There has always been “genetic drift,” and for millions of years nature selected for those hominid adaptations that best ensured the survivial of the species, ultimately giving rise to homo sapiens. In the paleo community its been said that since the advent of agriculture and the civilizations it made possible, 10,000 or so years ago, we have ceased to evolve. Of course our genome is still changing, but as the argument goes, in the civilized world favorable adaptions are not selected for; there is no “need” for the adaptation to ensure survival of the species. Similarly, unfavorable adaptations are not deselected; as was achieved in paleolithic times by the inability of the person carrying the unfavorable adaption to reach reproductive age or to actually reproduce the unfavorable adaptation in his or her offspring. As it turns out though, it’s not quite that simple.
“With savages, the weak in body or mind are soon eliminated; and those that survive commonly exhibit a vigorous state of health. We civilised men, on the other hand, do our utmost to check the process of elimination; we build asylums for the imbecile, the maimed, and the sick; we institute poor-laws; and our medical men exert their utmost skill to save the life of every one to the last moment. There is reason to believe that vaccination has preserved thousands, who from a weak constitution would formerly have succumbed to small-pox. Thus the weak members of civilised societies propagate their kind. No one who has attended to the breeding of domestic animals will doubt that this must be highly injurious to the race of man. It is surprising how soon a want of care, or care wrongly directed, leads to the degeneration of a domestic race; but excepting in the case of man himself, hardly any one is so ignorant as to allow his worst animals to breed.
Charles Darwin, The Descent of Man
Adaptation to Neolithic Foods
Survival of the species requires that the species reproduces at a rate sufficient to at least maintain its numbers. This means that “natural selection” is, or was, tightly focused on solving the problem of successfully reaching reproductive age. Frankly, natural selection cares little about us reaching the age of 60, and it cares even less about us aging with good health intact. Pre-agriculture and pre-civilization, natural selection was totally focused on the survival of the species, and that process isn’t always pretty. But this begs the question, was our survival as a species in doubt as we transitioned to agriculture, and hence did natural selection favor and focus genetic drift in that direction? Recently a Robb Wolf Paleo Solution Podcast came through my feed and I listened, and listened again, and I am now listening for the third or fourth time. This was Episode 416 with Dr Michael Rose – Aging, Adaptation, and Diet. If you are at or over the age of 30, I highly recommend that you give it a listen, or two or three. All quotes below are of Dr Michael Rose in the Podcast.
“Aging is not a process of cumulative molecular damage, aging is instead, a loss of adaptation with adult age.”
Adapted or Not, To Agricultural Foods?
And the answer IS … yes and no. Dissatisfying I know. First of all, “we are not adapted to high fructose corn syrup… Twinkies, Red Bull… because all of those things are completely novel,” according to Dr. Rose. But he also argues that we have genetically adapted to agricultural foods, to a greater or lesser degree based on our ancestry, at least to the extent that it favored our ability to reach reproductive age. Here’s the rub, we lose this adaptation as we age. And that knowledge is what’s new to me, and supported by lab experiements conducted by a former graduate student of Rose’s, Grant Rutledge, PhD. Grant made a presentation at the Ancestral Health Symposium (AHS) in 2016 titled Age-dependent Patterns of Adaptation, and Dr. Rose made a presentation on the subject at AHS in 2018 titled “Evolutionary Biology of Diet, Aging, and Mismatch.”
Yes, We are Adapted to Agricultural Foods
I find this to be good news, after all, I was raised to childbearing age in the 60’s and 70’s, so it’s comforting to believe that what I was eating was in alignment with my genetic predispositions. Thanks Mom!
Younger children, in most cases, not all but in most cases, will be reasonably adapted to an organic agricultural diet.
Unfortunately, the adaption does not last for life.
“…the basic mathematical logic of the evolutionary theory of aging suggests, unfortunately, that that rapid adaptation which should be present for those who are under 25 with Eurasian ancestry will steadily fade out with age…”
Therein lies the rub.
