Could getting too much of a certain B-vitamin (niacin) place you at greater risk of cardiovascular disease? At one time, physicians prescribed high doses of niacin to people with abnormal blood cholesterol levels. This practice became common after studies revealed that high doses of niacin increase HDL cholesterol and lower LDL cholesterol. But there are downsides to doing so, as this new research shows.
How Too Much Niacin Could Affect Your Heart
Niacin, also known as vitamin B3, is an essential nutrient found naturally in a variety of foods and is important for a healthy diet. Good food sources of niacin include meat, poultry, fish, nuts, legumes, and grains. Many breakfast cereals and breads are also fortified with niacin.
As part of a new study, researchers looked at the intriguing connection between niacin metabolism and heart health. To do this, they analyzed the blood of over a thousand individuals with stable heart conditions to see what their cardiovascular markers showed. The findings were surprising.
The researchers found that certain byproducts of niacin metabolism, specifically N1-methyl-2-pyridone-5-carboxamide (2PY) and N1-methyl-4-pyridone-3-carboxamide (4PY), were associated with a higher risk of major adverse cardiovascular events over a three-year period. These products form as your body breaks down niacin.
Digging deeper, the researchers examined the genetic makeup of these individuals and found a fascinating link. They identified a gene variant, rs10496731. This gene variant is connected to higher levels of both 2PY and 4PY in the blood. But the plot thickened as this gene variant was also associated with elevated levels of soluble vascular adhesion molecule 1 (sVCAM-1), a marker for inflammation. We know that inflammation inside the arterial wall is a driving force behind cardiovascular disease. So, this discovery could tie niacin byproducts to increased cardiovascular disease (CVD) risk.
Not content to rest on their laurels, the researchers conducted additional analyses and experiments to confirm their findings. They found that sVCAM-1 levels were correlated with levels of 2PY and 4PY in another group of patients, further strengthening the connection. It always helps when a second study supports the first!
In a bold move, the researchers administered 4PY (but not its similar counterpart, 2PY) to mice at normal physiological levels. The results were striking. Adding this by-product of niacin metabolism into the bloodstream of mice triggered an increase in the expression of VCAM-1. In turn, this led to more white blood cells sticking to the blood vessel walls, mimicking an inflammatory response. This observation provided a glimpse into the potential mechanisms at play.
Too Much Niacin Could Trigger Inflammation
So, getting high doses of niacin could cause inflammation inside arteries that contribute to cardiovascular disease, suggesting a potential new target for medications development. If a treatment could dial down that blood vessel inflammation response, it might lower the risk of serious cardiovascular conditions down the road. We still need more research, but uncovering this substance’s role is a crucial step forward in untangling the complex web of cardiac risk factors.
The implications are clear – this puzzling biomarker indicates heightened activity in inflammatory pathways known to drive atherosclerosis progression over time. Though more work remains, experts now have a new breadcrumb trail to follow in unraveling the intricate biology of heart attacks and strokes.
How Much Niacin Do You Need?
The recommended daily intake of niacin set by the National Institutes of Health is sixteen milligrams per day for adult men and fourteen milligrams for adult women who are not pregnant. While deficiency is rare in developed countries, getting enough niacin helps the body convert food into energy and is important for proper nervous system and digestive function.
Interestingly, recent national nutrition surveys have found that around 25% of American adults consume more niacin than the amount recommended for health and safety. The upper limit is 35 mg per day before potential negative side effects. However, researchers are still exploring at what point excess niacin intake could start causing heart issues.
Since the 1940s, manufacturers have fortified flours, grains, and cereals, with niacin. They took this step to prevent pellagra, a classic deficiency disease caused by not getting enough niacin. Pellagra was common before fortification started, particularly among poorer populations with limited food variety. The symptoms included severe skin rashes, digestive issues, and even mental confusion or dementia in advanced cases. Not getting enough niacin means your cells can’t access energy from food properly.
Once scientists realized that niacin deficiency was the root cause of pellagra, food fortification became an elegant solution. By adding a bit of extra niacin to the foods people commonly ate, it offered a safety net against pellagra. Cereals and enriched breads seemed so obvious because they were affordable, mass-produced, and popular.
Now pellagra is quite rare, though niacin is still added to many flours and breads and cereals for general nutritional insurance. The good news is niacin is water soluble, so any extra is flushed out in urine and not stored long-term. Overall experts consider niacin safe at the recommended daily values, with food being the best source for meeting your body’s needs. One takeaway is to avoid niacin in supplement form and get it naturally from food sources.
Conclusion
So, what can you take away from the study? The research sheds light on possible adverse effects of niacin on the heart and blood vessels. High levels of niacin, a B vitamin, might elevate the risk of heart disease by causing inflammation and damaging blood vessels. Fortunately, doctors no longer prescribe supplemental niacin to lower cholesterol. The question is whether we’re still getting too much niacin in our diet. The greatest risk, it would seem, is if you eat a lot of packaged foods fortified with niacin. It might be another reason to think out of the package and eat foods in their whole, unaltered state.
References:
- Ferrell M, Wang Z, Anderson JT, et al. A terminal metabolite of niacin promotes vascular inflammation and contributes to cardiovascular disease risk. Nature Medicine. 2024;30(2):424-434. Doi: HTTPs://doi.org/10.1038/s41591-023-02793-8.
- “Cleveland Clinic-Led Study Discovers Link between High Levels of Niacin ….” 19 Feb. 2024, https://newsroom.clevelandclinic.org/2024/02/19/cleveland-clinic-led-study-discovers-link-between-high-levels-of-niacin-a-common-b-vitamin-and-heart-disease/.
- Alfaddagh A, Martin SS, Leucker TM, Michos ED, Blaha MJ, Lowenstein CJ, Jones SR, Toth PP. Inflammation, and cardiovascular disease: From mechanisms to therapeutics. Am J Prev Cardiol. 2020 Nov 21;4:100130. doi: 10.1016/j.ajpc.2020.100130. PMID: 34327481; PMCID: PMC8315628.
- “5 Benefits of Niacin (Vitamin B3) That You May Not Know – Healthline.” 26 Jan. 2024, https://www.healthline.com/nutrition/niacin-benefits.
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