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Changes: Niacin heart effects

By Karen L. Kier
Pharmacist on behalf of the ONU Healthwise Team 

In 1971, David Bowie released his Grammy Hall of Fame song Changes. This song is considered one of his top 5 songs. In the lyrics, Bowie writes “time may change me.”  How have our thoughts changed on niacin over time?

Niacin is known as vitamin B3 and is commonly found in foods such as meats, fish, nuts, brown rice, seeds and bananas. Many cereals, grains, flour, and breads are enriched with niacin. 

A deficiency of niacin results in a condition called pellagra. The term comes from the impact on the skin involving rashes and sensitivity to the sun. Other symptoms can include weakness, confusion, and stomach pain. Alcohol consumption can reduce niacin levels in the body as well as the prescription drugs, phenytoin (Dilantin) or valproic acid (Depokote). 

The daily recommended dietary allowance (RDA) for niacin is 16mg for adult males and 14mg for adult females. In the 2009-2012 National Health & Nutrition Examination Surveys (NHANES), the average adult male consumed 31.4mg per day of niacin with women averaging 21.3mg. This number increased substantially in the 2017-2020 NHANES report to an average of 37mg per day. 

Niacin in high doses of 2,000 to 5,000mg per day (100 to 300 times higher than the RDA) have been used to manage cholesterol and other fats in the blood to manage heart disease. This management of heart disease fell out of favor based on studies published in 2016 because the research showed high-dose niacin provided no reduction in heart attacks or strokes. 

High-dose niacin can cause severe skin flushing with dizziness and an increase in heart rate. One 325mg aspirin given 30 minutes prior to taking high-dose niacin can reduce this risk. In addition, higher doses can increase the risk of gout, diarrhea, and liver damage. 

None of this is breaking news, so what has changed? 

Researchers from the Cleveland Clinic Research Institute published a study in Nature Medicine on February 19, 2024 raising concerns on an increase in heart disease in patients with high blood levels of niacin. The authors feel the high levels of niacin may actually contribute to the development of heart disease. The theory is the high levels may trigger an inflammation in our blood vessels allowing for fatty plaques to attach and build up on the walls of the vessels. This buildup decreases blood flow to the heart and brain resulting in heart attacks and strokes. 

The research found individuals with high blood levels of niacin were 2 times more likely to be at risk for heart attacks or strokes. The authors point out the large amounts of niacin may counter the benefit of lower dose niacin especially for the nervous system. The authors suggest a re-evaluation of fortifying foods such as flour, bread, and cereals with niacin. 

This research seems to provide some concern for supplemental niacin in our diets and with vitamin supplements. However, other published studies have found benefits for high-dose niacin. This creates a conflict in evidence. 

A 2024 JAMA Network Open study found high dietary levels of niacin could lower the risk of death related metabolic-dysfunction associated steatotic liver disease (MASLD) in individuals. The study evaluated 4,315 adults and showed a reduction in heart deaths. MASLD is often a silent disease of the liver, which many adults may not even realize they have. Another 2024 JAMA Network Open study showed a benefit of niacin in patients with nonalcoholic fatty liver disease (NAFLD). Niacin may have some benefits in different forms of liver disease.

A 2024 study in Scientific Reports found positive results when evaluating dietary niacin and chronic obstructive lung disease (COPD). In the subjects with high dietary intake of niacin, they were less likely to develop COPD compared to those with low intake. 

The early data from the Cleveland Clinic would provide justification to reduce niacin intake especially with over the counter supplements and vitamins. Consult your healthcare provider before adding additional niacin to your daily regimen. 

Science moves forward creating changes!

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