Name any common disease associated with aging — cancer, dementia, heart disease, metabolic syndrome, nonalcoholic fatty liver disease, type 2 diabetes — and chronic inflammation will play a role.
In a way, chronic inflammation is like too much of a good thing. After all, something such as your finger swelling around a cut means that immune cells are doing their job, rushing to the scene and spewing out inflammatory compounds that kill bacteria and prevent infection.
But chronic low-grade inflammation that persists for weeks, months or years is the disease-triggering variety. Again, it's your immune cells in action. But instead of fighting foreign bacteria, they silently attack your own body — your blood vessels, brain cells and organs included.
It's not entirely clear why this happens, though stress is known to raise levels of inflammatory compounds in the body — as does obesity, since fat cells parked deep in the belly emit inflammatory compounds when they reach a critical mass. Genetics is known to influence your susceptibility to inflammation.
But diet plays a very big role, too, — specifically, eating too much white flour, sugar and fried foods, and not enough fruit, vegetables and fish.
But if diet can cause inflammation, it can also make a real difference in fighting it.
For instance, closely following a Mediterranean-style diet was shown to reduce the odds of developing Alzheimer's disease by 34 to 61 percent in one meta-analysis of 12 specific Mediterranean diet studies by researchers at Brown University's Warren Alpert Medical School. Big declines in the rate of heart disease have also been seen in programs combining a similar diet with smoking cessation.
Below are foods that will rally to your defense; to work, they should form the base of your diet, which, yes, should look quite a bit like the traditional Mediterranean diet in order to get the most inflammation-busting benefit.
Fruits and vegetables
How they fight for you: Their arsenal of vitamins, minerals and thousands of phytonutrients (beneficial plant compounds) prevent and attack chronic inflammation on many fronts. Some, like the carotenoids that give carrots and tomatoes their hues, act as antioxidants, which keep potentially destructive molecules called “oxidants” in check. That's critical to our well-being because, in excess, oxidants destroy cells, give rise to chronic inflammation and in other ways put us at risk for heart disease, cancer and other killers. Other phytonutrients, like the anthocyanins in blueberries, work more directly — putting the brakes on the production of inflammatory compounds, including those produced in the brain.
And there's more! Fiber in produce becomes a feast for bacteria in your gut, which return the favor by producing anti-inflammatory substances. And by helping keep your weight down, fruits and vegetables help you skirt obesity-induced inflammation.
What to eat: All fruits and vegetables fight inflammation in some way. The following reliably pop up as protective in large-scale diet surveys: apples, berries, citrus fruit, pears, green leafy vegetables/salads, green/yellow vegetables (such as green beans and yellow peppers), cruciferous vegetables (like broccoli and cabbage) and tomatoes.
While many health organizations recommend five half-cup servings daily, some research studies suggest double that amount offers the most benefits.
And get this: Building on research showing that blueberries improve a rat's memory, researchers gave men and women ages 60 to 75 an ounce of freeze-dried blueberries per day (equivalent to one cup of fresh) to add to their usual diet. Another group got a blueberry-colored placebo. Three months later, blueberry eaters performed significantly better on tests of memory and other types of thinking. The small study was done at the Jean Mayer USDA Human Nutrition Research Center on Aging and published in 2017.
Skimping on fruits and vegetables may have caused 5.6 million to 7.8 million premature deaths worldwide in 2013, according to a meta-analysis of 95 separate studies that was reported in a 2016 issue of the International Journal of Epidemiology.
Herbs and spices
How they fight for you: Like fruits and vegetables, they're rich in vitamins, minerals and phytonutrients. For example, rosmarinic acid — found in rosemary, thyme and other herbs — is both an antioxidant and an anti-inflammatory.
What to eat: They all can be protective. Just to name a few: herbs such as basil, dill, oregano, parsley, rosemary, sage, tarragon and thyme, and spices such as black pepper, cinnamon, cumin, garlic, hot peppers, star anise and turmeric.
Without official guidelines on portions, just use them generously when making salads, dips, curries, stews, baked fish and chicken, and other dishes.
And get this: Oregano and rosemary reduce inflammation in lab animal studies. For example, in a University of Lisbon, Portugal, study, rats ingesting rosmarinic acid had 60 percent less swelling in their paws (in reaction to an irritant) than rats not receiving the supplement.
Compared with taking a placebo, ingesting 3 grams of ginger powder in capsule form for an eight-week period reduced fasting blood sugar levels by a significant 10 percent for 40 men and women with type 2 diabetes.
