Aging expert Dr. Stephen Austad of the University of Texas Health Science Center kicked off our research conference’s plenary session on diet, activity, aging and cancer this morning with an overview of the history of the study of calorie restriction (generally defined as a 30 to 40 percent fewer calories without nutrient deficiency).
The fact that calorie restriction has been linked to longevity and cancer prevention in particular has been established for decades in animal models. Dr. Austad began by reviewing that literature, and highlighting more recent work which suggests that the protective effect of calorie restriction on lifespan in these animal models seems to be growing less clear-cut: work with wild mice strongly suggests that genetics play a role in determining whether calorie restriction increases or decreases longevity.
Interestingly, however, the effect of calorie restriction on cancer prevention seems just as strong in wild mice as it is in lab mice, suggesting that diet’s protective role against cancer doesn’t strongly depend on genetics.
But in addition to calorie restriction’s long-term effects, Dr. Austad presented some data on a surprising short-term effect his team has uncovered — and posited an intriguing theory.
He’s found that short-term (1-2 day) fasting of mice seems to increase their ability to defend against some common toxins, including some chemical carcinogens. He offered an evolutionary thesis: “When you’re starving, you become less choosy about what you eat,” he said. “If you’re a mouse, and you can’t get seeds, you might turn to plants that contain toxins, or spoiled and bacteria-laden foods. Nature may have installed a mechanism to bolster the body’s defenses in times of extreme fasting.”
It’s preliminary research, and it’s certainly no reason to starve yourself before travelling to a malaria zone or anything, but it’s a fascinating theory, and one that Dr. Austad hopes to pursue in the future.