Chances are, you've been told since you were a child that you need to take your vitamins. Well, your childhood resistance to that ritual appears to have been vindicated, at least according to a new study published in the Journal of the American College of Cardiology.
The study reviewed data and clinical trials from 2012 to 2017 and discovered that most multivitamins and supplements of vitamin C, vitamin D and calcium do not provide benefits for the prevention of cardiovascular disease, heart attack or stroke.
"We were surprised to find so few positive effects of the most common supplements that people consume," the study's lead author Dr. David Jenkins told Insider. "Our review found that if you want to use multivitamins, vitamin D, calcium or vitamin C, it does no harm — but there is no apparent advantage either."
Another 2017 study published in the Journal of the American Medical Association also found an alarming lack of evidence for the effectiveness of many vitamins and supplements. Looking at calcium and vitamin D supplements in particular, researchers found absolutely no difference in the health outcomes for people on the supplements compared to people who didn't take them. Dozens of studies that involved over 50,000 adults over the age of 50 were reviewed as part of the research.
In fact, it was even worse than that. For some groups of people, taking vitamin D supplements increased their risk of hip fractures. The findings held true even when gender, supplement dose, normal dietary calcium intake, and current loads of vitamin D in the blood were taken into consideration.
"These findings do not support the routine use of these supplements ... in older people," the authors wrote.
A poor diet may be to blame
Other studies have shown that nutrients are not processed by your body as efficiently from pills and powders as they are from real food, so some of these ill-effects of supplements might simply be the cause of people mistakenly using them to cover up a poor diet, reports Business Insider.
In other words, it's poor diets that are probably to blame, not necessarily supplements. But the supplements still aren't helping either, and when you consider the substantial cost of taking daily vitamins, the issue takes on a larger frame.
Not all vitamins are the same
In fact, the supplement industry in the United States alone is worth over $37 billion, and it's largely unregulated. Because of this lack of oversight, pills that are later linked to negative conditions often only get recalled after they've already had a widespread public impact.
"In the U.S., no dietary supplements are pre-screened for safety and efficacy," said S. Bryn Austin, a professor at the Harvard T.H. Chan School of Public Health. "What that means is the FDA and consumers have no way to know if what's in the bottle or box is what's on the label. There's no way to know for sure that what's in the product is safe."
A 2013 study found that doses of ingredients in a supplement —even those from the same bottle — can vary significantly from pill to pill, and a 2016 study found that this has some extreme public health consequences: supplements send roughly 23,000 people to the emergency room each year.
Although this research is unnerving, it's important to note that everyone's health situation is unique, and supplements can have an important role to play when they are prescribed by a doctor.
Listen to your doctor, not to the labels on your favorite brands of multivitamins. And never use supplements to replace or excuse a poor diet.
Editor's note: This article has been updated since it was originally published in December 2017.