Do We Really Need Multivitamins?

One third of all adults in the US take multivitamins (MVI) and 70% of those over 65 take a MVI or supplement. It is a multibillion-dollar industry, so there is great incentive for companies to promote their use.

Since there are so many different vitamin formulations available, we will focus on a standard-type multivitamin which contains about 100% of the Recommended Daily Allowance of over 20 vitamins and minerals. Let’s begin with those that could benefit from a daily multivitamin.

Who might benefit from taking multivitamins?

Diseases caused by a lack of individual nutrients in the diet, like scurvy (vitamin C deficiency), or rickets (vitamin D deficiency), are rare in the US because there is access to a wide variety of foods, and many are fortified with vitamins. There are special situations where someone might need additional vitamins or minerals.  The elderly, pregnant women, those with malabsorption problems or on special diets, and those on certain medications, are all groups that might benefit from taking a multivitamin.

Elderly

As we age, we absorb less vitamin B12, so the National Academy of Medicine recommends those over 50 years old, consume food sources that are fortified with B12 or take a B12 supplement (though not necessarily in the form of a multivitamin).

Conception and Pregnancy

All women planning to get pregnant, or currently pregnant, should take folic acid supplements because it can prevent neural tube defects. However, even though most MVIs contain folic acid, pregnant women should not take a prenatal multivitamin with large amounts of vitamin A, because taking excessive vitamin A has been linked to congenital abnormalities.

Malabsorption

Those who have digestive issues causing nutrient malabsorption, or those who have had surgery where the stomach or intestines have been impacted, might benefit from taking a multivitamin. In some cases, multivitamins might be recommended because certain nutrients are not absorbed well. For example, in alcoholism, several B vitamins and vitamin C are not well absorbed.

Special diets

Those following special diets that might limit certain nutrients may become deficient in these nutrients. For example, vegans and possibly vegetarians may lack vitamin B12 since it is mainly found in animal foods. Other nutrients vegans may lack include calcium, vitamin D, iron, omega-3 fatty acids, zinc, and iodine, so they may benefit from taking a multivitamin or specific nutrients.

Medications

There are some medications that might deplete vitamins or minerals. Some diuretics used to lower blood pressure may deplete calcium, magnesium, and potassium. Some medications prescribed for acid reflux may impact absorption of vitamin B12, calcium, and magnesium and some medications prescribed for Parkinson’s disease may decrease absorption of folate, B6 and B12.

Is there a downside to taking multivitamins?

The drawbacks of multivitamins supplementation include possible toxicity from mega-dosing, potential interaction with medications, and cost.

If you decide to take a multivitamin, the following are tips for making a safer selection:

1. Pick a multivitamin labeled with United States Pharmacopeia (USP) designation. The USP designation means that the supplement is regulated to contain the ingredients it states it contains and that it meets certain minimum standards, such as not containing contaminants. The FDA does not regulate dietary supplements so they could actually contain more or less of the ingredient than the label states.
2. Select a multivitamin containing no more than the Recommended Daily Allowance (RDA) for each vitamin or mineral. Taking a “mega” vitamin that contains more than the RDA, especially with fat soluble vitamins (A, D, E, and K) can cause toxicity, as fat-soluble vitamins are stored in the liver. Smokers should not take large amounts of beta-carotene or vitamin A because they can increase the risk of lung cancer. Water soluble vitamins are excreted in the urine, so they are not accumulated in the body, but they can make for expensive urine.
3. If you are considering starting on a multivitamin, ask your pharmacist to check if any of your current medications might have an interaction with any of the vitamins or minerals in the MVI.

In a Nutshell

Though there are special groups, as described above, that could clearly benefit from taking multivitamins, most cases warrant only replenishment of certain specific vitamins and minerals. The bottom line is that most people eating a healthy diet don’t need to take a daily multivitamin, and the billions of dollars adults in the US spend on multivitamins might be better spent purchasing healthy foods like fruits, vegetables, whole grains, good sources of animal or plant protein, and healthy fats. If you are looking to consume more of these nutrient rich foods, there are many recipes including these nutrients in the Avance Care Cookbook.

If you want to know more about vitamin and mineral intake for your specific needs, schedule an appointment with an Avance Care Registered Dietitian, who can help you develop a nutritionally adequate eating plan. Appointments can be telehealth from the convenience of your home or office or schedule an in person meeting at one of our many locations. Call A Dietitian Coordinator today at 919.237.1337, or schedule online here.

References

1. Is There Really Any Benefit to Multivitamins? https://www.hopkinsmedicine.org/health
2. National Institutes of Health, Office of Dietary Supplements. Multivitamin/mineral Supplements fact sheet. https://ods.od.nih.gov/factsheets/MVMS-HealthProfessional/
3. Should I Take a Daily Multivitamin? https://www.hsph.harvard.edu/nutrition source/multivitamin
4. Teratogenicity of high vitamin A intake. N Engl J Med 1995 Nov 23:333(21):1369-73)
5. How prevalent is vitamin B12 deficiency among vegetarians? Nutr Rev. 2013 Feb;71(2):110-117)
6. Nutrition concerns and health effects of vegetarian diets. Nutr Clinical Practice. 2010 Dec;25(6):613-20)
7. Beta-carotene in multivitamins and the possible risk of lung cancer among smokers versus former smokers: a meta-analysis and evaluation of national brands (Cancer 2008 Jul 1;113(1):150-7)