1:  Obtain B12 directly from a cultivated microbial source, the production of which requires relatively little land and water and produces no urine or feces.  This source is free of saturated fats, cholesterol, heterocyclic amines, lipid peroxides, pathogenic organisms, or antigenic Neu 5Gc sialic acid (a suspect in human cancers and autoimmunity, found only in mammal’s products, 13 ).

Course 2: Obtain B12  from animal products, the production of which requires enormous amounts of land and water and produces tremendous amounts of urine and feces requiring safe disposal.  This source also supplies saturated fats and cholesterol,  heterocyclic amines (cooked meat), and lipid peroxides (cooked fat),  and is frequently contaminated with various potential pathogens (E. coli 0157:H7, MAR bacteria, salmonella, vibrio, etc.).  Red meats and mammalian milks also provide antigenic Neu5Gc sialic acid. [13]

As noted above, current science indicates that Course 2 is probably not reliable for people more than 50 years of age.

Course 3:  Use both B12 supplements and animal products.

Take your pick, or perhaps you will discover another way.

Thanks to the author/producer of the Primitive Nutrition video series for alerting me to the article on the B12 content mushrooms used in this post.

Epistemology: The Iceberg Fallacy

As I define it, the Iceberg Fallacy consists of imagining that nothing exists beyond what you can easily see (e.g. the tip of the iceberg).  

I coined this name for it after having an exchange with Dr. John McDougall, M.D., in the comments on my post Dr. McDougall on B12.  In response to my post, Dr. McDougall stated:

"Clinically significant diseases due to dietary B12 deficiency are so rare that they appear as case reports in medical journals, and then do so very infrequently. Thus, with millions of vegans worldwide and a handful of reported cases of clinical disease, I derived the estimate of fewer than one in a million risk."

This exemplifies the Iceberg Fallacy.  Dr. McDougall assumes that no one has suffered a clinically signficant disease due to dietary B12 deficiency except the "handful of reported cases of clinical disease" found in medical journals.  As I pointed out in response:

"Your estimate of the incidence of B12 deficiency related disease suffers from the problems of survivor bias and reporting bias. Reporting bias because not every incident of illness arising from vegan diet or B12 deficiency gets reported to any central database from which you can draw to make an accurate estimate of the incidence of such diseases. In fact, people who feel ill from vegan diets (as I did during the 12 years I avoided animal products) generally just end up discontinuing the diet, never to return and without reporting their adverse experience to any physician or database. This is especially true of vegans in isolated rural areas of India, China, etc. [Edit: who don't even have access to physicians or databases.]  Survivor bias emerges in developed nations; the people who continue eating vegan diets for long periods of time are "survivors" of a deficient diet, people who apparently have lower requirements for B12, iron, zinc, or whatever, or are among the people capable of converting carotenes to retinol (see below). You may not find deficiency-related diseases among these long-term vegans because they are the ones who tolerate the lower nutrient delivery of a vegan regime, or they use isolated nutrient supplements (multivitamin or minerals) [or fortified foods] regularly, thereby masking the deficiencies of their diet." 

This conversation reminded me of a statement attributed to Confucius, and another similar passage from the Tao Te Ching.  I paraphrase Confucius (because I don't have the text readily available):  To know that you do not know, that is true knowledge.  I quote the Tao, chapter 71 (Wu translation):

To realize that our knowledge is ignorance,
This is a noble insight.
To regard our ignorance as knowledge,
This is mental sickness.

Only when we are sick of our sickness
Shall we cease to be sick.
The Sage is not sick, being sick of sickness;
This is the secret of health.

The mind easily assumes that reality contains only what it "knows," forgetting that its ignorance far exceeds its knowledge. The mind tends to focus on the foreground, and ignore the background.  Hence, it easily commits the Iceberg Fallacy, by assuming that nothing exists except the obvious (the tip of the iceberg) or the documented.  By ignoring the submerged part of the iceberg, or the unknown, it gets itself into a lot of trouble. 

