Many of us have made multivitamins part of our daily routine, popping a tablet or two in the morning and feeling like the epitome of #HealthAndWellness.
Over the years however, there's been plenty of conflicting discourse about the effectiveness of vitamins; and now, a major study has revealed that in fact, people who take a daily multivitamin are no less likely to die from any cause than those who don't. In other words - there is no evidence to support that multivitamins improve longevity.
Perhaps more shockingly still, taking daily multivitamins was also associated with a 4 percent higher mortality risk. But before you ransack the medicine cabinet and discard your supplements, this increased mortality risk could have a relatively simple explanation: people with health issues are more likely to try them, compared to those who are in perfect health.
The findings, based on 20 years of data from almost 400,000 generally healthy US adults, support evidence that while multivitamins may offer some benefits, food should be the key focus when it comes to nutrition.
Speaking about the study to AM on Thursday, Professor of Māori Health and Nutrition Lisa Te Morenga noted that while discourse around multivitamins is complicated, in most cases, people are better off putting their money towards nutritious food than supplements they likely don't need.
"The effect [on mortality] that we're seeing is very small anyway. There have been a number of similar studies over the years, and they find the same thing; generally, no effect or maybe a slight benefit for some conditions and a slight harm for others," Professor Te Morenga explained.
"I think it's safe to say there's really no point in taking a multivitamin."
While most supplements aren't necessarily harmful, it can depend on preexisting conditions or unhealthy habits: for example, smokers may want to avoid supplements containing beta-carotene, Te Morenga said. One study of 29,000 male smokers found an 18 percent increase in lung cancer in the group receiving 20mg of beta-carotene a day for five to eight years.
"If you're a smoker, there is some evidence that vitamin supplements with beta-carotene in them could increase the risk of early death in smokers," she said.
"Other than that, it's not that they're really harmful - it's that they're not really needed. You're being scammed, really, into buying supplements that you don't need."
However, she noted that in cases where a person has an obvious deficiency, supplements can be useful - but should be prescribed by a health professional.
"Sometimes there are individual nutrients that people might need - women often need an iron supplement. We have low [levels of] selenium in our soil, so that could be useful, but you could get enough selenium by having a Brazil nut or two every day - and you'd get some dietary fibre and good fats with that Brazil nut," she explained.
"I would say the nut is probably a better investment than a multivitamin or a selenium supplement - unless your doctor has prescribed it to you for an obvious deficiency."
Folic acid is another vitamin that has some benefit in pregnant women or women hoping to become pregnant, Te Morenga added. As per the US Centers for Disease Control and Prevention (CDC), evidence indicates that 0.4 mg (400 ug) per day of folic acid can reduce the risk of the baby being born with neural tube defects.
"There's a definite benefit in taking folic acid and we recommend that women of childbearing age who are planning to have a baby should be taking a regular folic acid supplement. That's just to reduce the risk of having a neural tube defect with that baby - but it's most effective in the first 30 days of the pregnancy, so taking a multivitamin for the nine months of your pregnancy just for folic acid is a bit of a waste of money, as well," Te Morenga said.
Another possible benefit associated with taking a multivitamin is the "placebo effect", she added. Incorporating a multivitamin into our daily routine may make us feel better simply due to the action, she suggested: because we feel as though we are taking care of ourselves, we may notice positive changes as a result.
"There's that placebo effect; you feel like you're doing something good, you've taken out a small insurance policy on your health, and that in itself can improve your overall wellbeing."
The verdict?
According to the researchers, daily multivitamin use is not associated with a mortality benefit.
"If you're short on cash, I think you could use that money - which can be quite expensive - on more fruits and vegetables for a better outcome," Te Morenga concluded.
The research was published in the journal JAMA Network Open.
Watch the interview above.
