Chapter 30
Plant Yourself
The potentially strongest anti-inflammatory signaling molecule in the blood is interleukin 10 (IL-10). Is there a way to help boost its levels? Eat more fiber. Butyrate boosts IL-10 secretion “massively,” so increasing the amount of IL-10 in the blood is easy: You just need to swap refined grains for whole grains. It was found that a type of fiber called beta-glucan, found in brewer’s, baker’s, and nutritional yeast, increases IL-10. Two tablespoons of nutritional yeast daily triple IL-10 levels within four weeks. If, however, you have Crohn’s disease or the skin condition hidradenitis suppurativa, I urge caution with taking nutritional yeast because of a potential immune reaction (for details see see.nf/crohns).
After three decades of research on more than 1000 centenarians, scientists found the common denominator of a “pro-vegetarian diet, rich in vegetables and legumes.” Part of the centenarians’ successful aging could come from the anti-inflammatory boost from all that fiber, but they also ate only “relatively little meat and animal fats,” so it’s hard to isolate the decisive factors.
Plant Yourself
Saturated fats are at the very top of the list of pro-inflammatory dietary components, and fiber is the single strongest anti-inflammatory component, so an anti-inflammatory diet primarily means whole plant foods. For details go to see.nf/plantshift, but in principle dozens of intervention studies, testing different dietary patterns in thousands of people, showed that more plant-based eating more effectively lowers markers of systemic inflammation like C-reactive protein.
A completely plant-based diet causes CRP levels to drop by 30 to 40 percent in both adults and children within just a few weeks, but it doesn’t have to be all-or-nothing. Simply eating beans, yellow split peas, chickpeas, or lentils a few times a week instead of meat can drop CRP, IL-6, and TNF-α by about a third in two months. Or you can add plant foods on top of your normal diet. The so-called five a day, however, isn’t enough. Five servings of fruits and vegetables a day appear to do nothing, but at eight servings a day, CRP levels drop substantially compared to people who eat roughly like the American average, namely a modest two servings of fruits and vegetables a day. That’s why I recommend at least nine servings in my Daily Dozen.
Of course, not all plant foods work against inflammation. If you just ate more vegan junk food—for example, white bread, soda, and cake—your inflammation levels could go up. Are there particularly powerful plants?
What about fish?
First and foremost, an anti-inflammatory diet in clinical practice “focuses on the consumption of whole, plant-based foods.” But just as not all foods of plant origin are anti-inflammatory, not all animal foods are necessarily pro-inflammatory either. The omega-3 fatty acids in fish, for example, score as an anti-inflammatory component in the Dietary Inflammatory Index, though they seem to help only people with chronic diseases. When healthy people were given fish-oil supplements for weeks or months—equivalent to about a serving of salmon, a can of tuna, or ten tilapia fillets daily—their inflammation levels did not drop.
Eating fish itself does not appear to affect inflammation levels or reduce mortality from inflammatory diseases—in contrast to plant omega-3 sources like nuts. Maybe the benefit of omega-3 is being canceled out by the industrial toxins that now burden a large part of the ocean food chain. That could also explain the association found in the Harvard Nurses’ Health Study between consuming seafood not considered dark meat (such as canned tuna, shrimp, scallops, and lobster) and higher blood inflammation levels.
Berries Against Inflammation
One study followed 10 000 Norwegian men for over 40 years and found that those who ate berries more than 14 times a month had a significantly higher likelihood of still being alive at the end of the study. Higher intake of anthocyanins—the vividly colorful pigments in berries—is associated with anti-inflammatory effects, but to prove cause and effect you need intervention studies. In my video see.nf/berryinflammation I review dozens of such studies and show that common berries like blueberries and strawberries can substantially lower inflammation levels.
This isn’t just an effect of antioxidants. Free radicals can distort proteins in our body so badly that they are no longer recognizable to the immune system and the body attacks them as invaders. We can mitigate this inflammatory autoimmune reaction by supplying our body with enough antioxidants. Fruits and vegetables high in antioxidants like berries and leafy greens reduce systemic inflammation significantly better than the same amount of more common fruits and vegetables with lower antioxidant content like bananas and iceberg lettuce. Yet antioxidant vitamins and minerals such as vitamins C and E, beta-carotene, and selenium were found to offer no anti-inflammatory benefit, bringing us back to the bright red, blue, and purple plant pigments: the anthocyanins.
Dozens of randomized controlled trials of anthocyanin-rich supplements (mostly berry extracts) revealed their anti-inflammatory effect. Presumably that’s why red-fleshed plums beat yellow-fleshed apricots when it came to reducing CRP levels in the blood, and even extremely healthy fruits like mangoes were powerless against the inflammation from a fatty meat meal, while taken together, half a dozen studies showed that pomegranates—fruits stuffed to bursting with ruby-red anthocyanins—can dial down inflammation over time.
The anti-inflammatory effect of berries is so strong that you can actually feel it if you make the effort. The bioflavonoids in citrus fruit can help with muscle fatigue during a hard workout (see.nf/citrus), but the anthocyanins in berries can help you with post-exercise inflammation. Muscle biopsies confirm that eating berries can significantly reduce exercise-induced inflammation, and you recover faster. For details see see.nf/soreness. Antioxidants as supplements, however, don’t seem to help. Men who took vitamin C and did arm curls actually had more muscle damage and oxidative stress.
Optimizing recovery after a workout is considered the “Holy Grail of sports science,” but what about measurable effects on inflammatory diseases of aging, such as arthritis? Tart cherries are successfully used in the treatment of gout. Delicious food is more than welcome as a treatment, since some gout drugs cost $2000 per dose, have no clear line between nontoxic, toxic, and lethal dosages, and can have the rare side effect of causing the skin to peel off the body. (The best way to deal with gout is still not to get it in the first place, by drinking less alcohol and eating a plant-forward diet.) As I show in detail in see.nf/berryinflammation, the most common joint disease, knee osteoarthritis, can also be eased with a berry treatment.
Down with CRP
Given the known anti-inflammatory effects of plant foods and their components, it’s no surprise that more than 20 pooled studies show that people who eat more plant-based have lower CRP levels—especially those who eat exclusively plant-based. This has been confirmed by two dozen intervention studies that found randomized assignment to plant-based diets reduces systemic inflammation after months or even weeks. However, people can lose so much weight on plant-based diets that part of the inflammation drop could be indirect. But even after accounting for weight, those randomized to eat entirely plant-based saw CRP fall by 33 percent within eight weeks, compared with participants who, following American Heart Association recommendations, ate more fruits and vegetables but also low-fat animal products like skinless chicken breast, skim milk, and egg whites.