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Cas No.: 59-67-6
Ec No.: 200-441-0
Beilstein No.:109591
Empirical Formula (Hill Notation): C6H5NO2
Molecular Weight: 123.11
A nutrient in the vitamin B complex that the body needs in small amounts to function and stay healthy.
Vitamin B3 helps some enzymes work properly and helps skin, nerves, and the digestive tract stay healthy.
Vitamin B3 is found in many plant and animal products. It is water-soluble (can dissolve in water) and must be taken in every day.
Not enough vitamin B3 can cause a disease called pellagra (a condition marked by skin, nerve, and digestive disorders).
A form of vitamin B3 is being studied in the prevention of skin and other types of cancer.
Vitamin B3 may help to lower blood cholesterol. Also called niacin and nicotinic acid.
Vitamin B3 is a vitamin family that includes three forms or vitamers: nicotinamide (niacinamide), niacin (nicotinic acid), and nicotinamide riboside.
All three forms of vitamin B3 are converted within the body to nicotinamide adenine dinucleotide (NAD).
NAD is required for human life and people are unable to make it within their bodies without either vitamin B3 or tryptophan.
Vitamin B3 is a water-soluble vitamin that cannot be stored in body fat.
Vitamin B3 has two active components, nicotinic acid (niacin) and nicotinamide (niacinamide).
This vitamin plays a role in over 200 enzymatic reactions.
The body can synthesize vitamin B3 in small amounts, provided it has sufficient stores of magnesium, vitamins B6 and B2, and tryptophan.
The latter is an essential amino acid (part of a protein.
Vitamin B3 is not produced by the body and must be obtained from food sources.
Niacin is a member of the B family of vitamins (B complex).
Vitamin B3 a water-soluble vitamin.
Excess amounts come out in the urine.
Like the other B vitamins, niacin helps make energy in your body.
Vitamin B3 helps your body use carbohydrates, fatty acids, and proteins.
Nicotinamide riboside was identified as a form of vitamin B3 in 2004.
In the past, the group was loosely referred to as vitamin B3 complex.
Niacin was discovered by the oxidation of nicotine.
Niacin is derived from nicotinic acid + vitamin, as the name to be given to it is not intended to evoke nicotine.
Niacin can be seen in ancient texts that the name vitamin PP (short for the English term "pellegra prevention") was used for niacin.
Niacin is a B vitamin that's made and used by your body to turn food into energy.
Niacin helps keep your nervous system, digestive system and skin healthy.
Niacin (vitamin B-3) is often part of a daily multivitamin, but most people get enough niacin from the food they eat.
Foods rich in niacin include yeast, milk, meat, tortillas and cereal grains.
People use prescription niacin (Niacor, Niaspan) to help control their cholesterol.
The recommended daily amount of niacin for adult males is 16 milligrams (mg) a day and for adult women who aren't pregnant, 14 mg a day.
Vitamin B3 is found in many plant and animal foods, such as yeast, meats (especially liver), grains, legumes, corn treated with alkali (such as corn used in tortillas), and seeds.
Vitamin B3 can be made by the liver from the amino acid tryptophan.
Vitamin B3 works in 2 enzyme systems (NAD and NADP).
They affect all the tissues of the body.
These enzyme systems help move hydrogen within a cell.
They also make Vitamin B3 available for biosynthesis.
These 2 enzymes also work closely with the energy molecule adenosine triphosphate (ATP).
Vitamin B3 is known as a type of vitamin that should be taken by the body and is among the important vitamins from the sub-types of B vitamins.
In addition to being included in many products, Vitamin B3s deficiency is known to cause some diseases and disorders.
Vitamin B3, or Niacin is a water-soluble B vitamin found naturally in some foods, added to foods, and sold as a supplement.
The two most common forms of niacin in food and supplements are nicotinic acid and nicotinamide.
The body can also convert tryptophan—an amino acid—to nicotinamide.
