You go to any pharmacy, grocery store, or almost any other type of store, and are bombarded with vitamins and supplements lining the shelves. But are they actually beneficial? For example, Vitamin D has been prescribed to help treat and prevent bone density loss, but can it be used for other diseases and disorders as well? Preliminary research has shown that vitamin D might be able to help prevent cancer and heart disease as well, but this research has not been done rigorously, so scientists can’t say for sure. Therefore, researchers from all across the United States established the Vitamin D and Omega-3 Trial to try and see if high doses of vitamin D can help prevent cancer and heart disease.
This trial included 25,871 men over 50 years old and women over 55 years old throughout the United States. These men and women were randomized into 4 different groups, so that the researchers could tease out the specific effect that vitamin D has, if any, on cancer and heart disease. These four groups were: 2000 units per day of vitamin D and 840 milligrams/day of fish oil, the same amount of vitamin D but a placebo acting as the fish oil, the same amount of fish oil but a placebo acting as the vitamin D, and a placebo for both the vitamin D and the fish oil.
The men and women in the study took these pills every day for an average of 5.3 years, and had follow-up questionnaires and appointments at 6 months and 1 year after they started the study, and then annually after that, so the researchers could measure their occurrences of diseases, how well they took their vitamins, and any side effects from the vitamins. The primary outcomes of the study (i.e. what the researchers were looking to prevent) were invasive cancer of any type, heart attack, stroke, or death from heart disease.
Overall, 1617 people developed cancer throughout the study, which included 793 people in the vitamin D group and 824 people in the placebo group . For heart disease outcomes, 805 people had major heart disease events (heart attack, stroke, or death from heart disease), which included 395 people in the vitamin D group, and 409 people in the placebo group. In each case, the differences between the groups were small. Using statistics, the scientists were able to determine that these small differences were likely due to chance.
Therefore, while vitamin D is still helpful to take to prevent bone loss, this large controlled study did not show any benefit in taking vitamin D to prevent either cancer or heart disease. Hopefully this information is helpful to you the next time you brave the vitamins and supplements aisle at your local store!