The Fact That the Amino Acid Tryptophan Can Be Converted to Niacin by the Body Explains Why

• Consumer
• Datos en español
• Health Professional
• Other Resources

This is a fact sail intended for health professionals. For a reader-friendly overview of Niacin, see our consumer fact sail on Niacin.

Introduction

Niacin (as well known as vitamin B3) is one of the water-soluble B vitamins. Niacin is the generic name for nicotinic acid (pyridine-3-carboxylic acrid), nicotinamide (niacinamide or pyridine-3-carboxamide), and related derivatives, such as nicotinamide riboside [ane-three]. Niacin is naturally present in many foods, added to some nutrient products, and available as a dietary supplement.

All tissues in the torso convert absorbed niacin into its main metabolically active form, the coenzyme nicotinamide adenine dinucleotide (NAD). More than 400 enzymes crave NAD to catalyze reactions in the body, which is more than for any other vitamin-derived coenzyme [one]. NAD is too converted into some other active class, the coenzyme nicotinamide adenine dinucleotide phosphate (NADP), in all tissues except skeletal musculus [4].

NAD and NADP are required in about metabolic redox processes in cells where substrates are oxidized or reduced. NAD is primarily involved in catabolic reactions that transfer the potential energy in carbohydrates, fats, and proteins to adenosine triphosphate (ATP), the cell's primary free energy currency [four]. NAD is also required for enzymes involved in critical cellular functions, such as the maintenance of genome integrity, control of cistron expression, and cellular communication [three,4]. NADP, in contrast, enables anabolic reactions, such as the synthesis of cholesterol and fatty acids, and plays a citical role in maintaining cellular antioxidant function.

Well-nigh dietary niacin is in the form of nicotinic acid and nicotinamide, simply some foods contain pocket-size amounts of NAD and NADP. The body also converts some tryptophan, an amino acid in protein, to NAD, then tryptophan is considered a dietary source of niacin.

When NAD and NADP are consumed in foods, they are converted to nicotinamide in the gut and so absorbed [4]. Ingested niacin is absorbed primarily in the modest intestine, but some is absorbed in the stomach [one-3].

Fifty-fifty when taken in very loftier doses of 3–4 thou, niacin is almost completely absorbed. In one case absorbed, physiologic amounts of niacin are metabolized to NAD. Some backlog niacin is taken upwards past ruddy blood cells to form a circulating reserve puddle. The liver methylates any remaining excess to N1-methyl-nicotinamide, N1-methyl-2-pyridone-5-carboxamide, and other pyridone oxidation products, which are and then excreted in the urine. Unmetabolized nicotinic acid and nicotinamide might be nowadays in the urine also when niacin intakes are very loftier.

Levels of niacin in the blood are not reliable indicators of niacin status. The most sensitive and reliable measure out of niacin status is the urinary excretion of its two major methylated metabolites, N1-methyl-nicotinamide and N1-methyl-two-pyridone-five-carboxamide [ii]. Excretion rates in adults of more than 17.5 micromol/24-hour interval of these 2 metabolites reverberate adequate niacin status, while excretion rates between 5.eight and 17.5 micromol/day reflect low niacin condition. An developed has scarce niacin condition when urinary-excretion rates are less than 5.viii micromol/day. Indicators of inadequacy such as this and other biochemical signs (eastward.k., a 2-pyridone oxidation production of N1-methyl-nicotinamide below detection limits in plasma or low erythrocyte NAD concentrations) occur well before overt clinical signs of deficiency [ii]. Some other measure of niacin condition takes into account the fact that NAD levels reject as niacin status deteriorates, whereas NADP levels remain relatively constant [ane,iii,five]. A "niacin number" (the ratio of NAD to NADP concentrations in whole claret x 100) below 130 suggests niacin deficiency [half dozen,7]. A "niacin index" (the ratio of erythrocyte NAD to NADP concentrations) below 1 suggests that an individual is at hazard of developing niacin deficiency [8]. No functional biochemical tests that reverberate total body stores of niacin are available [v].

Recommended Intakes

Intake recommendations for niacin and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by an skilful committee of the Nutrient and Diet Board (FNB) at the National Academies of Sciences, Engineering, and Medicine [2]. DRI is the general term for a gear up of reference values used for planning and assessing nutrient intakes of healthy people. These values, which vary by historic period and sex, include:

• Recommended Dietary Allowance (RDA): Boilerplate daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy individuals; often used to plan nutritionally adequate diets for individuals.
• Adequate Intake (AI): Intake at this level is assumed to ensure nutritional capability; established when evidence is insufficient to develop an RDA.
• Estimated Average Requirement (EAR): Boilerplate daily level of intake estimated to come across the requirements of 50% of healthy individuals; unremarkably used to assess the nutrient intakes of groups of people and to plan nutritionally adequate diets for them; can also exist used to assess the food intakes of individuals.
• Tolerable Upper Intake Level (UL): Maximum daily intake unlikely to cause adverse wellness effects.