Vitamin B3 is water-soluble so that excess amounts the body does not need are excreted in the urine.
Vitamin B3 works in the body as a coenzyme, with more than 400 enzymes dependent on it for various reactions.
Vitamin B3 helps to convert nutrients into energy, create cholesterol and fats, create and repair DNA, and exert antioxidant effects.
Niacin is a form of vitamin B3 made in the body from tryptophan.
Vitamin B3's found in many foods including meat, fish, milk, eggs, green vegetables, and cereals.
Niacin is water-soluble so that excess amounts the body does not need are excreted in the urine.
Niacin works in the body as a coenzyme, with more than 400 enzymes dependent on it for various reactions.
Niacin helps to convert nutrients into energy, create cholesterol and fats, create and repair DNA, and exert antioxidant effects.
Vitamin B-3, also known as niacin, is one of eight B vitamins. It plays a role in converting the food we eat into energy.
Vitamin B-3 helps the body to use proteins and fats, and it keeps the skin, hair, and nervous system healthy.
Other possible benefits of vitamin B-3 stem from its potential cholesterol-lowering, antioxidative, and anti-inflammatory properties.
Other names for vitamin B-3 include nicotinamide, nicotinic acid, and vitamin PP, because it prevents pellagra.
The body excretes any niacin it does not need in urine.
The body does not store Vitamin B-3, and so people must consume it in food every day.
A healthful diet can provide all of a person’s vitamin B-3 needs. Vitamin B-3 deficiency is rare in the United States.
Vitamin B3 is required for the proper function of fats and sugars in the body and to maintain healthy cells.
At high doses, niacin might help people with heart disease because of its effects on blood clotting.
Vitamin B3 might also improve levels of fats called triglycerides in the blood.
Prescription forms of Vitamin B3 are approved by the US FDA for abnormal cholesterol levels and for preventing vitamin B3 deficiency and related conditions such as pellagra.
People use Vitamin B3 supplements for metabolic syndrome, heart disease, cataracts, high blood pressure, and many other conditions.
Vitamin B3, also called nicotinic acid and niacin, water-soluble vitamin of the B complex.
Niacin is a form of vitamin B3.
Niacin is found in foods such as yeast, meat, fish, milk, eggs, green vegetables, and cereal grains.
Niacin-containing enzymes are involved in fat, cholesterol and carbohydrate metabolism, and in the production of sex and adrenal hormones.
Niacin was found while investigating the cause of pellagra.
Niacin is used to lower cholesterol and triglycerides (a common form of fat) in your blood.
Niacin doesn’t work as well as statins for lowering cholesterol and it’s not used as commonly because it can cause many unwanted side effects like flushing and stomach upset.
Vitamin B3 is also called the pellagra-preventive vitamin because an adequate amount in the diet prevents pellagra, a chronic disease characterized by skin lesions, gastrointestinal disturbance, and nervous symptoms.
Vitamin B3 is interchangeable in metabolism with its amide, niacinamide (nicotinamide).
Like the vitamins thiamin (vitamin B1) and riboflavin (vitamin B2), Niacin (vitamin B3) functions as part of a coenzyme involved in the metabolism of carbohydrates and acts to catalyze the oxidation of sugar derivatives and other substances.
Do not confuse Vitamin B3 with NADH, niacinamide, inositol nicotinate, IP-6, or tryptophan.
These are not the same.
Niacin, or vitamin B3, is a water-soluble B vitamin found naturally in some foods, added to foods, and sold as a supplement.
The two most common forms of niacin in food and supplements are nicotinic acid and nicotinamide.
The body can also convert tryptophan—an amino acid—to nicotinamide.
Niacin, also known as nicotinic acid, is an organic compound and a form of vitamin B3, an essential human nutrient.
Vitamin B3 can be manufactured by plants and animals from the amino acid tryptophan.
