Vitamin D and Colds: What Studies Show

A German nutrition review found that low vitamin D levels are statistically linked to a higher risk of respiratory infections, but it does not guarantee protection against colds. The German Nutrition Society analyzed 73 studies, suggesting supplementation might help prevent infections in deficient individuals, though this is not certain. A 2021 Australian study of over 21,000 older adults found no significant difference in infection rates between those taking vitamin D and a placebo. Experts advise against high-dose supplementation for everyone, recommending a blood test to check status. A daily intake of 20 micrograms (800 IU) is suggested only for those with a deficiency, as extra doses offer no additional preventive benefit.