The study, reported in 2014 in Complementary Therapies in Medicine, found that ginger appears to improve the body's sensitivity to the insulin, which, in turn, leads to better blood sugar control. One proposed mechanism: It suppresses inflammatory compounds emitted by fat cells; these can make the body less responsive to insulin.
Extra-virgin olive oil
How it fights for you: A staple of the healthy Mediterranean diet, extra-virgin olive oil (EVOO) was considered medicinal as far back as ancient Greece. While more than 200 compounds have been teased out of extra-virgin and virgin olive oil, it's their anti-inflammatory phenolic compounds that appear to offer up the most potent health benefits.
What to eat: Buy extra-virgin olive oil that is pungent, even a little bitter, with that back-of-throat burn. That's how you know you're getting polyphenols.
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While there are no U.S. guidelines on intake, the European Food Safety Authority recommends 20 grams (1 1/2 tablespoons) daily.
And get this: To examine the health effects of a Mediterranean diet on cardiovascular disease, nearly 6,000 participants were assigned to either a Mediterranean diet that included 4 tablespoons of extra-virgin olive oil daily, a Mediterranean diet with a daily serving of an ounce of nuts, or a low-fat control diet. Heart disease dropped dramatically in both Mediterranean diet groups — by 30 percent, compared with the control group on a low-fat diet.
Nuts and seeds
How they fight for you: Nuts (such as almonds, cashews and peanuts) and seeds (such as flax, pumpkin, sesame and sunflower) are rich in healthy fats and contain a bevy of antioxidants, which indirectly fight inflammation. Nuts help reduce LDL ("bad") cholesterol, which is prone to free radical attack and inflammation. Nut eaters tend to weigh less than people who don't eat nuts, probably because nuts and seeds are particularly satiating. Less body fat helps stave off inflammation.
What to eat: All nuts and seeds are healthy. Walnuts contain ALA — the plant form of omega-3 fats, which is anti-inflammatory. Walnuts, as well as pecans and baru nuts (a new import from South America) are particularly rich in antioxidants. There are no official U.S. guidelines for nut consumption, but research studies show heart and other health benefits at 1 to 1 1/2 ounces daily.
And get this: Nut eaters have better heart health than people who don't eat nuts, concluded a 2018 review of the research by Loma Linda University scientists. They noted that that people who eat about 1 3/4 ounces of nuts daily show reduced levels of C-reactive protein, a marker of inflammation.
People who eat more nuts tend to weigh less, have smaller waistlines and are less likely to develop heart disease or metabolic syndrome (a cluster of risk factors such as high blood sugar, high blood pressure and excess fat deep in the abdomen, which raises risk for type 2 diabetes and heart disease).
Test tube studies show that sesamin, a phytonutrient in sesame seeds, is a potent cancer-fighter, thanks in part to its anti-inflammatory abilities.
Seafood and omega-3s
How they fight for you: Fish are the highest food source of two types of omega-3s: EPA and DHA. The American diet is woefully low in these fats, which not only prevent the formation of inflammatory compounds but also help destroy them. While scientists can't say for sure why fish eaters tend to be healthier, omega-3s get at least some of the credit.
What to eat: Follow the American Heart Association's recommendation to have at least two 3.5-ounce (cooked) servings of fish weekly. Your best bets are high in omega-3s but low in mercury: Arctic char, mackerel (Atlantic), rainbow trout, salmon and sardines.
And get this: Large-scale nutrition surveys find that fish eaters have a lower risk of developing heart disease, dementia and depression. Some, but not all, studies detected lower levels of inflammatory compounds in their blood.
One well-known Italian study that tracked more than 20,000 men and women age 35-plus for four years found that people who ate fatty fish at least four times a week were 40 percent less likely to develop heart disease. Fatty fish was particularly protective.
Averaging just 1.76 ounces of fish daily was linked to a 16 percent lower likelihood of having depression, according to a 2016 meta-analysis of 16 studies.
How they fight for you: Whole grains have all three components intact: the outer bran layer, the middle starchy endosperm and the little germ filled with vitamins and healthy fats. Refining gets rid of the most nutritious parts — the bran and germ — which offer a wealth of antioxidants. Whole grain's fiber is fuel for our gut bacteria, which in turn produce anti-inflammatory substances.
What to eat: Brown rice, barley, bulgur wheat, millet and whole rye are all healthy — as are many other whole grains. (Buckwheat and quinoa, while technically not grains, are nutritionally close enough.) A serving of whole grain is about a half cup of cooked grains (such as brown rice, oatmeal, quinoa), a slice of bread or about half a cup to three-quarters of a cup of a flaky whole-grain cereal. While the Dietary Guidelines for Americans recommend that half your grains should be whole, other research indicates that an even higher proportion is better.