If you assumed that no thefts happened yesterday except those that got reported in the newspapers, you would commit the same Iceberg Fallacy.   Probably, on any single day, more thefts occur than get noticed, and more thefts get noticed than get reported.  Similarly, in any time period, most likely more diseases due to B12 deficiency occur than get noticed by medical professionals, and more get noticed by professionals than get reported in medical journals. 

To wrap, if the mind sees only a few case reports of disease due to B12 deficiency of vegans in the medical literature, the most one can validly conclude is that very few cases of B12 deficiency disease due to vegan diets have actually gotten reported and published in the indexed medical literature.  You can't validly conclude that only those few cases have occurred. 

Crazy Moms and Crying Babies: Brain Damage By Vegan Diet

In 2004, Koebnick et al reported that a "Long-Term Ovo-Lacto Vegetarian Diet Impairs Vitamin B-12 Status in Pregnant Women."  They found that 22% of ovo-lacto vegetarians had demonstrable B-12 deficiency.


In 2011, Gilsing et al reported on the "Serum concentrations of vitamin B12 and folate in British male omnivores, vegetarians, and vegans: results from a cross-sectional analysis of the EPIC-Oxford cohort study."  They found that 52% of vegans had vitamin B-12 deficiency.

Now a 2011 study published in Early Human Development by Goedhart et al--"Maternal vitamin B-12 and folate status during pregnancy and excessive infant crying" -- finds that women with low B-12 status are more likely to have infants that cry more than 3 hours at a time:

Abstract

BACKGROUND: The etiology of excessive infant crying is largely unknown. We hypothesize that excessive infant crying may have an early nutritional origin during fetal development.

AIMS: This study is the first to explore whether (1) maternal vitamin B-12 and folate status during pregnancy are associated with excessive infant crying, and (2) whether and how maternal psychological well-being during pregnancy affects these associations.

STUDY DESIGN: Women were approached around the 12th pregnancy week to complete a questionnaire (n=8266) and to donate a blood sample (n=4389); vitamin B-12 and folate concentrations were determined in serum. Infant crying behavior was measured through a postpartum questionnaire (±3months; n=5218).

SUBJECTS: Pregnant women living in Amsterdam and their newborn child.

OUTCOME MEASURES: Excessive infant crying, defined as crying ≥3h/day on average in the past week.

RESULTS: Multiple logistic regression analysis was performed for 2921 (vitamin B-12) and 2622 (folate) women.Vitamin B-12 concentration (categorized into quintiles) was associated with excessive infant crying after adjustment for maternal age, parity, ethnicity, education, maternal smoking and psychological problems (OR[95%CI]: Q1=3.31[1.48-7.41]; Q2=2.50[1.08-5.77]; Q3=2.59[1.12-6.00]; Q4=2.77[1.20-6.40]; Q5 = reference). Stratified analysis suggested a stronger association among women with high levels of psychological problems during pregnancy. Folate concentration was not associated with excessive infant crying.

CONCLUSIONS: First evidence is provided for an early nutritional origin in excessive infant crying. A low maternal vitamin B-12 status during pregnancy could, in theory, affect infant crying behavior through two potential mechanisms: the methionine-homocysteine metabolism and/or the maturation of the sleep-wake rhythm.

Since meat and fish are the richest sources of B-12, as the Mail Online put it, "a steak for pregnant mothers could stop babies crying."  Forget the stupid final remark by the veg*n nutritionist Yvonne Bishop-Weston.  She proves herself clueless by it.  If anything will destroy your own or your baby's brain, its a vegan diet, not steak, as you will see below.

 I find their report of "a stronger association among women with high levels of psychological problems during pregnancy" intriguing.  Could B-12 deficiency due to meat avoidance increase psychological problems in adults?  Sure enough.

Durand et al reported on a case of "Psychiatric manifestations of vitamin B12 deficiency."

