Study Identifies Widespread Inadequacies of Immune Health Nutrients
Share this post
Key nutrient shortfalls may increase the risk of infections
Ideally, a well-balanced, nutrient-dense diet, including a variety of colorful fruits and vegetables, whole grains, legumes, healthy fats, and a balanced selection of proteins can meet all of one’s daily requirements for essential vitamins and minerals, as well as essential fatty acids (EFAs), amino acids, and other nutrients.
In practice, however, this is a tall order. It is difficult for many of us to obtain a sufficient variety and/or quantity of wholesome foods to fulfill all of our nutritional needs on a regular basis, and there is often a gap between what we consume and what we require. In addition to compromising overall health, inadequacies in key nutrients can impair immune function.
A recent article (which we’ll refer to as the 2020 study), published in the peer-reviewed scientific journal Nutrients, highlights the magnitude of the problem. The authors carried out an analysis of usual micronutrient intakes based on data from the National Health and Nutrition Examination Surveys (NHANES), a nationwide survey conducted by Centers for Disease Prevention and Control (CDC).
Using data obtained between 2005 and 2016, the authors compared the usual dietary intakes from food and supplements to the estimated average requirement (EAR) for a particular nutrient, with a focus on nutrients of importance for immune function. In addition to looking at nutrient intakes from food only, they also examined the effects of supplementation.
The results revealed substantial inadequacies in vitamins A, C, D, and E, as well as zinc, across the population, especially among individuals who relied on food alone to meet their nutrient needs. Insufficient intakes of these nutrients in particular significantly compromises immune function, as we’ll discuss today.
Vitamin D insufficiency has a significant impact on immune health. The 2020 study adds to the concern, showing that 95% percent of non-supplemented adults had vitamin D intakes below the EAR.
Vitamin D is known as the sunshine vitamin because it is generated within the skin upon exposure to ultraviolet B (UVB) rays, the rays responsible for suntans., Vitamin D status tends to be at its lowest in winter,, coinciding with the seasonal prevalence of respiratory infections. During the 1918-1919 “Spanish flu” pandemic, for example, greater fatality rates occurred in those with less sunlight exposure.
Insufficient vitamin D intakes are strongly associated with an increased risk of respiratory infections, including influenza and pneumonia, and with an increased severity of these infections.,, Further studies have shown that supplementation with vitamin D may cut the risk of acute respiratory tract infections by an average of one-third or more, and that individuals with low starting levels of 25(OH)D (<40 nmol/L) are likely to see the most benefit., A 2017 systematic review concluded that vitamin D supplementation could help protect against acute respiratory tract infections overall.
Vitamin E, the main lipid-soluble antioxidant in the body, prevents oxidative damage to membrane polyunsaturated fatty acids, and thereby preserves the function of immune cells. The 2020 study showed that 84% percent of non-supplemented adults had vitamin E intakes below the EAR.
Vitamin E deficiency impairs both humoral and cell-mediated immune functions.,, A deficiency of this vitamin can increase the risk of infections, and exacerbate the damage that occurs once an infection takes hold., Vitamin E supplementation has been shown to improve measures of immune function and to reduce the incidence and severity of respiratory infections in the elderly, whose immune systems may be compromised due to age.,,,
Vitamin C (ascorbic acid) is a water-soluble antioxidant that is indispensable for a healthy immune response against viral and bacterial infections.,,,,, The 2020 study showed that 46% of non-supplemented adults had vitamin C intakes below the EAR.
Multiple clinical trials have shown that vitamin C supplementation may shorten the duration and severity of common cold symptoms, and also reduce the incidence of colds in individuals with suboptimal vitamin C levels. A meta-analysis showed that extra doses of vitamin C could benefit patients who contract the common cold, even if they were already supplementing vitamin C regularly. More vitamin C is consumed by the cells of the body in the course of fighting infections, so relatively high doses are needed to influence the course of respiratory infections once they have taken hold.,,,,
Adequate vitamin A has long been associated with resistance to infections., This vitamin plays a critical role in the differentiation, maturation, and function of immune cells, both for innate and adaptive immunity,,,, and it can even favorably modulate the gut microbiota.