Table 1 lists the current RDAs for niacin as mg of niacin equivalents (NE) [two]. The FNB defines one NE as i mg niacin or 60 mg of the amino acrid tryptophan (which the body can convert to niacin). Niacin RDAs for adults are based on niacin metabolite excretion data. For children and adolescents, niacin RDAs are extrapolated from developed values on the basis of trunk weight. The AI for infants from nativity to half-dozen months is for niacin lone, as immature infants utilize almost all the poly peptide they consume for growth and development; information technology is equivalent to the hateful intake of niacin in healthy, breastfed infants. For infants aged 7-12 months, the AI for niacin is in mg NE and is based on amounts consumed from breast milk and solid foods.

Table 1: Recommended Dietary Allowances (RDAs) for Niacin [two]

Historic period	Male	Female	Pregnancy	Lactation
Birth to 6 months*	two mg	ii mg
7–12 months*	4 mg NE	iv mg NE
i–3 years	six mg NE	6 mg NE
4–eight years	8 mg NE	viii mg NE
9–13 years	12 mg NE	12 mg NE
xiv–xviii years	16 mg NE	14 mg NE	18 mg NE	17 mg NE
19+ years	sixteen mg NE	14 mg NE	18 mg NE	17 mg NE

* Adequate Intake

Sources of Niacin

Nutrient
Niacin is present in a wide variety of foods. Many beast-based foods—including poultry, beefiness, and fish—provide nigh 5-ten mg niacin per serving, primarily in the highly bioavailable forms of NAD and NADP [3]. Plant-based foods, such as nuts, legumes, and grains, provide virtually 2-v mg niacin per serving, mainly as nicotinic acrid. In some grain products, yet, naturally present niacin is largely jump to polysaccharides and glycopeptides that make it only about xxx% bioavailable [iii,4]. Many breads, cereals, and infant formulas in the The states and many other countries contain added niacin. Niacin that is added to enriched and fortified foods is in its free form and therefore highly bioavailable [ii].

Tryptophan is another food source of niacin because this amino acid—when present in amounts beyond that required for poly peptide synthesis—can exist converted to NAD, mainly in the liver [3,5]. The most commonly used estimate of efficiency for tryptophan conversion to NAD is 1:60 (i.east., ane mg niacin [NAD] from threescore mg tryptophan). Turkey is an example of a nutrient high in tryptophan; a 3-oz portion of turkey breast meat provides about 180 mg tryptophan, which could be equivalent to iii mg niacin [9]. However, the efficiency of the conversion of tryptophan to NAD varies considerably in different people [3].

Table 2 lists several food sources of niacin.

Table two: Niacin Content of Selected Foods [9]

Food	Milligrams (mg) per serving	Pct DV**
Beefiness liver, pan fried, three ounces	14.nine	93
Chicken breast, meat merely, grilled, three ounces	10.three	64
Marinara (spaghetti) sauce, set up to serve, 1 cup	10.3	64
Turkey breast, meat but, roasted, iii ounces	10.0	63
Salmon, sockeye, cooked, 3 ounces	viii.half-dozen	54
Tuna, light, canned in water, drained, iii ounces	8.six	54
Pork, tenderloin, roasted, 3 ounces	half-dozen.3	39
Beef, ground, 90% lean, pan-browned, 3 ounces	v.8	36
Rice, brownish, cooked, 1 cup	5.ii	33
Peanuts, dry out roasted, 1 ounce	4.2	26
Breakfast cereals fortified with 25% DV niacin	iv.0	25
Rice, white, enriched, cooked, 1 cup	ii.3	14
Potato (russet), broiled, 1 medium	2.three	14
Sunflower seeds, dry roasted, 1 ounce	2.0	xiii
Bread, whole wheat, one slice	i.4	9
Pumpkin seeds, dry roasted, 1 ounce	1.3	8
Soymilk, unfortified, 1 cup	ane.three	8
Bread, white, enriched, 1 slice	1.3	8
Lentils, boiled and drained, ½ cup	one.0	6
Bulgur, cooked, ane cup	0.nine	6
Assistant, ane medium	0.8	5
Edamame, frozen, prepared, ½ cup	0.7	4
Raisins, ½ cup	0.6	iv
Tomatoes, carmine, ½ cup	0.five	3
Broccoli, boiled, drained, chopped, ½ cup	0.four	3
Cashews, dry roasted, 1 ounce	0.4	iii
Yogurt, apparently, depression fat, i cup	0.three	2
Apple, 1 medium	0.ii	one
Chickpeas, canned, drained, one loving cup	0.2	one
Milk, 1% milkfat, i cup	0.2	1
Spinach, frozen, chopped, boiled, ½ loving cup	0.two	1
Tofu, raw, business firm, ½ cup	0.2	1
Onions, chopped, ½ cup	0.1	one
Egg, large	0	0

