Should You Be Taking a Multivitamin?
The global dietary supplements market was valued at US$133.1 billion in 2016. And, with an estimated one-third of Americans currently religiously popping a daily multivitamin, it’s clear that supplements are here to stay.
And while boosting your daily vitamin intake with a multivitamin may seem like a good idea, recent research findings warn that it may actually do more harm than good. But can one-third of the American population really be wrong? Let’s have a look at what the experts have to say.
Vitamins: Why do we need them?
But first: What exactly is a vitamin, and why do we need it? You might be surprised to hear that, in stark contrast to the more than 85,000 dietary supplements commercially available in America, there are only 13 vitamins essential to good health. These are:
- Vitamin A
- The B group of vitamins. This includes thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyroxidine (B6), biotin (B7), folate (B9) and cobalamin (B12).
- Vitamin D
- Ascorbic acid, or Vitamin C
- Vitamin E
- Vitamin K
Without these vitamins, the body cannot function optimally and can even be at risk of developing chronic diseases. For example, sub-optimal intake of folic acid, coupled with a deficiency in Vitamins B6 and B12, can be a potential risk factor for cardiovascular disease, colon and breast cancer. It may also contribute to neural tube defects in unborn children. A Vitamin D deficiency, on the other hand, could contribute to osteopenia and fractures. And that’s just the tip of the proverbial iceberg.
The case against multivitamins
So does that mean that, if small doses of vitamins are good for us, a lot must be better? Not necessarily. Consider the following cases against multivitamin supplementation:
1. Vitamin and mineral supplementation may cause an increased mortality risk
A 2011 women’s health study investigated the potential link between vitamin and mineral supplementation and mortality risk in 38,772 women. In conclusion, the research team stated that “in older women several commonly used dietary vitamin and mineral supplements may be associated with increased total mortality risk, most strongly supplemental iron”.
2. Multivitamin supplementation may have no impact on cognitive health later in life
A 2013 study that investigated the impact of multivitamin supplementation in 5,947 male physicians aged 65 and older over a 12-year period concluded that “no difference was found in mean cognitive change over time between the multivitamin and placebo groups”. Or, in other words, “in male physicians aged 65 years or older, long-term use of a daily multivitamin did not provide cognitive benefits”.
3. The supplements industry is poorly regulated
In a survey of 41 multivitamins commercially available in the US and Canada, watchdog group ConsumerLab found the contents of almost a third of these products to be inconsistent with what they promised. A number of these multivitamins contained more niacin, vitamin A, folate, and magnesium than is deemed safe by the Health and Medicine Division of the National Academies of Sciences, Engineering, and Medicine. In contrast, others products didn’t contain as much Vitamin A, niacin and folic acid as stated on the product label. In fact, one of the products tested only contained 17% of its listed folic acid content.
4. Many commercial multivitamins contain fillers and food dyes
In addition to the vitamins that you’re actually paying for, many commercially available multivitamins also contain fillers, food dyes, and other less-than-ideal ingredients. Some of these substances may negatively affect vitamin absorption, and may even be toxic in the long term. One more reason to carefully study ingredient lists, right?
5. Multivitamins could negatively affect cancer treatment
If you have a history of cancer or are currently receiving cancer treatment, Elizabeth Ward, RD, recommends that you check with your physician before taking a multivitamin. Since dietary supplements can potentially fuel the growth of cancer cells by providing the extra nutrients it needs to multiply, taking a multivitamin could negatively impact cancer treatment. So be sure to discuss this with your oncologist.
The case for multivitamins
And while these points discouraging multivitamin supplementation are enough to convince some to go without, others disagree. A scientific review published in the Journal of the American Medical Association in 2002 recommends that all adults take one multivitamin daily. The authors go on to state that “this practice is justified mainly by the known and suspected benefits of supplemental folate and vitamins B12, B6, and D in preventing cardiovascular disease, cancer, and osteoporosis and because multivitamins at that dose are safe and inexpensive”. They also go on to list some exceptions where additional supplementation on top of a single, daily multivitamin could also be beneficial. This includes the elderly, women hoping to conceive and those with a relatively high alcohol intake.
One such study that highlights the purported role of multivitamins in reducing cancer risk was published in the Annals of Internal Medicine in 1998. This study looked at cancer incidence in 88 756 women from 1980 to 1994 and recorded a number of variables in these women, including multivitamin supplementation. The study concluded that “multivitamins may substantially reduce the risk for colon cancer. This effect may be related to the folic acid contained in multivitamins”.
So where does that leave you?
And since the cases both for and against multivitamin supplementation are passionately defended, it may leave you more confused than ever. So what are you to do? According to NYC-based nutritionist, Rachael Link, the key lies in carefully considering both your dietary habits and current health status. If you follow a healthy, balanced diet, Link believes that, in most cases, a multivitamin is unnecessary. Says Link: “You can get all the vitamins and minerals you need from food, so you’re really just throwing away money on multivitamins”.
And while Link rarely recommends the use of multivitamins to her clients, there are some exceptions. “If you have a medical condition that puts you at risk for vitamin deficiencies, such as inflammatory bowel disease, celiac disease, or if you’ve had gastric bypass surgery, then a multivitamin may be necessary to help you meet your needs”, Link says.
So, to answer our own question, a lot of (synthetic) vitamins aren’t always better. Instead, take a critical, honest look at your diet and current health status. If both score an A+, you may be better off not popping that multivitamin after all. And if your diet is less than ideal? The current consensus from both camps appears to be to bump up your intake of whole fruits and vegetables before reaching for something from a bottle. Remember that multivitamins were developed as dietary supplements – not an excuse to skimp on healthy eating!
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