Can you overdose on vitamins? In short, yes.
Vitamins are an essential part of a healthy, balanced day and play a range of important roles within our bodies. However, studies have shown that—at least for some vitamins—it's possible to have too much of a good thing.
Niacin, also known as vitamin B3, is a water-soluble B vitamin found in meat, fish, nuts, legumes, brown rice and fortified cereals. Its main role in the body is as an assistant to our cell's molecular machines, helping convert sugar into energy, create and repair DNA, remove dangerous metabolic waste products and build healthy fats and "good" cholesterol.
Being water soluble, excess levels of niacin are usually excreted in our urine. But new research from the Lerner Research Institute in Cleveland, Ohio, has suggested that two of the breakdown products of this vitamin may be associated with an increased risk of heart disease and strokes.
In a study, published in the journal Nature Medicine, the team, led by Stanley Hazen, analyzed blood plasma samples from 4,325 people from across the U.S and Europe. From these blood samples, the team found that the presence of two molecules, produced by the breakdown of excess vitamin B3, was associated with an increased risk of major adverse cardiovascular events.
Following on from this finding, the team showed that in both humans and mice, one of these breakdown products has the ability to increase pro-inflammatory proteins in the cells that line our blood vessel walls, suggesting a potential mechanism for this increased risk.
This is concerning because, according to data from National Health and Nutrition Examination Surveys between 2018 and 2020, the average American eats 48 mg of niacin per day—roughly triple our recommended daily intake of 16 mg.
More studies are needed to confirm these results, and vitamin B3 still plays an essential role in maintaining a healthy, balanced diet. However, the team says that its findings warrant more research into these effects and raise questions about the mandated fortification of cereals with this vitamin in the U.S.
"Although such a mandate no doubt saved lives when first implemented more than 80 years ago, its long-term safety, particularly in more vulnerable populations, merits discussion," the authors write.
Is there a health problem that's worrying you? Do you have a question about vitamins? Let us know via health@newsweek.com. We can ask experts for advice, and your story could be featured on Newsweek.
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Pandora Dewan is a Senior Science Reporter at Newsweek based in London, UK. Her focus is reporting on science, health ... Read more
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