How vitamin B3 could be the secret to living longer and protecting your heart

By Dr. Sanchari Sinha Dutta, Ph.D.Nov 18 2024

Discover how a key nutrient in your diet could hold the secret to a longer life and better heart health with groundbreaking 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 can reduce the risks of all-cause and cardiovascular disease-related mortality 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 severe health conditions, including pellagra, a severe disease characterized by dermatitis, diarrhea, dementia, and fatality.

Some countries have adopted niacin fortification of wheat flour and cereals to prevent pellagra. Moreover, several common foods, including 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 surpasses the recommended dietary allowance by threefold.

Niacin is well-known for its therapeutic effects in dyslipidemia. Several studies have shown that niacin can significantly reduce 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 lipid profile improvements do not consistently lead to better cardiovascular outcomes. While some studies have found moderately beneficial effects of niacin on cardiovascular events, some have found that niacin does not reduce cardiovascular event risks and that it may increase the risk of all-cause mortality.

Given the scarcity of information on niacin's impact on long-term health outcomes, the current study was designed to investigate the association between dietary niacin intake and causes of cardiovascular mortality in the US general population.

Study Design

This study included 26,746 adult individuals who participated in the National Health and Nutrition Examination Survey (NHANES) 2003–2018. The median follow-up period was 9.17 years.

Niacin intake was obtained from two 24-hour dietary recall interviews. The participants were categorized into four groups based on their average intake over two days.

Statistical analyses were carried out to compare the risk of all-cause and cardiovascular mortality among participants grouped into different dietary niacin intake quartiles. Sensitivity analyses, such as excluding participants with pre-existing cardiovascular disease (CVD) or cancer, confirmed the robustness of these findings.

Important Observations

A total of 3,551 deaths from all causes and 1,096 deaths due to cardiovascular events occurred during the study follow-up period.

The statistical analyses showed a negative association between dietary niacin intake and risk of all-cause and cardiovascular mortality. Participants with the highest intake of niacin exhibited lower risks of all-cause and cardiovascular mortality than those with the lowest intake of dietary niacin.

A dose-response association was observed between dietary niacin intake and mortality risks, meaning that a reduction in all-cause and cardiovascular mortality risk was observed with increasing dietary niacin intake. However, the benefits plateaued when niacin intake exceeded the median value of 22.45 milligrams per day.

Subgroup analyses stratified by age, sex, ethnicity, educational level, smoking, alcohol consumption, body mass index (BMI), and disease conditions revealed that the impact of dietary niacin intake on the risk of all-cause mortality was significantly more pronounced in non-diabetic individuals compared to diabetic patients.

Regarding cardiovascular mortality risk reduction, the beneficial impact of niacin intake was observed in some subgroups, including older adults, females, non-Hispanic White individuals, higher education, obesity, smoking, non-hypertension, non-diabetes, non-dyslipidemia, and non-cardiovascular disease. Baseline characteristics showed that individuals with higher niacin intake were generally younger, more educated, and more likely to smoke or consume alcohol.

Study Significance

The study finds an inverse association between dietary niacin intake and risk of all-cause and cardiovascular mortality in the US adult population.

Niacin intake may be beneficial because it improves nicotinamide adenine dinucleotide (NAD) metabolism. As a NAD precursor, niacin can increase NAD levels, subsequently improve cellular metabolism and mitochondrial functions, and reduce DNA damage, inflammation, cell death, and cell aging via various mechanisms.

Niacin has been found to reduce chemotherapy-related muscle mass loss in cancer patients by restoring tissue NAD levels and improving mitochondrial metabolism. Niacin has also been found to increase muscle performance in adult-onset mitochondrial myopathy by mitigating systemic NAD deficiency and increasing mitochondrial biogenesis and functionality.

These observations provide an understanding of how niacin reduces mortality risks.

Niacin's cardiovascular benefits 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 free fatty acid production.

Recent research highlights how niacin-derived metabolites, such as 2PY and 4PY, may activate inflammatory pathways that contribute to cardiovascular risks. This underscores the need for continued evaluation of niacin’s dual effects on health.

The study finds a more pronounced effect of niacin intake on all-cause mortality risk reduction in non-diabetic individuals. 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 higher niacin intake might be recommended to reduce all-cause mortality risk in non-diabetic people but not in diabetic patients.

Further research is needed to clarify niacin’s variable effects across populations and its role as an NAD modulator versus a lipid-lowering agent in reducing long-term health risks.