Psychiatric manifestations are frequently associated with pernicious anemia including depression, mania, psychosis, dementia. We report a case of a patient with vitamin B12 deficiency, who has presented severe depression with delusion and Capgras' syndrome, delusion with lability of mood and hypomania successively, during a period of two Months. ...


At admission she was uncooperative, disoriented in time and presented memory and attention impairment and sleep disorders. She seemed sad and older than her real age. Facial expression and spontaneous movements were reduced, her speech and movements were very slow. She had depressed mood, guilt complex, incurability and devaluation impressions. She had a Capgras' syndrome and delusion of persecution....

Further investigations confirmed anemia (hemoglobin=11,4 g/dl) and revealed vitamin B12 deficiency (52 pmol/l) and normal folate level....Vitamin B12 replacement therapy was started with hydroxycobalamin 1 000 ng/day im for 10 days and iron replacement therapy. Her mental state improved dramatically within a few days. After one week of treatment the only remaining symptoms were lability of mood, delusion of persecution, Capgras' syndrome but disappeared totally 9 days after the beginning of the treatment. ...

To illustrate this illness we reviewed the literature regarding psychopathology associated with B12 deficiency. The most common psychiatric symptoms were depression, mania, psychotic symptoms, cognitive impairment and obsessive compulsive disorder. The neuropsychiatric severity by vitamin B12 deficiency and the therapeutic efficacy depends on the duration of signs and symptoms.

Conclusion - We recommend consideration of B12 deficiency and serum B12 determinations in all the patients with organic mental disorders, atypical psychiatric symptoms and fluctuation of symptomatology. B12 levels should be evaluated with treatment resistant depressive disorders, dementia, psychosis or risk factors for malnutrition such as alcoholism or advancing age associated with neurological symptoms, anemia, malabsorption, gastrointestinal surgery, parasite infestation or strict vegetarian diet. 

If you search Pub Med you can find lots of articles on psychiatric complications of B-12 deficiency.  Therefore, the finding that women with psychological problems during pregnancy were more likely to have cry babies probably means that those women were more severely B-12 deficient than others.

What else can happen if you don't get enough B-12 during pregnancy?

Lovblad et al reported a case of "Retardation of myelination due to dietary vitamin B12 deficiency:"

Abstract

Vitamin B12 deficiency is known to be associated with signs of demyelination, usually in the spinal cord. Lack of vitamin B12 in the maternal diet during pregnancy has been shown to cause severe retardation of myelination in the nervous system. We report the case of a 14(1)/2-month-old child of strictly vegetarian parents who presented with severe psychomotor retardation. This severely hypotonic child had anemia due to insufficient maternal intake of vitamin B12 with associated megaloblastic anemia. MRI of the brain revealed severe brain atrophy with signs of retarded myelination, the frontal and temporal lobes being most severely affected. It was concluded that this myelination retardation was due to insufficient intake of vitamin B12 and vitamin B12 therapy was instituted. The patient responded well with improvement of clinical and imaging abnormalities. We stress the importance of MRI in the diagnosis and follow-up of patients with suspected diseases of myelination.

 Casella et al reported on "Vitamin B12 deficiency in infancy as a cause of developmental regression."  

Abstract

Vitamin B12 deficiency can cause serious developmental regression, hypotonia and cerebral atrophy in infants. We report a 6-month-old infant, with insidious developmental regression and brain atrophy showed by CT scan, secondarily to vitamin B12 deficiency. His mother was a strict vegetarian and the patient was exclusively breastfed. The clinical symptoms and the brain CT were normalized after vitamin B12 administration.

So we can conclude:

• B-12 deficiency during pregnancy may produce cry babies.
• B-12 deficiency during pregnancy can give your baby brain damage. 
• B-12 deficiency can make you crazy.

So I guess that proves the superiority of a vegan diet, especially a raw one (sarcasm).   

Starting to understand why some long-term unsupplemented vegans can seem a little, well, light headed?  Perhaps some of that gray matter is missing?