And get this: Compared with those who eat the least amount of whole grains, people who eat the most cut their risk of heart disease (by 21 percent), cancer (by 11 percent) and death (by 18 percent) over the course of the study period, according to a meta-analysis of 45 studies by researchers at Norwegian University of Science and Technology and other institutions.
In a separate study from Denmark, 50 overweight or obese men and women ate diets either rich in whole grains or devoid of them for eight weeks. Whole-grain eaters lost a little weight, and blood tests showed reduced levels of inflammation.
How they fight for you: Legumes are rich in B vitamins, minerals and fiber. And like fruits and vegetables, they're rich in phytonutrients, which act as antioxidants. Soy foods are particularly high in isoflavones, which have anti-inflammatory effects.
What to eat: All legumes are nutritious — black beans, chickpeas (garbanzo), kidney beans, lentils and the others. The latest edition of the Dietary Guidelines for Americans suggests eating 1 1/2 cups per week, although more is certainly healthy.
And get this: Eating legumes can help reduce the risk of heart disease, type 2 diabetes, obesity and certain types of cancer, and doing so can also help to quell appetite, according to a review of the research by scientists at the University of Leeds, in the U.K., and other institutions.
A study that tracked 785 men and women age 70 and up for seven years — in four countries — found that of all the foods studied, legumes were most closely linked to longevity. Every 20 grams (about 2 tablespoons) of legumes eaten corresponded to an 8 percent reduced risk of death during the study period.
Coffee, tea, dark chocolate
How they fight for you: Like fruits, vegetables and other healthy plant foods, coffee tea and cocoa beans (the basis of chocolate) are rich in phytonutrients.
Just to name a few: Dark chocolate and tea are particularly rich in flavanols, while coffee is high in chlorogenic acid and diterpenes. All three contain caffeine, which appears to offer anti-inflammatory benefits for your brain. (Although in excess, it can make you jittery, induce heartburn and mess with your sleep!) Coffee has the most caffeine, followed by black tea, then green tea, which has about as much caffeine as an ounce of dark chocolate (70 to 85 percent cocoa).
What to eat (or drink): While major health authorities have not weighed in on ideal amounts, some research studies indicate that the following may offer protection.
- Coffee: 1 to 3 cups (or espresso cups) of brewed coffee daily, ideally unfiltered (such as French press or espresso) as to not lose beneficial compounds.
- Tea: White (unfermented), green (lightly fermented), oolong (medium fermentation) or black (fermented) are all beneficial. Studies vary in their recommended doses, but 1 to 5 cups seem to impart benefits.
- Chocolate: In general, the darker the chocolate (70 percent or higher), the healthier — you get less sugar and more flavanols. However, the cocoa bean growing region and the way chocolate is processed has a big impact on flavanols. A Consumer Lab analysis found that some dark chocolates have four times the flavanols as others. About an ounce a day of dark chocolate is probably the sweet spot — not too high in calories, and, hopefully, rich in flavanols.
And get this: Compared with abstainers, coffee drinkers were 15 percent less likely to die over the course of three large studies. These Harvard University studies tracked about 208,000 men and women for 21 to 28 years, recording diet and health outcomes. Drinking coffee appeared to help ward off killer diseases such as heart disease, a number of cancer types, neurological disorders such as Parkinson's, and it was also linked to a lower risk of suicide. Both regular and decaffeinated coffee appear to be protective. These findings mesh with other similar epidemiological research.
Tea drinkers tend to have a lower risk of heart disease. Why? A study by reseachers at Ochanomizu University in Tokyo, Japan, of 19 healthy men might help explain. An hour after taking a green tea supplement in pill form, their LDL ("bad") cholesterol was significantly less prone to oxidation than before taking the capsule (or compared with when they returned to the lab and took a placebo). Oxidized LDL becomes inflamed and can lead to artery-clogging plaque — a major cause of heart disease and stroke.
Cocoa flavanols can relax arteries, improving blood flow to the heart and brain. They also can protect arteries from free radical damage and inflammation. That may be why some studies indicate that people who eat chocolate have a lower risk of heart disease and stroke.
Chocolate may also make us smarter, according to a Columbia University research study of 37 men and women in their 50s and 60s. Half of them added to their daily diet a daily chocolate drink that was high in cocoa flavanols, while the other group added a flavanol-poor chocolate beverage. Three months later, the high flavanol group's scores on memory tests were equivalent to those of people 30 years younger. Brain scans showed improved blood flow to a region of the hippocampus — a part of the brain involved in memory.