The 2020 study showed that 45% of non-supplemented adults had vitamin A intakes below the EAR. Vitamin A deficiency has been observed to increase the risk for viral infections, in both children and adults.,, Acute illnesses and infections may also deplete serum retinol concentrations and increase the requirements for this vitamin.,, Vitamin A deficiency can also impair the efficacy of vaccinations by reducing antibody responses.
Zinc supports innate and acquired immunity through direct, indirect, and antioxidant mechanisms.,,, The 2020 study showed that 15% of non-supplemented adults had zinc intakes below the EAR. Additional studies have shown that the prevalence of marginal zinc intakes depends on age, ranging from 12% of younger adults to 30% or more of individuals over the age of 60.,,
Even mild zinc deficiencies can increase the risk and severity of viral infections, including respiratory infections such as influenza and pneumonia.,,, To illustrate the importance of zinc, an investigation of the nutritional status of patients admitted to a hospital’s infectious disease ward revealed that two thirds of the patients were deficient in zinc. Zinc deficiency not only compromises immunity, but also shifts the immune system toward an inflammatory state that can predispose the body for damage to the lungs and other organs., Conversely, supplemental zinc may help reduce the risk of infections.,,
A significant number of Americans did not meet estimated average requirements for vitamins A, C, D, and E, and zinc.
The immune system needs multiple micronutrients, including vitamins A, D, C, E, B vitamins (folate, vitamin B6, and B12), zinc, iron, copper, and selenium, which play vital, often synergistic roles at every stage of the immune response.,
The 2020 study shows that a significant number of Americans did not meet estimated average requirements for vitamins A, C, D, and E, and zinc. Selenium was not identified as having a high prevalence of inadequacy, but a study of infectious disease patients found that 47% were deficient in selenium.
The 2020 study further showed that the consumption of dietary supplements reduced the prevalence of nutrient inadequacies, although some adults taking supplements were still not meeting the EARs.
In sum, data strongly suggests we should assess whether our diets (and supplements) are providing adequate intakes of key immune health nutrients, and adjust our intakes accordingly.
For more information on the micronutrients discussed in this article, please see these additional NutritionInFocus articles:Click here to see References
 Wilson MM, et al. American diet quality: where it is, where it is heading, and what it could be. J Acad Nutr Diet. 2016 Feb;116(2):302-10.
 Reider CA, et al. Inadequacy of immune health nutrients: intakes in US adults, the 2005-2016 NHANES. Nutrients. 2020 Jun 10;12(6):E1735.
 Wacker M, Holick MF. Sunlight and vitamin D: a global perspective for health. Dermatoendocrinol. 2013 Jan 1;5(1):51-108.
 Nair R, Maseeh A. Vitamin D: the “sunshine” vitamin. J Pharmacol Pharmacother. 2012 Apr;3(2):118-26.
 Poskitt EM, et al. Diet, sunlight, and 25-hydroxy vitamin D in healthy children and adults. Br Med J. 1979 Jan 27;1(6158):221-3.
 Sheltawy M, et al. The contribution of dietary vitamin D and sunlight to the plasma 25-hydroxyvitamin D in the elderly. Hum Nutr Clin Nutr. 1984 May;38(3):191-4.
 Grant WB, Giovannucci E. The possible roles of solar ultraviolet-B radiation and vitamin D in reducing case-fatality rates from the 1918-1919 influenza pandemic in the United States. Dermatoendocrinol. 2009 Jul;1(4):215-9.
 Gunville CF, et al. The role of vitamin D in prevention and treatment of infection. Inflamm Allergy Drug Targets. 2013 Aug;12(4):239-45.
 Ginde AA, et al. Association between serum 25-hydroxyvitamin D level and upper respiratory tract infection in the Third National Health and Nutrition Examination Survey. Arch Intern Med. 2009 Feb 23;169(4):384-90.
