With the rapid spread of COVID-19 disease, more people are curious to know how they can boost their immune health. Though the immune system is a complex entity and not a single unit that can be easily boosted, there are several ways to support immune health. Different lifestyle changes can be adopted to optimize wellness, however, it is crucial to understand the importance of good nutrition to the immune system. In this article, physicians, scientists, and nutritionists share their thoughts on different classes of food important to immune systems with the goal of helping people to make intelligent food choices.
- Fiber-Rich Food
70% of our immune system is in our gut. Therefore, our immune system’s biggest exposure to the outside world is through what we eat. Every bite of food we eat is either building us up or taking us down. Now more than ever, we need to eat in a way that does not challenge our immune system. We need to avoid inflammatory foods, like sugar, gluten, and dairy. However, even that is not enough. Just as important as the food you don’t eat is the food that you eat! The more nutrient-dense food you eat, the healthier you will be. Our microbiome is in constant communication with all of our systems- the immune system, our hormonal system, everything. The health of our microbiome dictates our health. It is important to have lots of balance and diversity in your microbiome. The way to ensure that is to eat the things needed to promote gut health and diversity. Therefore, it is advisable that people aim to eat 6-9 cups of colorful, non-starchy vegetables a day. That is the key to a healthy gut and a healthy microbiome. If you have a healthy gut, and a healthy microbiome, you also have a healthy immune system. While I believe you should get most of your nutrients from foods, there are two areas of supplementation that are worth mentioning. Vitamin D plays a large role in the health of your immune system. Many of us live in an area of the world where we do not get enough sun exposure to manufacture enough vitamin D. Therefore unless you are getting 15 minutes of direct sun exposure to 75% of your body a day, you should be supplementing with vitamin D. I believe EVERYONE should be having their vitamin D levels checked. Aim to keep your vitamin D levels above 50 ng/ml. – Jenn Simmons MD
- Hydration
Drinking water, at least eight 8 ounce cups a day, is important for flushing out your mucus membranes so your body can fight and remove pathogens. Research has shown proper hydration will prevent the mucus from getting thick and harboring pathogens. Also, a beverage like green tea which contains the compound epigallocatechin gallate (EGCG) has been shown to help regulate the innate immune system response. This is important because the innate immune system response is the first line of defense to viruses coming into one’s body and its upregulation helps the body to recognize and fight the pathogen as it first appears which can overall limit the severity and negative impact of the virus or the virulence of it. – Jackie Elnahar RD, Esq
- Micronutrients
The immune system can be weaponized through a variety of micronutrients, but I would like to concentrate on four players acclaimed for having especially potent immunomodulating capabilities: Vitamins A, D and C, and Zinc. Vitamins A and D activate overlapping biochemical pathways, and as such, their functions are similar. Notably, they help preserve the mucosal layer of the digestive tract and regulate expression of monocytes, macrophages, dendritic cells and lymphocytes. They also promote production of antimicrobial peptides and antibodies in response to bacterial pathogens and vaccine injections, respectively. Low levels of both are highly associated with increased risk of infection. Vitamin C, best known for minimizing the duration and severity of common colds, supercharges immune cells by entering and creating reactive oxygen species to obliterate pathogens. Zinc helps generate and strengthen immune cells, as well as expedites the body’s response to pathogens in vaccines. Foods high in Vitamins A, D and Zinc include liver and shellfish; foods high in Vitamin C include strawberries and bell peppers. Note: since Zinc and Vitamin C are not fat-soluble, they must be consumed daily. – Brenda Burgress PhD
Our needs for nutrients are increased when our immune cells are fighting an infection such as coronavirus. One of those key nutrients is retinol (Vitamin A), which is essential to the development of immune cells, including T helper cells (Th cells), T regulatory cells (Tregs), and antibody-producing cells (B cells), as well as healthy barrier function in the gut. Inadequate vitamin A, vitamin C, and zinc levels may lead to abnormal immune function and increasing the risk of viral and bacterial infections. The liver is an excellent source of vitamin A, B vitamins, and minerals including zinc. It is recommended that people should consume liver once a week (6-8 oz per week). Also, improving the quality of diet by removing added sugar, white flour and pasta is helpful. A high–glycemic index diet dumps a lot of glucose (sugar) into your bloodstream, which decreases your immune cells’ effectiveness at protecting you from illness. – Terry Wahls MD