Vitamin dietary supplements
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The Role of Vitamin Dietary Supplements in Health
Prevalence of Vitamin Supplement Use
Vitamin dietary supplements are widely used among adults in the United States. Data from the National Health and Nutrition Examination Survey (NHANES) indicates that more than half of U.S. adults have used dietary supplements, with multivitamins/multiminerals being the most common 126. This widespread use is influenced by various demographic and lifestyle factors, including gender, age, education level, and physical activity 26.
Impact on Vitamin Intake
Higher Vitamin Intakes Among Supplement Users
Research shows that individuals who use dietary supplements generally have higher vitamin intakes from both food and supplements compared to nonusers. For instance, male supplement users have higher intakes of folate and vitamins A, E, and K from food sources, while female users have higher intakes of folate and vitamins A, C, D, and E 1. This increased intake helps reduce the prevalence of vitamin deficiencies but also raises the risk of exceeding the Tolerable Upper Intake Levels for certain vitamins, such as folic acid and vitamins A, B-6, and C 1.
Contribution to Nutrient Requirements
Dietary supplements play a crucial role in meeting the nutritional needs of individuals, especially those at risk of deficiencies. For example, vitamin A and iron supplements are essential in developing countries to address deficiencies among women of reproductive age, infants, and children. Similarly, folic acid is crucial for women of reproductive age and during pregnancy, while vitamin D and calcium are important for bone health in older adults 4.
Health Outcomes and Disease Prevention
Cancer and Chronic Disease Prevention
The potential of dietary supplements to prevent chronic diseases, including cancer, has been a subject of intense debate. Some studies suggest that daily low-dose multivitamin supplementation can reduce the incidence of cancer and cataracts, particularly among men 4. In Linxian, China, supplementation with beta carotene, vitamin E, and selenium was associated with a significant reduction in cancer mortality, particularly stomach cancer 8.
Mental Health Benefits
Dietary supplements also show promise in mental health, particularly in the treatment and prevention of depression. Supplements such as polyunsaturated fatty acids (PUFAs), vitamin D, and probiotics have been found effective in reducing depressive symptoms. For instance, beneficial effects were observed with daily doses of 0.7-2 g EPA and 0.4-0.8 g DHA over periods ranging from three weeks to four months 9.
Risks and Considerations
Potential for Excess Intake
While dietary supplements can help address nutrient deficiencies, there is a risk of excessive intake, particularly with fat-soluble vitamins that are stored in the body's tissues and organs. This can lead to toxicity, although it is less common with water-soluble vitamins, which are more readily excreted by the body 5.
Importance of Balanced Diet
Despite the benefits of dietary supplements, a balanced diet remains the best approach to meeting nutritional needs. Supplements should be used to complement, not replace, a healthy diet rich in fruits, vegetables, and whole foods 35.
Conclusion
Vitamin dietary supplements are a valuable tool in addressing nutrient deficiencies and improving overall health. They are particularly beneficial for specific populations at risk of deficiencies and in the prevention of certain chronic diseases. However, it is essential to use them judiciously to avoid the risks associated with excessive intake and to prioritize a balanced diet for optimal health.
Sources and full results
Most relevant research papers on this topic
Examination of vitamin intakes among US adults by dietary supplement use.
Supplement use is associated with higher mean intakes of some vitamins from foods than nonusers, but may contribute to excess intake for certain vitamins.
Observational Study
Highly CitedDietary supplement use by US adults: data from the National Health and Nutrition Examination Survey, 1999-2000.
Dietary supplement use is prevalent among US adults, with factors like gender, age, education, and lifestyle influencing supplement use.
Observational Study
Rigorous JournalHighly CitedHealth and Dietary Supplements
Nutritional supplements can improve performance, physical appearance, and avoid dangerous drugs, but excessive consumption may cause side effects.
Systematic ReviewDietary supplements and disease prevention — a global overview
Dietary supplements can improve health and meet micronutrient requirements, particularly in developing countries and those at risk of deficiencies.
Highly CitedRevisiting food-sourced vitamins for consumer diet and health needs: a perspective review, from vitamin classification, metabolic functions, absorption, utilization, to balancing nutritional requirements
Food-sourced vitamins are essential for human metabolism and health, with their bioavailability dependent on food composition and interactions, and their toxicity from supplementation is rare.
Systematic ReviewRigorous JournalDietary supplement use in the United States, 2003-2006.
Dietary supplement use in the U.S. is widespread, with one-third of adults aged 70 and older using multivitamin-multimineral supplements, and data on nutrient intake from foods should be combined with supplement data for accurate nutrient exposure.
Observational Study
Very Rigorous JournalHighly CitedVITAL Signs for Dietary Supplementation to Prevent Cancer and Heart Disease.
Dietary supplementation with vitamin D and omega-3 fatty acids may help prevent cancer and heart disease, but long-term health benefits remain inconclusive.
RCTRigorous JournalNutrition intervention trials in Linxian, China: supplementation with specific vitamin/mineral combinations, cancer incidence, and disease-specific mortality in the general population.
Dietary supplementation with beta carotene, vitamin E, and selenium may reduce cancer risk and mortality rates in Linxian adults.
RCTHighly CitedDietary Supplementations and Depression
PUFA, vitamin D, and probiotics are effective adjunctive therapies for depression treatment, with varying dosages and durations of use.
Systematic ReviewRigorous JournalThe use of dietary supplements by athletes
Dietary supplements may be useful for athletes in specific circumstances, but their use should be based on a full understanding of potential benefits and risks, and consulted with a sports nutrition professional.
Highly Cited