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    Ingredient guide · Ingredient reference

    Niacin foods and niacin equivalents: tryptophan also contributes

    Poultry, fish, meat, legumes, nuts and grains can supply vitamin B3. Niacin-equivalent values also account for conversion from tryptophan, so milligrams of niacin alone do not describe the whole nutritional contribution.

    Read the evidence ↓

    Supplement Science Insights Editorial Team

    Published September 23, 2026

    Use the portion as well as the food name

    ODS lists about 10.3 mg niacin in three ounces of grilled chicken breast, 8.6 mg in three ounces of cooked sockeye salmon and 4.2 mg in an ounce of dry-roasted peanuts. These are reference food-composition values, not exact measurements of every serving. [1]

    Enriched and fortified grains can also contribute. Naturally occurring niacin in some grains is relatively bound and less available, while added niacin is in a more available free form. A whole-food name alone does not determine absorbed exposure. [1]

    Tryptophan is included through a conversion convention

    The body can use tryptophan to make niacin-related compounds. The reference convention counts 60 mg tryptophan as one milligram of niacin equivalents, or NE. ODS emphasizes that conversion efficiency varies between people. [1]

    The adult RDA is 16 mg NE for men and 14 mg NE for women; pregnancy and breastfeeding values are 18 and 17 mg NE respectively. These values describe total nutritional supply, not a recommendation to take isolated tryptophan to reach the number. [1]

    Do not apply a food reference to a drug claim

    Niacin in ordinary nutrition and high-dose nicotinic acid used in a medical context are different questions. A food’s vitamin contribution does not establish cholesterol-treatment efficacy, and a dietary target is not a therapeutic regimen. [1]

    For a food record, preserve whether a value is measured niacin or a calculated equivalent. Mixing those definitions can create misleading comparisons. [1]

    Show what the arithmetic represents

    Using the convention, 120 mg tryptophan corresponds to 2 mg NE. That calculation is a nutritional accounting estimate, not a prediction that a particular person will produce exactly 2 mg from that amount.

    Hypothetical example — applying the distinction
    DetailInterpretation
    Food niacinDirect nutrient contribution
    Tryptophan conversionAdditional estimated contribution
    mg NEA combined nutritional reference
    Niacin foods and niacin equivalents: tryptophan also contributes — original article outline diagram
    Original editorial diagram of this article’s sections; no product photograph or clinical finding is depicted.

    Sources for this article

    1. NIH ODS: Niacin — Health Professional Fact Sheet
      Source consulted: 2026-09-17. This is a reference resource, not a claim that we conducted the studies or tested a product.