Might this explain why it can be so difficult to reason with vegan luminaries such as T. Colin Campbell?


Stay sane, stay smart.  Eat meat. 

Does a vegan diet cause B-12 deficiency diseases?

A commenter on my post on McDougall's ideas about B-12 claims:

"McDougall does have a point when he says that there is no good evidence so-called low B12 causes any diseases in vegans. This is the core of the debate. Most diseases that are associated with low B12 are found in the elderly who are in fact eating meat and dairy."

And:

"At the end of the day it has been shown that you can eat certain plant foods (chlorella in particular and purple nori) and they do increase plasma B12 (as measured by methy malonic acid) more so that meat and eggs do."

My quick response:


I followed McDougall and veganism for about 10 years. I made me sick. I saw many people get benefits in the first 1-2 years, then get ill. I saw babies impaired by B-12 deficiency in mothers. The idea that we have no evidence of B-12 deficiency causing illness in vegans and that B-12 deficiency diseases mostly occur in elderly omnivores is a crock of corn grits.

Vitamin B12 deficiency is associated with coronary artery disease in an Indian population.

Nutritional vitamin B12 deficiency in a breast-fed infant of a vegan-diet mother.

Severe vitamin B12 deficiency in infants breastfed by vegans


Metabolic complications and neurologic manifestations of vitamin B12 deficiency in children of vegetarian mothers


Subacute Combined Degeneration of the Spinal Cord in Vegetarians: Vegetarian's Myelopathy [free full text, includes radiographs of the lesions]

Pancytopenia in nutritional megaloblastic anaemia. A study from north-west India.
Low red and white blood cell counts in long term veg*ns and increased infections.

Vegetarian diet and cobalamin deficiency: their association with tuberculosis. [Full text, found nearly 3 times greater incidence of tuberculosis among vegetarians compared to omnivores.]


Vitamin B12 deficiency due to a strictly vegetarian diet in adolescence.

Brain damage in infancy and dietary vitamin B12 deficiency


A syndrome of methylmalonic aciduria, homocystinuria, megaloblastic anemia and neurologic abnormalities in a vitamin B12-deficient breast-fed infant of a strict vegetarian.

Low bone mineral density and bone mineral content are associated with low cobalamin status in adolescents.


Signs of impaired cognitive function in adolescents with marginal cobalamin status. [full text]

The commenter also claimed:

"At the end of the day it has been shown that you can eat certain plant foods (chlorella in particular and purple nori) and they do increase plasma B12 (as measured by methy malonic acid) more so that [sic] meat and eggs do."

Even veganhealth.org reviews the evidence and concludes we do not have evidence that chlorella and nori prevent B-12 deficiency (because they contain analogues).

On the page B12 in Tempeh, Seaweeds, Organic Produce, and Other Plant Foods you will find this:

"Until chlorella is tested on humans to determined whether it lowers MMA levels, it should not be considered to be a reliable source of vitamin B12, especially since the study by Pratt & Johnson showed no vitamin B12. "

This commenter also wrote:

"And this study found that meat and eggs do nothing to increase plasma B12 - "Dietary sources of vitamin B-12 and their association with plasma vitamin B-12 concentrations in the general population: the Hordaland Homocysteine Study.""

The abstract states: "Plasma vitamin B-12 was associated with intakes of increasing amounts of vitamin B-12 from dairy products or fish (P for trend <0.001 for both) but not with intakes of vitamin B-12 from meat or eggs. For the same content of vitamin B-12, intake from dairy products led to the greatest increase in plasma vitamin B-12. Total intake of vitamin B-12, particularly from milk and fish, decreased the risk of vitamin B-12 concentrations <200 pmol/L and impaired vitamin B-12 function (vitamin B-12 <200 pmol/L and methylmalonic acid >0.27 micromol/L) in the total group and in 71-74-y-old subjects."

