Multivitamins: Be Wise When You Supplement; Your Health Depends on it

May 27, 2016 by Joel Fuhrman, MD

All multivitamins are not created equal; some can do more harm than good. So how much do you know about the vitamins you are taking? Do you know the answers to these three questions?

  1. Do multivitamin and mineral supplements provide valuable nutritional insurance against deficiencies and insufficiencies?
  2. Can certain vitamins in pill form damage our health?
  3. Are most conventional multivitamins a waste of money?

You may be surprised to learn for conventional multivitamins, the answer yes to all three, because they are a mix of helpful and hurtful ingredients.

Most studies have not shown that taking a multivitamin and mineral supplement reduces the risk of cardiovascular events, cancer, or premature death.1-3 However, studies testing whether conventional multivitamins reduce cancer risk or have positive or negative effects on mortality are worthless because there are too many variables involved. And, unbeknownst to many, several ingredients included in typical multivitamin/multimineral supplements have been linked to increased risk of cancer.

Therefore, the values of potentially beneficial ingredients are most likely offset by the effects of the harmful ingredients, making the scientific value of such a study dubious.

Because most of these studies have shown no strong effect in either direction speaks to the fact that typical multivitamins are a mixture of helpful and harmful ingredients. In 2013, supporting this assertion, a systematic review on multivitamins overall found no effect of multivitamins on cardiovascular disease or cancer. But a few of the analyzed studies reported significant risks (increased risk of hip fracture or cancer) associated with individual ingredients, such as vitamin A, beta-carotene and folic acid.3

Of course, micronutrient deficiencies can damage our health, and well-designed supplements help us avoid those deficiencies. To supplement effectively and intelligently, what is needed is a careful analysis of the benefits and risks for every single ingredient, and utilizing only those individual elements that are helpful and safe, leaving out those that may cause harm.

Consider two common ingredients in multivitamin and mineral supplements: vitamin B12 and copper. Vitamin B12, which becomes more difficult to absorb with age, is a common deficiency in those 60 and older.Taking supplemental B12 is likely to be beneficial, especially since adequate vitamin B12 levels may help to protect against Alzheimer’s disease.5

Copper is an essential mineral, but in excess it may promote cognitive decline in older adults.6 Taking supplemental copper above the adequate amounts we can get from the diet is likely not beneficial, and may be harmful.

In a study on multivitamins containing both B12 and copper, would we see any significant effect in either direction on cognitive decline or dementia? Probably not, since the benefit from B12 adequacy would presumably be offset, or at least blunted, by a detrimental effect of excess copper.

In addition, one supplement doesn’t fit all. Individual diet style and lifestyle must be considered, and supplementation should accommodate that. For example, a vegan may need more B12 and zinc, whereas a high meat or high seafood eater may need more folate, mixed carotenoids, magnesium and plant phytochemical extracts.7-10

Another issue is iodine intake, which is dependent on whether one consumes iodized salt, seafood or seaweed, or none of these. We also have varying needs for Vitamin D depending on skin tone, body fatness and whether we work outdoors in a warm sunny climate or indoors in a northern climate.

It is impossible to make one multivitamin and mineral supplement meet the needs of everyone’s diet. However, we can offer a supplement that complements the benefits of a diet rich in natural plant foods, in which animal products are absent or low. From that multivitamin, additional supplements can be added occasionally depending on blood test results, because B12 absorption can fall with aging.

We must recognize that there is a broad range of individual variance and some people may need more of certain nutrients than others. We also have to recognize that even for the best ingredients; too much may not be health-supporting. For example even excessive amounts of certain B vitamins may have a negative influence on lifespan.11

However, the most powerful lifespan shortening substance is likely synthetic folic acid which has been found to increase risk for several cancers.12 Even taking supplemental natural folate may have a negative impact on someone who already consumes large amounts of food folate.

Both too little and too much of certain minerals may also have negative consequences, such as too much copper (as discussed) or selenium and for certain nutrients the potential risk of excess is more than other nutrients.6,13 And, some people, because of lower caloric intake or medical conditions, may require more of certain nutrients for repair and restoration of normalcy.

In other words, you need a team of experts who know the pros and cons of every ingredient, and who have an understanding of your potential dietary insufficiencies to properly advise your decision–making process regarding supplements.

