Nutritional Supplements Don’t Extend Life and May Have Harmful Effects, Study Warns

A pharmacy wall full of supplements. (Angel Sinigersky/Unsplash)

Taking vitamin supplements have no health benefit and some may even be harmful, a study published in the journal Annals of Internal Medicine reported on April 9.

The researchers from Tufts University in Massachusetts, who analysed the medical records of almost 31,000 adults aged 20 and above in the United States, found that taking vitamins in pill form had no significant positive impact on health and that benefits were only seen when nutrients were absorbed from food.

More than half of those who participated in the study that lasted for an average of 6.1 years took a supplement of some kind, while over a third took a multivitamin.

Data was gathered on the types, dosage, and frequency of supplement used by study participants in the previous 30 days. Information about nutrients from food intake was also analysed by trained interviewers who guided participants through 24-hour diet recalls, the Daily Mail reported.

The intake of a range of nutrients, such as magnesium, zinc, and vitamins A and K, were compared with death rates from cancer, cardiovascular disease and other causes.

Nutrient Source Important

Dietary supplements. (Wikimedia commons)

While adequate consumption of the nutrients were linked to a reduced risk of early death, this only applied to nutrients that had been absorbed from food, not supplements.

Dr. Fang Fang Zhang, the lead scientist for the study and an associate professor of epidemiology at the Friedman School of Nutrition Science and Policy at Tufts University, told Science Daily, “It is important to understand the role that the nutrient and its source might play in health outcomes, particularly if the effect might not be beneficial.

“Our results support the idea that, while supplement use contributes to an increased level of total nutrient intake, there are beneficial associations with nutrients from foods that aren’t seen with supplements.”

“This study also confirms the importance of identifying the nutrient source when evaluating mortality outcomes,” Zhang added.

Out of the 3,613 deaths during the duration of the study, 805 were from cancer and 945 were from cardiovascular disease.

Cancer Risk From Calcium, Vitamin D Supplements

The study also suggested taking excessive calcium in the form of supplements could double the risk of a person dying from cancer.

However, no link was found between consuming foods containing calcium and cancer, the research found.

Researchers believe excess calcium through supplements could be related to higher cancer risk because it could cause an increase in hormone production, although they could not explain the specifics of why this would be the case.

Doses of calcium supplements higher than 1,000 milligrams per day could put a person in danger as it was associated with a 53 percent increased risk of dying from cancer, the study found.

In addition, researchers found that taking vitamin D supplements in doses more than 10 micrograms per day was also linked to a higher risk of death from cancer or any other cause.

“The potential harm of vitamin D supplement use among individuals without vitamin D deficiency need to be further evaluated,” Zhang said.

Calcium and vitamin D supplements are typically taken to prevent osteoporosis in later life.

“Dietary supplements are not a substitute for a healthy balanced diet,” Zhang added.

“We should aim for adequate nutrition through diet rather than counting on supplements.

“Over half of Americans use these, and the reason is to improve or maintain health. That mindset needs to be changed, given the evidence.”