So this commenter ignores the finding that fish and milk do raise B-12, selectively citing the finding that B-12 from meat or eggs did not raise levels. I haven't read the full text, but I doubt they actually assayed the meat and eggs consumed, rather they probably relied on tables of nutritional value to estimate intakes of B-12 from meat and eggs.

This could mean the meat and eggs these people ate (factory farmed) had little B-12, compared to fish (mostly wild) and milk, and it does not prove anything about meat and eggs from grass fed animals. Further, fish and milk did increase B-12, so animal products did effectively raise B-12. This certainly does not support veganism.

Humans are omnivores and you pursue veganism at your own risk.

Dr. McDougall on B-12: A study in vegan thinking?

In his November 2007 Newsletter, Dr. John McDougall, a tireless advocate of a strict vegetarian (vegan) diet, writes the following:

“Since the usual dietary source of vitamin B12 for omnivores is the flesh of other animals, the obvious conclusion is that those who choose to avoid eating meat are destined to become B12 deficient. There is a grain of truth in this concern, but in reality an otherwise healthy strict vegetarian’s risk of developing a disease from B12 deficiency by following a sensible diet is extremely rare—less than one chance in a million.”

Dr. McDougall apparently has not read the scientific literature on B-12 deficiency in vegans and vegetarians. In 1999, Haddad et al reported a study that included 25 vegan participants. Of these, “2 had macrocytosis (mean red cell volume 398 fL), 3 had circulating concentrations of vitamin B-12<150>376 nmol/L, which is the critical cutoff point that represents
3 SDs above the population mean.” Macrocytosis represents gross vitamin B-12 deficiency, which in this study occurred in 2 of 25 vegan individuals, or 8% -- an 80,000 times greater incidence than “one-in-a-million” (i.e. 0.0001%). Three of 25 or 12% had low VT-B12 concentrations, and 5 of 25 or 20% had elevated methylmalonic acid concentrations, which most experts consider the most sensitive indicator of vitamin B-12 deficiency.

Furthermore, the Haddad et al reported that “Although the average time subjects consumed a vegan diet was 4.2 y in this study, the data showed that 10 of the 25 vegans had at least one indicator of vitamin B-12 deficiency, either macrocytosis, low serum vitamin B-12, or elevated methylmalonic acid concentration (Table 4).” Therefore, this study alone suggested that approximately 40% of vegans may suffer from some degree of vitamin B-12 deficiency. In other words, this study recorded an incidence of B-12 deficiency 400,000 times as high as McDougall claims. Meanwhile, not one of the non-vegetarians had any of the indicators of B-12 deficiency.

Of interest, in table 2 of this paper, Haddad et al report that average intakes of B-12 from both food and supplements did not differ much between the vegans and nonvegetarians. This suggests strongly that B-12 supplements and fortified foods (the only significant sources of B-12 in vegan diets) do not prevent B-12 deficiency in long-term vegans. This could occur because the form used in supplements and fortified foods, cyanocobalamin, differs from the form supplied by animal foods.

This deficiency also affects lacto-vegetarians. In 1999 Hokin and Butler reported a study of 340 Seventh Day Adventist Vegetarians, 245 of which were lactovegetarians or vegans. In the vegetarians, 53% had serum B-12 levels below the laboratory reference range of 171 pmol/L, and 73% had levels below 221 pmol/L, the level identified as normal for an individual with adequate production of the intrinsic factor required for vitamin B-12 absorption. By conducting the Schillings test for intrinsic factor activity, Holin and Butler determined that dietary inadequacy caused the B-12 deficiency in 70% of the vegetarian subjects in this study.

In 2003, Herrmann et al conducted a study of 66 lactovegetarians or lactoovovegetarians
(LV-LOV group), 29 vegans, and 79 omnivores. This team tested three indicators of B-12 deficiency in all subjects: holotranscobalamin II, methylmalonic acid (MMA), and homocysteine levels. Low serum B-12 or holotranscobalamin II, or elevated MMA or homocysteine, indicate B-12 deficiency. They reported:

“Irrespective of vitamin usage, low vitamin B-12 concentrations (<> 271 nmol/L) was found in 5% of the omnivores, 61% of the LV-LOV subjects, and 86% of the vegans.”