* These values are for the niacin content of foods but. They exercise non include the contribution of tryptophan, some of which is converted to NAD in the body.
** DV = Daily Value. The U.S. Nutrient and Drug Administration (FDA) developed DVs to help consumers compare the nutrient contents of foods and dietary supplements within the context of a total diet. The DV for niacin is 16 mg for adults and children aged four years and older [10]. The FDA does not require food labels to listing niacin content unless niacin has been added to the food. Foods providing 20% of more of the DV are considered to exist high sources of a nutrient.

The U.S. Department of Agriculture's (USDA's) FoodData Central lists the food content of many foods and provides a comprehensive list of foods containing niacin arranged past food content.

Dietary supplements
Niacin is available in multivitamin-mineral products, in supplements containing other B-complex vitamins, and in supplements containing niacin only. Nicotinic acid and nicotinamide are the two about common forms of niacin in supplements. Some niacin-only supplements contain 500 mg or more per serving, which is much higher than the RDA for this nutrient [11].

Nicotinic acid in supplemental amounts beyond nutritional needs can cause peel flushing, so some formulations are manufactured and labeled as prolonged, sustained, extended, or timed release to minimize this unpleasant side issue. Nicotinamide does non produce pare flushing considering of its slightly different chemical construction [2,12]. Niacin supplements are too available in the form of inositol hexanicotinate, and these supplements are frequently labeled as beingness "flush free" because they do not cause flushing. The absorption of niacin from inositol hexanicotinate varies widely but on boilerplate is 30% lower than from nicotinic acid or nicotinamide, which are most completely absorbed [12-14]. A niacin-similar chemical compound, nicotinamide riboside, is also available as a dietary supplement, merely it is non marketed or labelled as a source of niacin [11].

Medications

Niaspan® and generic niacin ER, available equally a prescription medicine, provides 500-i,000 mg extended-release nicotinic acrid. Information technology is used to treat high blood cholesterol levels.

Niacin Intakes and Status

Near people in the United States consume more than the RDA for niacin. An assay of data from the 2015–2016 National Health and Nutrition Examination Survey (NHANES) found that the average daily niacin intake from foods and beverages was 21.4 mg for ages 2–19 [15]. In adults, the average daily niacin intake from foods and beverages was 31.4 mg in men and 21.3 mg in women. An analysis of data from the 2009-2012 NHANES establish that but 1% of adults had intakes of niacin from foods and beverages below the EAR [16]. Among all racial and ethnic groups, Hispanics had the greatest prevalence, 1.three%, of niacin intakes beneath the EAR [17].

According to cocky-reported data from the 2013-2014 NHANES, 21% of all individuals anile 2 and older took a dietary supplement containing niacin [15]. The proportion of users increased with age from 8% of those aged 12-19 years to 39% of men and xl% of women anile 60 and older. Supplement use doubled or tripled full niacin intakes compared with intakes from diet lone. According to data from the 2003-2006 NHANES, 10% of all individuals aged ii and older who took dietary supplements had full niacin intakes that reached or exceeded the UL [18].

Niacin Deficiency

Severe niacin deficiency leads to pellagra, a disease characterized past a pigmented rash or brown discoloration on skin exposed to sunlight; the skin besides develops a roughened, sunburned-similar advent [ii,iv,19,xx]. In addition, pellagra can cause a bright scarlet tongue and changes in the digestive tract that lead to vomiting, constipation, or diarrhea. The neurological symptoms of pellagra tin can include depression; apathy; headache; fatigue; loss of memory that can progress to ambitious, paranoid, and suicidal behaviors; and auditory and visual hallucinations [2-4]. Equally pellagra progresses, anorexia develops, and the affected private eventually dies [iii].

Pellagra is uncommon in industrialized populations and is mostly express to people living in poverty, such as refugees and displaced people who eat very express diets low in niacin and protein [20,21]. Pellagra was non uncommon in the early 20th century among individuals living in poverty in the southern United States and parts of Europe whose limited diets consisted mainly of corn [two,iii]. The World Health Organization recommends treating pellagra with 300 mg/24-hour interval nicotinamide in divided doses for 3-iv weeks forth with a B-circuitous or yeast product to treat probable deficiencies in other B vitamins [twenty].

Although frank niacin deficiencies leading to pellagra are very rare in the United States, some individuals accept marginal or depression niacin status [2,xix,21,22].

Groups at Take chances of Niacin Inadequacy

Niacin inadequacy usually arises from bereft intakes of foods containing niacin and tryptophan. It tin also be caused by factors that reduce the conversion of tryptophan to niacin, such as low intakes of other nutrients [2,21]. The following groups are among those well-nigh probable to accept inadequate niacin status.

