(Source: SaluGenecists, Inc.)
Niacin, a term often used interchangeably with vitamin B3, is actually a non-technical term that refers to several different chemical forms of the vitamin including nicotinic acid and nicotinamide (nicotimamide is also called niacinamide). These names are all derived from the word nicotine since the first laboratory isolation of vitamin B3 occurred following research on nicotine obtained from tobacco leaves.
Physiological functions of vitamin B3
- Helps reduced cholesterol levels
- Stabilizes blood sugar levels
- Supports cellular genetic processes
- Helps the body to process fats
Physiological events that may signal a need for greater vitamin B3 intake
- Generalized weakness
- Muscular weakness
- Digestive problems
- Appetite loss
- Skin infections
Functions of vitamin B3
Production of energy
Vitamin B3 plays a very important role in energy production processes. Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two unique niacin-containing molecules that are essential for the conversion of proteins, fats and carbohydrates into usable energy. Vitamin B3 is also used to synthesize glycogen, starch that can be stored in the bodys muscles and liver, for eventual use as an energy source.
The chemical processing of fats in the body is dependent upon vitamin B3. The synthesis of fatty acid building blocks required to manufacture the bodys fat-containing structures (e.g., cell membranes) as well as many of the fat-based (steroid) hormones require the presence of vitamin B3.
It is interesting to note that while vitamin B3 is required for the liver to be able to produce cholesterol, this vitamin has been repeatedly demonstrated to successfully lower total blood cholesterol in individuals with hypercholesterolemia. While the vitamins cholesterol-lowering effect only occurs with high doses that must be obtained through supplementation, it most likely involves a mechanism of action that is not directly related to fat or fat processing.
Support of genetic processes
The production of deoxyribose nucleic acid (DNA), components of our primary cellular genetic material, requires vitamin B3 and deficiency of this nutrient (like of other B-complex vitamins) has been directly linked to genetic (DNA) damage. This nutrient-genetic integrity relationship appears to be particularly important concerning the development and prevention of cancer.
Insulin activity regulation
Vitamin B3 has repeatedly been demonstrated to be involved in insulin metabolism and blood sugar regulation. While experts have yet to conclude the precise mechanism through which it exerts these effects, a few researchers support the idea of a vitamin B3-containing glucose tolerance factor (GTF) molecule that must be present for optimal insulin activity.
Causes and symptoms of vitamin B3 deficiency
Vitamin B3 deficiency can be triggered by a variety of gastrointestinal problems such as inflammatory bowel disease, irritable bowel disease and chronic diarrhea. Insufficient intake of tryptophan, usually reflective of poor overall protein intake, is also a possible risk factor for deficiency since some of the bodys supply of vitamin B3 comes from the conversion of this amino acid. Other symptoms associated with vitamin B3 deficiency include stress, physical trauma, long-term fever and excessive alcohol consumption.
Vitamin B3 deficiency is often associated with muscular weakness, general weakness and appetite loss owing to its unique relationship with energy production. Deficiency may also manifest as skin infections and digestive problems.
Causes and symptoms of vitamin B3 toxicity
There have been no reports in the scientific literature of toxicity symptoms of niacin provided by food. Regarding amounts from supplementation, nutritional researchers have received a unique opportunity to examine possible toxicity symptoms of niacin since high supplemental doses of this vitamin are used to lower cholesterol levels.
In 1998, the Institute of Medicine at the National Academy of Sciences set a Tolerable Upper Intake Level (UL) for niacin at 35 milligrams per day. The UL is limited to niacin from supplements and/or fortified foods and applies to men and women 19 year and older.
Cooking, Storage and Processing
Effects of cooking, storage and processing on vitamin B3
As one of the more stable water-soluble nutrients, vitamin B3 is minimally susceptible to losses due to air, heat or light.
Drug & Nutrient Interactions
Interactions between medications and vitamin B3
Medicines that decrease the availability of vitamin B3 in the body include:
- Birth control pills (oral contraceptives)
Medicines that can result in severe vitamin B3 deficiency include:
- Isoniazid (antituberculosis drug)
Interactions that occur between vitamin B3 and other nutrients
Since a portion of the bodys vitamin B3 supply comes from conversion of tryptophan, the deficiency of this amino acid can increase the risk of vitamin B3 deficiency. Tryptophan status can be impaired by poor overall protein intake. Since the conversion of tryptophan to vitamin B3 requires vitamin B1 and vitamin B6, inadequate intake of these nutrients can contribute to a vitamin B3 deficiency. Additionally, vitamin B12 status appears to be related to vitamin B3 deficiency since even mild reduced levels of endogenous vitamin B12 increase vitamin B3 urinary losses.
Health conditions that require special emphasis on vitamin B3
Individuals who have the following health conditions should pay special attention to their vitamin B3 status:
- Inflammatory bowel disease
- Intermittent claudication
- Menstrual pain
- Multiple sclerosis
- Rheumatoid arthritis
- Smelling disorders
- Taste disorders
Forms in Dietary Supplements
Forms in which vitamin B3 is found in dietary supplements.
Vitamin B3 in dietary supplements can be found in either the nicotinic acid or nicotinamide form. These two forms have different healthcare applications and different safety profiles.
Nicotinic acid has well documented cholesterol-lowering potential although it also carries a greater risk of side effects. Dietary supplements that are designed for cholesterol reduction and alteration of fat metabolism feature vitamin B3 as nicotinic acid.
Nicotinamide is commonly used as the niacin form in dietary supplements that are not focused on cholesterol reduction or alterations of fat metabolism. It has a much lower risk of side effects and is often preferred especially in formulas designed for children or pregnant women.
Many dietary supplements feature both forms, including small amounts of nicotinic acid and larger amounts of nicotinamide.
Foods that are concentrated sources of vitamin B3
Excellent sources of vitamin B3 include chicken, crimini mushrooms, salmon, tuna, turkey and yeast. Very good sources include asparagus, basil, beef liver, halibut, lamb, mustard greens, sea vegetables, spinach, squash, turkey and venison.