Studies
110 curated research summaries. Filter by mechanism, condition, type, or outcome.
Relationship between dietary niacin intake and erectile dysfunction: a population-based study
A large U.S. study found men with higher dietary niacin (vitamin B3) intake had a lower risk of erectile dysfunction (ED). Men in the highest third of niacin intake were 56% less likely to have ED compared to those in the lowest third. This link held true even after accounting for other factors like age, weight, and health conditions.
Effects of dietary nicotinic acid supplementation on meat quality, carcass characteristics, lipid metabolism, and tibia parameters of Wulong geese
Feeding geese nicotnic acid improves muscle & fat tone, bone density, lipid metabolism. 80mg/kg per day was found to be optimal dose for improving quality of geese tibia ( longest bone in leg ).
Dietary Niacin Intake Predicts the Decrease of Liver Fat Content During a Lifestyle Intervention
In 58 patients with fatty liver disease, the ones with the most niacin in their diet had the most favorable outcome, with a 37% reduction in liver fat after 9 months of lifestyle interventions, vs only 10% reduction in the patients eating the least niacin.
Dietary nicotinic acid supplementation improves hepatic zinc uptake and offers hepatoprotection against oxidative damage
In rats, supplementing with high levels of nicotinic acid in diet before experiencing cell damage (induced by tert-butyl hydroperoxide injections) helped protect the liver, preserving its normal structure and improving its ability to absorb zinc, a beneficial element. This effect was less pronounced if the NA was increased after the cell damage had occurred. Rats with a deficiency of nicotinic acid in their diet exhibited the highest level of liver damage.
Iron deficiency reduces the efficacy of tryptophan as a niacin precursor
Iron deficiency impairs body converting tryptophan to niacin. Chicks fed the iron-deficient diets had markedly lower hemoglobin concentrations than those fed the iron-adequate diets. Regardless of iron level, chicks had linear growth responses to either nicotinic acid or tryptophan supplementation. Low bio-available iron contributes to niacin deficiency in populations.
Niacin ameliorates ulcerative colitis via prostaglandin D2‐mediated D prostanoid receptor 1 activation
Out of 26 patients with moderate ulcerative colitis (inflammation of the colon) who were unresponsive to conventional treatments, 92.3% responded positively and 88.5% went into remission after receiving a daily niacin enema treatment for 6 weeks. The had no serious side effects, showed notable improvements in intestinal healing, reduced symptoms like rectal bleeding and stool frequency. Niacin is a promising, well-tolerated alternative for inducing clinical remission of ulcerative colitis.
Studies on Tryptophan-Niacin Metabolism in Streptozotocin Diabetic Rats
Rats where split into 2 groups, one group was injected with a single does of streptozotocin at a dose of 60 mg/kg body weight, which is a chemical that is used to induce diabetes. After 12 weeks it was found that the diabetes group was only able to convert half as much tryptophan to niacins as the control group. The rats in the diabetic group had twice the excretion of xanthurenic acid in their urine. Xanthurenic acid is a waste product that is produced when tryptophan is not converted into niacin.
Low NAD+ Levels Are Associated With a Decline of Spermatogenesis in Transgenic ANDY and Aging Mice
A study in mice found that niacin supplementation increased NAD+ levels in the testes, which led to an improvement in sperm count and sperm motility. NAD+ deficient mice have ~30% smaller testes (balls) than the control mice (~1.5g vs ~2.17g). NAD+ is essential for spermatogenesis and that NAD+ deficiency leads to male infertility.
Intravenous Niacin Acutely Improves the Efficiency of Dietary Fat Storage in Lean and Obese Humans
24 healthy men and women with a mean age of 35 years, where injected Intravenously w/ 1g of niacin or placebo for 2 weeks. The niacin group ended up with acutely lower levels of FFAs (free fatty acids, fats floating around in the bloodstream) and significantly higher levels of triglyceride stored in visceral adipose tissue. This may help to reduce the amount of fat that is stored in the liver and other organs, which can help to improve insulin sensitivity and reduce the risk of metabolic complications. IE niacin may help people with diabetes and obesity to lose weight and improve their health.
A prospective and comparative investigation of blood sFlt-1, P1GF, and niacin concentrations in women with premature ovarian insufficiency
Niacin supplementation may prevent premature menopause. Women with premature menopause have significantly lower levels of niacin. Niacin levels lowest in women most severe symptoms.
Effects of Niacin and Vitamin C on Blood Sugar
Rats in group 1 received no treatment. Rats in group 2 received daily 100 mg/kg body weight niacin injections. Rats in group 3 received daily 50 mg/kg body weight vitamin C injections. Rats in group 4 received both niacin and vitamin C injections. Blood sugar levels were measured before and after treatment. The results showed that niacin and vitamin C both lowered blood sugar levels in normal rats. Niacin was more effective than vitamin C in lowering blood sugar levels in diabetic rats. The combination of niacin and vitamin C was the most effective in lowering blood sugar levels in diabetic rats.
