Vitamin D and Immunity

Vitamin D plays a critical role in supporting the immune system.^1-4

Low vitamin D levels have been associated with an increased risk of communicable diseases, including viral and bacterial infections.¹

Approximately 40% of Americans have insufficient blood levels of vitamin D, and close to 30% have deficient vitamin D. This represents a major health risk, especially for older individuals.⁵

Vitamin D supplementation has been shown to help protect against acute respiratory infections.¹

The following studies, published in the past few years, have added support to vitamin D’s role in boosting immunity and protecting against various infections:

• Vitamin D deficiency increases risk of respiratory tract infections.² In elderly, institutionalized individuals, vitamin D deficiency was associated with an increased incidence of respiratory tract infections. The researchers suggested supplementation with vitamin D as a method for preventing respiratory tract infections.
• Low vitamin D status is associated with increased risk of chronic rhinosinusitis.⁶ Researchers found a significant association between lower serum vitamin D status and having chronic rhinosinusitis, which is persistent inflammation of the upper respiratory tract caused by immune dysfunction.
• Vitamin D supplementation reduces the risk of acute respiratory tract infections.³ After reviewing evidence from randomized, controlled trials, researchers found that vitamin D supplementation is modestly effective at reducing the risk of acute respiratory tract infections, as well as shortening the duration of their symptoms.

Life Extension recommends maintaining vitamin D blood levels (25-hydroxyvitamin D) between 50-80 ng/mL with yearly blood testing to ensure optimal status.

If you have any questions on the scientific content of this article, please call a Life Extension Wellness Specialist at 1-866-864-3027.

References

1. Martineau AR, Jolliffe DA, Hooper RL, 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.
2. Kuwabara A, Tsugawa N, Ao M, et al. Vitamin D deficiency as the risk of respiratory tract infections in the institutionalized elderly: A prospective 1-year cohort study. Clin Nutr ESPEN. 2020 Dec;40:309-13.
3. Abioye AI, Bromage S, Fawzi W. Effect of micronutrient supplements on influenza and other respiratory tract infections among adults: a systematic review and meta-analysis. BMJ Glob Health. 2021 Jan;6(1).
4. Zdrenghea MT, Makrinioti H, Bagacean C, et al. Vitamin D modulation of innate immune responses to respiratory viral infections. Rev Med Virol. 2017 Jan;27(1).
5. Liu X, Baylin A, Levy PD. Vitamin D deficiency and insufficiency among US adults: prevalence, predictors and clinical implications. Br J Nutr. 2018 Apr;119(8):928-36.
6. Li B, Wang M, Zhou L, et al. Association between serum vitamin D and chronic rhinosinusitis: a meta-analysis. Braz J Otorhinolaryngol. 2021 Mar-Apr;87(2):178-87.