Thursday, March 19, 2009

Anti-Aging in the Media: National Post on Caloric Restriction

Caloric restriction: condition yourself to eat less
Caloric restriction: condition yourself to eat less. (Photo by oskay)

One more mainstream newspaper has discovered the secrets of caloric restriction. Following on the trails of Houston Press, who ran an article on caloric restriction and resveratrol last month, it's now National Post's turn to take a walk on the light side.

The story, with the less than exciting headline "Eat less, live longer", takes a somewhat different approach than many of the others we've seen so far. There's no interview with anyone doing calorie restriction, for one. Just some basic facts for those who might be tempted to trade their cheeseburgers for some extra years of life:

As early as the 1930s, it was shown that calorie reduction could double the lifespan of rats. What's more, a 1988 study noted that mice on a calorie-restricted diet had a more youthful appearance, a higher activity level and a delay in age-related diseases, compared with those on an unrestricted feeding schedule.

While the overall tone of the article is quite positive, some mandatory health warnings regarding cutting back on calories are also included:

In addition, it is known that excessive fasting may lead to anemia, muscle wasting, dizziness, fatigue, nausea and depression, among other symptoms and conditions. Even the Calorie Restriction Society warns that a reduction in nutrition may lead to bone and muscle loss, increased cold sensitivity, disrupted menstrual cycles, reduced athletic performance and decreased sex drive.

I think this is pushing it a little, since anemia, muscle wasting, dizziness, nausea and depression are not common symptoms of caloric restriction. Rather, they're symptoms of malnourishment, which is of course not the goal of CR – that's why it's often called CRON, from Calorie Restriction with Optimal Nutrition.

The rest of the issues are, however, quite real. But then, that's a trade-off some are willing to make in order to increase their lifespan. If you're young and athletic, seriously reducing your energy intake may not seem so appealing, but for those worried about aging-related diseases like Alzheimer's, caloric restriction might be an option to consider. The article mentions a study on elderly volunteers comparing the effects of omega-3 fatty acids and CR on memory:

Remarkably, the patients who were assigned to calorie restriction demonstrated marked improvement in memory, while those trying to increase their unsaturated fatty acid intake and those who maintained their usual diet showed no change. The researchers also took blood samples from all the study participants; the low-calorie group saw a reduction in their insulin and C-reactive protein levels.

So if you keep forgetting to eat your breakfast, you may actually be doing yourself some good. Speaking of memory, I don't recall ever reading anything about this one before:

The first studies on the effects of caloric reduction on humans were done in the 1940s, when it was observed that Scandinavians, living on a diet in which their calories were restricted by 20% because of the hardships of the Second World War, showed a decrease in cardiovascular disease.

Unfortunately, there's no source for this claim. I may have to do some digging to find out if it's true. Even though old studies on caloric restriction usually include plain starvation (as in malnourishment), they provide an interesting look on the subject anyway.

For more information on aging, see these posts:

Anti-Aging in the Media: Vancouver Sun on Immortality
Intermittent Fasting Reduces Mitochondrial Damage and Lymphoma Incidence in Aged Mice
Anti-Aging in the Media: Rolling Stone on Ray Kurzweil
Anti-Aging in the Media: 60 Minutes on Resveratrol

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