In conclusion, don’t follow the masses. If you follow a vegan or near vegan diet, make sure you are not deficient and have adequate exposure from your diet and supplement regimen to Vitamin D, iodine, zinc, B12, K2, and DHA and EPA.

Taking carefully and intelligently designed supplements is not only more convenient than trying to take each needed ingredient separately, but can also save you from worry and the continuing need to evaluate your blood tests for nutritional adequacy.

I want my loved ones, friends, patients and readers to receive the best possible nutritional protection so I advise the conservative use of supplements to achieve nutritional excellence.

Do not gamble with your health. Deficiencies can be dangerous, even life-threatening Over more than 25 years of practice, caring for a large community of plant-based eaters, I have seen vegans severely depressed and have had cases of irreversible dementia that never had to occur since DHA-EPA deficiency was a major contributor.

I have experienced patients with iodine issues, and even lower limb paralysis from B12 deficiency. I have even seen advanced atherosclerosis and death in those refusing to supplement with B12 following the advice of their health guru.

Death is a large price to pay for nutritional misinformation. We must always err on the side of caution and not let adherence to some rigid philosophy push us into risking the health of the only brain and body we have. Supplement wisely.

  1. Prentice RL. Clinical trials and observational studies to assess the chronic disease benefits and risks of multivitamin-multimineral supplements. Am J Clin Nutr 2007, 85:308S-313S.
  2. NIH State-of-the-Science Conference Statement on Multivitamin/Mineral Supplements and Chronic Disease Prevention. NIH Consens State Sci Statements 2006, 23:1-30. 
  3. Fortmann SP, Burda BU, Senger CA, 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 2013. 
  4. Allen LH. How common is vitamin B-12 deficiency? Am J Clin Nutr 2009, 89:693S-696S. 
  5. Hooshmand B, Solomon A, Kareholt I, et al. Homocysteine and holotranscobalamin and the risk of Alzheimer disease: a longitudinal study. Neurology 2010, 75:1408-1414. 
  6. Morris MC, Evans DA, Tangney CC, et al. Dietary copper and high saturated and trans fat intakes associated with cognitive decline. Arch Neurol 2006, 63:1085-1088. 
  7. de Bortoli MC, Cozzolino SM. Zinc and selenium nutritional status in vegetarians. Biol Trace Elem Res 2009, 127:228-233. 
  8. Burnett-Hartman AN, Fitzpatrick AL, Gao K, et al. Supplement use contributes to meeting recommended dietary intakes for calcium, magnesium, and vitamin C in four ethnicities of middle-aged and older Americans: the Multi-Ethnic Study of Atherosclerosis. J Am Diet Assoc 2009, 109:422-429. 
  9. Yang Q, Cogswell ME, Hamner HC, et al. Folic acid source, usual intake, and folate and vitamin B-12 status in US adults: National Health and Nutrition Examination Survey (NHANES) 2003-2006. Am J Clin Nutr 2010, 91:64-72. 
  10. Troesch B, Hoeft B, McBurney M, et al. Dietary surveys indicate vitamin intakes below recommendations are common in representative Western countries. Br J Nutr 2012, 108:692-698. 
  11. Bitterman KJ, Anderson RM, Cohen HY, et al. Inhibition of silencing and accelerated aging by nicotinamide, a putative negative regulator of yeast sir2 and human SIRT1. J Biol Chem 2002, 277:45099-45107. 
  12. Baggott JE, Oster RA, Tamura T. Meta-analysis of cancer risk in folic acid supplementation trials. Cancer Epidemiol 2011.
  13. Stranges S, Navas-Acien A, Rayman MP, Guallar E. Selenium status and cardiometabolic health: state of the evidence.Nutrition, metabolism, and cardiovascular diseases : NMCD 2010, 20:754-760.

Joel Fuhrman, M.D. is a board-certified family physician, seven-time New York Times bestselling author and internationally recognized expert on nutrition and natural healing, who specializes in preventing and reversing disease through nutritional methods. Dr. Fuhrman coined the term “Nutritarian” to describe his longevity-promoting, nutrient dense, plant-rich eating style.
For over 25 years, Dr. Fuhrman has shown that it is possible to achieve sustainable weight loss and reverse heart disease, diabetes and many other illnesses using smart nutrition. In his medical practice, and through his books and PBS television specials, he continues to bring this life-saving message to hundreds of thousands of people around the world.