Vitamin B3 is obtained in the diet from a variety of whole and processed foods, with highest contents in fortified packaged foods, meat, poultry, red fish such as tuna and salmon, lesser amounts in nuts, legumes and seeds.
Vitamin B3 as a dietary supplement is used to treat pellagra, a disease caused by niacin deficiency.
Signs and symptoms of pellagra include skin and mouth lesions, anemia, headaches, and tiredness.
Many countries mandate Vitamin B3s addition to wheat flour or other food grains, thereby reducing the risk of pellagra.
Vitamin B3 is also a prescription medication.
Amounts far in excess of the recommended dietary intake for vitamin functions will lower blood triglycerides and low density lipoprotein cholesterol (LDL-C), and raise blood high density lipoprotein cholesterol (HDL-C, often referred to as "good" cholesterol).
There are two forms: immediate-release and sustained-release Vitamin B3.
Initial prescription amounts are 500 mg/day, increased over time until a therapeutic effect is achieved.
Immediate-release doses can be as high as 3,000 mg/day; sustained-release as high as 2,000 mg/day.
Despite the proven lipid changes, niacin has not been found useful for decreasing the risk of cardiovascular disease in those already on a statin.
A 2010 review had concluded that niacin was effective as a mono-therapy,but a 2017 review incorporating twice as many trials concluded that prescription niacin, while affecting lipid levels, did not reduce all-cause mortality, cardiovascular mortality, myocardial infarctions, nor fatal or non-fatal strokes.
Prescription niacin was shown to cause hepatotoxicity and increase risk of type 2 diabetes.
Niacin prescriptions in the U.S. had peaked in 2009, at 9.4 million, declining to 1.3 million by 2017.
Vitamin B3, also called niacin, is a water-soluble vitamin found in many common foods such as chicken, tuna, beets, and lentils.
Niacin plays a role in countless bodily functions and helps convert the food we eat into energy.
Specifically, vitamin B3 plays an important role in digestion, mental health, heart health, the nervous system, maintaining healthy skin, making a variety of hormones, and acting as a precursor to the coenzyme nicotinamide adenine dinucleotide (NAD+).
But vitamin B3 is also a little more complex than your average vitamin.
Niacin naturally found in several different forms, each of which has a slightly different effect on the body.
Here, learn all about vitamin B3, its different forms and health benefits, signs of deficiency, common food sources, and when to consider a supplement.
Niacin is actually a blanket term for three different compounds that have similar activity in the body: nicotinic acid, nicotinamide (aka niacinamide), and nicotinamide riboside (NR).
You'll find that "vitamin B3" and "niacin" are often used interchangeably to refer to these compounds.
Of these, nicotinic acid and nicotinamide are the main forms of vitamin B3 or niacin—they're both widely available from the same food sources and sold as dietary supplements.
NR, on the other hand, is quite scarce in food and only recently started being sold as a supplement.
Niacin has the formula C6H5NO2 and belongs to the group of the pyridinecarboxylic acids.
As the precursor for nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate, niacin is involved in DNA repair.
Niacin is water-soluble so that excess amounts the body does not need are excreted in the urine.
Niacin works in the body as a coenzyme, with more than 400 enzymes dependent on it for various reactions.
Niacin helps to convert nutrients into energy, create cholesterol and fats, create and repair DNA, and exert antioxidant effects.
Niacin is a type of B vitamin.
Niacin is a water-soluble vitamin.
Niacin is not stored in the body.
Niacin is an antilipemic medication.
Niacin is a naturally occurring vitamin (vitamin B3) and it works by blocking, increasing, and lowering certain key pathways responsible for making cholesterol and triglyceride in the body.
As a result of these actions, it can help lower "bad" (LDL) cholesterol and triglyceride levels, while raising the "good" (HDL) cholesterol levels.
Niacin is used to lower blood levels of "bad" cholesterol (low-density lipoprotein, or LDL) and triglycerides, and increase levels of "good" cholesterol (high-density lipoprotein, or HDL).
