Educational Series
The Science of Nutrition
By: Mohammad Ahrar, PhD
Introduction
Inflammation is a natural body defense mechanism in response to an irritant that can be found in food or from other sources. Medical studies show that inflammation can be linked to a range of disorders and health issues. In this article, we will review the basic information about inflammation and its consequences, and how the body can react to inflammatory substances found in some foods that we eat or from internal and external factors. We will also review foods that may help reduce inflammation and what foods can cause inflammation.
Facts about inflammation
Inflammation is the body’s natural response to safeguard against foreign bacteria, viruses, and infection. In other words, inflammation is part of the body’s immune response. However, sometimes, inflammation can persist longer than necessary, causing more harm than benefit. That’s when inflammation can become your enemy. Reports indicate that many major diseases such as cancer, heart disease, diabetes, arthritis, depression, and Alzheimer’s have been linked to chronic inflammation (3).
General causes of inflammation
Inflammation can be a result of bacterial, viral, and fungal infection, or it can be a reaction to the food that we eat, or it could be due to other factors such as chemicals, radiation, autoimmune response, or physical and mental trauma. Other factors that may be linked to inflammation include genetics, obesity, stress, air pollution, and toxins in the environment.
The dangers of inflammation
Although acute inflammation is an essential part of the healing process, chronic inflammation can lead to many health problems. Medical reports indicate that inflammation is a key player in a wide range of chronic diseases that affect the cardiovascular and digestive systems, joints, and almost all body organs. Sometimes the immune system becomes hypersensitive to allergens like dust and pollen or some chemicals in the food. Repeated exposure to these factors can lead to inflammation, which, if left unchecked, can cause tissue damage. Many diseases can be life threatening, such as cancer and heart disease. Inflammation can alter blood flow to the brain, leading to tissue damage and cognitive decline that may lead to the creation of damaging proteins linked to Alzheimer’s (3).
What foods prevent inflammation
Research suggests that there is direct link between diet and inflammation. Studies have shown that chronic inflammation can be reduced with certain bioactive compounds found in food, including resveratrol in the skin of red grapes, theaflavins in tea, and omega-3 fatty acids in flax seed and fish. Use of these compounds in a daily diet may regulate the gene expression that causes inflammation (2). Foods rich in antioxidants can reduce oxidation associated with many chronic inflammations. (See Peyk #184 for more information.)
The common sources of foods that are high in antioxidants are summarized below:
Beta-carotene and other carotenoids are plentiful in apricots, asparagus, beets, broccoli, cantaloupe, carrots, corn, green peppers, kale, mangoes, turnip and collard greens, nectarines, peaches, pink grapefruit, pumpkin, squash, spinach, sweet potato, tangerines, tomatoes, and watermelon (Peyk #184).
Vitamin C is abundant in berries, broccoli, Brussels sprouts, cantaloupe, cauliflower, grapefruit, honeydew, kale, kiwi, mango, nectarine, orange, papaya, snow peas, sweet potato, strawberries, tomatoes, and red, green, or yellow peppers. For more information about the antioxidant properties of Vitamin C, visit Peyk #173.
Vitamin E is abundant in broccoli (boiled), avocado, chard, mustard and turnip greens, mangoes, nuts, papaya, pumpkin, red peppers, spinach (boiled), and sunflower seeds. For more information about the beneficial effects of Vitamin E, visit Peyk #171.
Omega-3 fats play a role in altering the inflammatory process and regulation of pain. Salmon, tuna, trout, mackerel, and herring are high in these fats. Soy-based foods, walnuts, pecans, and flaxseed are also good sources of omega-3 fats (4). More information about omega-3 fatty acids is listed in Peyk #160.
Colorful fruits and vegetables including leafy greens, avocados, beets, cherries, and berries are rich in antioxidants. Other foods such as lentils and beans, nuts and seeds, whole grains, green tea, and certain spices, such as ginger and turmeric, are rich in antioxidants.
Lycopene and flavonoids are potent antioxidants abundant in tomatoes. Processing of tomatoes—such as boiling or making sauce or paste—significantly increases the bio- accessibility of lycopene and flavonoid content in the product.
Probiotics, which are the indigenous probiotic bacteria consisting mainly of bifidobacteria and lactobacilli, beneficially affect the host physiology by modulating the lining of the intestine and systemic immunity, as well as improving microbial balance in the intestinal tract. Results of studies (more than 134 clinical trials) show that consumption of fermented dairy products using these species of bacteria may elicit anti-tumor and anti-mutagenic effects, which have been attributed to decreased tumor promoting agents, leading to suppression of tumors.
Turmeric, a spice that comes from the turmeric plant, contains the chemical curcumin and other chemicals that have powerful antioxidant and anti-inflammatory effects. However, the curcumin content of turmeric is not that high (about 3% by weight). Curcumin is poorly absorbed into the bloodstream. Research suggests that it helps to consume black pepper with it, which contains piperine, a natural substance that enhances the absorption of curcumin by thousand folds. Turmeric is fat soluble, so it may be a good idea to take it with some fat in the diet. Turmeric has been studied as a beneficial herb in many diseases, including cancers, such as colorectal cancer (7) and Alzheimer’s disease. It’s known that inflammation and oxidative damage to neurons play a role in Alzheimer’s disease. Since turmeric has beneficial effects on both, it can reduce the risks of the disease. In addition, a key feature of Alzheimer’s disease is a buildup of protein tangles called amyloid plaques. Studies show that the curcumin can help clear these plaques (7).
