Good nutrition is not the sole determinant of our health, but neither is our immune system on its own. Our nutrition status and immune system are meant to work together. For example, malnutrition can lead to poor immune function. However, over-nutrition does not necessarily indicate stronger immunity.
Imagine your body is like a castle. Some castles may have an inherently stronger defense system built in, like a moat, just like how some people are genetically born with better immune systems. Castles also train their soldiers to be prepared, similar to how we can train ourselves with healthy habits, such as washing hands frequently or coughing into your elbow. Lastly, castles are better prepared for potential invasion when they have adequate supplies and soldiers, just like how sufficient nutrition can better prepare your immune system for potential illness.
As we explore the current research surrounding nutrition and the immune system in this article, it is important to note that we cannot generalize recommendations – advice for disease prevention may not apply to disease treatment and vice versa. This article will discuss prevention strategies, so stay tuned for treatment strategies in our next article!
At the New Crown Epidemic Briefing held on February 10th, the President of Wuhan Jinyintan Hospital said that the COVID-19 virus is a self-limiting disease. In other words, many patients can overcome this disease through their own immune system. Therefore, we need to ensure that our immune system is in its optimal state to fight illnesses.
The immune system is complex and is affected by many factors, including lifestyle, sleep, stress, smoking, and diet. Current nutrition immunological research found the following nutrients to be beneficial in regulating the immune system.
Nutrient mechanisms in immune regulation
Vitamin D can enhance the elimination of certain bacteria, viruses, and fungi by stimulating our inherent antimicrobial immune response. Vitamin D can be used clinically to alleviate autoimmune and inflammatory diseases. Adequate intake of vitamin D can help maintain/enhance the body’s ability to fight infections by promoting the innate immune response. Ultraviolet rays are limited during winter and most people become deficient in vitamin D during this time, which may reduce their immune function. Foods high in vitamin D include the following: eggs, milk, fish, and mushrooms. The elderly population, whose absorption of vitamin D is low, and people with limited sun exposure can consider vitamin D supplements under the guidance of a doctor or a registered dietitian nutritionist.
Vitamin E is a fat-soluble vitamin present in cell membranes and also acts as a chain-breaking antioxidant. The concentration of vitamin E in immune cells is high, thus protecting them from oxidative damage associated with high metabolic activity and high dietary polyunsaturated fatty acids. Early animal experiments found that vitamin E deficiency can weaken immune function while vitamin E supplementation can reverse this effect. Due to the presence of multiple interfering factors in human experiments, there is no concluding evidence regarding the influence of vitamin E on the immune system. Some studies found that supplementation with 200 mg/day of vitamin E for one year reduced the incidence of upper respiratory tract infections in the elderly who lived in nursing homes and were over 65 years of age. A double-blind study of elderly, conducted in the Netherlands, revealed that there was no relationship between vitamin E and the incidence of respiratory diseases; in fact, there was evidence that reported a greater degree of infection with vitamin E supplementation. Vitamin E rich foods include: nuts, such as almonds, sunflower seeds, vegetable oils, and avocados.
Zinc deficiency is common in developing countries and is the fifth major risk factor associated with bacteria induced diarrhea and pneumonia. Zinc is a key nutrient that maintains homeostasis of the immune system. Correcting zinc deficiency by supplementing zinc can reverse some damage to the immune system and reduce mortality from certain infectious diseases. According to current research, children and elderly are at high risk for zinc deficiency, which is related to an impaired immune function. This leads to increased morbidity and mortality in these populations. Zinc supplements may help solve this problem, especially for people with low serum zinc levels. Zinc rich foods include: shellfish, seafood, beef, pork, poultry, nuts, and whole grains.
Fish oil and omega-3 unsaturated fatty acids
There is ample evidence that omega-3 unsaturated fatty acids can help to regulate the cellular and molecular events involved in the activation of immune cells, especially those related to cell-mediated immunity. Omega-3 unsaturated fatty acids can regulate and protect against chronic inflammation. Food