(RxWiki News) Vitamins help “fill in the gaps” of a diet by providing us with nutrients we may not be getting enough of, but can they actually lower our risk for common diseases like cancer and heart disease?
A recent review found no consistent evidence that vitamins had a positive effect on heart disease or cancer risk in the general population.
While researchers did find some evidence that taking multivitamins may be connected to a lower cancer risk, this was seen primarily for men.
"Speak with your doctor to determine if you need a multivitamin."
This review was led by Stephen P. Fortmann, MD, of the Kaiser Permanente Center for Health Research.
In an effort to help the US Preventive Services Task Force (USPSTF) update its recommendation on taking vitamins, Dr. Fortmann and team reviewed several studies looking at the effects of vitamins on cardiovascular disease and cancer risk in the general adult population.
This research team searched through five research databases to identify studies that looked at the effectiveness or safety of vitamins in the prevention of cardiovascular disease, cancer or death and were conducted on adults who had no chronic disease. They also reviewed all of the studies that were included in the three past reviews published by the USPSTF.
This review included a total of 26 studies, most of which were randomized controlled trials in which study participants were split into two groups and some participants were instructed to take a multivitamin while others were told not to.
The researchers specifically chose studies that involved several kinds of vitamins, including multivitamins, vitamins A, C, D and E, calcium, iron, magnesium, folic acid and beta-carotene.
One study involving only males found a 7 percent lower cancer risk for men who had been taking multivitamins for 10 years, and another study involving both men and women only found a lower risk of cancer for male participants.
The researchers also found that multivitamins had no effect on fatal and non-fatal heart disease-related events.
Beta-carotene, which can be found naturally in foods like sweet potatoes and carrots, and vitamin E were not found to have any effects on cancer or cardiovascular disease risk.
Most of the studies involving vitamin D showed no effect on cardiovascular disease or death. An increased risk for hip fractures was found, however, for participants who took vitamin A in two of the studies.
The authors of this review noted that their study only focused on primary prevention in generally healthy adults, so it is possible that for adults who have already been diagnosed with these diseases, the vitamins may have a more beneficial effect.
These authors concluded that, for healthy individuals, vitamins may not have an effect on cancer or heart disease risk.
This research was published on November 12 in the Annals of Internal Medicine.
Some of the researchers reported potential conflicts of interest with the Agency for Healthcare Research and Quality.