Introduction

Are supplements of vitamins and minerals beneficial? Approximately 80% of the elderly (60 years and older) regularly consume vitamin and mineral supplements without understanding whether such supplements are beneficial or harmful.

There are several reasons for the high consumption of vitamin and mineral supplements by the older adult.

 a)  There is a widespread unfounded concern that their current diet may be deficient in vitamins and minerals, hence necessitating supplements. 

b)  There is a desire to reduce the risk of disease such as cardiovascular disease and cancer.  Vitamin and mineral supplements are believed to lower this risk. 

c)  There is the common wish to forestall age changes such as cognitive decline.  As promoted in advertisements, supplements may minimize age changes. 

d)  Then there is the only demonstrated reason for taking vitamin and mineral supplements and that is to treat a known vitamin/mineral deficiency arising from disease, frailty, chemotherapy or an incredibly poor diet.

This blog will discuss the findings that show

1.  vitamin and mineral supplements do not decrease disease risk or age-related changes,

2.  that most diets supply adequate amounts of vitamins and minerals and

3.  only documented vitamin and mineral deficiencies should be treated with supplements.

Background

Vitamin and mineral supplements are classified as dietary supplements.  Dietary supplements are essentially ingested ingredients intended to supplement the diet (https://www.fda.gov/). Other dietary supplements include herbs and botanicals, probiotics, amino acids, to name a few.

The FDA loosely regulates dietary supplements.  Regulation covers the right to examine manufacturing facilities, handle complaints of adverse effects, and receive required notification for new supplements not found in food.  However, the FDA does not assess dietary supplements for safety or efficacy as required for a new drug prior to marketing.  Essentially, dietary supplements are regulated as a special category of foods.  Certain health claims are permitted as long as the supplement displays the FDA’s disclaimer that the product has not been evaluated by the FDA and is not intended to diagnose, treat, cure or prevent disease.  Thus, it is the manufacturer of the supplement that determines the quality and quantity of dietary supplements.

The dietary supplement industry is a multibillion dollar industry with projected continued growth. Ironically, it is especially lucrative in developed countries where there is an abundance of nutritious and fortified foods.  The most popular dietary supplements in the US are the vitamin/mineral supplements, followed by vitamin D, then omega-3 fatty acid, calcium and vitamin B12 (Mishra S et al., 2021).  

Vitamin and mineral supplements do not decrease the risk of disease.

The diseases in question are non communicable age-related diseases: cardiovascular disease, cancers, diabetes, and chronic kidney disease. 

The conclusion derived from results of the most rigorous clinical trials to date is that use of vitamin and mineral supplements, together or individually (for up to 16 years or more) do not decrease the risk of cardiovascular disease (and associated events e.g. stroke), cancer, type II diabetes, chronic kidney disease and all-cause mortality (Fortmann et al., 2013; Semsek et al., 2021; O’Connor et al., 2022). 

Study Details

The reviews cited above critiqued hundreds of relevant clinical studies, selecting those with definitive objectives and measurable endpoints.  Study duration ranged from 3 to 36 years with most under 10 yrs. Vitamins and minerals were either commercially available multivitamins or select vitamins and minerals prepared by the principal investigators.  These studies enrolled healthy adults without nutritional deficiencies.  Some early studies reported beneficial effects of vitamin and mineral supplements on disease risk but as the authors point out, these were observational studies that cannot control for confounding factors such as randomization of participants.  As a result of this flaw, the observed positive effects of supplements in observational studies cannot be separated from other significantly influencing factors such as  lifestyle choices of physical exercise and healthy eating.  

Reported Harm

It is noted that two clinical trials reported a borderline statistical decrease in cancer risk in men taking multivitamins and minerals (Hercberg et al., 2004; Grazino et al., 2012).  This minor effect, evident only in men, was not strong enough to alter the main conclusion that use of vitamin and mineral supplements do not provide a health benefit regarding disease suppression.  Furthermore, some vitamins alone or in combination actually increased risk of lung cancer.  Specifically, several trials showed increased lung cancer risk with use of beta-carotene (converted to vitamin A in the body)  alone or in combination with vitamin A and an increase in prostate cancer in smokers using vitamin E (Zhang et al., 2020).

Vitamin and mineral supplements do not reduce age-related changes.

A comprehensive literature addressing this issue does not exist at present.  Here is the current understanding.

Aging of Bone 

Vitamin D is an important player in maintaining bone density and hence optimizing bone strength to prevent breakage from a fall.  However, the body receives vitamin D from many sources such as sunshine-dependent synthesis in the skin and kidney, from a number of foods (tofu, seafood) and with consumption of fortified cereals and juices.

A recent review (Giustina et al., 2022) published a consensus statement that after reviewing the best studies to date, found that with the exception of house-bound or nursing home residents, the elderly receive sufficient amount of vitamin D from diverse sources mentioned above and hence do not need vitamin D supplements.  However, if in doubt, a simple blood test can determine whether the vitamin D level is at adequate (established range 30 to 50 nmol/L; 12–20 ng/mL).

