Rédaction Africa Links 24 with Annalisa Merelli
Published on 2024-02-19 16:00:29
Niacin, commonly known as vitamin B3, has been highly regarded within public health in the United States, so much so that it is legally required to be added to cereal products. However, a newly published study has suggested a potential concerning impact of an overabundance of niacin, as it may increase the risk of cardiovascular disease.
The study, which was recently published in Nature Medicine, scrutinized two groups of patients without active heart disease, 60% of whom were treated with statins. It concluded that there is a strong link between a metabolic product of excessive niacin and an increased risk of major adverse cardiovascular events such as a heart attack or stroke. Approximately one in four people in the study had an excess of niacin, doubling their risk of major cardiovascular events to levels comparable with diabetes or a previous heart attack.
Stanley Hazen, the section head of preventive cardiology and cardiac rehabilitation at the Cleveland Clinic and senior author of the study, stated, “It’s a fairly sizable risk. It’s on par with what we consider other large risks. This opens up the door; it lays the foundation for new studies and new interventions from both a diagnostic and therapeutic perspective to try to reduce inflammation and cardiovascular disease.”
Historically, niacin has been known to increase high-density lipoprotein cholesterol (HDL), commonly referred to as “good” cholesterol, and lower low-density lipoprotein cholesterol (LDL), often referred to as the “bad” type. This made it a primary treatment to prevent cardiovascular disease prior to the introduction of statins. However, the recent findings suggest that an excess of niacin, which is also thought to support nervous and digestive system health, may have disparate effects on the body. Although outside experts caution that it’s too early to conclusively affirm that niacin has a direct impact on cardiovascular risk.
Researchers of the study identified N1-methyl-4-pyridone-3-carboxamide (4PY), a niacin metabolite, as the cause of increased cardiovascular risk, arguing that 4PY boosts cardiovascular risk through an inflammatory reaction. They pointed out that they have found a previously unknown pathway that can cause adverse cardiovascular events. Hazen explained, “We began by looking to see if there was something in fasting blood samples from subjects who were followed over time to see who went on and developed a heart attack or stroke or died — and it ended up being a compound which was unknown. And when we finally figured out what it was and where it came from, it can only be made by excess niacin ingestion.”
Furthermore, excess niacin was also found to result in the production of N1-methyl-2-pyridone-5-carboxamide (2PY), which was not linked to inflammation or a higher risk of cardiovascular disease. These results were consistent with findings in two previous large niacin studies (HPS2-THRIVE and AIM-HIGH), which revealed that niacin led to worse cardiovascular outcomes for people who already had low levels of bad cholesterol, despite it being known to increase levels of good cholesterol.
The authors of the study contend that their findings are indicative of a potential need to reassess the mandatory fortification of foods with niacin, particularly cereals such as wheat and rice. While conceding that the mandated fortification has been highly effective in virtually eliminating pellagra and providing substantial health benefits, they argue that concerns about cardiovascular health may necessitate the need for non-fortified cereal products to be sold in the U.S.
However, other experts in the field strike a cautious tone in drawing definitive conclusions about the harm associated with niacin. Some are concerned that the study may lack clarity in determining the direct cause of the adverse cardiovascular outcomes. Additionally, questions surround the levels of 2PY and 4PY in people who receive pharmacologic niacin, which is delivered in significantly higher concentrations compared to niacin supplements.
In conclusion, the study has raised valuable concerns about the unintended effects of excess niacin on cardiovascular health, triggering a call for further research and potential re-evaluation of policies around niacin fortification in foods. Nonetheless, there are differing opinions on the interpretation of the findings, suggesting that more extensive investigations are necessary before any definitive conclusions can be drawn.