Again, the facts dispute McDougall’s claim. In this study, signs of B-12 deficiency appeared not only in up to 90% of vegans, but also in up to 73% of LV-LOVs, and this despite use of vitamin B-12 supplements among the vegetarians.

In table 2 of this study they report the following findings among subjects not using vitamins:

• Normal B-12 status occurred in 78% of omnivores, 11% of LV-LOVs, and only 8% of vegans.
• Stage I or II B-12 deficiency occurred in 10% of omnivores, 21% of LV-LOVs, and 8% of vegans.
• Stage III B-12 deficiency occurred in 3% of omnivores, 60% of LV-LOVs, and a disconcerting 83% of vegans.

McDougall also claims that vegan diets work the best for reduction of homocysteine because of their high levels of folate and low levels of methionine—an amino acid abundant in meat but not plant proteins. But in this study, vegans and LV-LOVs, not omnivores, had the highest homocsteine (tHcy) levels, due to their B-12 deficiency. Herrmann et al wrote:

“We found tHcy concentrations <> 7 nmol/L). In contrast, hyperhomocysteinemia occurred in the LV-LOV subjects and vegans when serum folate was as high as 42.0 nmol/L.”

In other words, high folate and low methionine intakes do not protect against elevated homocysteine. High homocysteine appears linked to heart disease, cancer, osteoporosis, and many other common degenerative conditions, none of which occurred in healthy hunting and gathering groups.

So McDougall doesn’t have his facts correct about the incidence of B-12 deficiency or elevated homocysteine levels in vegetarians. But he goes on from that error to add:

“Take a moment to compare the possible consequences of your dietary decisions. You could choose to eat lots of B12-rich animal foods and avoid the one-in-a-million chance of developing a reversible anemia and/or even less common, damage to your nervous system. However, this decision puts you at a one-in-two chance of dying prematurely from a heart attack or stroke; a one-in-seven chance of breast cancer or a one-in-six chance of prostate cancer. The same thinking results in obesity, diabetes, osteoporosis, constipation, indigestion, and arthritis. All these conditions caused by a B12-sufficient diet are found in the people you live and work with daily. How many vegans have you met with B12 deficiency anemia or nervous system damage? I bet not one! Furthermore, you have never even heard of such a problem unless you have read the attention-seeking headlines of newspapers or medical journals.”

This paragraph contains several fallacies. First of all, he asserts a false dilemma: Either eat no animal foods and court a miniscule risk of B-12 deficiency, or eat “lots of B12-rich animal foods” and incur a high risk of heart attack, stroke, breast cancer, prostate cancer, obesity, diabetes, osteoporosis, constipation, indigestion, and arthritis.” This dilemma is false in several ways:
• He suggests falsely that you have only two choices, either eat no animal foods, or eat an undefined “lots” of them, when in fact a diet can vary from 0% to 100% animal food.
• He has not defined what percent will constitute “lots” of animal food, and though it refers generally to large amounts, by contrasting it with “no” animal food, Dr. he implies without evidence that eating any amount of any kind of animal food will put you at high risk for the listed diseases
• He implies that eating “lots” of animal foods will put anyone or everyone at risk for the listed diseases, and conversely that eating a vegan diet will prevent all these diseases in anyone or everyone.

Traditional Eskimos eat a diet composed of up to 90% animal food, and on their traditional diet, they had a low risk of heart attack and no cancer, no obesity, no diabetes, and no constipation. I do not think the Eskimo diet is ideal, but traditional Eskimo dietary experience certainly disproves McDougall’s implied claim that eating “lots” of animal food causes all the disorders he listed.

Dr. McDougall goes on to cite one study finding that “The human gut also contains B12-synthesizing bacteria, living from the mouth to the anus.” Although apparently true, he fails to mention that in order to produce true vitamin B-12 (cobalamin), these bacteria would need a source of cobalt, since a functional B-12 molecule contains this mineral.

