VB3

Basic Information

• Chemical Properties: Nicotinic acid has the formula C6​H5​NO2​, while niacinamide has the formula C6​H6​N2​O. Both forms are stable under heat and cooking conditions, making them relatively resistant to food processing losses.
• Food Sources: Niacin is widely distributed in animal and plant foods. Rich animal sources include lean meats, fish, poultry, and eggs. Plant-based sources include whole grains, legumes, nuts, and seeds. Additionally, the human body can synthesize niacin from the amino acid tryptophan, with about 60 mg of tryptophan converting to 1 mg of niacin.

Physiological Functions

1. Energy Metabolism Core Role

    

   Niacin is a precursor to two critical coenzymes: nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). These coenzymes are involved in hundreds of enzymatic reactions, facilitating the breakdown of carbohydrates, fats, and proteins to produce adenosine triphosphate (ATP), the body’s main energy currency.
    
2. Skin and Mucous Membrane Health

    

   It supports the integrity and function of the skin, oral, and gastrointestinal mucous membranes. Adequate niacin intake helps maintain healthy skin barrier function, prevent dryness and irritation, and support the repair of damaged skin tissue.
    
3. Cardiovascular Health Support

    

   Nicotinic acid (but not niacinamide) has been shown to help regulate blood lipid levels: it can lower low-density lipoprotein (LDL, "bad" cholesterol) and triglycerides, while raising high-density lipoprotein (HDL, "good" cholesterol). This effect may reduce the risk of cardiovascular diseases when used under medical supervision.
    
4. Nervous System Function Maintenance

    

   Niacin plays a key role in maintaining the health of neurons and supporting proper nerve signal transmission. It also contributes to the synthesis of neurotransmitters, which are essential for mood regulation and cognitive function.
    

Deficiency and Toxicity

• Deficiency Symptoms: Severe niacin deficiency causes a condition called pellagra, characterized by the "four Ds": dermatitis, diarrhea, dementia, and death (if untreated). Mild deficiency may lead to fatigue, poor appetite, indigestion, and skin rashes.
• Toxicity: Unlike most B vitamins, high-dose niacin (especially nicotinic acid, often used in supplements for lipid control) can cause adverse effects, such as flushing (a warm, red, itchy sensation on the skin), nausea, liver function abnormalities, and elevated blood sugar levels. Niacinamide has a lower risk of flushing and is generally better tolerated at high doses.

Recommended Intake