Top High-Fiber Foods to Fight Inflammation

No food is a cure-all for inflammation, but if you’re aiming to eat to reduce inflammation, high-fiber diets are a good bet. Chronic inflammation is a primary driver of chronic diseases, such as diabetes, heart disease and rheumatoid arthritis, and is a significant threat to long-term health, according to StatPearls in 2023.

For this article, we consulted registered dietitians who reveal the top high-fiber foods to fight inflammation and boost overall health. Plus, they share expert tips for incorporating them into your diet. Read on to learn more.

How Does Fiber Lower Inflammation?

High-fiber diets work in the gut by improving the health of your microbiome (the colony of trillions of bacteria and other organisms that live in the gut), according to a 2020 review published in Biomolecules. These foods change the pH of the gut and decrease its permeability (how easily substances can pass through your gut lining), and therefore lower inflammation.

The pH level in your gut refers to its acidity or alkalinity. An optimal pH environment creates less favorable conditions for harmful bacteria and supports the growth of beneficial microbes. This balance is crucial for a healthy gut and why fiber can help lower inflammation.

Additionally, high-fiber foods can strengthen your gut lining by reducing its permeability, which is how easily substances can pass through your gut lining. A healthy gut barrier prevents the entry of harmful substances, such as bacteria and toxins, into the bloodstream, helping reduce inflammation.

The Best High-Fiber Foods to Fight Inflammation

1. Avocados

Bursting with heart-healthy monounsaturated fats and fiber, avocados provide 5 grams of fiber per half of the fruit, according to the USDA. Additionally, 2020 research in The Journal of Nutrition points out that the high antioxidant content of avocados provides an extra layer of defense against oxidative stress, helping reduce inflammation. 

And, there’s more: “In a clinical study, researchers found when adults with insulin resistance exchanged carbohydrate foods in their usual diet with avocado, c-reactive protein (CRP) levels were significantly lower. CRP is a marker of inflammation in the body,” says Erin Palinski-Wade, RD, CDCES, author of 2-Day Diabetes Diet. She is referring to another study in The Journal of Nutrition in 2022, which further concluded that the avocado eaters in the study ate a healthier diet in general and had better blood sugar control.

2. Broccoli

Broccoli, a member of the cabbage family, is packed full of fiber, vitamins and antioxidants, making it a nutritional powerhouse for decreasing inflammatory responses and lowering oxidative stress. Each cup of chopped raw broccoli delivers more than 2 grams of fiber, per the USDA.

“One cup of raw broccoli provides a good source of fiber while also providing a source of the anti-inflammatory compounds sulforaphane, indole-3-carbinol and isothiocyanates,” explains Palinski-Wade. “These help reduce inflammation by inhibiting the production of inflammatory substances and suppressing the activity of certain enzymes that promote inflammation in the body,” she adds.

3. Oats

Oats are a popular breakfast staple, brimming with a soluble fiber called beta-glucan. This type of fiber increases feelings of fullness while supporting gut health, concludes a 2023 review in Current Nutrition Reports. One cup of cooked oatmeal contains 4 grams of fiber, according to the USDA. 

“Oats are a fabulous addition to your breakfast routine,” says Caroline Young, RD, a registered dietitian and owner of Whole Self Nutrition. “For a well-rounded breakfast, I recommend cooking your oats in milk and topping them with fruit, nuts or nut butter and flaxseed.” (More on flaxseed below.)

4. Raspberries

They’re tiny, but mighty when it comes to fiber. “Raspberries are one of the highest-fiber fruits,” says Palinski-Wade. “Also, these berries are rich in polyphenols, including ellagic acid, quercetin and gallic acid, which have been shown to have anti-inflammatory effects in the body,” she says. 

Raspberries boast an impressive fiber content with 8 grams per cup, per the USDA. This not only aids digestion but also contributes to the regulation of inflammation. Packed with antioxidants, these berries are crucial in mitigating oxidative stress, a common trigger for inflammation.

5. Whole-Wheat Bread

Whole-wheat bread is loaded with fiber, vitamins and minerals, and switching from white to whole-wheat bread is an easy way to contribute to digestive health and lower your inflammation. “Another excellent source of cereal fiber is whole-wheat bread. Any brand will do, but ensure it's 100% whole wheat,” says Young. Read the ingredients label on yours to ensure that it’s made with whole wheat. One slice of whole-wheat bread contains 2 grams of fiber, according to the USDA. (That’s 4 grams of fiber per sandwich.)

6. Chia seeds

Don’t let their small size fool you—chia seeds are nutritional giants, especially when combating inflammation. “Chia seeds can help reduce inflammation due to their rich antioxidants, omega-3 fatty acids and fiber content. The antioxidants in chia seeds, such as quercetin and caffeic acid, have been shown to fight inflammation in the body,” says Palinski-Wade. One ounce of chia seeds delivers a whopping 10 grams of fiber, says the USDA.

7. Black beans

Black beans are loaded with fiber, protein and other essential nutrients, making them an excellent addition to an anti-inflammatory diet. One cup of black beans contains 15 grams of fiber, according to the USDA.

“Black beans are a good source of plant-based protein and fiber, along with additional nutrients that contribute to reducing inflammation in the body and promoting gut health,” Palinski-Wade says. “When beans are used as a plant-based source of protein in replacement of high-fat animal proteins, this can reduce the saturated fat intake in the body, helping to reduce inflammation further,” she adds.

8. Flaxseed

Rich in alpha-linolenic acid (ALA), a plant-based omega-3 fatty acid, flaxseed offers plenty of anti-inflammatory benefits. According to a 2019 study published in Nutrients, the soluble fiber in flaxseed also supports good digestive health, further reducing inflammation levels. According to the USDA, 1 tablespoon of ground flaxseed contains 2 grams of fiber.