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We all know people who take a fistful of vitamins and mineral supplements every day. They swear by them. They say they feel better when they take them. They claim to have more energy and sleep better, and when they don’t take them they feel bad. Many are so convinced of their benefit, they make a business of selling them, and you’re their number one target.

Well, do these supplements really help? Is there scientific evidence that they work? Is the expense of buying them justifiable? Do they cause any harm? I always thought that taking vitamins was a waste of money, and told patients I didn’t recommend them. There are, however, instances where they do help, and I’ll come to that later.  

Statistics show that one-third of US children and adolescents, take multi-vitamin-mineral supplements of various combinations. Children don’t actually take them. They are given to them by their parents. Healthcare professionals often recommend them as part of routine well-child care. At certain ages, children have increased need for supplementation and vitamins are indicated. Also, some families eat poorly because of financial challenges, or have well water, and need vitamins and/or fluoride supplementation. Free samples of multi-vitamins were always available at my office to dispense to those children in need. 

One established fact is as family income and educational levels increase, so does the use of supplements. 40% of Asian and White children and teens take supplements compared to 21% of Black and 27% of Hispanic children. Vitamin D, Vitamin C, probiotics, melatonin, calcium, and omega-3 fatty acids are the types most frequently taken. Taking multiple supplements sometimes can lead to excessive intake of some vitamins or minerals, and that’s an issue of its own. 

Adults are a different animal. They reside at both ends of the spectrum; some take handfuls of anything, some take nothing, and the rest take only those things the doctor recommends. Which group you fall into depends on your mindset. Either you’re Mr. Macho and don’t need any of “that stuff,” or you’re Nervous Mervis who takes anything he’s heard might help, and lots of it, or you’re Alan Average who takes what you and your doctor think you need. “Over-the-counter supplements are most often taken by people with no clinical signs of deficiency.”

Some supplements, like vitamin D, have scientific evidence of benefit. Some have scant evidence and only help as placebo. Some, like vitamin E, are continually being either advocated or discouraged depending on the study du jour. One day you read that it prevents cardiovascular disease; the next, you hear it doesn’t. No one can make up their mind! 

Vitamin D usage in adults increased fourfold between 1999 and 2012 when it was thought deficiency was the basis for a number of medical problems. It has since lost its place of prominence when it was not found to be the panacea it was once thought to be. Omega-3 fatty acid use has increased sevenfold because it was thought to prevent arteriosclerosis. Opinions on this change back and forth. American women over age 65 are the demographic who most frequently use vitamins and supplements.

There also can be “too much of a good thing.” Too much vitamin D, A, E, K, niacin, B6, selenium, and calcium all can cause problems called HYPERVITAMINOSES. The excessive intake of these vitamins can be just as bad as the lack of them. But “substantial evidence indicates that intakes greater than the recommended dietary allowances (RDAs) of certain vitamins and minerals such as calcium, folic acid, vitamin D, selenium, and chromium reduce risk of certain diseases for some people. Limitation of intakes to the RDA’s would preclude reductions in disease from these nutrients,” meaning sometimes you have to take more than  the recommended amount of a supplement for it to help.

The bad news is “Evidence from randomized control trials does not support benefits of supplements in reducing the risks of cardiovascular disease, cancer, or type 2 diabetes in healthy people with no clinical nutritional deficiencies.” In other words, those mega-doses of vitamins aren’t going to prevent a stroke or heart attack or keep you alive any longer. “Anti-oxidants…vitamin D…omega-3 fatty acids…had no effect on cardiovascular risk.” 

Another fact is, “Current evidence does not support a role of vitamin and mineral supplements in reducing cancer risk.” That would include the use of Beta-carotene, vitamins A and E, and folic acid. The same is true for reducing type 2 diabetes—vitamins C, E, fish oil, and Beta carotene are of no help.

Vitamin D and calcium do help osteoporosis, but fracture risk is either unaffected or only slightly decreased. Your bones get stronger but are no less susceptible to fracture.

Since the elderly often have “reduced nutrient intake” or poor intestinal absorption of food, they are at increased risk of “malnutrition.” Supplementation in those cases is necessary. 

In the reference by Comerford, studies of the effects of vitamin and mineral supplementation on certain diseases were reported. In all 16 studies cited, supplements caused improvements in only a few measures—mathematical processing, energy and mood, and memory and recall. However, other similar studies using the same supplements did not show the same results. 

Dr. G’s Opinion: This is a controversial subject. Vocal supporters line up both for and against. I sit in the “against” camp and feel vitamins and minerals are only indicated where there is a scientifically proven need, eg. osteoporosis, measured vitamin D deficiency, pernicious anemia (measurable lack of vitamin B-12), unfluorinated water, restricted diets lacking in certain nutrients, etc. Taking vitamin C to prevent colds is ineffective. Taking Centrum Silver does not lower cholesterol, blood sugar, or keep you young. It also has no effect on prostate, breast, or other cancers. Taking shark cartilage to prevent arthritis is also ineffective. The jury is still undecided on whether selenium really slows macular degeneration.

Some of the handful of pills people take are helpful, but most of them just enter the bloodstream without helping anything and are eliminated in the urine. Unless there is a proven need, money spent on most supplements could be better used for something else, and in my opinion should be.

References: Hathcock JN. Vitamins and Minerals: efficacy and safety Am J Clin Nutr 1997 Aug;66(2):427-437.

Zhang FF, Barr SI, et al. Health effects of vitamin and mineral supplements. BMJ 2020 Jun 29;369:2511.

Comerford KB. Recent Developments in Multivitamin/Mineral Research Am Soc Nutr Adv Nutr 2013;4:644-656. 

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