Foods can supply cobalt, either as B-12 or in elemental form. A study by Hokin et al found that in Australia meat and potatoes are the main dietary cobalt sources. Comparing cobalt intakes of 10 omnivores, 10 lacto-ovo-vegetarians, and 10 vegans, Hokin et al found that lacto-ovo-vegetarians had the lowest cobalt intakes, that vegans who ate large amounts of potatoes had cobalt intakes similar to omnivores, and that vegans who did not eat large amounts of potatoes had cobalt intakes similar to lacto-ovo-vegetarians. Hokin et al found no correlation between dietary cobalt intake and serum B-12 concentrations in any of the dietary groups.

Hokin et al reported both vegans and vegetarians had mean serum B-12 levels of 175 pmol/L, compared to 366 pmol/L in omnivores. (As noted above, levels below 221 pmol/L are considered deficient and are associated with macrocytosis and elevated homocysteine in vegetarians.) Hokin et al noted that even the lowest cobalt consumption in the groups studied (6.67 mcg/d) would support the production of 165 mcg of B-12, about 80 times the RDA for B-12 – but that did not happen in the vegans, indicating that human gut flora does not produce significant or adequate amounts of B-12 from dietary cobalt.

Dr. McDougall goes on to discuss the fact that the intestinal flora of ruminant animals (such as cattle, sheep, deer, bison, giraffes, and goats) produce vitamin B-12. These animals ingest cobalt, carbon, hydrogen, phosphorus, and nitrogen by eating grass, a food inedible to humans, and their intestinal flora use that material to produce B-12. They absorb and use some of that B-12, so that the B-12 appears in the meat and milk of these animals, but they also pass much out in their feces.

McDougall goes on to say:

“The [human] colon contains the greatest number of bacteria (4 trillion/cc of feces), and here most of our intestinal B12 is produced. However, because B12 is absorbed in the ileum, which lies upstream of the colon, this plentiful source of B12 is not immediately available for absorption—unless people eat feces (don’t gasp). Feces of cows, chickens, sheep and people contain large amounts of active B12. Until recently most people lived in close contact with their farm animals, and all people consumed B12 left as residues by bacteria living on their un-sanitized vegetable foods.”

Why shouldn’t we gasp? Is he suggesting that it is healthier to eat feces than to eat meat or milk? I venture to say without any scientific reference that people all over the planet feel revulsion at the idea of eating feces, and that no successful culture has failed to recognize the need to take steps to remove fecal matter from foods before consumption.

Moreover, every culture that keeps farm animals does so to have access to meat, milk, and eggs, not so as to have vegetables contaminated with fecal matter. But McDougall writes as if he wants us to believe that in the old days people avoided eating animal products and only kept farm animals so they could have access to vegetables contaminated with fecal matter.

I don’t know of any human group that has a tradition of keeping farm animals just for the purpose of eating unwashed vegetables contaminated with feces. I find his insinuation insulting to the intelligence of the reader and the human race in general. In case the reader or McDougall does not know, consumption of fecal matter can kill by ingestion of deadly coliform bacteria or protozoans. Yet McDougall appears to think it is better to eat vegetables contaminated with fecal matter than to eat animal flesh.

McDougall goes further to say: “Why would a plant-food-based diet, heralded as a preventative and cure for our most common chronic diseases be deficient in any way? Such a diet appears to be the proper, intended, diet for humans, except for this one blemish.”

Okay, one thing at a time. First, here he clearly uses the phrase “plant-food-based diet” to refer only to a vegan diet. But in fact the phrase “plant-based” does not mean plant-only. Any diet that provides more than 50% of its bulk or energy from plant foods can legitimately be called plant-based. What else would you call a diet that provided 75% of its energy from plant foods and 25% from animal foods? I certainly would not call that diet “animal-based.”

