Should You Take A Multivitamin? Benefits & Side Effects
Put simply, a multivitamin is a nutritional supplement that includes a combination of vitamins, and often minerals. Vitamins are good for you, right? So it should be a no-brainer: why not take a multivitamin.
The hitch is that there is no standard or regulatory definition for multivitamins, meaning that the composition and quality can vary significantly from product to product.
Originally designed to protect against micronutrient deficiencies resulting from inadequate dietary intake, multivitamins’ application has been broadened over time. Now not only do you have vitamins to supplement nutrient deficiencies, but products with specialized formulas which purport to meet a variety of goals, including: increasing performance, aiding in weight loss, protecting against cancer and other illnesses, and improving longevity. Can vitamins really do all that, or is it just a big marketing game?
Multivitamin Summary: Key Takeaways
As this is a long article, here are the key takeaways so you can quickly reference them:
- The long term health benefits and risks of multivitamins are inconclusive
- If you do not have a balanced diet that includes fruits and vegetables, a multivitamin may be beneficial as nutritional insurance
- A whole foods powder supplement is likely the best bet, my favorites are Lindberg Fruits & Greens+
- If you don’t want to drink a powdered supplement, consider a true whole foods multivitamin supplement by Megafood, or Garden of Life
- While challenging, eating as much as 10 servings of fruits and vegetables a day is ideal
Whole-Food Vitamins vs Synthetic Vitamins
I like to break down multivitamins into two broad categories: whole-food derived (found in natural, whole foods) and synthetic (created in laboratories). Without getting too technical, it is important to understand that just because something has been synthesized in a laboratory doesn’t necessarily mean it is not the same as what is found in nature. However, it is often different – for instance, synthetic Vitamin E is structurally unique from that of natural Vitamin E.
With both types of vitamin on the market, the argument against using synthetic – which include chemical distillates – is that they are not recognized and used by the body the same way vitamins from whole foods are. In research on scurvy (a disease defined by a Vitamin C deficiency), for example, it was found that whole foods containing Vitamin C quickly eliminated the illness while ascorbic acid (the distillate) supplementation had little effect.1 Whole food vitamins (in their highest quality form) contain the vitamin complexes as they exist in nature, and are theoretically recognized by the body as whole foods.
Vitamins Do Not Have To Be Tested Before Appearing On Store Shelves
Although the FDA has established “current Good Manufacturing Practice” (cGMP) regulations (requiring that vitamin manufacturers evaluate their products by testing purity, strength, and composition), because vitamins are classified by the FDA as general food products under the category of dietary supplements, and no testing is required before the manufacturer brings a product vitamin to market.
The primary safety concern with multivitamins is toxicity from over ingestion of a vitamin, or mineral, leading to increased risk of illness. For example, ingesting too much zinc interferes with copper and iron absorption. Since people do not need to consult a doctor before ingesting vitamins, you can potentially take vitamins that interact with one another in ways that can hurt, rather than help, your health.
Additionally, as with any nutritional supplement, there is a risk of impurities in the product, which can have severe consequences. For example, a contaminated batch of tryptophan from a particular manufacturer in Japan was linked to 37 deaths and 1500 cases of permanent disability.2
Long Term Health Benefits of Multivitamins Are Inconclusive
Diets high in fruits and vegetables reduce the risk of diabetes, cancer, heart disease, and a host of other medical conditions.3 4 5 It’s hypothesized the high concentrations of anti-oxidants & fiber reduce inflammation and protect against chronic disease. So, the natural progression from this is the belief that supplementing with isolated forms of the anti-oxidants and nutrients found in fruits and vegetables would confer the same benefits.
The research, however, on the benefits (and harms) of vitamin supplementation in the general population is inconsistent. Supplementation of a nutrient confers health benefits if a person is deficient in that nutrient. That should be obvious, but that is not what this article is about. The question we need to know the answer to is: will taking a multivitamin make us live longer or perform better?
The gold standard of research study design is a randomized, placebo controlled trial, in which subjects are divided into experimental and “control” groups, with the experiment group receiving a placebo, or inactive substance, and the experimental group receiving the substance to be studied.
Last year, the Journal of the American Medical Association published the results of the first large scale, placebo controlled trial examining the long-term effects of multivitamin supplementation on cancer. The researchers found an 8% decrease in total cancer incidence in men taking a multivitamin. However, other observational studies find no association between multivitamin use and lower cancer rates, and some even find evidence that supplemental intake of certain vitamins may actually increase risk of certain cancers.
