Studies published within the past 15 years show that much of our produce is relatively low in phytonutrients, which are the compounds with the potential to reduce the risk of four of our modern scourges: cancer, cardiovascular disease, diabetes and dementia. The loss of these beneficial nutrients did not begin 50 or 100 years ago, as many assume. Unwittingly, we have been stripping phytonutrients from our diet since we stopped foraging for wild plants some 10,000 years ago and became farmers.Breeding the Nutrition Out of Our Food (New York Times)
These insights have been made possible by new technology that has allowed researchers to compare the phytonutrient content of wild plants with the produce in our supermarkets. The results are startling.
Wild dandelions, once a springtime treat for Native Americans, have seven times more phytonutrients than spinach, which we consider a “superfood.” A purple potato native to Peru has 28 times more cancer-fighting anthocyanins than common russet potatoes. One species of apple has a staggering 100 times more phytonutrients than the Golden Delicious displayed in our supermarkets.
Were the people who foraged for these wild foods healthier than we are today? They did not live nearly as long as we do, but growing evidence suggests that they were much less likely to die from degenerative diseases, even the minority who lived 70 years and more. The primary cause of death for most adults, according to anthropologists, was injury and infections.
Each fruit and vegetable in our stores has a unique history of nutrient loss, I’ve discovered, but there are two common themes. Throughout the ages, our farming ancestors have chosen the least bitter plants to grow in their gardens. It is now known that many of the most beneficial phytonutrients have a bitter, sour or astringent taste. Second, early farmers favored plants that were relatively low in fiber and high in sugar, starch and oil. These energy-dense plants were pleasurable to eat and provided the calories needed to fuel a strenuous lifestyle. The more palatable our fruits and vegetables became, however, the less advantageous they were for our health.
The food we eat today, even the fruits and vegetables, are not the same as our hunter-gatherer ancestors ate. Another blow to agricuture as a dramtic leap forward. And there's also this:
“Fiber is not a single nutrient,” Sonnenburg said, which is why fiber supplements are no magic bullet. “There are hundreds of different polysaccharides” — complex carbohydrates, including fiber — “in plants, and different microbes like to chomp on different ones.” To boost fiber, the food industry added lots of a polysaccharide called inulin to hundreds of products, but that’s just one kind (often derived from the chicory-plant root) and so may only favor a limited number of microbes. I was hearing instead an argument for a variety of whole grains and a diverse diet of plants and vegetables as well as fruits. “The safest way to increase your microbial biodiversity is to eat a variety of polysaccharides,” he said.Say Hello to the 100 Trillion Bacteria That Make Up Your Microbiome (New York Times). Our cleanliness has delivered benefits, but at a cost.
His comment chimed with something a gastroenterologist at the University of Pittsburgh told me. “The big problem with the Western diet,” Stephen O’Keefe said, “is that it doesn’t feed the gut, only the upper G I. All the food has been processed to be readily absorbed, leaving nothing for the lower G I. But it turns out that one of the keys to health is fermentation in the large intestine.” And the key to feeding the fermentation in the large intestine is giving it lots of plants with their various types of fiber, including resistant starch (found in bananas, oats, beans); soluble fiber (in onions and other root vegetables, nuts); and insoluble fiber (in whole grains, especially bran, and avocados).
With our diet of swiftly absorbed sugars and fats, we’re eating for one and depriving the trillion of the food they like best: complex carbohydrates and fermentable plant fibers. The byproduct of fermentation is the short-chain fatty acids that nourish the gut barrier and help prevent inflammation. And there are studies suggesting that simply adding plants to a fast-food diet will mitigate its inflammatory effect.
When I asked Gordon about do-it-yourself microbiome management, he said he looked forward to a day “when people can cultivate this wonderful garden that is so influential in our health and well-being” — but that day awaits a lot more science. So he declined to offer any gardening tips or dietary advice. “We have to manage expectations,” he said.That reminds me of this old article from the Times: The Great Unwashed
Alas, I am impatient. So I gave up asking scientists for recommendations and began asking them instead how, in light of what they’ve learned about the microbiome, they have changed their own diets and lifestyles. Most of them have made changes. They were slower to take, or give their children, antibiotics. (I should emphasize that in no way is this an argument for the rejection of antibiotics when they are medically called for.) Some spoke of relaxing the sanitary regime in their homes, encouraging their children to play outside in the dirt and with animals — deliberately increasing their exposure to the great patina. Many researchers told me they had eliminated or cut back on processed foods, either because of its lack of fiber or out of concern about additives. In general they seemed to place less faith in probiotics (which few of them used) than in prebiotics — foods likely to encourage the growth of “good bacteria” already present. Several, including Justin Sonnenburg, said they had added fermented foods to their diet: yogurt, kimchi, sauerkraut. These foods can contain large numbers of probiotic bacteria, like L. plantarum and bifidobacteria, and while most probiotic bacteria don’t appear to take up permanent residence in the gut, there is evidence that they might leave their mark on the community, sometimes by changing the gene expression of the permanent residents — in effect turning on or off metabolic pathways within the cell — and sometimes by stimulating or calming the immune response.