Always at the top of the list for immune support, much has been written and talked about zinc in recent months. Micronutrients such as vitamins and minerals have the power to support health right at the foundation level; they are the raw ingredients that the body needs to support every aspect of health including immune function, and if these aren’t present in sufficient quantities in the diet then these important jobs simply cannot be done properly. Here we take a closer look at the vital ways zinc supports optimal immune function.
Zinc & immune function
A severe deficiency of zinc is known to suppress immune function, and even mild to moderate deficiency can have a negative impact on the immune system’s ability to deal with infection. Zinc supports the function and proliferation of various immune cells, and without it, the capacity of the body to defend against harmful invaders is diminished.
Zinc supports both innate (non-specific, short term, first line of defence) and adaptive (specific, longer term, second line of defence) immune responses. Interestingly, harmful pathogenic organisms also need zinc to invade and thrive, so the body has an important antimicrobial defence mechanism in place whereby it hides zinc away from potential pathogens so they cannot use it!1 Another important defence mechanism the body uses is to intoxicate intracellular microbes within macrophages (immune cells which engulf harmful organisms) with excess zinc!2
Everyone needs optimal dietary zinc for their immune system to function properly, and particular consideration should be given to elderly adults who may be most at risk of having low zinc status. In fact, low levels of zinc are relatively common among the elderly and this is a likely factor contributing to age-related decline in immune function.3,4 Zinc deficiency, cell-mediated immune dysfunction, susceptibility to infections, and increased oxidative stress have all been observed in elderly subjects. A 2007 randomised, double-blind, placebo-controlled trial of zinc supplementation was carried out on 50 elderly subjects and published in the American Journal of Clinical Nutrition. Following zinc supplementation, the researchers found that incidence of infections was significantly lower, plasma zinc was significantly higher, and generation of inflammatory and oxidative stress markers were significantly lower in the zinc-supplemented than in the placebo group.5
A 2014 AREDS trial observed a significant 27% reduction in total mortality in elderly subjects who received high dose zinc.6 Multiple studies have also shown low levels of zinc are associated with increased risk of infections such as pneumonia in elderly adults and children in developing countries.7-9
Ensuring optimal dietary zinc intake
Ensuring optimal levels of zinc, particularly in children and the elderly would therefore seem sensible. The body doesn’t have much ability to store zinc so it’s crucial that your diet regularly supplies plenty of this immune-supportive mineral. You’ll find good levels of zinc in meat, chickpeas & lentils, pumpkin and sesame seeds. Whilst it’s vital to ensure you are regularly consuming plenty of zinc-rich foods, it’s also important to note that some compounds in plant foods can actually block the absorption of zinc. Phytates are found in beans, seeds, nuts and grains, and can bind minerals such as zinc in the intestines making them unavailable for the body to use. The best way to ensure optimal dietary zinc intake therefore is to include both animal and plant sources of the mineral. If you are completely reliant on plant sources of zinc however, it is useful to note that phytates can be inactivated by heating and soaking.
You can also take extra zinc in supplement form to keep your levels topped up and gently support your immune function. If you regularly take zinc in supplement form however (such as in a daily multi) it is important to balance this with copper, as excess zinc can cause copper deficiency and vice versa.
Find out more on the many dietary and lifestyle ways you can support optimal immune function here.
1. Subramanian Vignesh K, Deepe GS, Jr. Immunological orchestration of zinc homeostasis: The battle between host mechanisms and pathogen defenses. Arch Biochem Biophys. 2016; 611: 66-78
2. Subramanian Vignesh K, Landero Figueroa JA, et al. Granulocyte macrophage-colony stimulating factor induced Zn sequestration enhances macrophage superoxide and limits intracellular pathogen survival. Immunity. 2013;39(4):697-710.
3. Bao B, Prasad AS, et al. Zinc decreases C-reactive protein, lipid peroxidation, and inflammatory cytokines in elderly subjects: a potential implication of zinc as an atheroprotective agent. Am J Clin Nutr 91 (6) (2010 June), pp. 1634-1641
4. Mocchegiani E, Romeo J, Malavolta M, et al. Zinc: dietary intake and impact of supplementation on immune function in elderly. Age (Dordr). 2013;35(3):839-860.
5. Bao B, Prasad AS, et al. Zinc supplementation decreases incidence of infections in the elderly: effect of zinc on generation of cytokines and oxidative stress. Am J Clin Nutr 85 (3) (2007 March), pp. 837-844
6. Clemons TE, Kurinij N, et al. Associations of mortality with ocular disorders and an intervention of high-dose antioxidants and zinc in the Age-Related Eye Disease Study: AREDS Report No. 13 Arch Ophthalmol 122 (5) (2004 May), pp. 716-726
7. Brooks WA, Santosham M, et al. Effect of weekly zinc supplements on incidence of pneumonia and diarrhoea in children younger than 2 years in an urban, low-income population in Bangladesh: randomised controlled trial. Lancet 2005; 366: 999 -1004.
8. Meydani SN, Barnett JB, Dallal GE, Fine BC, Jacques PF, Leka LS, et al. Serum zinc and pneumonia in nursing home elderly. Am J Clin Nutr 2007; 86:1167-73.
9. Black RE. Zinc deficiency, infectious disease and mortality in the developing world. J Nutr 2003; 133: 1485S-9S