Niacin is involved in energy metabolism as part of reduction/oxidation coenzymes, the metabolism of amino acids, as well as in detoxification reactions for drugs and other substances.
Niacin also represents an important therapeutic option for several conditions.
What is Vitamin B3?
Vitamin B3 is one of the eight B vitamins, and it’s also called vitamin B3.
There are two main chemical forms of niacin:
-nicotinic acid
-niacinamide (sometimes called nicotinamide)
Both forms are found in foods as well as supplements .
The key role of niacin in your body is to synthesize the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), which are involved in over 400 biochemical reactions in your body — mainly related to obtaining energy from the food you eat .
Vitamin B3 is water-soluble, so your body does not store it.
This also means that your body can excrete excess amounts of the vitamin through urine if they are not needed.
Your body gets Vitamin B3 through food, but Vitamin B3 also makes small amounts from the amino acid tryptophan, which can be found in protein sources like turkey and other animal foods.
A lack of niacin can result in a disease called pellagra.
This condition has been common throughout human history, namely among impoverished people whose diet consisted almost entirely of corn products.
This type of diet lacks an adequate amount of niacin, thus triggering in turn symptoms such as diarrhea, inflamed mucous membranes, skin sores, weakness, irritability, and mental delusions.
Vitamin B3 is the generic name used for a group of water-soluble compounds (nicotinamide and nicotinic acid) that belong to the family of B-vitamins.
While we can find niacin in a variety of foods, this is one of the few vitamins (alongside vitamin D and choline), that our bodies can produce on their own by converting the essential amino acid tryptophan into niacin.
This means that protein-rich foods containing the amino acid tryptophan, such as meat, fish, eggs and dairy can also help us meet the recommended amounts of niacin when there’s not enough from the diet.
Vitamin B3 is involved in many bodily processes and it’s important to help our cells grow and function.
Our bodies also use Vitamin B3 to convert nutrients into energy, to make fats and cholesterol and to form and repair our genetic material.
How does it work?
As with all B vitamins, Vitamin B3 helps convert food into energy by aiding enzymes.
Specifically, Vitamin B3 is a major component of NAD and NADP, two coenzymes involved in cellular metabolism.
Furthermore, Vitamin B3 plays a role in cell signaling and making and repairing DNA, in addition to acting as an antioxidant.
Why do people take Vitamin B3?
As a cholesterol treatment, there are good studies showing that niacin can boost levels of good HDL cholesterol and lower triglycerides.
Vitamin B3 also modestly lowers bad LDL cholesterol.
Vitamin B3's sometimes prescribed in combination with statins for cholesterol control, such as rosuvastatin (Crestor, Ezallor), simvastatin, fluvastatin (Lescol), atorvastatin (Lipitor) and pravastatin (Pravachol).
However, niacin is only effective as a cholesterol treatment at fairly high doses.
These doses could pose risks, such as liver damage, gastrointestinal problems, or glucose intolerance.
So don't treat yourself with over-the-counter niacin supplements.
Instead, get advice from your health care provider, who can prescribe FDA-approved doses of niacin instead if recommended.
In addition, niacin is an FDA-approved treatment for pellagra, a rare condition that develops from niacin deficiency.
Niacin is indicated to prevent vitamin deficiencies in pediatric and adult patients receiving parenteral nutrition as part of multivitamin intravenous injections.
Niacin oral tablets are indicated as a monotherapy or in combination with simvastatin or lovastatin to treat primary hyperlipidemia and mixed dyslipidemia.
Niacin can also be used to reduce the risk of nonfatal myocardial infarctions in patients with a history of myocardial infarction and hyperlipidemia.
Niacin is also indicated with bile acid binding resins to treat atherosclerosis in patients with coronary artery disease and hyperlipidemia or to treat primary hyperlipidemia.
Finally niacin is indicated to treat severe hypertriglyceridemia.