Turmeric has been used to reduce inflammation of the joints. Arthritis is a common disorder characterized by joint inflammation. Many studies show that curcumin, the main ingredient in the turmeric, can help treat symptoms of arthritis and, in some cases, more effectively than anti-inflammatory drugs.
What foods cause inflammation
Studies show that chronic inflammation is linked to an increased risk of diseases like diabetes, heart disease, and obesity. The foods you eat can significantly affect inflammation in your body. Some foods that can cause inflammation are listed below:
Sugar and high-fructose corn syrup – The table sugar (sucrose) and high fructose corn syrup (artificially made) are the two main types of added sugar in the Western diet. Sucrose is made of glucose and fructose. Fruits and vegetables contain small amounts of both sugars in the right proportion. Researchers have noted that excess fructose from fructose corn syrup causes inflammation within the endothelial cells that line your blood vessels, which is a risk factor for heart disease (8). When the smooth lining of the arteries and arterioles get roughened as the result of inflammation, fats and cholesterol can attach to the endothelium, clog the arteries and bring about heart attack and stroke. Diets high in sugar and high-fructose corn syrup may also counteract the anti-inflammatory effects of omega-3 fatty acids, an essential fatty acid (Peyk #160).
Artificial trans fats – Artificial trans fats are created by adding hydrogen to unsaturated fats, which are liquid, to give them the stability of a more solid fat. Trans fats are often listed as partially hydrogenated oils on food labels. Unlike the naturally occurring trans fats found in dairy and meat, artificial trans fats have been shown to cause inflammation and increase disease risk. Trans fats also lower HDL (good) cholesterol and may impair the function of the endothelial cells lining your arteries, which is a risk factor for heart disease. Foods high in trans fats include French fries and other fried fast food, some varieties of microwave popcorn, certain margarines and vegetable shortenings, and packaged cakes and cookies.
Omega-6 fatty acids – Some studies suggest that some vegetable oils contain high omega-6 fatty acid that may promote inflammation when consumed in high amounts. However, the evidence is inconsistent, and more research is needed. See Peyk #160 for more information.
Refined carbohydrates – Carbohydrates have gotten a bad rap. However, the truth is that not all carbs are problematic. Refined carbs—those which have most of their fiber removed through processing—are not considered good carbs. Researchers suggest that refined carbs in the modern diet may encourage the growth of inflammatory gut bacteria that can increase your risk of obesity and inflammatory bowel disease. Refined carbs have a higher glycemic index (GI) than unprocessed ones. High GI foods raise blood sugar more rapidly than low GI foods.
Excessive alcohol– Moderate alcohol consumption, mainly of red wine, has been shown to provide some health benefits. However, higher amounts can lead to severe problems. Studies show that people who drink heavily may develop problems with bacterial toxinsmoving out of the colon and into the body. This condition—often called “leaky gut”—can drive widespread inflammation that leads to organ damage (7).
Processed meat – Common types of processed meat include sausage, bacon, ham, smoked meat, and beef jerky. Chemicals (such as glycan) are formed by cooking meats and some other foods at high temperatures. Harmful compounds are formed when protein or fat combine with sugar. Foods that have been exposed to high temperatures—such as during grilling, frying, or toasting—tend to be very high in these compounds which are known to cause inflammation. Consuming excessive processed meat is associated with an increased risk of heart disease, diabetes, and stomach and colon cancers.
Frying – Although frying may give flavor to food, the frying process results in substantial oxidation of frying oil. With increased lipid oxidation, there is a greater likelihood that aldehydes formed, which can react with amino acid lysine to render it unavailable for absorption. Additionally, some vitamins will be also be destroyed. Studies have shown that thermally oxidized lipids enhance peroxidation of cell membrane, which could potentially lead to carcinogenesis (8). Researchers have also discovered the presence of certain aldehydes in food, which are believed to be related to some neurodegenerative diseases and some types of cancer. These toxic compounds can be found in some oils, such as sunflower oil, when heated for frying. Results of other studies show that sunflower and linseed oil (especially sunflower oil) are the ones that create the most toxic aldehydes in less time (9).
A summary of foods that may reduce or enhance inflammation is shown in the graph below, adopted from Harvard Health Publishing (3).
Summary
A quote from experts at Harvard Medical School says: “What do heart disease, obesity, rheumatoid arthritis, diabetes, gout, asthma, and other chronic conditions have in common? Inflammation!” Carotenoids, Vitamins C and E, omega-3 fatty acids, and turmeric are among the food ingredients that reduce inflammation. Sugars, trans fats, refined carbs, and processed meats are linked to cause inflammation. More information about fats, carbohydrates, omega-3 fatty acids, Vitamins C and E, and antioxidants have been discussed in previous Peyk editions.
References
1- Modern Nutrition in health and disease, Maurice E. Shills, et. al., 10th ed. Lippincott, Williams and Wilking.
2- Nutrition, from science to you, Joan Salge Blake, Kathy D Munoz, and Stella Volpe- 3rd ed. 2016, Pearson Education, Inc.
3- https://www.health.harvard.edu/staying-healthy/foods-that-fight-inflammation
4- https://www.painexpertnews.com/turmericcbd_clean_pb/
5- https://www.sciencedaily.com/releases/2019/09/190926161356.htm
6- https://www.nature.com/articles/s41398-019-0528-0
7- https://www.healthline.com/nutrition/6-foods-that-cause-inflammation#1
8- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5616019/
9- https://www.sciencedaily.com/releases/2012/02/120222093508.htm