Aging of the brain 

Although there are many proven ways to optimize cognitive function (see Insight 6 – More longevity building: Ways to minimize brain aging), older adults obsess about their mental acuity.  Two studies (Grodstein et al., 2013; Baker et al., 2022) examined the effect of daily use of a commercially available multivitamin (containing minerals).  The first of the two, the Physicians’ Health Study II measured cognitive function 4 times over a 12 year period. 

Nearly 6000 males ≥ 65 years (included nearly 6,000)participated in the first study.  This study found no effect of supplements on cognitive test scores.  The second study was smaller with a test group of 500 participants. This study included both men and women and assessed cognitive function annually over a 3 year period.  This study concluded that global cognitive scores improved with supplementation. 

Whether supplements benefit the mind remains unresolved with these conflicting results. However, there are some interesting aspects to these two studies.  Both studies, although using comparable and acceptable cognitive tests, measured cognitive function over the telephone.  The investigators indicate that telephone testing is less expensive and yields the same results as in-person testing.  The reference for this was the comparison to in-person test results of 24 individuals.  Secondly, there was a expected “practice” effect with repeat testing in both studies.  This means the test scores increase with repeat testing in both the supplement group and the placebo group.  As a result, the benefit reported in the second study on the last round of testing is modest at best.  Whether this small effect will translate into significant mental acuity in daily life was not measured and remains unknown. 

Healthy adults are unlikely to be vitamin and mineral deficient.

The Food and Nutrition Board of the National Research Council determines the recommended dietary allowance (RDA) of essential nutrients including vitamins and minerals (https://www.ncbi.nlm.nih.gov/books/NBK234926).  This board defines RDAs as “the levels of intake of essential nutrients that, on the basis of scientific knowledge, are judged by the Food and Nutrition Board to be adequate to meet the known nutrient needs of practically all healthy persons.”  They also indicate that consumption of a varied diet (“variety of foods from diverse food groups”) achieves the RDA for vitamins and minerals for most adults.   In addition, the availability of fortified foods further assures attainment of the RDA.  

Vitamin and mineral supplements ameliorate confirmed vitamin and mineral deficiencies.

Scientists define nutritional deficiencie as “intake of nutrients that is lower than the estimated average requirement” (Kiani et al, 2022).   Nutritional deficiencies are likely in situations of poor appetite due to medications, frailty syndrome and metabolic diseases limiting nutrient absorption.  Symptoms and low blood concentrations of vitamins and minerals alert the physician to a possible deficiency.  Uncorrected vitamin/mineral deficiencies definitely lead to serious debilitating conditions. They are goiter (iodine), rickets (and osteomalacia) (vitamin D), beriberi (thiamine, B1), pellagra (niacin, B3), and pernicious anemia (B12).  Correcting vitamin/mineral deficiencies under physician supervision is necessary. It should be the only reason older adults should consume select vitamin/mineral supplements.

Conclusions

There is little convincing evidence for the older adult to take vitamin and mineral supplements.  Diets provide adequate amounts of vitamins and minerals and supplements do not lower the risk for age-related diseases.

In place of supplements

To minimize disease risk and age-related age changes, scientist suggest alternatives to supplements that include the following:

a) adherence to the Mediterranean and related diets (Insight 10-Best Longevity diet = Mediterranean Diet), b) commitment to a physical exercise program (Insight 3: Ways to retard skeletal muscle aging Insight 4: Anti-aging benefits of aerobic and stretch exercises, Insight 5 – Optimizing Balance) c)engagement in mentally challenging activities (Insight 6 – More longevity building: Ways to minimize brain aging) and d) adequate sleep (Insight 7 – Brain Health and Sleep).

References

Baker et al., Effects of cocoa extract and a multivitamin on cognitive function: A randomized clinical trial. Alzheimers Dement  Sep 14, 2022.

Fortmann SP et al., Vitamin and Mineral Supplements in the Primary Prevention of Cardiovascular Disease and Cancer: An Updated Systematic Evidence Review for the U.S. Preventive Services Task Force Ann Intern Med.159:  824-834, 2013.

Giustina A. et al., Vitamin D in the older population: a consensus statement Endocrine. Oct 26:1-14, 2022.

Grodstein et al., A Randomized Trial of Long-term Multivitamin Supplementation and Cognitive Function in Men: The Physicians’ Health Study II  Ann Intern Med. 159(12): 806–814, 2013.

Kiani et al, Main nutritional deficiencies. J Prev Med Hyg  63(SUPPL. 3): E93-E101, 2022.

Mishra S et al., Dietary Supplement Use Among Adults: United States, 2017–2018  NCHS Data Brief No. 399, Feb;(399):1-8, 2021.

O’Connor EA et al., Vitamin, Mineral, and Multivitamin Supplementation for the Primary Prevention of Cardiovascular Disease and Cancer: A Systematic Evidence Review for the U.S. Preventive Services Task Force Evidence Synthesis, No. 209 Agency for Healthcare Research and Quality (US);  Jun Report No: 21-05278-EF-1, 2021.

Simsek B. et al., Effects of vitamin supplements on clinical cardiovascular outcomes: Time to move on! – a Comprehensive review. Clinical Nutrition ESPEN 42:  1-14, 2021

Zhang et al., Health effects of vitamin and mineral supplements BMJ  369: m2511, 2020.