Pro-Inflammatory Diet Linked to Increased Risk for Dementia


The American Heart Association reports that dementia is strongly associated with a pro-inflammatory diet (Stroke, Mar 15, 2021:52(6A);52:e295–e308). Dementia means loss of brain function, and your chance of having dementia increases as you age. A new study from Greece found that people who eat a pro-inflammatory diet are far more likely to suffer from dementia, compared to those eating an anti-inflammatory diet (Neurology, Nov 10, 2021;10.1212). This study is especially important because it analyzed the entire diet and classified 45 different groups of foods into:
• pro-inflammatory foods that raise blood markers of inflammation, and
• anti-inflammatory foods that lower these same blood markers.

The authors divided 1059 non-demented people, average age 73, into three groups based on high, medium and low-inflammatory diet scores. Each week for three years, the people with the best anti-inflammatory scores had eaten an average of:
• 20 servings of fruit
• 19 servings of vegetables
• 4 servings of beans or other legumes
Those with the worst scores had eaten an average of:
• 9 servings of fruit
• 10 servings of vegetables
• 2 servings of legumes
At the end of the three-year study period, 62 of the participants had become demented. Those with the worst inflammatory diet scores were 3.5 times more likely to become demented than those with the best scores.

What Makes a Diet Pro-Inflammatory or Anti-Inflammatory?
Chronic inflammation increases risk for heart disease, diabetes, Alzheimer’s disease, certain cancers, and many other diseases. The more pro-inflammatory foods you eat, the greater your risk for these conditions. The more anti-inflammatory foods you eat, the greater your protection from chronic inflammation and the diseases it causes.

Many previous scientific papers have associated risk for dementia with what you eat. Examples of anti-inflammatory diets include the MIND diet, the DASH diet or Mediterranean-style diets which are based on:
• eating anti-inflammatory foods such as fruits, vegetables, fermented foods, whole unground grains, beans, nuts and other seeds
• restricting pro-inflammatory foods such as red meat and processed meats, non-fermented dairy products, fried foods, sugar-added foods, and all drinks with sugar in them including fruit juices.

How Your Immune System Protects You
You have no germs in your body before you are born, but soon after birth, bacteria start to grow everywhere on your skin surface, in your respiratory tract and in your entire digestive tract. Most of these germs are good for you and help in many different ways. They help you to digest and absorb nutrients from the food that you eat, and to eliminate waste products. They colonize the linings of your respiratory tract and intestines to help keep harmful germs from growing there.

Germs are not supposed to get into your bloodstream. However, when germs invade your bloodstream through breaks in your skin, intestinal tract or respiratory tract, your immune system recognizes that the germs’ sugar-proteins are different from the sugar-proteins on your own cells. Your immune system produces proteins called antibodies that attach to and try to kill the invading bacteria or virus, cells that literally eat the invading germs, and cytokines that marshal your entire immune system to destroy harmful germs that are trying to invade your body. The visible signs of inflammation — redness, swelling, tenderness or soreness, fever — tell you that your immune system is working to combat an infection.

Wben Inflammation Causes Problems
Your body’s immune system helps to protect you from harmful invading germs and to heal injuries. As soon as the wound is healed or the germ is gone, your immune system is supposed to dampen down and stop making large amounts of these cells and antibodies. 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 damage:
• your brain to cause dementia,
• your arteries to cause plaques to form and break off to cause heart attacks and strokes,
• your DNA in cells to block apoptosis that can lead to cancer,
• your liver to cause diabetes, and
• your own immune system itself, leading to auto-immune diseases such as rheumatoid arthritis.

Pro-Inflammatory or Anti-Inflammatory Foods
You have more than 100 trillion bacteria living in your colon, and what you eat determines the proportions of good and bad bacteria. The good bacteria are happy to eat the same food that you eat, while the bad bacteria are not happy with your food supply and try to enter your colon cells. This turns on your immune system and keeps it on to cause excessive inflammation. What you eat and other lifestyle factors determine which types of bacteria grow in your colon.

A diet rich in soluble fiber found in most plants helps to reduce the growth of harmful bacteria (JAMA Oncol, 2017 Jul 1;3(7):921-927). Lack of fruits and vegetables can cause inflammation by encouraging the growth of harmful bacteria. You cannot absorb soluble fiber from plants in your upper intestinal tract, so they pass to your colon where specific bacteria ferment them to generate short chain fatty acids (SCFAs) that help you to avoid overweight and dampen down inflammation (Proc Nutr Soc, 2015;74:23–36).

Other lifestyle factors that can turn on your immune system to cause inflammation include:
• smoking
• drinking too much alcohol
• being overweight
• lack of exercise
• exposure to excess sunlight
• vitamin D deficiency
• exposure to X rays and other radiation
• exposure to harmful chemicals such as certain insecticides, herbicides or industrial chemicals
• chronic infections anywhere in your body

My Recommendations
The risk for dementia increases with age, and more than 50 percent of North Americans over 85 suffer from some degree of dementia (Alzheimer’s Assoc Facts and Figures, 2018). Your diet affects your susceptibility to dementia because it influences the types of bacteria that grow in your colon. You can reduce your chances for suffering dementia by following an anti-inflammatory diet:
• Eat lots of fruits, vegetables, whole grains, beans, seeds, nuts, whole un-ground grains, and non-fried fish
• Restrict the pro-inflammatory foods such as all processed and ground up foods, red meat, processed meats, foods with added sugar, all drinks with sugar in them including fruit juice, and alcohol.