People with undernutrition
People who are undernourished considering they live in poverty or accept anorexia, alcohol use disorder, AIDS, inflammatory bowel disease, or liver cirrhosis often have inadequate intakes of niacin and other nutrients [ii,19,21,22].

People with inadequate riboflavin, pyridoxine, and/or iron intakes
People who practise not eat enough riboflavin (vitamin B2), pyridoxine (vitamin B6), or iron convert less tryptophan to niacin considering enzymes in the metabolic pathway for this conversion depend on these nutrients to function [2,21].

People with Hartnup disease
Hartnup disease is a rare genetic disorder involving the renal, abdominal, and cellular transport processes for several amino acids, including tryptophan. The affliction interferes with the absorption of tryptophan in the small intestine and increases its loss in the urine via the kidneys [ii,22,23]. As a result, the body has less bachelor tryptophan to convert to niacin.

People with carcinoid syndrome
Carcinoid syndrome is acquired by slow-growing tumors in the gastrointestinal tract that release serotonin and other substances. It is characterized by facial flushing, diarrhea, and other symptoms. In those with carcinoid syndrome, tryptophan is preferentially oxidized to serotonin and non metabolized to niacin [2]. As a issue, the torso has less available tryptophan to catechumen to niacin.

Niacin and Health

Cardiovascular disease
Very high doses of nicotinic acid—more than 100 times the RDA—taken for months or years are constructive treatments for dyslipidemias. Nicotinamide does not accept this outcome because, unlike nicotinic acrid, it does not bind to the receptors that mediate nicotinic acid's effects on lipid profiles [1]. Studies conducted since the tardily 1950s evidence that these doses tin can increment high-density lipoprotein (HDL; "expert") cholesterol levels by 10-30% and reduce low-density lipoprotein (LDL; "bad") cholesterol levels past 10-25%, triglyceride levels by 20-50%, and lipoprotein(a) levels by 10-thirty% [12]. Together, these changes in lipid parameters might be expected to reduce the risk of showtime-time or subsequent cardiac events, such as heart attacks and strokes, in adults with atherosclerotic cardiovascular disease. Nonetheless, despite dozens of published clinical trials, experts exercise non agree on the value of nicotinic acid to treat cardiovascular disease, peculiarly given its side effects, safety concerns, and poor patient compliance [24].

In one large clinical trial from the 1970s, eight,341 participants aged 30 to 64 years who had had one or more eye attacks were randomized to take one of five lipid-lowering medications, including 3,000 mg/solar day nicotinic acrid, or a placebo for an average of half dozen.2 years [25]. Those taking nicotinic acid lowered their serum cholesterol levels by an average of 9.nine% and triglyceride levels by 26.1% over 5 years of treatment. During 5 to 8.five years of treatment, these participants had significantly fewer nonfatal myocardial infarctions but more cardiac arrhythmias than those in the placebo group. Their overall rates of mortality and cause-specific mortality, including from coronary eye disease, did non decline. But 9 years after the study concluded, participants who had taken the nicotinic acid experienced significantly fewer (11%) deaths from all causes than those who had taken the placebo [26,27].

Statin medications have become the handling of choice for hyperlipidemia and lowering the risks of atherosclerotic cardiovascular disease. For this reason, clinical trials of nicotinic acid in the by several decades have examined whether information technology provides any additional cardiovascular protection to people taking statins [28].

In the largest international, multicenter, clinical trial of nicotinic acid to date, 25,673 adults aged l-80 years (83% men) with cardiovascular disease who were taking a statin were randomized to take 2 grand/day extended-release nicotinic acid with a medication to reduce nicotinic acid's flushing upshot and therefore improve handling compliance or a matching placebo for a median of four years [29,30]. The nicotinic acid group had a mean reduction in LDL cholesterol (of 10 mg/dl) and triglycerides (of 33 mg/dl) and an increase in HDL cholesterol (of vi mg/dl), but this group had no pregnant reduction in rates of major vascular events compared with the placebo (statin-simply) group. Furthermore, the nicotinic acid group had a significantly greater risk of diabetes, gastrointestinal dyspepsia, diarrhea, ulceration, haemorrhage events in the gut and brain, and skin rashes and ulcerations. An earlier randomized clinical trial of 3,414 patients with established cardiovascular disease was stopped after three years when the researchers found that patients taking niacin (1,500-2,000 mg/twenty-four hour period extended release) in add-on to their cholesterol-reduction medications did not have fewer cardiovascular events than those taking medication lonely, even though the niacin reduced triglyceride and LDL-cholesterol levels further and raised HDL cholesterol levels further [31]. The results also showed that patients taking niacin had an increased risk of ischemic stroke.

