Transcript: The Benefits of Caloric Restriction Without the Actual Restricting
Why can’t we live forever? Some animals do. And I’m not talking about a 200 year old whale or even a thousand year old tree, I’m talking about immortal. There are actually species that apparently don’t age and could technically go on forever--and why not? In a sense humans are immortal in that a few of our cells live on, sperm or egg cells lucky enough to find each other. Each of our kids grow out of one of our cells, and that alone—the fact that a single cell can grow into person should make, in comparison, the notion of keeping our bodies going indefinitely seem trivial.
Well it’s certainly a hot research topic. Much has focused on the role of DHEA, dehydroepiandrosterone, the most abundant steroid hormone in the human body, whose levels drop significantly as we age. It is a cortisol antagonist, meaning that it helps counteract the effects of stress. It appears to rejuvenate female fertility, and most importantly, appears to be a strong predictor of longevity. In fact one of the ways caloric restriction appears to extend the lifespan of many animals may be the upregulation of DHEA.
So, no surprise, it is sold as a “fountain of youth” over-the-counter supplement raising all sorts of concerns about safety, side effects, “and the lack of quality control in this increasingly financially rewarding business.” For example, some supplements just totally lie and have no DHEA in them, and other's have significantly more than the claimed dose. And so for this and other reasons taking DHEA supplements is recommended against.
Are there natural ways to boost levels? Well we’ve known a number of individual dietary components, like fiber intake, are associated with better levels so why not just put them all together: “Short-Term Impact of a Lactovegetarian Diet.” After just 5 days on an egg-free vegetarian diet, blood levels of DHEA rose about 20% compared to the normal diet, and it’s interesting why, it wasn’t necessarily because they were making producing more of it, but instead losing less. The bodies of those eating vegetarian appear to try to hold onto it, which is normally something you only see in fasting. But these were all isocaloric diets—same calories in each, so the thought is that by eating vegetarian one may be able to mimic the effects of caloric restriction, but without walking around starving all the time.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Serena
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