Significance and sources of biotin

1. Significance and sources of biotin
Domina Petric, MD

2. • A key feature of biotin metabolism is that
it is recycled by proteolytic cleavage from
the four biotinyl carboxylases by the
enzyme biotinidase.
• This recycling, and the prevalent hind gut
microbial synthesis of the vitamin, allow
quantitative dietary requirements for
biotin to be relatively small.
April 18, 2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
2
Significance

3. Most foods contain the vitamin
as free biotin and as biocytin.
Biocytin is biotin covalently
bound to protein lysyl residues.
April 18, 2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
3
Distribution in foods

4. Dairy product Biotin μg/100 g
Milk 2
Cheeses 3-5
April 18, 2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
4
Dairy products and other
Other Biotin μg/100 g
Eggs 20
Brewer´s yeast 80
Alfalfa meal 54
Molasses 108

5. Meats Biotin μg/100 g
Beef 3
Chicken 11
Pork 5
Calf kidney 100
April 18, 2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
5
Meats

6. Cereal Biotin μg/100 g
Barley 14
Cornmeal 7,9
Oats 24,6
Rye 8,5
Sorghum 28,8
Wheat 10,1
Wheat bran 36
April 18, 2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
6
Cereals

7. Oilseed meal Biotin μg/100 g
Rapeseed meal 98,4
Soybean meal 27
April 18, 2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
7
Oilseed meals

8. Vegetable Biotin μg/100 g
Soybeans 60
Cauliflower 17
Lentils 13
Corn 6
Peas 9
Spinach 7
Tomatoes 4
Onions 4
Carrots 3
April 18, 2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
8
Vegetables
...

9. Fruit Biotin μg/100 g
Walnuts 37
Peanuts 34
Watermelons 4
Bananas 4
Grapefruit 3
Grapes 2
Apples 1
Oranges 1
Peaches 2
April 18, 2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
9
Fruits
...

10. Biotin is unstable to oxidizing conditions and is
destroyed by heat, especially under conditions
that support simultaneous lipid peroxidation.
Such processing techniques as the canning of foods
can result in substantial losses of biotin.
These losses can be reduced by the use of an
antioxidant: vitamin C, vitamin E, butylated
hydroxytoluene [BHT], butylated hydroxyanisole [BHA].
April 18, 2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
10
Stability

11. Total fecal excretion of biotin exceeds the
amount consumed in the diet.
This is due to the biosynthesis of significant
amounts of biotin by the microflora of the
proximal colon.
April 18, 2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
11
Synthesis by intestinal microflora

12. • Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
Literature
April 18, 2018 12