 Pham H, et al. Acute respiratory tract infection and 25-hydroxyvitamin D concentration: a systematic review and meta-analysis. Int J Environ Res Public Health. 2019 Aug 21;16(17).
 Bergman P, et al. Vitamin D and respiratory tract infections: a systematic review and meta-analysis of randomized controlled trials. PLoS One. 2013 Jun 19;8(6):e65835.
 Simpson S, et al. Weekly cholecalciferol supplementation results in significant reductions in infection risk among the vitamin D deficient: results from the CIPRIS pilot RCT. BMC Nutrition. 2015 Dec;1(1):7.
 Martineau AR, et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ. 2017 Feb 15;356:i6583.
 Lewis ED, et al. Regulatory role of vitamin E in the immune system and inflammation. IUBMB Life. 2019 Apr;71(4):487-94.
 Han SN, Meydani SN. Impact of vitamin E on immune function and its clinical implications. Expert Rev Clin Immunol. 2006 Jul;2(4):561-7.
 Wu D, et al. Nutritional modulation of immune function: analysis of evidence, mechanisms, and clinical relevance. Front Immunol. 2018;9:3160.
 Lee GY, et al. The role of vitamin E in immunity. Nutrients 2018;10:1614.
 Aibana O, et al. Vitamin E status is inversely associated with risk of incident tuberculosis disease among household contacts. J Nutr. 2018 Jan 1;148(1):56-62.
 Beck MA, et al. Vitamin E deficiency intensifies the myocardial injury of coxsackievirus B3 infection of mice. J Nutr. 1994 Mar;124(3):345-58.
 Mileva M, Galabov AS. Vitamin E and influenza virus infection. Vit E Health Dis. 2018 Oct 24;67.
 De la Fuente M, et al. Vitamin E ingestion improves several immune functions in elderly men and women.
Free Radic Res. 2008 Mar;42(3):272-80.
 Meydani SN, et al. Vitamin E supplementation enhances cell-mediated immunity in healthy elderly subjects. Am J Clin Nutr. 1990 Sep 1;52(3):557-63.
 Meydani SN, et al. Vitamin E and respiratory tract infections in elderly nursing home residents: a randomized controlled trial.
 Neupane B, et al. Predictors of in-hospital mortality and re-hospitalization in older adults with community-acquired pneumonia: a prospective cohort study. BMC Geriatr. 2010;10:22.
 Wintergerst ES, et al. Immune-enhancing role of vitamin C and zinc and effect on clinical conditions. Ann Nutr Metab. 2006;50(2):85-94.
 Mousavi S, et al. Immunomodulatory and antimicrobial effects of vitamin C. Eur J Microbiol Immunol (Bp). 2019 Aug 16;9(3):73-9.
 Hemilä H. Vitamin C and infections. Nutrients. 2017 Mar 29;9(4):339.
 Carr AC, Maggini S. Vitamin C and immune function. Nutrients. 2017 Nov 3;9(11):1211.
 KimY, et al. Vitamin C is an essential factor on the anti-viral immune responses through the production of interferon-α/β at the initial stage of influenza A virus (H3N2) infection. Immune Netw. 2013 Apr;13(2):70-4.
 Furuya A, et al. Antiviral effects of ascorbic and dehydroascorbic acids in vitro. Int J Mol Med. 2008 Oct;22(4):541-5.
 Johnston CS, et al. Vitamin C supplementation slightly improves physical activity levels and reduces cold incidence in men with marginal vitamin C status: a randomized controlled trial. Nutrients. 2014 Jul 9;6(7):2572-83.
 Ran L, et al. Extra dose of vitamin C based on a daily supplementation shortens the common cold: a meta-analysis of 9 randomized controlled trials. Biomed Res Int. 2018 Jul 5;2018:1837634.
 Hunt C, et al. The clinical effects of vitamin C supplementation in elderly hospitalised patients with acute respiratory infections. Int J Vitam Nutr Res. 1994;64(3):212-9.
