Leslie Beck, a Toronto-based private practice dietitian, is Director of Food and Nutrition at Medcan.
It’s increasingly recognized that chronic inflammation is a major contributor to illnesses including heart disease, type 2 diabetes, certain cancers, asthma, arthritis, depression and Alzheimer’s disease. And the foods you eat have the potential to either accelerate or dampen inflammation.
Intermittent bouts of inflammation are protective. This type of inflammation is the response of your immune system as it works to heal wounds and fight infection. If the process persists, however, excessive inflammatory compounds are released that can silently damage the body and increase illness.
The North American diet, heavy in red and processed meats, refined grains, added sugars and unhealthy fats, is linked to higher levels of inflammation in the body. A Mediterranean-style diet on the other hand, plentiful in fruit, vegetables and olive oil, and low in red meat, is associated with lower inflammation levels.
One measure of inflammation is a blood marker called high-sensitivity C-reactive protein (hs-CRP). People who eat pro-inflammatory diets have been found to have higher hs-CRP levels, which is associated with a greater risk of developing heart disease.
Now, new research has tied a pro-inflammatory diet to an increased risk of cancer. Participants whose diets had the highest inflammatory score were 58-per-cent more likely to develop cancer than individuals whose diets were the least inflammatory.
For the study, published last month in the American Journal of Clinical Nutrition, researchers analyzed 44 previously published high-quality studies involving 1,082,092 participants. The studies investigated the relationship between participants’ dietary inflammatory index and cancer risk.
The dietary inflammatory index, developed at the University of South Carolina’s Cancer Prevention and Control Program, is a scoring system based on 45 inflammation-promoting and anti-inflammatory food components. Diets are scored on a continuum from maximally inflammatory to maximally anti-inflammatory.
The researchers found that, compared with anti-inflammatory diets, highly inflammatory diets significantly increased the risk of colorectal, breast, esophageal, prostate, ovarian and kidney cancers. They also observed a dose-response relationship; as the dietary inflammatory score increased, so did overall cancer risk.
It’s unclear exactly how a pro-inflammatory diet influences cancer risk. Chronic inflammation may contribute to insulin resistance and elevated insulin levels, which are thought to increase the risk of cancer. A Western-style diet may lead to obesity, which is associated with a higher risk of many cancers. (Obesity itself can cause inflammation). An inflammatory diet may also alter gut microbes in a direction that promotes inflammation.
Building an anti-inflammatory diet
An anti-inflammatory diet is a pattern of eating that includes foods and food components known to suppress inflammation, and limits ones that promote inflammation, such as refined grains, added sugars, processed red meat and unhealthy fats.
Increase fibre. High-fibre diets have been shown to reduce inflammation. Choose fibre-rich whole grains such as oats, freekeh, millet, quinoa, brown rice, spelt berries, wheat berries and 100-per-cent whole-grain pastas and breads.
Include beans and lentils in your diet at least four times a week. Add chickpeas or kidney beans to salads and soups, replace meat with black or pinto beans in tacos and serve a lentil or bean salad with dinner.
Eat more produce. Besides fibre, fruits and vegetables deliver nutrients and phytochemicals that curb inflammation. Eat a minimum of seven servings a day by including fruits and vegetables in every meal. (One serving is a medium sized fruit, one cup of berries, one half-cup of cooked or raw vegetables or one cup of salad greens).
Choose a variety of colourful produce for a wide variety of anti-inflammatory phytochemicals. Try dark leafy greens, oranges, berries and cherries, sweet potato and mango, tomatoes and eggplant.
Include polyphenols. This large group of phytochemicals found in plant foods has strong anti-inflammatory properties. Polyphenols are also thought to feed so-called good gut microbes.
Excellent sources include berries, red grapes, tea (green, white, oolong or black), apples, cocoa, onions, kale, broccoli, citrus fruit and soybeans.
Boost omega-3’s. Eat fatty fish such as salmon, sardines, anchovies and trout at least twice a week to get DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), strong anti-inflammatory fatty acids.
Plant sources of omega-3 fatty acids, called ALA (alpha linolenic acid), include chia seeds, ground flax, flax oil, hemp seeds, walnuts, walnut oil, canola oil and soybeans.
Add herbs and spices. Many herbs and spices contain polyphenols and have been shown to reduce inflammation, especially ginger and turmeric. Garlic, cayenne, parsley, mint, oregano, basil, rosemary and thyme also have anti-inflammatory properties.
Cook with herbs and spices as often as possible. Add fresh ginger to smoothies. Toss fresh parsley, basil and mint into salads.
Consider your oil. For baking and sautéing over medium-high heat, use extra virgin olive oil, a rich source of anti-inflammatory monounsaturated fat. Olive oil also includes anti-inflammatory phytochemicals.
Other sources of monounsaturated fat: avocado, avocado oil, almond oil, canola oil, almonds, cashews, hazelnuts and peanuts.