Niacin is a B vitamin used to treat vitamin deficiencies as well as hyperlipidemia, dyslipidemia, hypertriglyceridemia, and to reduce the risk of myocardial infarctions.
Niacin acts to decrease levels of very low density lipoproteins and low density lipoproteins, while increasing levels of high density lipoproteins.
Niacin has a wide therapeutic window with usual oral doses between 500mg and 2000mg.
Patients with diabetes, renal failure, uncontrolled hypothyroidism, and elderly patients taking niacin with simvastatin or lovastatin are at increased risk of myopathy and rhabdomyolysis.
Food Sources
A vitamin b3 deficiency is rare because it is found in many foods, both from animals and plants.
-Red meat: beef, beef liver, pork
-Poultry
-Fish
-Brown rice
-Fortified cereals and breads
-Nuts, seeds
-Legumes
-Bananas
How much niacin should you take?
Since niacin can be used in different ways, talk to your health care provider about the best dosage for you.
Everyone needs a certain amount of niacin -- from food or supplements -- for the body to function normally.
This amount is called the dietary reference intake (DRI), a term that is replacing the older and more familiar RDA (recommended daily allowance).
For vitamin B3, the DRIs vary with age and other factors and are given in milligrams of niacin equivalents:
-Children: between 2-16 milligrams daily, depending on age
-Men: 16 milligrams daily
-Women: 14 milligrams daily
-Women (pregnant): 18 milligrams daily
-Women (breastfeeding): 17 milligrams daily
-Maximum daily intake for adults of all ages: 35 milligrams daily
Can you get vitamin B3 naturally from foods?
Vitamin B3 occurs naturally in many foods, including greens, meat, poultry, fish, and eggs, although in a fraction of the dose shown to achieve changes in cholesterol.
Many products are also fortified with niacin during manufacturing.
Niacin is a form of vitamin B3.
Niacin is found in foods such as yeast, meat, fish, milk, eggs, green vegetables, and cereal grains.
Niacin is also produced in the body from tryptophan, which is found in protein-containing food.
When taken as a supplement, niacin is often found in combination with other B vitamins.
Niacin is taken by mouth for high cholesterol and other fats.
Niacin is also used for low levels of a specific type of cholesterol, HDL.
Niacin is also used along with other treatments for circulation problems, migraine headache, Meniere's syndrome and other causes of dizziness, and to reduce the diarrhea associated with cholera.
Deficiency
Vitamin B3 deficiency can cause serious symptoms such as muscle weakness, digestive upsets (irritation of the mucus layer in the mouth, stomach, and intestines), loss of appetite, and skin rashes.
Vitamin B3 can cause lesions in the central nervous system, leading to confusion and disorientation.
Vitamin B3 can significantly lower cholesterol levels, but because the product is inexpensive, the pharmaceutical industry has not commercialized this supplement as a combined treatment for hypercholesteremia.
Since Vitamin B3 helps regulate fat and cholesterol levels, it can be used for the prevention or treatment of cardiovascular ailments.
A Vitamin B3 deficiency is rare in the United States and other industrialized countries because Vitamin B3 is well-absorbed from most foods (with the exception of some cereal grains in which niacin is bound to its fibers, decreasing the absorption) and is added to many foods and multivitamins.
A severe Vitamin B3 deficiency leads to pellagra, a condition that causes a dark, sometimes scaly rash to develop on skin areas exposed to sunlight; bright redness of the tongue; and constipation/diarrhea.
These are some of the symptoms of vitamin B3 deficiency :
-skin rash or discoloration
-bright red tongue
-vomiting
-constipation or diarrhea
-depression
-fatigue
-headache
-memory loss
-loss of appetite
That said, deficiency is very rare in most Western countries.
People who are malnourished — which may stem from HIV/AIDS, anorexia nervosa, liver failure, alcohol abuse, or other medical problems, or poverty — are most at risk.
