Do You Have “Paleo-Deficit Disorder”?
The trendy “Paleo” diet is a diet that emphasizes eating foods presumably available to our ancestors in the Stone Age—and nothing else. Going back about 10,000 years, to a time right before agriculture became common, means some foods are in, and some are strictly out. For some strict Paleo adherents, that means no dairy, no grains, no refined sugars, and of course, no processed foods of any kind.
Critics argue it’s overly simplistic to assume our ancient ancestors ate only what they could hunt or gather. They argue that foods available today are simply not the same foods available ten millennia ago. Critics worry that people who adhere strictly to the diet may miss out on some key nutrients. While people often lose weight on the paleo diet, critics argue that’s because they’re eliminating simple carbohydrates—especially refined sugar—from the diet, and that’s the real cause of any benefits.
But other respectable scientists argue there may be something more going on. Modern life has insulated us from many aspects of life in the natural world. And that loss of contact with nature may account for “psychological distress,” with symptoms such as depression and anxiety. There’s tantalizing evidence that being in a green, growing environment is simply good for our mental health. Numerous studies have concluded that spending time in nature lowers blood pressure and elevates mood. And just having a little green in an urban landscape appears to improve people’s mood and general mental health. Taken together, all this evidence suggests that as humans, we are hard-wired to feel more at ease in a green, living environment than among concrete, steel, asphalt, and glass.
But what about the Paleo diet? Is it really healthier than other diets? In an intriguing pair of articles published in Environmental Science & Technology, scientists speculate that many factors of our former “natural” lives contributed to overall health and well-being. Among these may be a more diverse collection of beneficial gut microbes. Between our obsession with cleanliness, our use of antibiotics, and our consumption of homogenized, factory-processed foods, they argue, we’ve lost much of the gut microbe biodiversity that is present even among modern hunter-gatherer peoples. As long ago as the early 1970s, Dr. Rene Dubos proposed that our efforts to protect our children from exposure to “dirt” may be counterproductive, in that their immune systems are never allowed to develop fully.
The present paper proposes the existence of “paleo-deficit disorder,” meaning a lack of gut microbe biodiversity that is causing numerous health problems for modern humans. There’s some supporting evidence for this effect. Studies have shown that modern-day “stone-age” hunter-gatherer tribes tend to have far more gut microbe biodiversity than modern urban or suburban humans. And that lack of diversity may account for higher rates of various common diseases, and higher rates of mental illness, among people living in industrialized nations.
Indeed, emerging research has demonstrated that people with greater gut microbiome diversity are less prone to inflammation. Inflammation is now believed to be a driving force behind many common diseases that afflict us. All of which suggests that much of the advice I’ve been dispensing all along is on target: eat a whole foods diet, buy organic when possible, avoid refined and processed foods (especially foods with added sugars), spend time outdoors whenever possible, breastfeed your baby if possible, and avoid antibiotics if you can.
Bendiks M1, Kopp MV. The relationship between advances in understanding the microbiome and the maturing hygiene hypothesis. Curr Allergy Asthma Rep. 2013 Oct;13(5):487-94. doi: 10.1007/s11882-013-0382-8.
Ian Alcock, Mathew P White, Benedict W. Wheeler, Lora E. Fleming, Michael H. Depledge. Longitudinal Effects on Mental Health of Moving to Greener and Less Green Urban Areas. Environmental Science & Technology, 2013; 131209122554002 DOI: 10.1021/es403688w
Grasa L1, Abecia L, et al. Antibiotic-Induced Depletion of Murine Microbiota Induces Mild Inflammation and Changes in Toll-Like Receptor Patterns and Intestinal Motility. Microb Ecol. 2015 Apr 21. [Epub ahead of print]
Logan AC1, Katzman MA2, Balanzá-Martínez V3. Natural environments, ancestral diets, and microbial ecology: is there a modern "paleo-deficit disorder"? Part II. J Physiol Anthropol. 2015 Mar 10;34(1):9. doi: 10.1186/s40101-014-0040-4.