Many Americans take supplements for immune support, but doctor recommendations are low

By Dr. Sanchari Sinha Dutta, Ph.D.Reviewed by Danielle Ellis, B.Sc.Feb 11 2025

Before the pandemic, about 1 in 9 U.S. adults used dietary supplements for immune benefits, with usage varying by age and health status

Researchers at the National Institutes of Health (NIH) have recently conducted a study to determine the prepandemic prevalence of dietary supplement usage for immune benefits among US residents. The study findings are published in JAMA Network Open.

Background

Dietary supplements are synthetic products that are intended to be added to the conventional diet to improve or maintain overall health. Common examples of dietary supplements include vitamins, minerals, herbs, botanical products, amino acids, and probiotics. These supplements also provide essential nutrients required for normal physiological activities.

According to the US Food and Drug Administration (FDA), consuming dietary supplements without a healthcare professional’s recommendation could be risky. Some supplements can interfere with medications, influence diagnostic processes, or have dangerous effects during surgery.

In the US, dietary supplement use is common, and the word immune or immunity is the most frequently used term. The word is found on more than 25,000 supplement labels in the Dietary Supplement Label Database. This suggests that immune benefits are a prevalent and marketable motivation for dietary supplement use.

One recent study has shown that a significant proportion of dietary supplements with immune health claims have inaccurate labels and contain additional ingredients not mentioned on the label.

These findings indicate that the claims made on the labels of dietary supplements could be misleading for consumers and that consumption of these supplements without a doctor’s recommendation might have negative health impacts.

In the current study, researchers determined the prevalence of using dietary supplements with perceived immune benefits, i.e., supplements to prevent colds or boost the immune system.

The study

The most recent National Health and Nutrition Examination Survey (NHANES) data and the Dietary Supplement Label Database (DSLD) were analyzed in the study to determine the proportions and characteristics of people who reported using dietary supplements for perceived immune benefits. Specifically, the study included pre-pandemic NHANES data from January 2017 to March 2020.  

The study also investigated whether label claims or recommendations by healthcare professionals influence the use of these dietary supplements.

Important observations

The study analyzed data from 15,560 participants in the NHANES. About 11% of them reported using dietary supplements for perceived immune benefits.

The usage of these supplements showed a positive association with several sociodemographic and health characteristics, including education, family income, food security, self-rated diet quality, and self-rated health status.

The prevalence of supplement usage also differed by age and was higher among those who identified as non-Hispanic Black, non-Hispanic White, and others.

Among consumers of these supplements, 28% reported using them exclusively for perceived immune benefits. Such prevalence was higher among older people, financially stable people, and those with poor health status.

About 60% of participants who consumed dietary supplements for immune benefits reported choosing a supplement based on the label claim related to immune benefits. In contrast, only 17% reported consuming these supplements based on a healthcare professional’s recommendation.

The prevalence of supplement usage due to healthcare professional’s recommendations was higher among older people and those with poor health status.

Study significance

The study finds that approximately 1 in 9 US residents uses a dietary supplement for perceived health benefits. Label claims related to immune benefits appear to be the most significant motivation for consuming dietary supplements for perceived immune benefits.

Besides preventing colds or boosting the immune system, the second most common reason for consuming these supplements is to maintain health or stay healthy. 

The study finds a low prevalence of dietary supplement usage among participants due to healthcare professionals' recommendations. However, such usage increases with increasing age and deteriorating health status.   

Researchers mentioned some study limitations in the published article. The study relied on self-reported data and potentially misidentified products, which might be associated with potential recall bias and measurement error.

However, the major strength of the study is its use of nationally representative data and detailed dietary supplement collection in NHANES.  

Overall, the study provides an overview of the frequency of dietary supplement usage for perceived immune benefits among US residents during the prepandemic period from January 2017 to March 2020.    

Given the high prevalence of dietary supplement usage in the US, the study findings highlight the need for further research in diverse populations to determine their clinical relevance. Although dietary supplements help improve nutrient intake, upstream nutritional disparities must also be addressed.