Effectiveness of niacin supplementation for patients with type 2 diabetes: A meta-analysis of randomized controlled trials
Review of many clinical trials concludes niacin supplementation can improve lipid profiles without affecting the glycemic levels for patients with Type 2 diabetes.
Vitamin b3 and Seborrheic dermatitis - a phase IV clinical study of FDA data
Study of 4,269 people that take niacin or have Seborrheic dermatitis finds no cases of Seborrheic dermatitis in people who take niacin.
Supplementation of nicotinic acid and its derivatives up-regulates cellular NAD+ level rather than nicotinamide derivatives in cultured normal human epidermal keratinocytes
In cultured skin cells, nicotinic acid supplementation 1.3-fold up-regulated intracellular NAD+ level significantly and its metabolites nicotinic acid mono nucleotide also increased NAD+ level by 1.5-fold with 100 μM application. Surprisingly, NAM and its derivatives could not up-regulate cellular NAD+ levels in keratinocytes.
Dyssebacia: An Early Cutaneous Marker of Niacin Deficiency
Dyssebacia ( reddening, greasy, flaky scales often around nose and mouth ) is a sign of niacin deficiency.
Acne Vulgaris Is a Special Clinical Type of Pellagra
People with acne often have abnormal lipid profiles and elevated oily secretion on their skin. Foam cells are an important pathological change in acne lesions. Acne is not a skin disease induced by infection, because no bacteria, fungi or parasites can be seen in early phase of acne lesion. The foam cells in acne lesions are white blood cells that have ingested large amounts of lipids. Niacin is the only vitamin that promotes the ability of HDL to scoop up cholesterol particles from plaques in the heart's blood vessels and move those particles to the liver for disposal, which prevents foam cell formation. Foam cells in acne lesions suggest that patients with acne are deficient in niacin and that acne can be considered a type of pellagra (niacin deficiency).
Nicotinic Acid Treatment Shifts the Fibrinolytic Balance Favourably and Decreases Plasma Fibrinogen in Hypertriglyceridaemic Men
23 hypertriglyceridaemic men took 4g/day of niacin for 6 weeks and saw very significant improvements in lipoprotein concentrations (reducing very low density cholesterol and triglycerides by ~50%) as well as reduced blood clotting and thrombosis factors.
Emerging roles of GPR109A in regulation of neuroinflammation in neurological diseases and pain
Summary of GPR109A (niacin receptor) role in inflammation of the nervous system, especially the brain, and how activation of GPR109A plays a role in healing may conditions such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, stroke, and pathological pain.
Deficiency of metabolite sensing receptor HCA2 impairs the salutary effect of niacin in hemorrhagic shock
Niacin improves organ function and survival following hemorrhagic shock. Rats and mice where bled 60% of their blood volume, and replaced with Ringers lactate solution to induce hemorrhagic shock ( deprive tissue of oxygen and blood ). After 10 minutes of shock the animals where split into 3 groups and injected with nicotinic acid, NMN or DMSO, at 3 levels of dosing. Niacin at 10mg/kg, which was the highest dose given, had by far the best level of survivability. Rats, given NMN even at a 5x higher dose than niacin at 50mg/kg did not achieve a survival rate to the level observed in the 10mg/kg or the even 5mg/kg treated mice. Use of GPR109A knockout mice confirmed that the niacin GPR109A receptor plays a major role in the survivability enhancing effect of niacin.
Pharmacological bypass of NAD+ salvage pathway protects neurons from chemotherapy-induced degeneration
Axon degeneration from NMN accumulation can be prevented by bypassing the NAD+ salvage pathway (which is associated with the production of NMN) by providing nicotinic acid riboside (a precursor to nicotinic acid mononucleotide) as substrate for the body to make NAD+ via the primary Preiss Handler pathway instead.
Wallerian Degeneration Is Executed by an NMN-SARM1-Dependent Late Ca2+ Influx but Only Modestly Influenced by Mitochondria
Nicotinamide mononucleotide (NMN) accumulation in the extra cellular environment contributes to the breakdown of axons (nerve fibers).
Bacteria Boost Mammalian Host NAD Metabolism by Engaging the Deamidated Biosynthesis Pathway
This research used stable isotope tracing and microbiota-depleted mice to reveal that salvage NAD+ precursor supplements like nicotinamide (NAM) and nicotinamide ribose (NMR) don't actually boost NAD+, but depend on bacteria to first convert them into nicotinic acid. And that the resulting nicotinic acid is the converts to NAD+ via the Preiss Handler pathway.
