Supplements

Vitamin B3 (Niacin, Nicotinic Acid, Niacinamide)

Vitamin B3 (niacin) is a water-soluble vitamin, absorbed in the small intestine and excreted in the urine. Because it is not stored, it is needed in frequent, small doses. Niacin needs adequate supplies of all the other B-vitamins to function properly. Because it is easily excreted, it is also less likely to reach toxic levels.

Vitamin B3 aids in the functioning of the nervous system, in the metabolism of carbohydrates, fats, and proteins, and in the production of hydrochloric acid for the digestive system involving the secretion of bile and stomach fluids. It is also needed for proper circulation and healthy skin.

Vitamin B3 is one of the most effective cholesterol-normalizing supplements of all. It has been shown to lower blood cholesterol and triglycerides by up to 50 percent and more in some individuals. Therapeutic dosing in the treatment of high blood cholesterol levels can cause dangerous side effects, especially liver problems, and must be monitored closely.

In addition, vitamin B6 manufactures many body compounds including sex and adrenal hormones. Niacin is helpful for schizophrenia and other mental illnesses, and is also a memory enhancer. Vitamin B3 has also been used to aid in cancer prevention, treats epilepsy, migraines, and leg cramps.

Vitamin B3 is critical for energy production, heart health and optimal circulation. It is involved in over fifty reactions that turn sugar and fat into energy.

Although Niacin can raise the blood sugar in people who have diabetes, diabetics need the arterial protection more than other people do. Glucose disturbance can be avoided by taking lower doses of niacin along with chromium. This combination is beneficial in reducing both blood sugar and cholesterol levels.

Niacin is also needed for amino acid metabolism and is involved in converting fats into compounds known as eicosanoids, hormone-like agents that control our bodies' metabolic pathways.

Vitamin B3 comes in two forms: niacin (nicotinic acid or nicotinate) and niacinamide (nicotinamide). Both forms will meet the requirements of B3. However, B3 in the form of niacin, is the form used to lower cholesterol and triglycerides, while niacinamide helps osteoarthritis and may prevent diabetes.

Inositol hexaniacinate (see precautions) is a specific kind of niacin which does not cause flushing (No-Flush Niacin) and has been used in Europe to treat high cholesterol and impaired blood flow for decades.

Deficiency: Pellagra is a disease caused by niacin deficiency. Some symptoms of niacin deficiency are canker sores, depression, diarrhea, dizziness, fatigue, halitosis, headaches, indigestion, irritability, insomnia, limb pains, loss of appetite, muscular weakness, skin eruptions, inflammation, emotional instability, blood-sugar fluctuations and arthritis.

Depleting Agents: Antibiotics, caffeine, alcohol, estrogen, sleeping pills, sulfa drugs, and excessive consumption of white sugar.

Sources: Organ meats (especially beef liver), brewer's yeast, broccoli, carrots, cheese corn flour, dandelion greens, dates, eggs, fish, milk, peanuts, pork, potatoes, tomatoes, wheat germ, legumes, mil, avocados, whole grains with the exception of corn.

Herb Sources: Alfalfa, burdock root, catnip, cayenne, chamomile, chickweed, eyebright, fennel seed, hops, licorice, mullein, nettle, oat straw, parsley, peppermint, raspberry leaf, red clover, rose hips, slippery elm, and yellow dock.

Precautions: The most common side effect of niacin at doses of 75 mg or more is "niacin flush," a sometimes painful tingling sensation and flushing of the face and upper torso caused by dilation of capillaries. Onset of niacin flush is seen 15 to 30 minutes after ingestion. While generally not harmful, it can be uncomfortable or frightening for some people. Niacin flush can be reduced or sometimes eliminated by the ingestion of 80 to 325 mg of aspirin 30 minutes prior to taking the niacin.

The most serious problem associated with high-dose niacin therapy is the risk of liver toxicity. Doses over 2,000 mg increase the risk of abnormal liver function and necessitate frequent monitoring. Side effects can be reduced by developing tolerance to niacin supplementation over several weeks. Starting at low doses and increasing every four to seven days up to a therapeutic dose (500 mg to 2 g/day) may help reduce the amount of flushing and also reduce the risk of liver toxicity. Niacin flush is caused by a release of histamines; therefore, asthma sufferers should avoid high doses.

Other side effects of high doses of niacin include heartburn, nausea, vomiting, diarrhea, ulcers, liver malfunction, low blood pressure, and fainting. High doses of niacin (nicotinic acid) can also increase the blood levels of uric acid and glucose, leading to possible misdiagnosis of diabetes or gout.

Niacinamide does not cause niacin flush even at high doses, but also does not provide the beneficial cholesterol-lowering effects of niacin. Niacinamide can also have a sedative effect. Inositol hexaniacinate is an effective delivery method not thought to cause liver problems. High doses may cause nausea or extreme drowsiness. For basic health maintenance, a daily 100 mg tablet should suffice. If you have Type I diabetes, take 300-600 mg daily. If you've been diagnosed recently with Type I diabetes or if you're trying to relieve osteoarthritis pain, your physician may prescribe 1,500-2,000 mg.

