1. Significance and sources of riboflavin
Domina Petric, MD

2. Significance of riboflavin
Riboflavin is essential for the intermediary metabolism of carbohydrates, amino acids and lipids.
Riboflavin also supports cellular antioxidant protection.
The vitamin discharges these functions as coenzymes that undergo reduction through two sequential single-electron transfer steps.
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

3. Significance of riboflavin
This allows the reactions catalyzed by flavoproteins (flavoenzymes) to involve single- as well as dual-electron transfers.
Flavoproteins serve as switching sites between obligate two-electron donors, such as the pyridine nucleotides, and various obligate one-electron acceptors.
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

4. Significance of riboflavin
Deficiency of the vitamin B2 first manifests itself in tissues with rapid cellular turnover: skin and epithelium.
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

5. Distribution in foods
Riboflavin is widely distributed in foods, where it is present almost exclusively bound to proteins, mainly in the form of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD).
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

6. Rapidly growing, green, leafy vegetables are rich in the vitamin.
Distribution in foods
Rapidly growing, green, leafy vegetables are rich in the vitamin.
Meats and dairy products are the most important contributors of riboflavin in diets, with milk products providing about one-half of the total intake of the vitamin.
Animal tissues have been found to contain small amounts of riboflavin-5′α-D-glucoside, which appears to be as well utilized as free riboflavin.
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

7. Riboflavin contents of foods, expressed in riboflavin mg/100 g.
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

8. Diary products Diary product Riboflavin mg/100 g Milk 0,17 Yogurt 0,16
American cheese
0,43
Cheddar cheese
0,46
Cottage cheese
0,28
Ice cream
0,21
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

9. Meats Meat Riboflavin mg/100 g Liver, beef 3,50 Beef 0,24 Chicken 0,19
Lamb
0,22
Pork
0,27
Ham, cured
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

10. Cereals Cereals Riboflavin mg/100 g Wheat, whole 0,11 Rye 0,08
Oat meal
0,02
Rice
0,01
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

11. Vegetables Vegetables Riboflavin mg/100 g Asparagus 0,18 Broccoli 0,20
Cabbage
0,06
Carrots
Cauliflower
0,08
Corn
Lima beans
0,10
Potatoes
0,04
Spinach
0,14
Tomatoes
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

12. Fruits Fruits Riboflavin mg/100 g Apples 0,01 Bananas 0,04 Oranges
0,03
Peaches
Strawberries
0,07
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

13. Other
Eggs: 0,30.
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

14. Stability Riboflavin is stable to heat.
Most means of heat sterilization, canning and cooking do not affect the riboflavin contents of foods.
Exposure to light (sun drying, sunlight exposure of milk in glass bottles, cooking in an open pot) can result in substantial losses, for the vitamin is very sensitive to destruction by light.
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

15. Stability
Riboflavin photodegradation can be exacerbated by sodium bicarbonate, which is used to preserve vegetable colors.
As riboflavin in cereal grains is located primarily in the germ and bran, the milling of such materials, which removes those tissues, results in considerable losses in their contents of the vitamin.
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

16. Bioavailability
The non covalently bound forms of riboflavin in foods (FMN, FAD) and free riboflavin appear to be well absorbed.
Covalently bound flavin complexes, such as are found in plant tissues, are stable to digestion and thus unavailable.
In general, riboflavin in animal products tends to have a greater bioavailability than that in plant products.
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

17. Riboflavin is synthesized by the bacteria populating the hindgut.
Hindgut microflora
Riboflavin is synthesized by the bacteria populating the hindgut.
Microfloral riboflavin can be absorbed across the colon to contribute to nutritional riboflavin status of the host.
November 10, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

18. Literature
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc
November 10, 2018