This blog has been almost entirely populated with entries written by Colby undergraduate students since its inception in 2010 with just a few stray posts from me here and there. Consequently, it’s been pretty quiet over here since the flurry of posts associated with our foray into the neuroblogosphere for the annual Society for Neuroscience meeting in November of last year and then the (sad) conclusion of the Psych/Neuro seminar in December. In the interest of a potential bid to neuroblog again at the annual meeting, I am breaking my radio silence to span the gaps during the times when my students are elsewise engaged.
To pierce through the cricket calls over here, I planned to pimp my latest paper (why not) but then I heard something intriguing on the radio (go figure) this morning: very low calorie diets might not extend lifespan as we always thought! Until now, oodles of data in rodents and at least one study with monkeys pretty compelling indicated that some serious food restriction, even if initiated late in life, conferred significant life-extending effects. The latest study, published this month in Nature, was conducted using monkeys and began in 1987 (I think I had a mullet that year and wore a lot of makeup and pink plaid). The results (of the study, not of my misspent youth) were not supportive of past findings: the calorie-restricted monkeys were leaner but lived no longer than their non-restricted counterparts.
I smell danger and it smells a lot like a game of “telephone” with a circle of children. I sincerely hope that by the time we get to the last child (the public) the message is not something like: less food makes you die! or eat more live longer! rather than the much more modest conclusion that in this group of monkeys (for the record there was a lot of them), aged under those specific circumstances (what did they do for 25 years?), calorie restriction of a specific amount (30% reduction from the comparison group) didn’t lead them to live any longer than the monkeys that ate more. We shall see.
Selfishly, as a researcher who frequently studies nutrient supplementation I am happy to have some ambiguity to reference when I am inevitably asked to reconcile healthy aging with a “supplemented” diet in light of the data that overall calorie restriction promotes healthy aging and prolongs lifespan. Nonetheless, I’m not sure I’m ready to give up on the data that I’m familiar with from the rat and mice studies conducted over the last few decades. I do think there may be something interesting here about the contrast between monkeys and rats and ultimately humans, though I’m not that willing to speculate at this time on what that might be. But more importantly, the details of these studies need to be carefully examined to understand why their outcomes are not in agreement. What can we learn from the differences? And what did the food restriction do, even if it didn’t extend the monkeys’ lives? I’d love to answer these questions directly but several impending deadlines means a more careful scrutiny of these papers will have to wait for another day. Intriguingly, both the NPR report and the article over at Nature point out some key differences (links below). For example, in the latest study the comparison monkeys, those not on the low calorie diet, didn’t have free access to food while the monkeys from the previous study did. Those are very different comparison groups! I smell something else… a study with all 3 groups represented perhaps? Scheduled intake may be very important indeed. Plus genetics. Oh, and epigenetics. Also, nutrient composition (what was the food stuffs?) and personality (do grumpy monkeys live longer?). So much to learn, so little time.