The authors of two 2022 systematic reviews examining the clinical trial data ended that nicotinic acid therapy provides picayune if any protection from atherosclerotic heart illness, even though the therapy raises HDL cholesterol levels and lowers total cholesterol, LDL cholesterol, and triglyceride levels. One of these reviews examined 23 randomized controlled trials of moderate to high quality in 39,195 participants aged 33-71 years (average 65 years; bulk were male person). Some had experienced a heart attack, and nearly were taking a statin. The doses used and treatment elapsing in these studies varied widely; the median dose of nicotinic acrid was 2 g/day (range 0.5 to 4 one thousand/24-hour interval) for a median of 11.five months (range vi months to 6 years) [24]. Overall, utilize of nicotinic acrid did not reduce overall mortality or cardiovascular mortality rates or the number of fatal or nonfatal myocardial infarctions or strokes. Eighteen percent of participants taking nicotinic acid discontinued treatment considering of side furnishings. The 2d review examined 13 randomized controlled trials with 35,206 participants with, or at run a risk of, atherosclerotic cardiovascular disease [32]. Overall, the addition of nicotinic acrid supplementation (dose range non specified) to statin therapy taken for a mean of 33 months (with a broad range of six to 60 months) did non lead to significant reductions in rates of all-cause or cardiovascular mortality, myocardial infarction, or stroke. Nicotinic acid treatment was associated with a significantly college risk of gastrointestinal and musculoskeletal adverse events. In addition, four of the studies that examined diabetes equally an outcome found that the patients taking niacin had a significantly higher adventure of developing the illness.

A 2022 review of three randomized controlled trials with 29,195 patients found that all-cause bloodshed increased past 10% more in those who took 1 to 3 g/mean solar day extended release nicotinic acid in addition to a statin medication than patients taking the statin alone [33].

In their guidelines for lowering blood cholesterol levels, the American College of Cardiology and the American Heart Association advise that nonstatin therapies, compared with or in improver to statin therapy, exercise non provide atherosclerotic cardiovascular illness risk-reduction benefits that outweigh the potential harms of their adverse furnishings [28]. When discussing the use of nicotinic acrid supplements to reduce the risk of hyperlipidemia (for example, in patients unable to tolerate statin medications), the two professional person societies recommend that patients have 500 mg/mean solar day extended-release nicotinic acid supplements and increase the dose to a maximum of two,000 mg/twenty-four hours over four to viii weeks or take 100 mg immediate-release nicotinic acrid iii times a day and increase the dose to iii,000 mg/twenty-four hours divided into two or three doses. (Their articulation statement about monitoring supplement users who accept niacin to reduce hyperlipidemia risk for adverse furnishings is described in the Health Risks from Excessive Niacin department below.) In their 2022 study, these two professional societies stated what although niacin may exist useful in some cases of severe hypertriglyceridemia, it has only mild LDL-lowering furnishings. The societies therefore do not recommend using it as an add-on drug to statin therapy [34].

Overall, the evidence indicates that nicotinic acid supplementation improves blood lipid profiles but has no significant effects on risk of cardiovascular events. Although nicotinic acid is a nutrient, if very high doses (thousands of mg) are taken to treat hyperlipidemias, the supplement is being used equally a drug. Such doses should only be taken with medical approval and supervision.

Health Risks from Excessive Niacin

No adverse furnishings have been reported from the consumption of naturally occurring niacin in foods [2]. However, high intakes of both nicotinic acid and nicotinamide taken equally a dietary supplement or medication can cause adverse effects, although their toxicity profiles are not the same.

Xxx to 50 mg nicotinic acid or more typically causes flushing; the skin on the patient's face up, arms, and chest turns a reddish colour because of vasodilation of pocket-sized subcutaneous claret vessels. The flushing is accompanied by burning, tingling, and itching sensations [2,12,35]. These signs and symptoms are typically transient and tin occur within 30 minutes of intake or over days or weeks with repeated dosing; they are considered an unpleasant, rather than a toxic, side effect. However, the flushing can be accompanied by more than serious signs and symptoms, such as headache, rash, dizziness, and/or a decrease in blood pressure level. Supplement users tin reduce the flushing effects by taking nicotinic acid supplements with food, slowly increasing the dose over fourth dimension, or just waiting for the body to develop a natural tolerance.

