It is true that certain nutrients are essential for the body's immune response. Examples of these vitamins and minerals include vitamin C, vitamin D, zinc, selenium, iron, and proteins (including the amino acid glutamine). While vitamins can help prevent diseases and other health problems in people who are severely malnourished, they are unlikely to have any effect on the average American adult. Unfortunately, many of us don't eat enough fruits, vegetables, and other fresh foods that we need to stay healthy all year long.
Healthy foods provide many substances, including vitamins and minerals, to keep us strong and healthy. You can't just eat an orange or a grapefruit or take a vitamin pill and expect it to prevent a cold and boost your immune system. Vitamin C, or ascorbic acid, is a water-soluble vitamin well known for its role in supporting a healthy immune system. Because your body can't produce vitamin C, it must come from the foods you eat every day.
Biochemical mechanisms quickly identify any foreign molecules and destroy them through a myriad of immune cells. Probiotics have been found to play a key role in helping maintain a healthy balance of bacteria in the gut, and new research supports the idea that they have beneficial effects on immunity. High levels of vitamin C have been found to reduce tissue damage associated with neutrophil extracellular traps (NETs). Iron is another important nutrient for the body's immune system as it helps carry oxygen to cells.
Many experts believe that the current recommended daily dose of vitamin D is not enough to support healthy immune function. Anyone with nutrient deficiencies who cannot eat a healthy, balanced diet may find it beneficial to take a daily multivitamin. T cells differentiate into Th1 and Th2 cells depending on the cytokines they secrete and the immune responses they generate. In the United States, nearly 95% of the population doesn't meet their daily vitamin D needs, 84% don't get enough vitamin E, 46% don't get enough vitamin C, 45% don't get enough vitamin A, and 15% don't get enough zinc.
A zinc deficiency can weaken the immune system by affecting the formation, activation and maturation of lymphocytes. Chemical responses such as the activation of the complement system and the release of pro-inflammatory cytokines require certain vitamins and minerals (in particular, vitamins A, D and C, zinc, iron, and selenium). Therefore, there is a gap between dietary intake and levels for optimal immune function. Supplementing the diet with a combination of multiple selected micronutrients that support the immune system may help optimize immune function and reduce the risk of infection.
In Europe, reported intakes of vitamins D and E, folate and selenium were inadequate in all age groups.