Bacterial PncA improves diet-induced NAFLD in mice by enabling the transition from nicotinamide to nicotinic acid
Gut bacteria play an important role in NAD production. NAD boosting effect of oral NAM (nicotinamide) NR (nicotinamide riboside) is largely dependent on gut bacteria breaking them down to nicotinic acid, and that nicotinic acid being processed via Preiss Handler pathway. Nicotinic acid highly efficient at boosting NAD in mammals.
Blood levels of nicotinic acid negatively correlate with hearing ability in healthy older men
Higher levels of nicotinic acid in blood are strongly correlated with better hearing ability in 42 Japanese senior men.
Reversing Chronic Kidney Disease with Niacin and Sodium Bicarbonate
25 individuals with CKD (chronic kidney disease) stages 2-4 treated with a combination of supplements, including 500mg niacin 3x/day for three months, improved the disease by at least one stage.
Antidepressants may lead to a decrease in niacin and NAD in patients with poor dietary intake
Authors hypothesis that antidepressants tilt tryptophan metabolism towards making serotonin instead of niacin, which in turn can lead to niacin/NAD+ deficiency that exacerbates common psychiatric problems.
The β-hydroxybutyrate receptor HCA2 activates a neuroprotective subset of macrophages
Nicotinic acid mimics the effect of a ketogenic diet in activating HCA2, which induces a neuroprotective phenotype in bone marrow-derived macrophages that infiltrate the brain and that this results in an improved outcome in a mouse model of stroke.
A comparison of the efficacy and toxic effects of sustained vs immediate-release niacin in hypercholesterolemic patients
The effects on cholesterol of modified "sustained release" niacin was compared to immediate release niacin (aka nicotinic acid) and showed that sustained release tends to lower LDL more, while immediate release raises HDL more at all dosage levels. The key takeway though is that 52% of the patients taking sustained release developed signs of liver toxixity, while 0% of the ones taking immediate release did.
NAD+ repletion rescues female fertility during reproductive aging
Loss of fertility is associated with lower NAD+ levels. Restoring NAD+ in aged mice by putting nicotinamide mononucleotide (NMN) in their drinking water at 2g/L restored their fertility as well as the adverse effect of old age on the development of the embryo.
The Importance of "Folic Acid" in Rations low in Nicotinic Acid
Dogs with severe niacin deficiency required folic acid to be administered in tandem with niacin in order to recover and avoid death.
Effect of pharmacological doses of niacin on testicular structure and function in normal and diabetic rats
Feeding normal and diabetic rats 800mg of niacin per kg of diet increased testicular weight in all rats and decreased testicular MDA (a biomarker for cancer). Normal rats, but not diabetic ones, also had an increase in sperm count and serum testosterone.
Niacin regresses collagen content in human hepatic stellate cells from liver transplant donors with fibrotic non-alcoholic steatohepatitis (NASH)
Taking niacin ~1-3g daily clears up liver collagen and fat deposits which are associated with liver disease. It also prevents them from forming.
Politics and Pellagra: The Epidemic of Pellagra in the U.S. in the Early Twentieth Century
The 1906 to 1940 epidemic of pellagra was around 3 million cases, with 1 in 30 resulting in death. A Dr Goldberger was appointed to study the cause. Even though correctly identified the root cause as a nutritional deficiency (later to be confirmed as niacin specifically) his prognosis was rejected by politicians in affected regions since they basically didn't want to admit that a diet consisting of largely degerminated cornmeal (which was a key economic export) was not appropriate for human wellbeing. The invention of degerminating corn, which removes nutrients but prolongs shelf-life, coincided with the appearance of the disease. Goldberger would cure orphans suffering from pellagra by feeding them a more varied diet including fresh milk and meat.
Plasma acetylcholine and nicotinic acid are correlated with focused preference for photographed females in depressed males: an economic game study
This study showed depressed males have a narrower preference for female photographs (only preferring good looking ones) which is a marker for lower cognitive flexibility. The less nicotinic acid in their body, the narrower their preference. This indicates nicotinic acid may regulate human social decision-making (especially preference-related behaviors) by acting on the HCAR2 in microglia (the resident immune cells of the brain and spinal cord which constantly patrol the cerebral microenvironment to respond to pathogens and damage).
Niacin reduces abdominal fat: pilot study
Participants in an open label study at Kaiser Permanente in San Francisco supplemented ~3g niacin a day. After about 1 year, 81% of patients had an by an average reduction of 27% in intra-abdominal fat. The degree of fat loss was associated with the degree of increase in HDL cholesterol and a reduced Total Cholesterol/HDL cholesterol ratio.
Impact of Nuclear De Novo NAD+ Synthesis via Histone Dynamics on DNA Repair during Cellular Senescence To Prevent Tumorigenesis
The de novo production of NAD+ in the cell nucleus is central to the DNA repair capacity of aging cells and thus against preventing tumors.
