Jul. 13, 2020
Biotin,also called D-biotin, also known as vitamin H or coenzyme R, is a water-soluble B-vitamin (vitamin B7).This water-soluble vitamin is a cofactor for five carboxylases (propionyl-CoA carboxylase, pyruvate carboxylase, methylcrotonyl-CoA carboxylase [MCC], acetyl-CoA carboxylase 1, and acetyl-CoA carboxylase 2) that catalyze critical steps in the metabolism of fatty acids, glucose, and amino acids . Biotin also plays key roles in histone modifications, gene regulation (by modifying the activity of transcription factors), and cell signaling
Most biotin in foods is bound to protein, although some dietary biotin is in the free form. Gastrointestinal proteases and peptidases break down the protein-bound forms of ingested biotin into biocytin and biotin-oligopeptides, which undergo further processing by biotinidase, an enzyme, in the intestinal lumen to release free biotin. The free biotin is then absorbed in the small intestine, and most biotin is stored in the liver.
Intake recommendations for biotin and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the National Academies of Sciences, Engineering, and Medicine . DRI is the general term for a set of reference values used for planning and assessing nutrient intakes of healthy people. These values, which vary by age and sex, include:
Recommended Dietary Allowance (RDA): Average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy individuals; often used to plan nutritionally adequate diets for individuals.
Adequate Intake (AI): Intake at this level is assumed to ensure nutritional adequacy; established when evidence is insufficient to develop an RDA.
Estimated Average Requirement (EAR): Average daily level of intake estimated to meet the requirements of 50% of healthy individuals; usually used to assess the nutrient intakes of groups of people and to plan nutritionally adequate diets for them; can also be used to assess the nutrient intakes of individuals.
Tolerable Upper Intake Level (UL): Maximum daily intake unlikely to cause adverse health effects.
The FNB found the available data to be insufficient to derive an EAR and RDA for biotin. For this reason, the FNB established only AIs for biotin. The FNB based its determination of AIs for all populations on the amount of biotin in human milk consumed by infants and then used body weight to extrapolate AIs for other groups . Table 1 lists the current AIs for biotin .
Table 1: Adequate Intakes (AIs) for Biotin 
Birth to 6 months
|5 mcg||5 mcg|
|7–12 months||6 mcg||6 mcg|
|1–3 years||8 mcg||8 mcg|
|4–8 years||12 mcg||12 mcg|
|9–13 years||20 mcg||20 mcg|
|25 mcg||25 mcg||30 mcg||35 mcg|
|30 mcg||30 mcg||30 mcg||35 mcg|
Sources of Biotin
Many foods contain some biotin. Foods that contain the most biotin include organ meats, eggs, fish, meat, seeds, nuts, and certain vegetables (such as sweet potatoes) [2,12]. The biotin content of food can vary; for example, plant variety and season can affect the biotin content of cereal grains, and certain processing techniques (e.g., canning) can reduce the biotin content of foods .
Dietary avidin, a glycoprotein in raw egg whites, binds tightly to dietary biotin and prevents biotin’s absorption in the gastrointestinal tract [13,14]. Cooking denatures avidin, making it unable to interfere with biotin absorption .
Several food sources of biotin are listed in Table 2.
Table 2: Selected Food Sources of Biotin 
Micrograms(mcg) per serving
|Beef liver, cooked, 3 ounces||30.8||103|
|Egg, whole, cooked||10.0||33|
|Salmon, pink, canned in water, 3 ounces||5.0||17|
|Pork chop, cooked, 3 ounces||3.8||13|
|Hamburger patty, cooked, 3 ounces||3.8||13|
|Sunflower seeds, roasted, ¼ cup||2.6||9|
|Sweet potato, cooked, ½ cup||2.4||8|
|Almonds, roasted, ¼ cup||1.5||5|
|Tuna, canned in water, 3 ounces||0.6||2|
|Spinach, boiled, ½ cup||0.5||2|
|Broccoli, fresh, ½ cup||0.4||1|
|Cheddar cheese, mild, 1 ounce||0.4||1|
|Milk, 2%, 1 cup||0.3||1|
|Plain yogurt, 1 cup||0.2||1|
|Oatmeal, 1 cup||0.2||1|
|Banana, ½ cup||0.2||1|
|Whole wheat bread, 1 slice||0.0||0|
|Apple, ½ cup||0.0||0|
*DV = Daily Value. The U.S. Food and Drug Administration (FDA) developed DVs to help consumers compare the nutrient contents of foods and dietary supplements within the context of a total diet. The DV for biotin on the new Nutrition Facts and Supplement Facts labels and used for the values in Table 2 is 30 mcg for adults and children age 4 years and older . FDA required manufacturers to use these new labels starting in January 2020, but companies with annual sales of less than $10 million may continue to use the old labels that list a biotin DV of 300 mcg until January 2021 . FDA does not require food labels to list biotin content unless biotin has been added to the food. Foods providing 20% or more of the DV are considered to be high sources of a nutrient, but foods providing lower percentages of the DV also contribute to a healthful diet.
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