Glucose restriction extends lifespan of human cells, kills human cancer cells

Researcher Confuses Glucose and Calorie Restriction

I subscribe to news feeds that report on new nutrition research and today one directed me to this article in Medical News Today:

Calorie Intake Linked To Cell Lifespan, Cancer Development

So I read that headline, then this first paragraph:

"Researchers from the University of Alabama at Birmingham (UAB) have discovered that restricting consumption of glucose, the most common dietary sugar, can extend the life of healthy human-lung cells and speed the death of precancerous human-lung cells, reducing cancer's spread and growth rate."

Wait a minute. The headline says that someone linked calorie intake to lifespan and cancer development, but the first paragraph says the research involved restricting glucose.

I read on and find a poorly constructed paragraph relaying that the principal investigator, Trygve Tollefsbol, Ph.D., D.O., a professor in the Department of Biology at UAB, believes that this research points to "ways in which calorie-intake restriction can benefit longevity and help prevent diseases like cancer that have been linked to aging."

But the next paragraph relates this:

"The UAB team conducted its tests by growing both healthy human-lung cells and precancerous human-lung cells in laboratory flasks. The flasks were provided either normal levels of glucose or significantly reduced amounts of the sugar compound, and the cells then were allowed to grow for a period of weeks."

So the experiment actually involved glucose restriction as the form of calorie restriction. Tollefsbol says:

"In that time, we were able to track the cells' ability to divide while also monitoring the number of surviving cells. The pattern that was revealed to us showed that restricted glucose levels led the healthy cells to grow longer than is typical and caused the precancerous cells to die off in large numbers."

After discussing the different effects that the glucose restriction had on healthy and pre-cancerous cells, causing the former to grow more vigorously and the latter to die off, the article again quotes Tollefsbol:

"Our results not only support previous findings from the feeding of animals but also reveal that human longevity can be achieved at the cellular level through caloric restriction," Tollefsbol said.

"The hope is that this UAB breakthrough will lead to further discoveries in different cell types and facilitate the development of novel approaches to extend the lifespan of humans," he added.

So again he calls it caloric restriction, despite admitting that the study protocol involved restricting glucose.

Finally the report gives us the title Tollefsbol and his team gave to their report, published in the online edition of The Journal of the Federation of American Societies for Experimental Biology, or FASEB Journal: "Glucose Restriction Can Extend Normal Cell Lifespan and Impair Precancerous Cell Growth Through Epigenetic Control of hTERT and p16 Expression."

Frankly, this bugs me. He accurately titles his research on glucose restriction, but then when he talks to the press, he calls it caloric restriction. Yes, glucose restriction can be caloric restriction, but glucose restriction could also be accomplished without caloric restriction, by supplying fat to replace calories removed by restricting glucose.

This study did not demonstrate that "calorie restriction" produces the outcome they achieved simply because it appears that they failed to test a glucose-restricted but not calorie-restricted feed. This study showed that caloric restriction will prolong human cell lifespan and kill cancer cells if you achieve it by restricting glucose.

This means that excessive intake of glucose -- carbohydrate in the diet -- shortens cells' lifespans and promotes cancer cell growth. Why not say that?

Might not go over well with advertisers, I suppose.

I wonder what McDougall and Campbell will say to defend their 70% carbohydrate diet recommendations?

This research dovetails with Cynthia Kenyon's research with glucose restriction in C. elegans (roundworms). Kenyon found that glucose and insulin restriction extends lifespan in worms. Now we know that glucose restriction also extends lifespan of human cells.

Now we need to determine just how much dietary glucose restriction we need to achieve this effect.