We all want to avoid illness at all times but as the colder days draw nearer you may be looking for ways to prevent winter infections. Your body avoids and fights infection through your immune system. You need to keep warm, exercise, relax and eat the foods to keep your immune system strong.
Research shows that many nutrients are important for immunity; one of the most widely researched is zinc. The immune system has different types of cells to protect the body from infection. Zinc is crucial for the functioning of all these different immune cells to work[1, 2]. Studies demonstrate that zinc is most likely to be low in the elderly[3-8] and the very young[9-13]. Men too are likely to have low zinc levels although the research tends to relate this to low fertility.
Low zinc levels increase the likelihood getting any type of infections and inflammation[2, 5] and very low zinc levels increase the risks of serious conditions such as pneumonia[3, 8, 11], severe diarrhoea[10, 11, 13], and malaria[9, 11].
Zinc is an important antioxidant[2, 5, 7]. Antioxidants keep the cells in your body healthy. In New Zealand a study that measured zinc and selenium levels in the elderly, found when either were low an important immune antioxidant enzyme called glutathione peroxidase was also low. Therefore infection and disease were more likely to occur.
The best way to get zinc from your food is to include lots of seafood esp. oysters, sunflower seeds, pumpkinseeds, meat (best organic), poultry (best organic) mushrooms, organic soybeans, and brewers yeast[14, 15].
Cadmium a toxic element also depletes zinc. The commonest sources of toxic levels of cadmium is cigarette smoke (stop smoking now!). If you find you cannot stop smoking immediately supplements of zinc may help to decrease the immune damage caused by cadmium. But there are many more damaging aspects of smoking so work towards quitting as soon as possible.
Iron in some supplement forms reduces the availability of zinc, however iron in food or in the food state supplement form will not affect the absorption of zinc. Always be careful if supplementing your diet with zinc as too much zinc can have detrimental effects on immunity and other aspects of your health. If supplements are used I recommend the Entire Katoa Food State supplements for the best absorption and bioavailability, and effective low doses[19, 20].
References (Click on the title to link to the research)
1. Ibs K-H, Rink L: Zinc-Altered Immune Function. J Nutr 2003, 133(5):1452S-1456.
2. Prasad AS: Zinc: Mechanisms of Host Defense . J Nutr 2007, 137(5):1345-1349.
3. Meydani SN, Barnett JB, Dallal GE, Fine BC, Jacques PF, Leka LS, Hamer DH: Serum zinc and pneumonia in nursing home elderly . Am J Clin Nutr 2007, 86(4):1167-1173.
4. Molls RR, Ahluwalia N, Mastro AM, Smiciklas-Wright H, Handte GC: Nutritional Status Predicts Primary Subclasses of T Cells and the Lymphocyte Proliferation Response in Healthy Older Women . J Nutr 2005, 135(11):2644-2650.
5. Prasad AS, Beck FWJ, Bao B, Fitzgerald JT, Snell DC, Steinberg JD, Cardozo LJ: Zinc supplementation decreases incidence of infections in the elderly: effect of zinc on generation of cytokines and oxidative stress . Am J Clin Nutr 2007, 85(3):837-844.
6. Belbraouet S, Biaudet H, Tebi A, Chau N, Gray-Donald K, Debry G: Serum Zinc and Copper Status in Hospitalized vs. Healthy Elderly Subjects . J Am Coll Nutr 2007, 26(6):650-654.
7. de Jong N, Gibson RS, Thomson CD, Ferguson EL, McKenzie JE, Green TJ, Horwath CC: Selenium and Zinc Status Are Suboptimal in a Sample of Older New Zealand Women in a Community-Based Study . J Nutr 2001, 131(10):2677-2684.
8. Hamer DH, Sempertegui F, Estrella B, Tucker KL, Rodriguez A, Egas J, Dallal GE, Selhub J, Griffiths JK, Meydani SN: Micronutrient Deficiencies Are Associated with Impaired Immune Response and Higher Burden of Respiratory Infections in Elderly Ecuadorians. J Nutr 2009, 139(1):113-119.
9. Duggan C, MacLeod WB, Krebs NF, Westcott JL, Fawzi WW, Premji ZG, Mwanakasale V, Simon JL, Yeboah-Antwi K, Hamer DH et al: Plasma Zinc Concentrations Are Depressed during the Acute Phase Response in Children with Falciparum Malaria. J Nutr 2005, 135(4):802-807.
10. Baqui AH, Zaman K, Persson LA, Arifeen SE, Yunus M, Begum N, Black RE:Simultaneous Weekly Supplementation of Iron and Zinc Is Associated with Lower Morbidity Due to Diarrhea and Acute Lower Respiratory Infection in Bangladeshi Infants. J Nutr 2003, 133(12):4150-4157
11. Black RE: Zinc Deficiency, Infectious Disease and Mortality in the Developing World. JNutr 2003, 133(5):1485S-1489.
12. Coles CL, Sherchand JB, Khatry SK, Katz J, LeClerq SC, Mullany LC, Tielsch JM: Zinc Modifies the Association between Nasopharyngeal Streptococcus pneumoniae Carriage and Risk of Acute Lower Respiratory Infection among Young Children in Rural Nepal . J Nutr 2008, 138(12):2462-2467.
13. Sheikh A, Shamsuzzaman S, Ahmad SM, Nasrin D, Nahar S, Alam MM, Al Tarique A, Begum YA, Qadri SS, Chowdhury MI et al:Zinc Influences Innate Immune Responses in Children with Enterotoxigenic Escherichia coli-Induced Diarrhea. J Nutr 2010, 140(5):1049-1056.
14. NIH-USA:Selected Food Sources of Zinc.In: Health Professional Fact Sheet: Zinc. National Institutes of Health, NIH; 2009.
15. NZ MoH: Food and Nutrition Guidelines for Healthy Adults. In: Other Nutrients Zinc Ministry of Health NZ; 2003
16. Lonnerdal B: Dietary Factors Influencing Zinc Absorption. J Nutr 2000, 130(5):1378S-1383.
17. Bachelet M, Pinot F, Polla RI, Francois D, Richard MJ, Vayssier-Taussat M, Polla BS: Toxicity of cadmium in tobacco smoke: protection by antioxidants and chelating resins . Free Radic Res 2002, 36(1):99-106.
18. Chowdhury BA, Friel JK, Chandra RK: Cadmium-Induced Immunopathology Is Prevented by Zinc Administration in Mice . J Nutr 1987, 117(10):1788-1794.
19. Tompkins TA, Renard NE, Kiuchi A:Clinical Evaluation of the Bioavailability of Zinc-enriched Yeast and Zinc Gluconate in Healthy Volunteers . Biological Trace Element Research 2007, 120(1-3).
20. Vinson J, Tompkins T, Agbor G: Comparative Bioavailability of Mineral-enriched Gluconates and Yeast in Rat Liver After DepletionRepletion Feeding. Biological Trace Element Research 2007, 118(2):104-110.