Many types of arthritis are believed to be caused by inflammation, where a person’s own immune system attacks and damages joints and other tissues in the body. An anti-inflammatory diet may help to control arthritis (Cells, 2020;9(4):827) as well as giving its well-established benefit of helping to prevent heart attacks (Nutr J, 2021;20(1):9). Mediterranean-type (plant based) diets have been shown to reduce symptoms in rheumatoid arthritis (Autoimmun Rev, 2018;17(11):1105-1114; Front Nutr, 2019;6:141).

What is inflammation?
When germs try to enter your cells, your immune system produces certain cells, antibodies and cytokine chemicals that attack and kill them. As soon as the germs are gone, your immune system is supposed to dampen down and stop making large amounts of these cells, antibodies and chemicals. If your immune system does not stop making excessive amounts of cells and proteins to kill germs, these same cells and proteins can attack you to cause “auto-immune” diseases such as rheumatoid arthritis, lupus, dermatomyositis or scleroderma. Your overactive immune system can also attack other organ systems to cause heart attacks, cancers, strokes, diabetes and many other diseases.

Harmful Colon Bacteria Can Cause Inflammation
About 40 trillion bacteria live in your colon (PLoS Biol, Aug 19, 2016;14(8):e1002533). Of the more than 1000 different types of bacteria that live in there, some are good for you while others can be harmful (Nature, 2014 Jan 23; 505(7484): 559–563). The healthful bacteria are content to eat what you eat, so they stay in your colon and do not try to cross into your cells and bloodstream. Healthful colon bacteria can form metabolites, such as short chain fatty acids (SCFAs), that help to prevent arthritis, obesity, diabetes, and heart attacks. On the other hand, the harmful bacteria are not happy with your food supply so they try to find food somewhere else by invading the cells lining your colon. The damage caused by invading colon bacteria turns on your immune system to cause inflammation (PLoS One , Apr 13, 2017:12(4):e0176062).

How to Follow an Anti-Inflammatory Diet
The best way to grow healthful bacteria in your colon is to follow an anti-inflammatory diet, which means eating primarily anti-inflammatory foods and avoiding pro-inflammatory foods.
• Eat lots of fruits, vegetables, whole grains, beans, nuts and other seeds. They are high in fiber that fosters healthful colon bacteria (Food Funct, Apr 2016;7(4):1788-96).
• Restrict meat from mammals (J Transl Med, Apr 8, 2017; 15: 73) and processed meats.
• Restrict refined carbohydrates (Diabetes Metab Syndr Obes, 2012;5:175-89).
• Restrict fried foods (Amer Journal Clin Nutr, Aug 2014;100(2):667–675).
• There is growing evidence that artificial sweeteners may stimulate the growth of unhealthful colon bacteria (Nutrition Today, May 6, 2021;56(3):105-113), so I recommend limiting or avoiding them.

Other Lifestyle Habits That Increase Inflammation
For most people, correcting a faulty diet is the most important lifestyle change to reduce inflammation, but other unhealthful lifestyle habits can also promote chronic inflammation. Scientists have not worked out all of the mechanisms, but it appears that any infection, anything that damages cells in your body, or anything that promotes high blood sugar levels can cause inflammation, such as:
• smoking
• drinking too much alcohol
• being overweight
• lack of exercise
• vitamin D deficiency

Other sources of chronic inflammation include:
• exposure to X rays and other radiation, including excessive sunlight
• exposure to harmful chemicals such as certain insecticides, herbicides or industrial chemicals
• a chronic infection anywhere in the body

The Importance of Maintaining a Healthful Weight
Obesity is associated with increased joint damage in rheumatoid arthritis (RMD Open, 2017;3(2):e000458), and probably in other types of arthritis as well. Several studies show that obesity may be caused by unhealthful colon bacteria (Postgrad Med J, May 2016;92(1087):286-300). A study of twins of which one was fat and the other was skinny showed that transferring the colon bacteria from the fat twin to mice made mice fat, while colon bacteria from the skinny twin did not fatten the mice (Science, 2013 Sep 6; 341(6150):10.1126). Overweight people may have colon bacteria that specifically help them to absorb more calories and form more fat in their bodies (Nature, 2006;444:1027–1031).

My Recommendations for an Anti-Inflammatory Lifestyle
Rheumatoid arthritis and many other types of arthritis are worsened by an overactive immune system and improved by reducing the inflammation it causes. If you already have any form of arthritis or would like to reduce your risk for suffering joint pains in the future, I recommend following an anti-inflammatory diet and eliminating all of the known sources of inflammation that you can control with your lifestyle. You will also be helping to protect yourself from heart attacks, strokes, diabetes, and the many other debilitating diseases and conditions that are linked to inflammation.