Discover how a key nutrient in your diet could hold the secret to longer life and better heart health with ground-breaking insights into niacin’s role in metabolic and cellular rejuvenation.
Study: Association of dietary niacin intake with all-cause and cardiovascular mortality: National Health and Nutrition Examination Survey (NHANES) 2003–2018. Image credit: Shutterstock AI
A study published in the journal Scientific Reports reveals that dietary intake of vitamin B3 may reduce the risks of all-cause mortality and cardiovascular disease among US adults.
Background
Vitamin B3, also known as niacin, is a water-soluble micronutrient vital for various physiological processes. Niacin deficiency can lead to serious health conditions, including pellagra, a serious disease characterized by dermatitis, diarrhea, dementia, and death.
Some countries have adopted niacin fortification of wheat flour and cereals to prevent pellagra. In addition, many common foods, such as beef, pork, chicken, coffee, and tea, contain high amounts of niacin.
This makes niacin a highly prevalent dietary micronutrient in modern Western diets, especially in the United States, where niacin intake exceeds three times the recommended dietary allowance.
Niacin is known for its therapeutic effects on dyslipidemia. Several studies have shown that niacin can significantly lower the level of low-density lipoprotein cholesterol (bad cholesterol) and increase the level of high-density lipoprotein cholesterol (good cholesterol) in the blood.
Studies have produced mixed results regarding the cardioprotective effects of niacin. This phenomenon, known as the “niacin paradox,” highlights cases where improving the lipid profile does not consistently lead to better cardiovascular outcomes. While some studies have found modest beneficial effects of niacin on cardiovascular events, some have found that niacin does not reduce the risks of cardiovascular events and that it may increase the risk of all-cause mortality.
Given the paucity of information on the impact of niacin on long-term health outcomes, the present study was designed to investigate the relationship between dietary niacin intake and causes of cardiovascular mortality in the US general population.
Study Design
This study included 26,746 adults who participated in the 2003–2018 National Health and Nutrition Examination Survey (NHANES). The median follow-up period was 9.17 years.
Niacin intake was obtained from two 24-hour dietary recall interviews. Participants were categorized into four groups based on their average intake over two days.
Statistical analyzes were performed to compare the risk of all-cause and cardiovascular mortality among participants grouped into different dietary quartiles of niacin intake. Sensitivity analyses, such as excluding participants with pre-existing cardiovascular disease (CVD) or cancer, confirmed the robustness of these findings.
Important Notes
A total of 3,551 all-cause deaths and 1,096 cardiovascular deaths occurred during the study follow-up period.
Statistical analyzes showed a negative association between dietary niacin intake and the risk of all-cause and cardiovascular mortality. Participants with the highest niacin intake had lower risks of all-cause and cardiovascular mortality than those with the lowest dietary niacin intake.
A dose-response relationship was observed between dietary niacin intake and mortality risks, meaning that the risk of all-cause mortality and cardiovascular disease decreased with increasing dietary niacin intake. However, the benefits increased when niacin intake exceeded the median value of 22.45 milligrams per day.
Subgroup analyzes stratified by age, sex, ethnicity, education level, smoking, alcohol consumption, body mass index (BMI) and disease conditions revealed that the effect of dietary niacin intake on the risk of all-cause mortality was significantly stronger in non-diabetic subjects compared to diabetic patients.
In terms of reducing the risk of cardiovascular mortality, the beneficial impact of niacin intake was seen in some subgroups, including the elderly, women, non-Hispanic whites, higher education, obesity, smoking, non-hypertensive, non-diabetic , non-dyslipidemia and non-cardiovascular disease. Baseline characteristics showed that people with higher niacin intake were generally younger, more educated and more likely to smoke or drink alcohol.
Importance of study
The study finds an inverse relationship between dietary niacin intake and the risk of all-cause and cardiovascular mortality in the US adult population.
Niacin intake may be beneficial because it improves the metabolism of nicotinamide adenine dinucleotide (NAD). As a precursor of NAD, niacin can increase NAD levels, subsequently improve cell metabolism and mitochondrial functions, and reduce DNA damage, inflammation, cell death, and cell aging through various mechanisms.
Niacin has been found to reduce chemotherapy-related muscle loss in cancer patients by restoring tissue NAD levels and improving mitochondrial metabolism. Niacin has also been found to increase muscle performance in adult mitochondrial myopathy by alleviating systemic NAD deficiency and increasing mitochondrial biogenesis and functionality.
These observations provide an understanding of how niacin reduces mortality risks.
The cardiovascular benefits of niacin may be attributed to its role as a lipid-lowering agent. As a potent G protein-coupled receptor agonist, niacin can inhibit lipolysis and reduce the production of free fatty acids.
Recent research highlights how niacin-derived metabolites such as 2PY and 4PY may activate inflammatory pathways that contribute to cardiovascular risks. This highlights the need for continued evaluation of the dual effects of niacin on health.
The study finds a stronger effect of niacin intake on reducing the risk of all-cause mortality in non-diabetic subjects. In this context, previous studies have shown that niacin increases the risk of diabetes by increasing blood glucose levels and reducing insulin sensitivity.
These observations suggest that a higher niacin intake may be recommended to reduce the risk of all-cause mortality in nondiabetic but not diabetic patients.
Further research is needed to clarify the variable effects of niacin in populations and its role as an NAD regulator versus a lipid-lowering agent in reducing long-term health risks.
Journal Reference:
- Lin, L., Chen, S., Zhang, C., Li, L., Chen, Y., Li, D., Cai, Q., Zhou, X., & Yang, F. (2024). Association of dietary niacin intake with all-cause and cardiovascular mortality: National Health and Nutrition Examination Survey (NHANES) 2003–2018. Scientific Reports, 14(1), 1-12. DOI: 10.1038/s41598-024-79986-9,
