A study of 4125 patients, 65 years or older, followed for an average of almost 11 years, found that higher total fiber intake from grains, fruits and vegetables was associated with lower inflammation rates (JAMA Netw Open, 2022;5(3):e225012). The reduction in markers of inflammation improved even more in patients who ate an additional five grams per day of fiber from grains. This improvement in markers of inflammation was not seen in those who ate more fiber in vegetables or in fruits.

Many previous studies show that a high-fiber diet is associated with lower markers of inflammation (Am J Clin Nutr, 2006;83(4):760-766; Kidney Int, 2012;81(3):300-306; Diabetes Care, 2006;29(2):207-211; Int J Food Sci Nutr, 2015;66(1):114-119). Inflammation is associated with an increased risk of various diseases, including heart attacks and cancers (Eur Heart J, 2019;40(48):3901-3909), chronic kidney disease (Kidney Int, 2012;81(3):300-306), diabetes (Diabetes Care, 2006;29(2):207-211), and obesity (Int J Food Sci Nutr, 2015;66(1):114-119).

What is Inflammation?
Your immune system is supposed to protect you. When you get an infection, your immune system produces white blood cells and chemicals that attack and kill germs. When you injure yourself, your immune system produces exactly the same white blood cells and chemicals and uses them to heal damaged tissue. As soon as your tissue is healed or the infection is gone, your immune system is supposed to dampen down. However, if your immune system stays active all the time, it can attack your healthy tissue in the same way that it attacks invading germs or injuries. This is called inflammation.

Many studies show that inflammation (an overactive immune system) can lead to clots that cause heart attacks and strokes. Heart attacks are not caused by narrowed arteries; they are caused by a plaque breaking off from an artery, followed by bleeding and clotting. Then the clot extends to completely block blood flow to a part of the heart muscle. Inflammation, which is supposed to punch holes in the membranes of attacking germs, also punches holes in the inner linings of arteries to cause plaques to form and then knocks off plaques to cause the bleeding and clotting that leads to a heart attack. Inflammation can also attack the DNA in cells to cause uncontrolled growth, which is cancer (Ann Afr Med, Jul-Sept, 2019;18(3):121-126).

How Does Fiber Reduce Inflammation?
More than 38 trillion bacteria live in your colon and they affect your immune system in ways that are both helpful and harmful. The helpful bacteria stay inside the colon and do not try to penetrate its lining, but the harmful types of bacteria try to invade the cells on the inner lining of your colon.

Studies on gut bacteria help to explain why fiber-rich foods are beneficial. Researchers at Georgia State University and the University of Gothenburg in Sweden showed that a low-fiber diet decreased the mucus lining the inner colon in mice, which allowed the bad bacteria to enter cells lining the inner colon (Cell Host & Microbe, December 21, 2017 ). The types of bacteria in their colons changed significantly, they developed signs of chronic inflammation, they lost much of their ability to respond to insulin, their blood sugar rose and they got fatter. Conversely, feeding the mice a high-fiber diet increased the mucus layer to push bacteria away from the cell walls and reduce inflammation.

Fiber Nourishes the Good Gut Bacteria
Fiber passes unabsorbed through your upper intestines to your colon. In your colon, bacteria eat fiber to form short-chain fatty acids (SCFAs) that can pass into the bloodstream to reduce inflammation (Nature, 2016 Jan 14; 529(7585): 212-215). SCFAs help to prevent heart attacks because they are absorbed into your bloodstream and pass to your liver to lower blood levels of the bad LDL cholesterol and to lower high blood pressure. They also reduce inflammation because they build up the mucus layer that prevents bad bacteria from getting into the cells lining your inner colon. The good bacteria increase in number when you eat plenty of fiber-rich foods, and this reduces the number of bad bacteria because they have difficulty passing through the mucus to get their food from the cells lining your inner colon. Adding extra fiber to the diet also helps people to lose weight and lowers blood levels of sugar and insulin (Am J Of Clinical Nutrition, Nov 1, 2017).

Other Lifestyle Changes to Reduce Inflammation
• Exercise: Exercising muscles help to control after-meal blood sugar rises that damage tissues to cause inflammation. An extensive review of studies showed that exercise can reduce inflammation even more than statins do (Clin Chim Acta, Jun 3, 2010;411(0):785-793).
• Weight Loss: Excess fat, particularly in your liver, causes inflammation, and having markers of inflammation can predict future weight gain (Diabetes, 2003 Aug; 52(8): 2097-2101). Apparently healthy people who have elevated blood markers of inflammation are at high risk for developing insulin resistance and diabetes (Circulation, Jul 4, 2000;102(1):42-7) and gaining fat that, by itself, increases inflammation (J Clin Invest, 2005;115(5):1111-1119). I recommend intermittent fasting for weight loss and weight control.
• Avoid Toxins: Toxic substances damage cells to cause inflammation, so you should avoid or limit as much as possible your exposure to smoke, alcohol, recreational drugs or unnecessary prescription drugs, industrial chemicals, pollutants and so forth.
• Treat Chronic Infections: Having any chronic infection turns on your immune system to cause inflammation (J Clin Invest, May 2, 2005;115(5):1111-1119), so identifying and treating chronic infections should be part of an anti-inflammatory lifestyle.

The anti-inflammatory lifestyle recommended here will help to protect you from heart attacks, strokes, diabetes, auto-immune diseases and the many other debilitating conditions that are linked to inflammation. See Anti-Inflammatory Lifestyle to Treat Many Diseases

My Recommendations
What you eat is a major determinant of whether you suffer from inflammation that can shorten your life by increasing risk for heart attacks, strokes and some types of cancers. Eating lots of fiber in plants helps to reduce inflammation. Grains are a major source of this protective soluble fiber (wheat, oats, rice, corn, barley, quinoa and so forth). Increasing the amount of grains in your diet may also help you by reducing the proportion of pro-inflammatory foods that you eat, such as meat from mammals, processed meats, sugar-added foods and fried foods.