Study on Dietary Supplements and Mortality Among American Adults

Market Overview of Dietary Supplements

In 2015, the vitamin supplement market generated over US$50 billion in revenue. Projections suggest that by 2024, the global dietary supplements market will expand to US$278 billion. Many individuals take dietary supplements to address nutrient deficiencies, prevent health issues, or potentially lower the risk of certain diseases.

Definition and Common Types of Dietary Supplements

According to the U.S. Federal Food, Drug, and Cosmetic Act, a dietary ingredient can include vitamins, minerals, herbs, amino acids, and other substances that help supplement the diet. The FDA identifies commonly consumed dietary supplements as calcium, vitamin D, fish oil, Echinacea, garlic, and green tea.

Research Objectives and Methodology

A recent study published in the Annals of Internal Medicine examined the relationship between dietary supplement usage and mortality rates, focusing on all causes, cancer, and cardiovascular disease (CVD). The study also analyzed the impact of nutrient intake from food compared to supplements on mortality.

Data for the study was gathered from participants in the U.S. National Health and Nutrition Examination Survey (NHANES). Participants reported their dietary supplement usage over the past 30 days, including names, frequency, and duration of intake. Trained interviewers assessed nutrient intake from foods through 24-hour diet recalls. Mortality outcomes were linked to the National Death Index using probabilistic matching.

Findings on Nutrient Intake and Mortality Risk

The study revealed that the most frequently used dietary supplements included vitamin D, vitamin C, vitamin E, calcium, magnesium, and zinc. Adequate intake of vitamin K and magnesium was associated with a lower risk of all-cause mortality, while sufficient levels of vitamin A, vitamin K, copper, and zinc correlated with reduced mortality from CVD. Notably, these benefits were linked solely to nutrient intake from food, not supplements.

Conversely, excessive calcium intake (1,000 mg/day or higher) from supplements was associated with a heightened risk of cancer mortality. Additionally, vitamin D supplementation exceeding 10 mcg/day was linked to increased all-cause mortality and cancer risk in individuals with blood levels of 25-hydroxyvitamin D at 50 nmol/L or higher, although this was not observed in those with lower levels.

Strengths and Limitations of the Study

A significant strength of this study is its inclusion of a nationally representative sample of U.S. adults. However, several limitations were noted. The assessment of dietary supplement use was limited to the previous 30 days, potentially misrepresenting habitual usage. Additionally, self-reported supplement and dietary intake may introduce recall bias and measurement errors.

Healthier Lifestyle Among Supplement Users

Researchers found that supplement users generally led healthier lifestyles compared to non-users, exhibiting better dietary habits, healthier weights, increased physical activity, and lower smoking rates. This may have influenced the study’s results. Furthermore, supplement users had higher nutrient intakes from food than non-users, potentially lowering their risk of nutrient inadequacy and mortality.

Conclusions on Dietary Supplements and Health Benefits

The study concluded that dietary supplements did not demonstrate a direct link to mortality benefits. Instead, adequate nutrient intake from food was associated with lower mortality rates, while excessive nutrient intake from dietary supplements could pose health risks. These findings suggest that dietary supplements alone do not confer significant health advantages.

Reference

Chen F et al. “Association Among Dietary Supplement Use, Nutrient Intake, and Mortality Among U.S. Adults: A Cohort Study.” Annals of Internal Medicine. 2019.

For further information on the dietary supplements market, visit:
– https://www.grandviewresearch.com/press-release/global-dietary-supplements-market
– https://www.fda.gov/Food/DietarySupplements/ProductsIngredients/default.htm
– https://www.fda.gov/food/resourcesforyou/consumers/ucm109760.htm