Severe vitamin B3 deficiency, or pellagra, mostly occurs in developing countries, where diets are not as varied.
Vitamin B3 deficiency can be treated with niacinamide supplementation.
Other signs of severe niacin deficiency include:
-Depression
-Headache
-Fatigue
-Memory loss
-Hallucinations
-Groups at risk for deficiency
In the past, niacin deficiency was common, especially in the Southern States of the U.S.
Now, however, most people get enough vitamin B-3 in their diet.
Deficiency of a Vitamin B3
-a pigmented rash on skin that is exposed to the sun
-rough appearance to the skin
-bright red tongue
-fatigue or apathy
-vomiting, constipation, and diarrhea
-circulatory problems
-depression
-headache
-memory loss
-in severe cases, hallucinations
-A severe lack of vitamin B-3 can result in pellagra.
The condition can be fatal.
Factors that can lead to low levels of B-3 include:
-having a diet low in tryptophans or a condition that reduces the body’s ability to convert tryptophan to niacin, such as Hartnup disease or carcinoid syndrome
-undernutrition, for example, due to alcohol use disorder, anorexia, and inflammatory bowel disease
-a low intake of vitamin B-2, B-6, or iron, as this can reduce the amount of tryptophan that converts to niacin
Limited diets.
People whose diets are limited in both variety and quantity of foods, such as those living in poverty or who are very ill and cannot eat a balanced diet, are at increased risk.
Developing countries that eat corn or maize as a main food source are at risk for pellagra, as these foods are low in both absorbable Vitamin B3 and tryptophan.
Chronic alcoholism.
The absorption of several nutrients, particularly water-soluble vitamins including the B family, is decreased with excessive alcohol intake.
Carcinoid syndrome.
This is a disease of slow-growing cancer cells in the gut that release a chemical called serotonin.
The syndrome causes tryptophan in the diet to be converted into serotonin rather than niacin, which increases the risk of decreased Vitamin B3.
Niacin, an enzymatic component, has an important role in the metabolism of fats and sugars.
In this way, cells have the ability to provide the energy they need to continue their normal functions.
The use of supplements containing niacin may be beneficial in terms of weight loss, as the substance will stimulate energy synthesis and help reduce the feeling of fatigue caused by weight loss.
Vitamin B3 also positively affects the vitality and health of the skin, eyes and hair and can be used for the treatment of skin conditions such as dermatitis, skin irritation and acne.
Adequate consumption of niacin contributes to the strengthening of the digestive and immune systems, while helping to fight oxidative stress.
The substance also has positive effects on the health of the nervous system (it triggers units related to cognitive functions and memory).
Niacin, also known as B3, nicotinic acid or nicotinamide, is an important enzymatic component required for the body to function normally.
This vitamin allows us to obtain energy from macronutrients (carbohydrates and fats).
Niacin, a very important micronutrient for energy synthesis, also contributes to the healthy functioning of the nervous and digestive systems.
In addition to these, Niacin is known that it is good for skin health and vitality, hair and eyes.
5 health benefits of Vitamin B3
1. Improves blood fat levels
Vitamin B3 may help to improve your blood fat levels by:
-increasing your HDL (good) cholesterol
-reducing your LDL (bad) LDL cholesterol
-reducing your triglyceride levels
This may translate to a decrease in heart disease risk, although several studies have found no link between Vitamin B3 supplementation and a decrease in heart disease risk or deaths.
2. May reduce blood pressure
One role of Vitamin B3 is to release prostaglandins, or chemicals that help your blood vessels widen — improving blood flow and reducing blood pressure.
For this reason, Vitamin B3 may play a role in the prevention or treatment of high blood pressure.
In one observational study of over 12,000 adults, researchers found that each 1 mg increase in daily Vitamin B3 intake was associated with a 2% decrease in high blood pressure risk — with the lowest overall high blood pressure risk seen at a daily Vitamin B3 intake of 14.3 to 16.7 mg per day.