When taken in pharmacologic doses of 1,000 to iii,000 mg/twenty-four hour period, nicotinic acrid tin can likewise cause more than serious adverse effects [2,4,12,35]. Many of these effects have occurred in patients taking high-dose nicotinic acid supplements to treat hyperlipidemias. These adverse effects can include hypotension astringent plenty to increment the risk of falls; fatigue; impaired glucose tolerance and insulin resistance; gastrointestinal effects, such as nausea, heartburn, and abdominal pain; and ocular effects, such as blurred or dumb vision and macular edema (a buildup of fluid at the heart of the retina). High doses of nicotinic acid taken over months or years tin can also be hepatotoxic; furnishings can include increased levels of liver enzymes; hepatic dysfunction resulting in fatigue, nausea, and anorexia; hepatitis; and acute liver failure [2,12,28,36]. Hepatotoxicity is more likely to occur with the employ of extended-release forms of nicotinic acid [12,37,38].

To minimize the risk of adverse furnishings from nicotinic acid supplementation or to identify them before they become serious, the American College of Cardiology and the American Heart Association recommend measuring hepatic transaminase, fasting blood glucose or hemoglobin A1C, and uric acid levels in all supplement users before they start therapy, while the dose is being increased to a maintenance level, and every six months thereafter [28]. The societies also recommend that patients not apply nicotinic acrid supplements or stop using them if their hepatic transaminase levels are more than two or 3 times the upper limits of normal; if they develop persistent hyperglycemia, acute gout, unexplained abdominal pain, gastrointestinal symptoms, new-onset atrial fibrillation, or weight loss; or if they take persistent and astringent skin reactions, such as flushing or rashes.

Nicotinamide does not cause skin flushing and has fewer agin effects than nicotinic acid, and these effects typically begin with much higher doses [12]. Nausea, vomiting, and signs of liver toxicity can occur with nicotinamide intakes of three,000 mg/day [2]. In several small studies of participants undergoing hemodialysis, the most mutual adverse effects from 500-1,500 mg/day nicotinamide supplementation for several months were diarrhea and thrombocytopenia (low platelet count) [35,39-41].

The FNB has established ULs for niacin that use only to supplemental niacin for healthy infants, children, and adults [ii]. These ULs are based on the levels associated with skin flushing. The FNB acknowledges that although backlog nicotinamide does not cause flushing, a UL for nicotinic acid based on flushing tin can prevent the potential adverse effects of nicotinamide [2]. The UL, therefore, applies to both forms of supplemental niacin. Even so, the UL does not apply to individuals who are receiving supplemental niacin under medical supervision [2].

Table 3: Tolerable Upper Intake Levels (ULs) for Niacin [2]

Age	Male	Female	Pregnancy	Lactation
Birth to 6 months	None established*	None established*
seven–12 months	None established*	None established*
i–3 years	10 mg	ten mg
four–8 years	15 mg	15 mg
9–13 years	twenty mg	twenty mg
xiv–18 years	thirty mg	xxx mg	thirty mg	30 mg
19+ years	35 mg	35 mg	35 mg	35 mg

* Breast milk, formula, and food should exist the only sources of niacin for infants.

Interactions with Medications

Niacin can interact with certain medications, and several types of medications might adversely affect niacin levels. A few examples are provided below. Individuals taking these and other medications on a regular ground should talk over their niacin status with their healthcare providers.

Isoniazid and pyrazinamide
Isoniazid and pyrazinamide (together in Rifater®), used to treat tuberculosis, are structural analogs of niacin and interrupt the product of niacin from tryptophan by competing with a vitamin B6-dependent enzyme required for this process [2,21]. In addition, isoniazid tin can interfere with niacin'southward conversion to NAD [42]. Although pellagra can occur in patients with tuberculosis treated with isoniazid, it tin can exist prevented with increased intakes of niacin.

Antidiabetes medications
Big doses of nicotinic acid can raise blood glucose levels past causing or aggravating insulin resistance and increasing hepatic product of glucose [42]. Some studies accept found that nicotinic acid doses of i.5 g/day or more are most likely to increment claret glucose levels in individuals with or without diabetes [37]. People who take whatever antidiabetes medications should have their blood glucose levels monitored if they take high-dose nicotinic acid supplements concomitantly because they might require dose adjustments [42].

Niacin and Healthful Diets

The federal authorities's 2020–2025 Dietary Guidelines for Americans notes that "Because foods provide an array of nutrients and other components that accept benefits for wellness, nutritional needs should be met primarily through foods. ... In some cases, fortified foods and dietary supplements are useful when it is not possible otherwise to meet needs for one or more than nutrients (east.g., during specific life stages such as pregnancy)."

For more than data about building a salubrious dietary blueprint, refer to the Dietary Guidelines for Americans and the U.S. Department of Agriculture'south MyPlate.

The Dietary Guidelines for Americans describes a healthy dietary pattern equally one that:

• Includes a variety of vegetables; fruits; grains (at to the lowest degree one-half whole grains); fat-gratuitous and low-fat milk, yogurt, and cheese; and oils.

  Many vegetables, fruits, whole grains, and dairy products provide some niacin. Enriched grains are also a source of niacin.

