 Why can't we live forever? Some animals do. And I'm not talking about some 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? I mean, in a sense, humans are immortal and 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. I mean, the fact that a single cell can grow into a person should make, in comparison, the notion of keeping our bodies going indefinitely seem biologically trivial. Well, it's certainly a hot research topic. Much is 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 others have significantly more than the claim dose. And so for this, and other reasons, making DHEA supplements is recommended against. But are there natural ways to boost levels of this hormone? Well, we've known a number of individual dietary components, like fiber intake, are associated with better levels. So why not just put all the dietary components together? Short-term impact of a lacto-vegetarian diet. So, after just five days on an egg-free vegetarian diet, blood levels of DHEA rose about 20% compared to the meaty diets. And it's interesting why. It wasn't necessarily because they were making more, producing more of it, but instead they were losing less. The bodies of those eating vegetarian appear to hold on to it, which is normally something you only see in fasting. But these were all isocaloric diets, meaning same calories in both diets. So by eating vegetarian, one may be able to mimic the effects of caloric restriction, but without walking around starving all the time.