According to the latest data from the National Health and Nutritional Examination Survey, 52% of U.S. adults reported using at least one dietary supplement in the prior 30 days, and 31% reported using a multivitamin-mineral supplement. The most common reason given for using supplements was for overall health and wellness and to fill nutrient gaps in the diet. If you have read this column before, then you know I often write about disease prevention strategies that are periodically reviewed by the U.S. Preventive Services Task Force (USPSTF). Because new studies and information are released and published in the medical literature every day, the USPSTF will periodically review topics to keep their recommendations up to date. Recently, the USPSTF released its latest findings regarding the use of vitamins and supplements to prevent various diseases.
Over the years I have known quite a few patients who spend inordinate sums of money on all kinds of vitamins, minerals, and supplements. They do so believing that they are preventing various diseases and conditions from affecting them, often without a shred of real clinical evidence to back up their beliefs. In 2014, the USPSTF last released their findings on the use of vitamins and minerals to prevent disease, especially cardiovascular disease and cancer. They found no evidence of any benefit from these supplements. This year the USPSTF reviewed data from more than 90 randomized clinical trials (RCTs) published since 2014 that studied the same topic. Here is what they found:
The review findings applied to adults who were not pregnant or trying to become pregnant and who lived in the community. They found the current evidence is insufficient (I recommendation) to assess the balance of benefits and harms for the use of multivitamins for the prevention of cardiovascular disease or cancer. They also found that the current evidence is insufficient (I recommendation) to assess the balance of benefits and harms for the use of single or paired nutrient supplements (other than beta carotene and vitamin E) for the prevention of cardiovascular disease or cancer. Thirdly, they recommended against the use of beta carotene or vitamin E supplements for the prevention of cardiovascular disease or cancer. The reason for this last recommendation is due to the harm of increased lung cancer incidence that has been found with the use of beta carotene by individuals who smoke or have occupational exposure to asbestos.
Among the various combinations of supplements that were studied were beta carotene and vitamin A, vitamin E, vitamin D with or without calcium, and calcium without vitamin D. One of the main reasons for the two I, or data insufficient, recommendations is that most of the trials they reviewed were too short. Because cardiovascular disease and cancer both develop so slowly, in order for a study to truly measure whether or not these supplements either cause or prevent these conditions, the study needs to be very long, as in 10 or 20 years at least. Meanwhile, if you want to continue to take a daily multivitamin (as I do) there does not appear to be any harm in doing so. However, if you spend serious cash for supplements, you might want to talk it over with your doctor.
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By Peter Galvin, MG