• Includes a diverseness of protein foods such as lean meats; poultry; eggs; seafood; beans, peas, and lentils; nuts and seeds; and soy products.

  Fish, beef, chicken, and turkey are good sources of niacin. Many legumes, nuts, seeds, and soy products provide some niacin.

• Limits foods and beverages higher in added sugars, saturated fat, and sodium.


• Limits alcoholic beverages.


• Stays within your daily calorie needs.

References

1. Penberthy WT, Kirkland JB. Niacin. In: Erdman JW, Macdonald IA, Zeisel SH, eds. Present Knowledge in Nutrition, 10th ed. Washington, DC: Wiley-Blackwell; 2012:293-306.
2. Institute of Medicine. Nutrient and Nutrition Board. Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, DC: National Academy Press, 1998.
3. Kirkland JB. Niacin. In: Ross Air conditioning, Caballero B, Cousins RJ, Tucker KL, Ziegler TR, eds. Mod Nutrition in Health and Affliction, 11th ed. Baltimore, MD: Williams & Wilkins; 2014:331-forty.
4. Bourgeois C, Moss J. Niacin. In: Coates PM, Betz JM, Blackman MR, Cragg GM, Levine M, Moss J, White JD, eds. Encyclopedia of Dietary Supplements, second ed. New York, NY: Informa Healthcare; 2010:562-9.
5. Gibson, RS. Principles of Nutritional Assessment, 2d Edition. New York: Oxford Academy Printing. Copyright 2005.
6. Jacobson EL, Jacobson MK Tissue NAD equally a biochemical measure of niacin status in humans. Methods in Enzymology 1997;280:221-30. [PubMed abstract]
7. Shah GM, Shah RG,Veillette H, Kirkland JB, Pasieka JL,Warner RRP. Biochemical assessment of niacin deficiency among carcinoid cancer patients. American Journal of Gastroenterology 2005;100:2307-14. [PubMed abstract]
8. Fu CS, Swendseid ME, Jacob RA, McKee RW. Biochemical markers for assessment of niacin status in young men: Levels of erythrocyte niacin coenzymes and plasma tryptophan. J Nutr 1989;119:1949-55. [PubMed abstract]
9. U.S. Department of Agriculture, Agronomical Enquiry Service. FoodData Cardinal, 2019.
10. U.Due south. Food and Drug Administration. Food Labeling: Revision of the Nutrition and Supplement Facts Labels. 2016.
11. National Institutes of Health. Dietary Supplement Characterization Database. 2018.
12. MacKay D, Hathcock J, Guarneri. Niacin: chemical forms, bioavailability, and wellness furnishings. Nutr Rev 2012;70:357-66. [PubMed abstract]
13. Norris RB. "Flush-free niacin": Dietary supplement may exist "benefit-free." Preventive Cardiology 2006;9:64-5. [PubMed abstract]
14. Keenan JM. Wax-matrix extended-release niacin vs inositol hexanicotinate: A comparison of wax-matrix, extended-release niacin to inositol hexanicotinate "no-flush" niacin in persons with balmy to moderate dyslipidemia. Journal of Clinical Lipidology 2013;7:fourteen-23. [PubMed abstract]
15. What We Swallow in America Data Tables.
16. Blumberg JB, Frei BB, Fulgoni III VL, Weaver CM, Zeisel SH. Impact of frequency of multi-vitamin/multi-mineral supplement intake on nutritional capability and food deficiencies in U.Due south. adults. Nutrients 2017;August 9. [PubMed abstract]
17. Blumberg JB, Frei B, Fulgoni 3 VL, Weaver CM, Zeisel SH. Contribution of dietary supplements to nutritional adequacy in race/ethnic population subgroups in the The states. Nutrients 2017;November 28. [PubMed abstract]
18. Fulgoni III VL, Keast DR, Bailey RL, Dwyer J. Foods, fortificants, and supplements: Where do Americans become their nutrients? J Nutr 2011;141:1847-54. [PubMed abstruse]
19. Savvidou Southward. Pellagra: a non-eradicated old disease. Clinics and Practice 2014;four:637. [PubMed abstract]
20. Globe Health Organization. Pellagra and its prevention and control in major emergencies. 2000.
21. Li R, Yu 1000, Wang Q, Wang L, Mao J, Qian J. Pellagra secondary to medication and alcoholism: A instance written report and review of the literature. Diet in Clinical Practice 2016;31:785-9. [PubMed abstract]
22. Crook MA. The importance of recognizing pellagra (niacin deficiency) as it still occurs. Nutrition 2014;30:729-30. [PubMed abstract]
23. National Organization for Rare Disorders. Hartnup disease. 2016.
24. Schandelmaier S, Briel Chiliad, Saccilotto R, Olu KK, Arpagaus A, Hemkens LG, Nordmann AJ. Niacin for primary and secondary prevention of cardiovascular events (review). Cochrane Database of Systematic Reviews 2017, Result 6. Art. No.:CD009744. [PubMed abstract]