A vegan diet is not only plant-based, it is plant-only. Vegans quite commonly apply the concept of dietary base inconsistently. They commonly call the omnivorous diet “animal-based” when in fact the majority of modern omnivores eat plant-based diets, i.e. the bulk of the diet of omnivores comes from plants, not animals. If a diet contains any animal foods at all, vegans call it “animal-based,” but will call a diet “plant-based” only if it is 100% plant food.

Moreover, B-12 deficiency is not the only “blemish” on plant-only diets. Plant-only diets may fail to meet human needs for taurine, DHA, zinc, iron, vitamin B-6, and vitamin A.

Further, what does he mean when he says a plant-only diet is the “proper, intended” diet for humans? Who does he think “intended” for humans to eat a plant-only diet? Does he opine that some supernatural creator “intended” for humans to eat vegan diets? I find this sudden reference to an “intended” diet creepy.

I know many readers may believe in a god, but no one has ever produced any scientific evidence that any of Nature or human physiology occurred as a result of the “intention” of any supernatural entity. In addition, various human tribes have claimed to “know” the existence, will, or intent of many different gods– the Judeo-Christian God, the Islamic Allah, Vishnu, Brahman, Zeus, Poseidon, Buddha, etc. The opinions as to what these entities supposedly “intended” for humans appear quite contradictory. Compare the dietary proscriptions of Islam and Hinduism, or of Seventh Day Adventists and Jews, etc., and you will quickly see that the experts on the gods’ wills for human diets have major disagreements. Even within cults there appears dispute about what the god wants. Some Buddhists claim Buddha prohibits meat-eating, some say not. Some Christians say their God allows meat-eating, some say not.

Discussions of human nutritional requirements require evidence from scientific research, not vague references to the “intended” diet of man without reference to any entity that could have intent (such as humans). Certainly rice did not “intend” for humans to eat its seeds; apple trees did not produce apples for humans; soybean plants do not intend for humans to eat their seeds; and so on.

Nature did not “intend” for humans to eat any diet; rather, humans adapted to eating what Nature provided in the ecological niche humans chose to inhabit. All the scientific evidence indicates not only that humans have always eaten omnivorously, but in fact that prehistoric humans depended primarily on animal-source foods for millions of years during the ice ages.

In fact, humans could not have spread from Africa to inhabit Europe, starting 50, 000 years ago, unless they heavily utilized meat, poultry, fish, and eggs as staple foods. From that time until about 10, 000 years ago, an ice age gripped the planet, and humans moved out of Africa into Central Asia, and from there eventually to Australia, Europe, China, Siberia, and North America. The climate did not allow the earth to produce sufficient quantities of edible plant foods along many of the routes of migration humans followed. So they lived on meat and fish of whatever type they could find.

What every vegan needs to know about B-12: http://www.veganhealth.org/articles/everyvegan/

Another study showing low B-12 levels and elevated homocysteine in vegans and vegetarians:
http://content.karger.com/ProdukteDB/produkte.asp?Aktion=ShowAbstract&ArtikelNr=12827&Ausgabe=224621&ProduktNr=223977

Notes

Haddad et al, Dietary intake and biochemical, hematologic, and immune status
of vegans compared with nonvegetarians, Am J Clin Nutr 1999;70(suppl):586S–93S.

Hokin and Butler, Cyanocobalamin (vitamin B-12) status in Seventh-day Adventist
ministers in Australia, Am J Clin Nutr 1999;70(suppl):576S–8S.

Herrmann et al, Vitamin B-12 status, particularly holotranscobalamin II and
methylmalonic acid concentrations, and hyperhomocysteinemia
in vegetarians, Am J Clin Nutr 2003;78:131–6.

Albert MJ, Mathan VI, Baker SJ. Vitamin B12 synthesis by human small intestinal bacteria. Nature. 1980 Feb 21;283(5749):781-2.

Hokin et al, Comparison of the dietary cobalt intake in three different Australian diets, Asia Pac J Clin Nutr 2004;13 (3):289-291.