 Hume R, Weyers E. Changes in leucocyte ascorbic acid during the common cold. Scott Med J. 1973 Jan;18(1):3-7.
 Hemilä H. Vitamin C supplementation and common cold symptoms: factors affecting the magnitude of the benefit. Med Hypotheses. 1999 Feb;52(2):171-8.
 Hemilä H. Vitamin C and infections. Nutrients. 2017 Mar 29;9(4):339.
 Wiseman EM, et al. The vicious cycle of vitamin A deficiency: a review. Crit Rev Food Sci Nutr. 2017 Nov 22;57(17):3703-14.
 Imdad A, et al. Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age. Cochrane Database Syst Rev. 2017 Mar 11;3(3):CD008524.
 Kim MH, et al. Retinoic acid differentially regulates the migration of innate lymphoid cell subsets to the gut. Immunity. 2015;43:107-19.
 Huang Z, et al. Role of vitamin A in the immune system. J Clin Med. 2018;7:258.
 Gombart AF, et al. A review of micronutrients and the immune system – working in harmony to reduce the risk of infection. Nutrients. 2020;12:236.
 El-Zayat SR, et al. Effect of vitamin A deficiency on thymosin-β4 and CD4 concentrations. J Genet Eng Biotechnol. 2018 Jun 1;16(1):57-61.
 Lee H, Ko G. New perspectives regarding the antiviral effect of vitamin A on norovirus using modulation of gut microbiota. Gut Microbes. 2017 Nov 2;8(6):616-20.
 Zhang J, et al. Correlation of serum vitamin A, D, and E with recurrent respiratory infection in children. Eur Rev Med Pharmacol Sci. 2019 Sep;23(18):8133-8.
 Bitetto D, et al. Vitamin A deficiency is associated with hepatitis C virus chronic infection and with unresponsiveness to interferon‐based antiviral therapy. Hepatology. 2013 Mar;57(3):925-33.
 Stinchfield PA, Orenstein WA. Vitamin A for the management of measles in the United States. Infect Dis Clin Pract. 2020 Jul 1;28(4):181-7.
 Iyer N, Vaishnava S. Vitamin A at the interface of host-commensal-pathogen interactions. PLoS Pathogens. 2019 Jun 6;15(6):e1007750.
 Rosales FJ, et al. Effects of acute inflammation on plasma retinol, retinol-binding protein, and its mRNA in the liver and kidneys of vitamin A-sufficient rats. J Lipid Res. 1996;37(5):962-71.
 Neuzil KM, et al. Serum vitamin A levels in respiratory syncytial virus infection. J Pediatr. 1994 Mar;124(3):433-6.
 Penkert RR, et al. Prevnar-13 vaccine failure in a mouse model for vitamin A deficiency. Vaccine. 2017 Nov 1;35(46):6264-8.
 Wessels I, et al. Zinc as a gatekeeper of immune function. Nutrients. 2017 Nov 25;9(12):1286.
 Sapkota M, Knoell DL. Essential role of zinc and zinc transporters in myeloid cell function and host defense against infection. J Immunol Res. 2018 Oct 17;2018:4315140.
 Prasad AS, Bao B. Molecular mechanisms of zinc as a pro-antioxidant mediator: clinical therapeutic implications. Antioxidants (Basel). 2019 Jun 6;8(6):164.
 Gao H, et al. The role of zinc and zinc homeostasis in macrophage function. J Immunol Res. 2018 Dec 6;2018:6872621.
 Blumberg JB, et al. Contribution of dietary supplements to nutritional adequacy in various adult age groups. Nutrients. 2017 Dec 6;9(12):1325.
 Ervin RB, Kennedy-Stephenson J. Mineral intakes of elderly adult supplement and non-supplement users in the Third National Health and Nutrition Examination Survey. J Nutr. 2002 Nov;132(11):3422-7.
 Vural Z, et al. Trace mineral intake and deficiencies in older adults living in the community and institutions: a systematic review. Nutrients. 2020 Apr 13;12(4):1072.