25. The Coronary Drug Project Enquiry Group. Clofibrate and niacin in coronary heart disease. JAMA 1975;231:360-81. [PubMed abstract]
26. Berge KG, Canner PL. Coronary drug project: Experience with niacin. Eur J Clin Pharmacol 1991;40:S49-51. [PubMed abstract]
27. Canner PL, Berge KG, Wenger NK, Stamler J, Friedman L, Prineas RJ. Friedewald W. Fifteen yr bloodshed in Coronary Drug Project patients: Long-term benefit with niacin. J Am Coll Cardiol 1986;8:1245-55. [PubMed abstract]
28. Stone et al. American College of Cardiology/American Heart Association Job Force on Practice Guidelines. 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular hazard in adults. J Am Coll Cardiol 2014;63:2889-934. [PubMed abstruse]
29. HPS2-THRIVE Collaborative Group. Furnishings of extended-release niacin with laropiprant in high-take chances patients. New Engl J Med 2014;371:203-12. [PubMed abstract]
30. Lloyd-Jones DM. Niacin and HDL cholesterol—time to face facts. N Engl J Med 2014;371:271-three. [PubMed abstract]
31. The AIM-HIGH Investigators. Niacin in patients with depression HDL cholesterol levels receiving intensive statin therapy. E Engl J Med 2011;365:2255-67. [PubMed abstruse]
32. Garg A, Sharma A, Krishnamoorthy P, Garg J, Virmani D, Sharma T, et al. Part of niacin in current clinical practice: A systematic review. The American Journal of Medicine 2017;130:173-87. [PubMed abstract]
33. Jenkins DJA, Spence JD, Giovannucci EL, Kim Y, Josse R, Vieth R, et al. Supplemental vitamins and minerals for CVD prevention and treatment. Journal of the American College of Cardiology 2018;71:2570-84. [PubMed abstract]
34. Grundy SM, Stone NJ, Bailey AL, Axle C, Birtcher KK, Blumenthal RS, et al. 2022 AHA/ACC/AACVPR/AAP/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the management of blood cholesterol. Circulation. Published November 10, 2018. [PubMed abstract]
35. Minto C, Vecchio MG, Lamprecht M, Gregori D. Definition of a tolerable upper intake level of niacin: a systematic review and meta-analysis of the dose-dependent effects of nicotinamide and nicotinic acrid supplementation. Nutr Rev 2017;75:471-90. [PubMed abstract]
36. McKenney JM, Proctor JD, Harris Southward, Chinchili VM. A comparison of the efficacy and toxic effects of sustained- vs immediate-release niacin in hypercholesterolemic patients. JAMA 1994;271:672-7. [PubMed abstract]
37. McKenney J. New perspectives on the use of niacin in the treatment of lipid disorders. Arch Intern Med 2004;164:697-705. [PubMed abstract]
38. Leung K, Quezada M, Chen Z, Kanel Thou, Kaplowitz N. Niacin-induced anicteric microvesicular steatotic acute liver failure. Hepatol Commun 2018;2:1293-viii. [PubMed abstract]
39. Cheng SC, Young DO, Huang Y, Delmez JA, Coyne DW. A randomized, double-blind, placebo-controlled trial of niacinamide for reduction of phosphorus in hemodialysis patients. Xlin J Am Soc Nephrol 2008;3:1131-eight. [PubMed abstruse]
40. Shahbazian H, Mohtashami AZ, Ghorbani A, Abbaspour MR, Musavi SSB, Hayati F, Lashkarara GR. Oral nicotinamide reduces serum phosphorus, increases HDL, and induces thrombocytopenia in hemodialysis patients: a double-blind randomized clinical trial. Nefrologia 2011;31:58-65. [PubMed abstruse]
41. Takahashi Y, Tanaka A, Nakamura T, Fukuwatari T, Shibata Thou, Shinada N, et al. Nicotinamide suppresses hyperphosphatemia in hemodialysis patients. Kidney International 2004;65:1099-1104. [PubMed abstract]
42. Natural Medicines. Niacin.

Disclaimer

This fact sheet past the National Institutes of Wellness (NIH) Office of Dietary Supplements (ODS) provides information that should non take the identify of medical advice. We encourage y'all to talk to your healthcare providers (doc, registered dietitian, pharmacist, etc.) about your interest in, questions about, or use of dietary supplements and what may exist best for your overall health. Any mention in this publication of a specific product or service, or recommendation from an arrangement or professional society, does not correspond an endorsement by ODS of that product, service, or proficient communication.

bartongerentow.blogspot.com

Source: https://ods.od.nih.gov/factsheets/Niacin-HealthProfessional/

Share this post