Niacin supplementation at therapeutic doses can cause liver damage and peptic ulcers; therefore, persons with a history of these ailments should not take large doses. Asthma sufferers should not take more than 75 mg of niacin due to histamine release, but can safely take niacinamide for dietary supplementation or other purposes. To avoid toxic side effects, diabetics, gallbladder patients, and gout patients should be supervised closely by a health care practitioner if taking therapeutic doses of niacinamide. Liver function and blood glucose should be closely monitored in all patients early in therapy.

Dosage Ranges and Duration of Administration: Because niacin can be obtained from tryptophan, it is measured in "niacin equivalents" and is based on estimates from overall calorie consumption. The niacin RDA is 6.6 mg equivalents/1,000 kcals, or a minimum of 13 mg daily, which should be consumed to maintain tissue store in healthy adults. The 1989 RDAs for niacin are:

• Infants up to 6 months: 5 mg
• Infants 6 months to 1 year: 6 mg
• Children 1 to 3 years: 9 mg
• Children 4 to 6 years: 12 mg
• Children 7 to 10 years: 13 mg
• Males 11 to 14 years: 17 mg
• Males 15 to 18 years: 20 mg
• Males 19 to 50 years: 19 mg
• Males 50+: 15 mg
• Females 11 to 18 years: 15 mg
• Females 19 to 50 years: 15 mg
• Females 50+: 13 mg
• Females pregnant: 17 mg
• Females lactating: 20 mg

Requirements may be higher for those who have cancer, those who are being treated with isoniazid (for tuberculosis), women taking oral contraceptives, and people with protein deficiencies.

Therapeutic dosing in the treatment of high blood cholesterol levels is within the range of 1,500 to 2,000 mg of pure crystalline niacin daily in divided doses. This level should be reached gradually over a period of four to six weeks. It should be taken with meals to minimize GI irritation.

Therapeutic doses of 150 mg/day have been reported to aid in migraine relief.

INTERACTIONS

Aspirin
In a randomized, double-blind, placebo-controlled study with 31 healthy subjects, administration of aspirin (325 mg) prior to treatment with niacin (500 mg) significantly reduced the incidence of flushing associated with niacin. However, concomitant administration of higher doses of aspirin (1 g) with niacin (0.075 to 0.100 mg/kg/min IV) reduced the clearance of niacin in six healthy volunteers. Administration of aspirin (325 mg) at least 30 minutes before niacin treatment may alleviate intolerance to cutaneous reactions associated with niacin therapy.

Biguanide Antidiabetic Agents
Lipid-lowering doses of nicotinic acid may cause hyperglycemia and lead to loss of glycemic control. Patients taking niacin while on metformin should be monitored closely for glycemic control.

Bile Acid Sequestrants
Niacin binds to these bile acid sequestrants and should be taken at different times of the day.

HMG-CoA Reductase Inhibitors
Niacin combined with fluvastatin is more effective at lowering serum lipids than either substance administered alone. A more recent study evaluating the combination of an extended-release form of niacin (1 to 2 g/day) with a statin drug in 269 hypercholesterolemic adult patients supported these findings.In a prospective, open-label trial, the combination of niacin with pravastatin produced favorable results on lipid profiles in 16 diabetic patients over 14 weeks. The addition of niacin (up to 500 mg tid) to pravastatin (20 mg/day) significantly lowered LDL cholesterol levels. Only five patients required minor modifications to their hypoglycemic therapy to maintain glycemic control. However, the risk of myopathy and/or rhabdomyolysis is increased when HMG- CoA reductase inhibitors are coadministered with niacin. The degree of risk may depend upon the type of drug administered because myotoxicity has been observed with lovastatin but not with fluvastatin. In addition, hepatic dysfunction may be associated with high dose niacin therapy; liver function tests should be performed periodically.

Insulin Preparations
Lipid-lowering doses of nicotinic acid may cause hyperglycemia and lead to loss of glycemic control. However, nicotinamide has been used in conjunction with intensive insulin therapy to reduce beta-cell dysfunction in patients with recent-onset Type I diabetes. In a randomized, blinded, multicenter trial with 74 patients on insulin therapy for the treatment of Type I diabetes, nicotinamide (25 mg/kg and 50 mg/kg) affected clinical remission and markers of metabolic control such as insulin dose, HbA(1c), and C-peptide. Lower doses of nicotinamide are preferable to avoid the development of insulin resistance. Patients taking both insulin and niacin should be monitored closely to maintain glycemic control.

Neomycin
Administration of neomycin sulfate (1 g bid) with niacin (maximum dose of 1 g tid) decreased levels of total cholesterol by 26%, LDL cholesterol by 32%, and lipoprotein by 45. Neomycin monotherapy only decreased levels by 18%, 23%, and 24%, respectively.

Nicotine
Repeated exposure to niacin (250 mg tid) and transdermal nicotine patches (21 mg/day) in a 60-year-old female patient resulted in flushing reactions within 30 minutes after taking niacin.

Sulfonylureas
Nicotinic acid may decrease the hypoglycemic effect of sulfonylureas and cause significant deterioration in glycemic control.

Tetracycline
In one study, the bioavailability of tetracycline hydrochloride was reduced significantly by concomitant administration of vitamin B complex to healthy subjects. Patients should be cautioned to take vitamin B complex supplements at different times from tetracycline.