 Mocchegiani E, Muzzioli M. Therapeutic application of zinc in human immunodeficiency virus against opportunistic infections. J Nutr. 2000 May;130(5S Suppl):1424S-31S.
 Read SA, et al. The role of zinc in antiviral immunity. Adv Nutr. 2019 Jul 1;10(4):696-710.
 Eijelkamp BA, et al. Dietary zinc and the control of Streptococcus pneumoniae infection. PLoS Pathog. 2019 Aug 22;15(8):e1007957.
 McCarty MF, DiNicolantonio JJ. Nutraceuticals have potential for boosting the type 1 interferon response to RNA viruses including influenza and coronavirus. Prog Cardiovasc Dis. 2020 Feb 12 [online ahead of print.]
 Dizdar OS, et al. Nutritional risk, micronutrient status and clinical outcomes: a prospective observational study in an infectious disease clinic. Nutrients. 2016 Feb 29;8(3):124.
 Kido T, et al. Inflammatory response under zinc deficiency is exacerbated by dysfunction of the T Helper type 2 lymphocyte-M2 macrophage pathway. Immunology. 2019 Apr;156(4):356-72.
 Gammoh NZ, Rink L. Zinc in infection and inflammation. Nutrients. 2017 Jun 17;9(6):624.
 Barnett JB, et al. Low zinc status: a new risk factor for pneumonia in the elderly? Nutr Rev. 2010 Jan;68(1):30-7.
 Yasuda H, Tsutsui T. Infants and elderlies are susceptible to zinc deficiency. Sci Rep. 2016 Feb 25;6:21850.
 Meydani SN, et al. Serum zinc and pneumonia in nursing home elderly. Am J Clin Nutr. 2007 Oct;86(4):1167-73.
 Maggini S, et al. Vitamins C, D and zinc: synergistic roles in immune function and infections. Vitam Miner. 2017;6(2):167.
Share this post
Marina MacDonald, MS, PhD
Enhancing Immunity with Glandulars
“Beasty bits” for autoimmunity, cancer recovery, and more The phrase “natural immune support” typically calls to mind vegetables, botanicals, probiotics, and fungi, but immune-enhancing therapies also come to us from the animal kingdom. While the meat of animals is rich in iron, vitamin B12, vitamin A, and protein,,, the glands of these creatures may…
Are You Getting Enough Sleep?
The link between sleep deficiency, metabolism, and weight gain Good nutrition, adequate exercise, and sufficient sleep are all essential for health and happiness. And yet many of us find it difficult to get enough sleep. Experts recommend that adults obtain at least seven hours of nightly sleep on a regular basis., In a U.S….
Vitamin C to Ease the Pain
Nutritional support for acute, chronic, surgical, and cancer-related pain Part 1 in our three-part series on vitamin C, pain, and opioid addiction. What do humans have in common with other primates, bats, and guinea pigs? (No, not a love of cheese!) We cannot make L-gulonolactone oxidase (GLO), the enzyme needed to biosynthesize ascorbate (vitamin…
Mushrooms for Whole Immune Support
The profound response of the human immune system to mushrooms Living in the Pacific Northwest, I often find myself staring up at the grey sky, wondering, “What’s good about all this rain?” As my eyes scan my surroundings and take in the lush, green foliage of the region, it doesn’t take long for the…
Lutein and Zeaxanthin: Blue Light Interceptors
Just what we need to protect our eyes and skin in 2020 and beyond? Perhaps you have heard of lutein or zeaxanthin, or the term “carotenoids”, which describes the larger family they belong to. Better known members of this family are lycopene, found at high levels in tomatoes, and beta-carotene, precursor to vitamin A….
The Fat-Soluble Vitamins: A, D, E and K
Nutrients for strong bones and a healthy heart Vitamins are classified into two groups: fat-soluble (vitamins A, D, E, and K) and water-soluble (B-complex vitamins and vitamin C). Fat-soluble vitamins are absorbed best when consumed with higher-fat foods. Fatty fish, vegetable oils, green vegetables, and nuts and seeds are good sources of vitamins A,…