A high quality study also noted that single doses of 100 mg and 500 mg of Vitamin B3 slightly reduced right ventricular systolic pressure.
3. May help treat type 1 diabetes
Type 1 diabetes is an autoimmune disease in which your body attacks and destroys insulin-creating cells in your pancreas.
There’s research to suggest that niacin could help protect those cells and possibly even lower the risk of type 1 diabetes in children who have a higher chance of developing this condition.
However, for people with type 2 diabetes, the role of Vitamin B3 is more complicated.
On one hand, Vitamin B3 can help lower the high cholesterol levels that are often seen in people with type 2 diabetes.
On the other, Vitamin B3 has the potential to increase blood sugar levels.
As a result, people with diabetes who take niacin to treat high cholesterol also need to monitor their blood sugar carefully.
4. Boosts brain function
Your brain needs Vitamin B3— as a part of the coenzymes NAD and NADP — to get energy and function properly.
In fact, brain fog and even psychiatric symptoms are associated with Vitamin B3 deficiency.
Some types of schizophrenia can be treated with niacin, as Vitamin B3 helps undo damage to brain cells that’s caused by a niacin deficiency.
Preliminary research shows that Vitamin B3 could also help keep the brain healthy in cases of Alzheimer’s disease.
5. Improves skin health
Vitamin B3 helps protect skin cells from sun damage, whether it’s used orally or applied as a lotion.
Vitamin B3 may help prevent certain types of skin cancer as well.
One high quality study in over 300 people at high risk of skin cancer found that taking 500 mg of nicotinamide twice daily reduced rates of nonmelanoma skin cancer compared to a control.
Niacin (also known as “vitamin B3” or “vitamin PP”) includes two vitamers (nicotinic acid and nicotinamide) giving rise to the coenzymatic forms nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP).
The two coenzymes are required for oxidative reactions crucial for energy production, but they are also substrates for enzymes involved in non-redox signaling pathways, thus regulating biological functions, including gene expression, cell cycle progression, DNA repair and cell death.
In the central nervous system, vitamin B3 has long been recognized as a key mediator of neuronal development and survival.
Here, we will overview available literature data on the neuroprotective role of niacin and its derivatives, especially focusing especially on its involvement in neurodegenerative diseases (Alzheimer’s, Parkinson’s, and Huntington’s diseases), as well as in other neuropathological conditions (ischemic and traumatic injuries, headache and psychiatric disorders).
Pharmacodynamics
Niacin and nicotinamide are both converted into the coenzyme NAD.
NAD converts to NADP by phosphorylation in the presence of the enzyme NAD+ kinase.
NAD and NADP are coenzymes for many dehydrogenases, participating in many hydrogen transfer processes.
NAD is important in catabolism of fat, carbohydrate, protein, and alcohol, as well as cell signaling and DNA repair, and NADP mostly in anabolism reactions such as fatty acid and cholesterol synthesis.
High energy requirements (brain) or high turnover rate (gut, skin) organs are usually the most susceptible to their deficiency.
Activating HCA2 has effects other than lowering serum cholesterol and triglyceride concentrations: antioxidative, anti-inflammatory, antithrombotic, improved endothelial function and plaque stability, all of which counter development and progression of atherosclerosis.
Niacin inhibits cytochrome P450 enzymes CYP2E1, CYP2D6 and CYP3A4.
Niacin produces a rise in serum unconjugated bilirubin in normal individuals and in those with Gilbert's Syndrome.
However, in the Gilbert's Syndrome, the rise in bilirubin is higher and clearance is delayed longer than in normal people.
One test used to aid in diagnosing Gilbert's Syndrome involves intravenous administration of nicotinic acid (niacin) in a dose of 50 mg over a period of 30 seconds.
Pharmacokinetics
Both niacin and niacinamide are rapidly absorbed from the stomach and small intestine.
Absorption is facilitated by sodium-dependent diffusion, and at higher intakes, via passive diffusion.