And No, We are Not Adapted to Agricultural Foods
So Rose’s hypothesis was, that our adaption, one that favors the attainment of childbearing age, will disappear.
“When that point is will depend on your ancestry. So, for example, if your ancestry is some combination of African and North American native then probably that point is reached very early, maybe when you’re 15 years old. If you come from a very longstanding agricultural ancestry such as perhaps Persians, Iraqis then maybe they’ll do well on organic agricultural foods until 40 or 45. But eventually you’re going to lose your adaptation on agricultural foods. That was my inference from the theory.”
This lines up with my own experience. I now believe that the first evidence that I was suffering from autoimmunity surfaced circa 2000; excema around my eyes. Of course I had no idea what autoimmunity was in 2000, and the meds prescribed were steroids which had the effect of tamping down the symptoms, so long as I continued to apply the creams. When I stopped, the symptoms returned with a vengance. I would have been 40 or 41 at the time, right at the opening of Rose’s hypothetical window in time of adaptation loss. n=1. My personal experiment seems to support the hypothesis.
I think after the age of 50, no matter where you come from, basically, the Paleo diet is best advised. Because whatever local adaptation to an agricultural your ancestors achieved, it didn’t penetrate into the much later ages.
I was finally diagnosed with an autoimmune disease in 2014, at age 55. Rose does talk of autoimmunity as perhaps being a symptom of the loss of adaptation, and it rings true with me. It was at that point that Geri and I made a hard right turn to the Paleo Diet, and specifically to the Paleo Autoimmune Protocol (AIP). As if by magic my antibody numbers dropped precipitously, and my overall health improved.
Does That Mean Adaptation to a Diet of Only Plant Foods?
No, is the short anwer, in my somewhat-informed opinion. Since going “paleo” I’ve been on relatively higher carbohydrate excursions, higher fat, and now a higher protein excursion. I tried vegetarianism back in the mid-90’s and reverted to omnivory about a year later; I simply could not build or even maintain muscle mass. It was that simple, and I didn’t know much more about nutrition or evolutionary biology at the time.
I’m going to say a relatively old school evolutionary biology thing right now. You can’t really account for the evolution of our very costly brains. Costly, in terms of both calories and nutrient quality. Unless you’re talking about an animal that has access to lots of high nutrient quality animal derived foods, the basic budget for nutrition and development doesn’t make sense on any kind of vegetarian diet.
Now that I’ve been probing pretty deeply into the science, and the history of the human race, I am more convinced than ever of the need for meat in the diet. Of course we can argue about the ethics of modern-day meat production, and I would agree that there is huge room for improvement along that line. But as I am fond of saying in private conversation, ” I won’t let someone else’s ethics trump my physiology.” Is good or even great health possible on a vegetarian or vegan diet? Perhaps, I’m no expert on that subject, but I do think it’s safe to say that to optimize human health supplementation would be required. It’s all about personal choices, and I’ve made mine.
The Paleo diet is right for me, and it has probably been right for me since I was 40, at the latest. The minutia regarding the implementation of that diet to fully optimize my health and performance is a work-in-progress, but I’m well along the path at this point, and I will continue looking for improvements. The latest resource with a lot to say on the subject of aging in particular, is Dr Gabrille Lyon.
Sometime between the ages of 30 and 50, depending on your ancestry, the Paleo theory that has been propounded for a long time by Loren Cordain and others like yourself <Robb Wolf> is, in fact, correct. That’s the basic conclusion of our research on diet and health.
What about you? I would suggest that if you are over the age of 50 you urgently consider a Paleo diet. It’s likely that a transition to Paleo somewhat earlier depending on your heritage, will be or would have been advantageous. Find resources that you trust. Dig in. Read, watch, listen, and get on the path; you won’t regret it.
I’ve added two my book list as a result of listening to the podcast and watching the videos; Paleo Fantasy, by Marlene Zook (she makes the case that we have had ample time to adapt to neolithic foods), and Food & Western Disease, by Staffan Lindberg. I will be ordering those up soon.