The Multivitamin Conundrum

Did you take any vitamins this morning?

By Kevin RR Williams

NUTRITION Based on recent news reports, you may have wondered whether to take vitamins with breakfast or throw them in the garbage. Evidence-based medicine relies heavily on clinical studies, as it aims to address the persistent problem of clinical practice variation. So whenever a new clinical study is published, it provides fodder for change and debate. More controversial subjects generate correspondingly more intense debate. Expect more confusion as the $28 billion vitamin industry pours over the data and responds.

With regard to vitamin supplements, many people appear to be taking a specifically focused bit of information and applying it in an absolute sense. Here's a real headline pulled from the Web: "Multivitamins and dietary supplements are a waste of money, doctors say." It's true that some doctors said that but the implication is that all doctors do. Such headlines increase readership but they can distort accuracy.

What Were The Multivitamin Studies About?

Adding to the sensationalism is the bold title of the report on the three categories of clinical studies in the Annals of Internal Medicine:

    Enough Is Enough: Stop Wasting Money on Vitamin and Mineral Supplements:
    After reviewing 3 trials of multivitamin supplements and 24 trials of single or paired vitamins that randomly assigned more than 400,000 participants [with no nutritional deficiencies], the authors concluded that there was no clear evidence of a beneficial effect of supplements on all-cause mortality, cardiovascular disease, or cancer.

    Second, Grodstein and coworkers evaluated the efficacy of a daily multivitamin to prevent cognitive decline among 5947 men aged 65 years or older. After 12 years of follow-up, there were no differences between the multivitamin and placebo groups in overall cognitive performance or verbal memory.

    Third, Lamas and associates assessed the potential benefits of a high-dose, 28-component multivitamin supplement in 1708 men and women with a previous myocardial infarction. After a median follow-up of 4.6 years, there was no significant difference in recurrent cardiovascular events with multivitamins compared with placebo.

Basically, in two of these massive studies, healthy people taking vitamins were studied with a control group who received fake vitamins. There was no significant difference in death, heart attacks, cancer, or memory. The third study, which focused on participants with prior heart attacks, likewise showed no significant difference.

Now note the conclusions in this report by Eliseo Guallar, MD, et al.:

    The message is simple: Most supplements do not prevent chronic disease or death, their use is not justified, and they should be avoided. This message is especially true for the general population with no clear evidence of micronutrient deficiencies, who represent most supplement users in the United States and in other countries.

    In conclusion, β-carotene, vitamin E, and possibly high doses of vitamin A supplements are harmful. Other antioxidants, folic acid and B vitamins, and multivitamin and mineral supplements are ineffective for preventing mortality or morbidity due to major chronic diseases.

We can agree that hyper-doses of various vitamins or minerals can be harmful. Too much calcium, for example, can contribute to kidney stones. But does this warrant applying a study to a broad swath of supplements? Are news media outlets, or perhaps even the researchers themselves taking the findings out of context?

Is Anyone Malnourished?

The assumption that the general population, despite the vast reliance on fast food, has no micronutrient deficiencies is noteworthy. Not only does this diet create excesses in fat, sugar and sodium, it doesn’t provide many of the required vitamins and nutrients.

Malnutrition can be defined as the insufficient, excessive or imbalanced consumption of nutrients. A minority of individuals restrict themselves to plant-based diets. A 2012 Gallup poll found 5% of Americans identify as vegetarian and 2% as vegan. Without supplements, many vitamins and minerals found within meat, go missing among those on plant-based diets. Vegans and vegetarians should be mindful to consume protein, calcium, vitamin D, B12, iron, zinc, and omega-3 fatty acids from natural food sources or supplements. Additional studies make this clear.

  • The Vegan Society and Vegan Outreach, and others, recommend that vegans either consistently eat foods fortified with B12 or take a B12 supplement.
  • A 5.2 year study, released in February 2007 by Oxford, showed that vegans have an increased risk of bone fractures over both meat eaters and vegetarians, likely due to lower dietary calcium intake.
  • Studies have found EPA and DHA levels in vegans to be about two thirds lower than in omnivorous people. The extent to which this poses a health risk is not yet known, but vegans have been advised to increase their intake of alpha-linolenic acid, and reduce their intake of omega-6 fatty acids and saturated fatty acids, which can limit the rate of conversion.

The studies seeking a dietary solution to cardiovascular disease did not isolate a subgroup of plant-based dieters. The study group was large enough, however, for them to be randomized within. A 1999 meta-analysis of five studies comparing mortality rates in Western countries found that mortality from ischemic heart disease was 26 percent lower in vegans than in regular meat-eaters. This was compared to 20 percent lower in occasional meat eaters, 34 percent lower in pescetarians, and 34 percent lower in ovo-lacto vegetarians.

People who eat well-balanced meals can receive most nutrients from food without supplementation — provided they drink fresh fruit and vegetable juice regularly. Those who are not juicing may require vitamins, but people should be juicing.

Those who eat nutritionally devoid junk food can experience malnutrition. A number of individuals take vitamins to supplement a nutritionally poor breakfast of coffee and bagel. Then there are those who already have chronic diseases that differ from the ones studied. For example, vitamin D deficiency is common among patients with active ulcerative colitis, particularly those requiring corticosteroids.

Don’t Be Gullible

As is the case with most things, balance is necessary. The notion that if a little is good then a lot of a little is better is not always true. Um-teen thousand percent of the recommended daily allowance of essential minerals can cause complications.

Let's not forget that the primary goal of the Guallar, et al. studies was to see if vitamins prevent the occurrence or progression of chronic diseases — specifically, heart attacks and cancer. Clinical findings do seem to support their negative claim. So (news flash), to date, there's no clinically proven vitamin that cures cancer.

Perhaps it would have been sufficient to suggest that people symptomatic of nutritional deficiencies or those in high-risk groups be professionally evaluated to see if they warrant specific supplements. The report title is misleading. Vitamins did not improve outcomes in the study population and the authors extrapolate they will have zero benefit, in this regard, on the general population. Are you going to stop taking vitamins as a result of these studies?

References
  1. Enough Is Enough: Stop Wasting Money on Vitamin and Mineral Supplements. Eliseo Guallar, MD, et al. annals.org
  2. Hungry For Change. Documentary, amazon.com
  3. Are Multivitamins Essentially Placebos? myanatomyart.com