In the latest Australian nutrition survey, 29% of people say they have taken at least one dietary supplement. This proportion was even higher in the United States at 52%.
A new study released today aimed to examine the benefits of vitamin and mineral supplements for the prevention of heart disease, stroke and premature death (called “all-cause mortality”). This revealed that the more commonly studied ones had no effect, while some less common ones had an effect. The review also revealed that some supplements may be harmful.
What did the study find?
The study was a Systematic review, meaning the research team reviewed all relevant research papers (179 in total) and combined the results. Supplements reviewed included vitamins A, B1 (thiamin), B2 (riboflavin), B3 (niacin), B6 (pyridoxine), B9 (folic acid), C, D, E, beta-carotene, and the minerals calcium, iron, zinc, magnesium and selenium. Multivitamins have been defined as including most of these vitamins and minerals.
In studies testing the four common multivitamin, vitamin D, calcium, and vitamin C supplements, there was no reduction in the incidence of heart disease, stroke, or premature death. This means there was no benefit to taking them, but also no harm.
They also evaluated less common supplements that had positive effects on early death, heart disease and stroke. Here they found that folic acid supplements showed a reduction in heart disease and stroke.
It was calculated that to prevent one case of heart disease or stroke, 111 people needed to take folic acid supplements (this is called the “numbers needed to process”). For a stroke, 167 people would need to take folic acid to prevent one case, and 250 people would need to take B-complex vitamins (which contain folic acid, which is vitamin B9) to prevent one case.
Before you rush out to buy folic acid supplements, there are a few things to consider. First, some fear that high levels of folic acid In the blood may increase the risk of prostate cancer, even if the results are mixed.
Second, of the studies testing folic acid supplements, stroke was only reduced in two of the seven gold standard studies (called randomized controlled trials). One of them was a very large study of 20,000 people in China. China does not have a food fortification program with folic acid, while in Australia and the United States it is commonly added to breads and breakfast cereals.
While a small benefit for taking folic acid was found, researchers also found adverse effects of supplementation. In people taking statins to lower blood cholesterol, slow- or sustained-release vitamin B3 (niacin) increased the risk of premature death by 10%, with a “number needed to harmof 200. This means that 200 people would have to take statins and niacin before seeing one case of premature death.
For studies testing “antioxidant” supplements, there was a slightly increased risk of early death, with a “number needed to harm” of 250 people.
The most studied supplement was vitamin D. Researchers found no benefit for preventing heart disease or stroke, but also no harm. This was a surprise, given that vitamin D is commonly taken for other conditions, such as diabetes. But no benefit was seen in early death, although the study authors acknowledged that longer follow-up may be needed.
What does all this mean?
The authors concluded that there is low-to-moderate quality evidence for taking folic acid for the prevention of heart disease and stroke, as well as for taking B-complex vitamins that include folic acid. for strokes.
Most people in Western countries do not have an optimal diet. This review shows that taking supplements as an “insurance policy” against bad eating habits doesn’t work. If so, there would have been a reduction in premature deaths.
Taking supplements is very different from eating whole foods. Complications or health problems due to nutrient intake are almost always due to taking supplements and not eating food. When you focus on one vitamin, mineral, or nutrient in a supplement, you miss the other. phytonutrients found in plant foods that contribute to overall health.
The rise in premature deaths for taking certain categories of supplements should be a wake-up call that tighter regulation is needed around supplements, and that people need a lot more support to eat better. .
Ultimately, we need to eat more nutrient-dense whole foods, including folate-rich foods such as green leafy vegetables, legumes, seeds, poultry, eggs, grains, and citrus fruits. Many breads and breakfast cereals in Australia are fortified with folate. Good dietary sources of niacin (vitamin B3) are lean meats, milk, eggs, whole grain breads and cereals, nuts, leafy green vegetables, and foods containing protein.