Protective effects of niacin against methylmercury-induced genotoxicity and alterations in antioxidant status in rats
Rats being poisoned with methylmercury have less adverse effects when their diet is supplemented with niacin (50md/day).
Treatment of Asthma by Nicotinic Acid
Relief of the asthma attacks was obtained in 21 out of 30 cases with niacin either via intravenous injection (16 out of 21 patients relieved) or orally (5 out of 9 patients relieved). A series of 50 or 100 mg doses used. Relapse was common once niacin was discontinued.
A Detoxification Intervention for Gulf War Illness: A Pilot Randomized Controlled Trial
~30% of Gulf War veterans got Gulf War Illness, which is likely caused by toxic exposure to pesticides and chemical warfare agents. There is no known medical treatment. A regimen of niacin, sauna and exercise cured 11 of 22 participants.
NAD+ homeostasis in human health and disease
In depth review of NAD+, how its made in the human body, how it becomes deficient, and how its deficiency is a causal factor of a wide range of diseases. And how boosting NAD+ via enhancing agents like niacin ( especially niacin since it is the primary, so called Preiss-Handler pathway of manufacture ) can help cure a wide range of diseases.
Effect of Different Levels of Niacin on Serum Biochemical Parameters, Antioxidant Status, Cytokine Levels, Inflammatory Gene Expression and Colonic Microbial Composition in Weaned Piglets
Piglets separated from their mother in agriculture tend to struggle health wise. Supplementing their diet with niacin significantly improves their survivability via factors like improved colonic microbial diversity, intestinal health, reduced intestinal inflammation and improved overall immunity.
Action of nicotinic acid on the reversion of hypoxic-inflammatory link on 3T3-L1 adipocytes
Niacin reduces inflammation caused by low levels of oxygen in tissue that is associated with obesity.
Treatment of Arthritis by Nicotinic Acid and Nicotinamide
Reports of patients successfully managing or curing various forms of arthritis via nicotinic and/or nicotinamide supplementation. A daily dosage of about one gram per 50 lb. body weight is necessary.
Nicotinic Acid Long-Term Effectiveness in a Patient with Bipolar Type II Disorder: A Case of Vitamin Dependency
Case report of a patient with bipolar disorder who had been on lithium and other bipolar meds who was able to get off all meds after starting taking 1g niacin 3 times a day. He has been stable for 11 years on this niacin supplementation regimen. Stopping niacin leads a return of his symptoms within 2-3 days and clears up in one day after resuming the niacin regimen.
Nicotinic acid inhibits glioma invasion by facilitating Snail1 degradation
This study grafted malignant gliomas cells (which are one of the most common types of primary brain tumors) into rat brains to see if nicotinic acid administration would help regulate the implanted tumor. ~70% of the allografted rats that were continuously administered with nicotinic acid were still alive on day 58. 100% of control group died by day 24. Biopsy showed much less tumor spread in nicotinic acid rats. Their results suggest that niacin the helps prevent the invasion of other kinds of malignant cells such as melanoma ( skin cancer ) cells and that this points to a general role of nicotinic acid in regulating tumor invasion.
Inflammation stimulates niacin receptor (GPR109A/HCA2) expression in adipose tissue and macrophages
Many of the beneficial and adverse effects of niacin are mediated via GPR109, which is highly expressed in adipose tissue and macrophages. Multiple infectious and inflammatory stimuli stimulate GPR109A expression in adipose tissue and in macrophages.
The Lifespan Extension Ability of Nicotinic Acid Depends on Whether the Intracellular NAD+ Level Is Lower than the Sirtuin-Saturating Concentrations
Cultural cell study indicates the lifespan extension ability of niacin depends on whether the intracellular NAD+ level was lower than the sirtuin-saturating concentration.
Antiatherothrombotic effects of nicotinic acid
Niacin reduces blood viscosity through a variety of mechanisms, thus improving blood flow and perfusion through choke points of the vasculature. Finally, niacin has cardioprotective effects that may limit ischemia–reperfusion injury. By preserving glycolysis during periods of inadequate blood supply and improving blood flow to the heart after a stroke, niacin can improve the functional recovery of the muscular tissue of the heart.
Activation of Gpr109a, receptor for niacin and the commensal metabolite butyrate, suppresses colonic inflammation and carcinogenesis
Niacin, a pharmacological Gpr109a agonist, suppressed colitis and colon cancer in a Gpr109a-dependent manner in mice. Thus, Gpr10a has an essential role in mediating the beneficial effects of gut microbiota and dietary fiber in colon.
Coronavirus infection and PARP expression dysregulate the NAD metabolome: An actionable component of innate immunity
The antiviral activities of noncanonical PARP isozyme activities are limited by the availability of NAD and that nutritional and pharmacological interventions to enhance NAD levels may boost innate immunity to coronaviruses.