There’re so many amazing science stories in the daily news – it’s hard to keep up. Yeah yeah – now you know my pathetic excuse for another two-month post-lapse. Since we all know the topic I love most though, I just gotta share when some tidbit about my favorite primate has me humming Roots Rock Reggae (uh huh, from back in the day…).
This recent news story made me feel infinitely better about occasionally seeking solace in the bread box: “Study: Dietary carbohydrate essential for evolution of modern big-brained humans” (- the study, authored by Karen Hardy et al, is here). It’s one of those research papers that seems to tie a number of loose root-ish threads together: how early humans’ changing ability to digest edible roots (aka USOs – underground storage organisms) is correlated with human brain enlargement over the past 2 million years; the deep contribution women & grandmothers made (& continue to make) toward providing essential food for the tribe; & why the (overlooked & under-appreciated) sea & water environment is one of the keys to human evolution.
I know we love meat – there’s evidence of early humans scavenging meat as early as 2.5 million years ago. But more & more research is also pointing to shellfish, water plants, roots & tubers as the primary sources of digestible protein & carbohydrate energy that helped feed our ancestors’ ever-larger energy-sucking brains & ever-more-immature milk-sucking babies – even before the monumental evolutionary change of controlling fire.
The conclusions of this study address a number of problems with the long-held meat-made-our-brains-big scenario (loved by steak-wielding guys everywhere): #1 is that the earliest evidence of humans controlling fire is about 800,000 years ago. While scientists may find evidence of earlier use of fire (which has so far proven difficult because, well, the evidence was burned), we’ll need to surmise, in the meantime, that either our ancestors were eating uncooked meat (which was possible if they’d figured out a way to make steak tartare with flesh from a very young animal, but generally-speaking, raw meat isn’t easily digestible); &/or early humans (or at least those who survived to evolve into us) had figured out other ways to make the broader range of foods they were eating more palatable (maybe via drying, soaking, fermenting, & pickling), which in turn was more likely if they were thriving by living & eating along waterways, lakes & coastlines. Sadly, that evidence is also lost – either composted or hundreds of meters under water due to many periods of rapid climate and sea level change over the past 2 million years.
But we have genetics! This study analyzes the evolution of salivary & other digestive enzymes in early humans & correlates that analysis with evidence of cooking; reviews the body & brain’s need for energy produced by glucose; & describes how cooking starchy carbohydrates would have increased survival rates, in particular among infants & lactating women.
OK – I admit it: I especially dug this report because I love slow roasted USOs (also love ’em frittered or fried with salt…as in that favorite fast food). And sashimi – double yum. Probably that’s why this research resonates: the proof is in our genes.
In any event, I’m rooting for this narrative of how our (mostly useful) pre-frontal cortex mushroomed over the past 2M years: it was enriched by women’s work, fertile earth & muddy marshes.
& here’s carl zimmer’s take: http://www.nytimes.com/2015/08/13/science/for-evolving-brains-a-paleo-diet-full-of-carbs.html?_r=0
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