There is good news and bad news when it comes to vitamins and minerals: The good news is that intake of certain vitamins and minerals is linked to a lower risk of premature death. The bad news is that this link is only visible when these nutrients come from food and not supplements, according to a new study.
“Our results support the idea that there are beneficial associations with nutrients from foods not seen with supplements,” lead study author Dr Fang Fang Zhang, associate professor at the Friedman School of Nutrition Science and Policy from Tufts University. in Massachusetts, said in a statement.
What’s more, consuming high doses of certain nutrients through supplements can be harmful – the study found that getting high levels of calcium from supplements was linked to an increased risk of cancer death. [7 tips for moving towards a more plant-based diet]
The study is published Monday, April 8 in the journal Annals of Internal Medicine.
Food vs. supplements
The study analyzed information from more than 27,000 adults in the United States aged 20 and older who participated in a national health survey between 1999 and 2010. For the survey, interviewers asked participants what that they had eaten in the past 24 hours and whether they had taken supplements in the past 30 days. Participants were then followed for about six years, on average.
During the study period, approximately 3,600 people died; and of these, 945 died of heart disease and 805 died of cancer.
The study found that people who consumed adequate amounts of vitamin K or magnesium had a lower risk of death from any cause during the study period, compared to those who did not get not adequate levels of these nutrients. Additionally, people who consumed adequate levels of vitamin A, vitamin K, zinc or copper had a lower risk of death from heart disease, compared to those who did not get adequate levels of these nutrients.
But when researchers looked at the source of these nutrients – food versus supplements – only nutrients from food were linked to a lower risk of death from any cause or from heart disease.
Additionally, the study found that consuming high levels of calcium from supplements – at least 1,000 milligrams per day – was linked to a higher risk of cancer death. But there was no link between calcium intake from food and the risk of cancer death.
The results suggest that “adequate nutritional intake from food was associated with reduced mortality, [while] excessive supplementation could be harmful,” the researchers concluded.
Still, the researchers noted that they did not objectively measure what participants were consuming, but instead relied on their self-reports, which may not be entirely accurate. Future studies should continue to examine the potential risks and benefits of supplements.
The risks of supplements
The new study isn’t the first to link supplement use to harmful effects. In 2011, a large study found that the use of vitamin E supplements was linked to an increased risk of prostate cancer in men. Also that year, a separate study in older women found that supplement use was linked to an increased risk of death over the 20-year study period.
The Academy of Nutrition and Dietetics recommends that people try to get their nutrients from food by eating a healthy diet that includes nutrient-dense foods. The academy points out that foods can contain beneficial components that aren’t supplements, such as fiber or bio active compounds.
“Real food contains healthy things that a pill can’t give us,” says the academy. “When we take a nutrient from a food and concentrate it in a pill, it’s not quite the same thing.”
Yet, people with certain illnesses or conditions may not be able to get all of the nutrients they need from food and therefore may need to take a supplement. For example, pregnant women often need to take folic acid or iron supplements to prevent birth defects and help the growing fetus. People with food allergies or digestive problems may also need to take supplements.