TABLE 2.
Principal nutrients supporting the immune system in the general population
| DRI2 | ||||
|---|---|---|---|---|
| Nutrient | Rationale | Suggested intake1 | Recommended Dietary Allowances | Tolerable upper levels of intakes |
| Vitamins and trace elements | These micronutrients play important roles in supporting the cells and tissues of the immune system. Deficiencies or suboptimal status negatively affect immune function and can decrease resistance to infections | Daily multivitamin and trace element complements that supply the micronutrient requirements (e.g., DRI) are recommended in addition to the consumption of a balanced diet | Varies according to nutrient | |
| Vitamin C | Doses of ≥200 mg/d provide saturating concentrations in the blood, and support reduction in the risk, severity, and duration of upper and lower respiratory tract infections | Daily intake of at least 200 mg/d for healthy older adults | Men: 90 mg/dWomen: 75 mg/d | Men: 2000 mg/dWomen: 2000 mg/d |
| Vitamin D | Daily supplementation of vitamin D reduces the risk of acute respiratory tract infections. Dietary intake and endogenous synthesis is low in most older people | Intake of 2000 IU/d (50 μg/d) | Men: 20 μg/dWomen: 20 μg/d | Men: 100 μg/dWomen: 100 μg/d |
| Vitamin E | Emerging evidence indicates that current recommendations are too low to compensate for age-related losses and to counter imbalances in the immune system resulting in hyperinflammation in older people | A complementary intake of 200 IU/d3 | Men: 15 mg/dWomen: 15 mg/d | Men: 1000 mg/dWomen: 1000 mg/d |
| Selenium | Selenium is important in the regulation of inflammation by preventing excessive and chronic inflammation and is essential for a well-functioning immune system | An intake from supplements in the range of 50 to 100 μg/d of selenium for those with low selenium status | Men: 55 μg/dWomen: 55 μg/d | Men: 400 μg/dWomen: 400 μg/d |
| Zinc | Marginal zinc deficiency can impact immunity. Those deficient in zinc are prone to increased diarrheal and respiratory morbidity | Daily intake in the range of 30 mg/d in those with low zinc status; a higher level maybe needed for older adults with very low serum zinc concentrations | Men: 11 mg/dWomen: 8 mg/d | Men: 40 mg/dWomen: 40 mg/d |
| DHA + EPA | DHA and EPA support an effective immune system, including by helping to resolve inflammation | Daily intake of up to 500 mg/d of EPA + DHA | NA | NA |