Chapter 29
Salt in the Wound
Since humans and plants do not produce Neu5Gc, do we really have only the choice between cannibalism and veganism if we want to avoid being exposed to it—or what? No. For organ transplants, transgenic pigs without Neu5Gc have already been developed, so one proposal is that we could use “genetically modified livestock as a source of red meat.” Or we could stick with eating animals that naturally don’t produce it. Neu5Gc is found in most mammals, amphibians, and fish, with caviar containing the highest amount, but in birds and reptiles it is rare. Among mammals, goat meat contains the most, but with regard to “potential candidates for human consumption,” levels were low in game, and there was no Neu5Gc at all in the muscles of kangaroos and dogs (but not cats). Another proposal would be to take a Neu5Gc blocker every time we eat meat. The researchers concede that “in practice it may be difficult to have such an antidote available at each meal …”.
Salt in the Wound
Too much salt not only drives up our blood pressure, but also the amount of inflammation in the body. It’s not easy to monitor people’s food intake over the long term to study the effect—unless, of course, you lock them in a space capsule. Mars500 was a 520-day spaceflight simulation designed to see how people would fare on the trip to Mars and back. For several months at a time, the crew was given differing amounts of salt, and the results clearly showed that a little less salt leads to a reduction in inflammation. This has implications for inflammatory diseases such as asthma, multiple sclerosis, psoriasis, lupus, and arthritis. For more details, see my video see.nf/saltinflammation.
Anti-inflammatory Foods
On the Dietary Inflammatory Index, the spice turmeric is the most strongly anti-inflammatory food, followed by ginger and garlic, and tea, green or black, is the most anti-inflammatory beverage. When it comes to the most powerful anti-inflammatory components, fiber and flavones are at the top. Fiber, found in all unprocessed plant foods, is most concentrated in whole grains and legumes such as chickpeas, beans, lentils, and yellow peas. Flavones are plant components found in concentrated form in fruits, herbs, and vegetables, and in the American diet, apples, oranges, parsley, celery, and bell peppers are the leading sources; among beverages, it is chamomile tea.
Fiber Tames the Monster
Why is fiber so anti-inflammatory, and how does it work? You can see the whole story at see.nf/fiber, but essentially we feed our good gut bacteria with prebiotics such as fiber, and in return they supply us with short-chain fatty acids such as butyrate, the primary food source of the cells that line the colon. The good gut bacteria feed us and keep us healthy because they’ve made themselves at home inside us. The gut is warm and moist, and food comes down from above as if by magic. If we die, all that is gone. If we’re dead, they’re dead too, so it is in their own evolutionary interest to keep us happy. But there are also bad bacteria like cholera that cause diarrhea. They pursue a different strategy: The sicker they make us, the more explosive the diarrhea, for example, the better their chances of jumping to other people and getting into other colons. They don’t care if we die, because they don’t plan on going down with us.
So how does the body manage to keep the good bacteria and get rid of the bad? Think about how tricky that is. We literally have trillions of bacteria in the gut, so our immune system must constantly balance letting the good bacteria be and fighting the bad ones. Shouldn’t the good bacteria have a way to signal to the immune system that they’re the good guys? They do. Researchers found that butyrate suppresses the inflammatory response and tells the immune system to hold back: “The good guys are on board; everything is fine.” (This does not apply to fiber supplements like Metamucil, which don’t ferment and therefore are not edible for our good bacteria.)
And we’re not talking only about gut inflammation. If you eat whole-grain barley in the evening, your good gut bacteria get it for breakfast the next morning and release butyrate into the bloodstream to carry out widespread anti-inflammatory actions throughout the body. Thus, people who eat a high-fiber diet likely get fewer inflammatory ailments, from knee pain and osteoarthritis to pneumonia and respiratory diseases such as COPD (chronic obstructive pulmonary disease). And most importantly: Those who eat more fiber live longer.
All in One
An analysis of ten studies encompassing, in total, data from more than ten million person-years found that higher fiber intake is associated with a 15 percent lower risk of premature death than eating only a small amount of fiber.
But since fiber is found in the healthiest foods in the world—fruits, vegetables, whole grains, beans, and nuts—how do we know that fiber intake isn’t simply an indicator of a healthy diet in general, and that long life isn’t just the product of the countless other beneficial substances in whole plant foods? You may recall that we faced a similar dilemma when we tried to pin down the benefits of foods with a low glycemic load. The solution was provided by acarbose, a starch-blocking drug that slows carbohydrate digestion.
Fiber is simply an indigestible chain of carbohydrates, so acarbose can convert some of the normal starch we eat into fiber. And indeed, those taking acarbose had more starch in their stool, an abundant food supply for our good gut bacteria. That’s why acarbose can increase the amounts of good bacteria such as Bifidobacterium, Lactobacillus, and Prevotella. That means more anti-inflammatory butyrate gets into the blood, and it also gives scientists a tool to investigate the link between fiber, inflammation, and life expectancy.
Just as you can give rats longer lives by feeding them fiber, you can make mice live longer by not changing their diet but giving them acarbose. How do we know the life extension isn’t just an effect of blood sugar? Because the greater life expectancy correlates with the butyrate concentration in the feces. A stool sample taken several months before death (a span corresponding to several human years) could predict the mouse’s likely life expectancy. How can we replicate the effect of acarbose without taking a drug?
Switching from refined grains to whole grains delivers more fiber to the colon, but the next step, switching to intact grains (cracked), would not only give us more fiber but also load us up with a whole lot of starch. To find out how finely ground grain can starve our internal microbial landscape, see my video see.nf/intact. Researchers found that subjects given the same amount of the same food produced twice as much stool when they ate intact grain rather than ground. Our stool is not primarily undigested food. Most of it—about 75 percent—is pure bacteria, more than a trillion per teaspoon. No matter how well we chew unprocessed plant foods, when we eat the way nature intended, we send lots of starch and other prebiotic nutrients down to the good bacteria, which flourish and multiply. Short-chain fatty acid production is revved up, and we get to enjoy all the anti-inflammatory benefits of butyrate.
Aging to 100 on Anti-Inflammaging
Since inflammation plays a crucial role in aging, wouldn’t you expect centenarians to have somehow escaped inflammaging? But that’s not the case. As is logical in advanced age, people over 100 have large amounts of pro-inflammatory substances in their blood. So what is special about them? The counterbalance of just as many anti-inflammatory substances in the blood. This response is called anti-inflammaging. “If inflammaging is key to understanding the aging process,” explained an Italian research team, “then anti-inflammaging could be one of the secrets of longevity.”