To further complicate matters, the few randomized controlled trials that have been done have produced conflicting results. Some show decreased cancer incidence6 and others show no effect or elevated risks.7
As far as improving performance, the research is also equivocal. For example, a study published in the Journal of the American Society of Clinical Nutrition shows no performance improvement in runners after 3 months of multivitamin supplementation. Similarly, a study entitled “Chronic multivitamin-mineral supplementation does not enhance physical performance” concluded just that.8 A study from 2006 in Research and Sports concluded that a liquid multivitamin supplement had no effect on “Anaerobic Exercise Performance” in people consuming an adequate diet.
Herein lies the problem and its resulting million dollar questions: What is an adequate diet and does the definition change depending on exercise habits and goals?
The research on multivitamins is lacking overall and even the research that has been done shows conflicting results. So what are we to do?
Ideally, an individual should strive to eat a variety of fresh fruits and vegetables (10+ servings) every day. Few people would disagree that this is the best way to get nutrients, improve energy and performance, and guard against disease. There is certainly a synergistic health effect from the contents of fruit and vegetables (both the things we know about and probably things we don’t know about), as nature’s design is most likely the best. The problem lies in executing this type of plan over the long run.
This is especially true for people who are trying to restrict calories to lose body fat, as 10 pieces of fruit would provide about 1000 calories per day. So what is the next best thing to eating that much produce? The makers of Centrum will say that taking a Centrum a day is the best alternative. Companies that sell whole food vitamin supplements will tell you that taking Centrum will do more harm than good, as the body doesn’t recognize and utilize synthetic vitamins the same way it does natural micronutrients. Unfortunately, there is no clear answer provided by research.
If eating 10+ servings of fruit and vegetables per day is not feasible for you, the next best thing is a product that most closely approximates it, namely, a “super greens and reds powder,” which is essentially fruit and vegetables concentrated down into a powder to be taken daily. This bypasses the issue of poor use of isolated nutrients and the idea that nutrients in real food exist in combinations impossible to replicate in a lab. There are many of them out there, but Lindberg Fruits & Greens+ is my choice.
If using a super foods powder is not feasible, the next best thing is a whole food multivitamin. It is very important to scrutinize the label of whatever product you’re thinking about buying, as often times products label “whole food multivitamins” are actually synthetic compounds combined with yeast (a whole food). Megafood, makes a good product, as does Garden of Life.
I recommend against the routine use of traditional multivitamins, unless you are part of a special population that research has shown to benefit from them. Still, if you are a hard training athlete, or are at risk for deficiencies due to restricted nutritional plans, you will likely derive more benefit from supplementation with traditional products than none at all. It is, however, a much better idea to use a preparation that more closely mimics eating real food.
In conclusion, there are no clear answers, and in the end the decision to supplement with multivitamins needs to be tailored to the situation of each individual. For most of the population, and especially athletes and people looking to improve body composition, a whole food derived nutrition supplement is a solid bet.
- THE POTATO IN SEA-SCURVY. The Lancet. 1970;38(992):789. ↩
- Toyo’oka T, Yamazaki T, Tanimoto T, et al. Characterization of contaminants in EMS-associated L-tryptophan samples by high-performance liquid chromatography. Chem Pharm Bull. 1991;39(3):820-2. ↩
- Bazzano LA, He J, Ogden LG, et al. Fruit and vegetable intake and risk of cardiovascular disease in US adults: the first National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. Am J Clin Nutr. 2002;76(1):93-9. ↩
- Cohen JH, Kristal AR, Stanford JL. Fruit and Vegetable Intakes and Prostate Cancer Risk. JNCI Journal of the National Cancer Institute. 2000;92(1):61-68. ↩
- Bazzano LA, Li TY, Joshipura KJ, Hu FB. Intake of fruit, vegetables, and fruit juices and risk of diabetes in women. Diabetes Care. 2008;31(7):1311-7. ↩
- Blot WJ, Li J, Taylor PR, et al. Nutrition Intervention Trials in Linxian, China: Supplementation With Specific Vitamin/Mineral Combinations, Cancer Incidence, and Disease-Specific Mortality in the General Population. JNCI Journal of the National Cancer Institute. 1993;85(18):1483-1491. ↩
- Omenn GS, Goodman GE, Thornquist MD, et al. Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. N Engl J Med. 1996;334(18):1150-5. ↩
- Singh A, Moses FM, Deuster PA. Chronic multivitamin-mineral supplementation does not enhance physical performance. Med Sci Sports Exerc. 1992;24(6):726-32. ↩