Unlike some other vitamins, the percent absorbed does not decrease with increasing dose, so that even at amounts of 3-4 grams, absorption is nearly complete.
With a one gram dose, peak plasma concentrations of 15 to 30 μg/mL are reached within 30 to 60 minutes.
Approximately 88% of an oral pharmacologic dose is eliminated by the kidneys as unchanged niacin or nicotinuric acid, its primary metabolite.
The plasma elimination half-life of niacin ranges from 20 to 45 minutes.
Niacinamide is the major form in the bloodstream. In the liver, niacinamide is converted to storage nicotinamide adenine dinucleotide (NAD).
As needed, liver NAD is hydrolyzed to niacinamide and niacin for transport to tissues, there reconverted to NAD to serve as an enzyme cofactor.
Excess niacin is methylated in the liver to N1-methylnicotinamide (NMN) and excreted in urine as such or as the oxidized metabolite N1-methyl-2-pyridone-5-carboxamide (2-pyridone).
Decreased urinary content of these metabolites is a measure of niacin deficiency.
Niacin (nicotinic acid) in hydrochloric acid is highly suitable for checking the photometric accuracy of spectrometers in the UV range.
The Niacin spectrum shows a relatively broad maximum at the wavelengths 213 nm and 261 nm.
The Niacin filter solutions are filled and immediately fused under controlled conditions to become permanently airtight.
NIACIN (NYE a sin) is used in combination with a healthy diet to lower bad cholesterol and increase good cholesterol.
This medicine is also used to decrease triglycerides.
If triglycerides are too high, you may be at risk of developing pancreatitis.
This is a painful condition that causes inflammation of the pancreas and can lead to serious health problems.
This medicine can also be helpful in patients who have heart disease or who have had a heart attack.
Biosynthesis
In addition to absorbing niacin from diet, niacin can be synthesized from the essential amino acid tryptophan, a five-step process with the penultimate compound being quinolinic acid.
Some bacteria and plants utilize aspartic acid in a pathway that also goes to quinolinic acid.
For humans, the efficiency of conversion is estimated as requiring 60 mg of tryptophan to make 1 mg of niacin.
Riboflavin, vitamin B6 and iron are required for the process.
Pellagra is a consequence of a corn-dominant diet because the niacin in corn is poorly bioavailable and corn proteins are low in tryptophan compared to wheat and rice proteins.
Industrial synthesis
Nicotinonitrile is produced by ammoxidation of 3-methylpyridine. Nitrile hydratase is then used to catalyze nicotinonitrile to nicotinamide, which can be converted to niacin.
Alternatively, ammonia, acetic acid and paraldehyde are used to make 5-ethyl-2-methyl-pyridine, which is then oxidized to niacin.
The demand for commercial production includes for animal feed and for food fortification meant for human consumption.
Worldwide 31,000 tons of nicotinamide were sold in 2014.
Niacin (or nicotinic acid as it’s referred to in medical circles) was the third B vitamin to be discovered (hence the name B3).
Niacin wasn’t until about 1943, though, that a couple of doctors reported that niacin worked wonders in relieving the pain and stiffness associated with arthritis.
Niacin has a unique characteristic.
If you haven’t experienced it personally, you’ve probably heard about the “flush” that as little as 50 mg of niacin can cause.
While not dangerous, it can be uncomfortable, or even alarming, if you aren’t prepared for it.
Niacin, also known as vitamin B3, is a water-soluble vitamin.
Water-soluble vitamins are stored in the body in very limited amounts and are excreted through the urine.
Therefore, Niacin is a good idea to have them in your daily diet.
In addition to getting niacin from dietary sources, the body can synthesize a form of niacin from the amino acid tryptophan.
Synonym(s):
-Pellagra preventive factor
-Niacin
-Pyridine-3-carboxylic acid
-Vitamin B3
-3-Picolinic acid
