My post on May 14 discussed why claims of foods and supplements to increase immune system health and protect against coronavirus are often false. There is no definitive proof you can increase your immune system using supplements of nutrients, or with any specific foods.
High dosages of one nutrient may cause deficiencies in others, including nutrients needed for immune function. People require multiple vitamins and minerals-including vitamin C, vitamin D, and zinc for proper immune function, and clinical deficiencies in these nutrients may increase susceptibility to infections. High-dose zinc supplements taken over a long period of time may cause deficiency in copper, another nutrient needed for proper immune system function.
Taking zinc may help accelerate healing from surgical wounds, as well as boosting your immune system. Research has shown that fruits and vegetables contain nutrients such as beta-carotene, vitamin C, and vitamin E that may enhance immune function. Like gasoline for a car, eating a healthy diet is essential for providing nutrients the immune system needs to stay functioning. Make nutrient-dense foods a large part of your plate so that you are providing a broad array of nutrients needed by your immune system cells and functions.
Certain nutrients, like vitamins A and D, and certain nutrient metabolites are direct regulators of gene expression in immune cells, and they play key roles in the maturation, differentiation, and responsiveness of immune cells. Other ingredients of dietary supplements, such as botanicals and probiotics, have no important roles in the body, however, the ingredients in other supplements may influence immune function. While vitamins and nutritional or dietary supplements may benefit your health, they may also pose health risks. Measuring the effects on your immune system from vitamins, minerals, and other ingredients in dietary supplements is challenging, as your immune system is a complex network of organs, tissues, and cells; there is no single, direct measurement for the functioning of the immune system and its ability to resist disease.
However, excessive vitamin D may overwhelm the immune system, potentially leading to damage with COVID-19. In addition, excess vitamin D may be toxic to the heart and kidneys. Vitamin D in the blood has been linked to prevention of other chronic diseases, including tuberculosis, hepatitis, and cardiovascular disease.
Vitamin A deficiency is associated with decreased barrier function, altered immune responses, and increased susceptibility to a number of infections. Among individuals who are treated for heart disease with blood-thinning warfarin, the individuals who are more likely to have bleeding events have higher levels of vitamin E in their bodies. People taking metformin to manage their type 2 diabetes have lower levels of vitamin B12. Both vitamin E and the herb St. Johns wort may have dangerous interactions with blood-thinning drugs used for heart disease – increasing the risk of bleeding.
The jury is still out on vitamin D. There is a link between higher concentrations of vitamin D in your blood in childhood and lower risk for type 1 diabetes. The jurys still out on vitamin D. There is an association between higher concentrations of vitamin D in the blood during childhood and a lower risk of type 1 diabetes. There appears to be specific benefits to supplementing the elderly with vitamin E. Meydani and colleagues9495 have shown that high-dose vitamin E supplementation (800 mg/day was used in one study94, while the doses used were 60, 200, and 800 mg/day) can improve immune responses by T-helper1 cells (cell proliferation, IL-2 production) and improved responses to vaccinations, including against Hepatitis B viruses. There is a positive association between plasma vitamin E and cell-mediated immune responses, and a negative association has been demonstrated between plasma vitamin E and the risk of infections in healthy adults over 60 years of age. There appears to be particular benefit of vitamin E supplementation for the elderly. Studies by Meydani et al 94 95 demonstrated that vitamin E supplementation at high doses (one study94 used 800 mg/day and the other95 used doses of 60, 200 and 800 mg/day) enhanced T helper 1 cell-mediated immunity (lymphocyte proliferation, IL-2 production) and improved vaccination responses, including to hepatitis B virus. Perhaps the most straightforward evidence of vitamin C in the case of covid-19. Vitamin C has been used for years to reduce symptoms of common colds, roughly a quarter of which are caused by other coronaviruses, and a meta-analysis of studies enrolling more than 11,000 patients found it also reduced the risk of contracting common colds.
Vitamin C also plays roles in different aspects of immunity, including the migration of leucocytes to sites of infection, phagocytosis and killing of bacteria, the activity of natural killer cells, T-cell function (especially that of CD8+ cytotoxic T-cells), and antibody production. Sources of vitamin C include red peppers, oranges, strawberries, broccoli, mangoes, lemons, and other fruits and vegetables. Foods high in vitamin C include broccoli, Brussels sprouts, cabbage, cantaloupe, cauliflower, cabbage, kiwis, oranges, sweet potatoes, strawberries, and tomatoes.
Studies have also looked at the effects of Vitamin C given intravenously. Some studies have suggested that dietary vitamin C improves immune function , but the effects may differ depending on an individuals vitamin C status . Ironically, in some cases, products touted as improving immune function may actually inhibit it. The COVID-19 pandemic has seen an enormous rise in searches for immunity-boosting products, including things such as supplements that claim to boost immune function.
The dietary health supplement market has seen an uptick since COVID-19, as many people are hoping these products may offer some protection against the infection with SARS-CoV-2, and, for those developing COVID-19, may help to decrease disease severity. There are a few serious problems with these claims-namely, vitamin companies are not regulated as medicines by the FDA, and many supplements fail to function as claimed. Amid the COVID-19 pandemic, the FDA has issued warning letters to at least 68 companies selling products – primarily supplements that make fraudulent claims about treating or preventing infection from coronavirus, including a handful of products that claim immunity from COVID-19. Using AICRs Cancer Prevention Recommendations as the template for your own diet is an excellent way to help your immune system protect your body from infections, including COVID-19, and to continue on a long-term pathway to reduce cancer risk. Finally, make sure you speak to your diabetes care team before making changes: Your healthcare team can help you decide whether adding a vitamin or supplement to your routine is the right move. Unless your health care provider is prescribing a particular vitamin or supplement, adding another pill to your regimen is likely not that beneficial or cost-effective.