Significance and sources of riboflavin Domina Petric MD

Significance and sources of riboflavin Domina Petric, MD

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. December 18, 2021 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 2

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. December 18, 2021 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 3

Significance of riboflavin Deficiency of the vitamin B 2 first manifests itself in tissues with rapid cellular turnover: skin and epithelium. December 18, 2021 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 4

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). December 18, 2021 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 5

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. December 18, 2021 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 6

Riboflavin contents of foods, expressed in riboflavin mg/100 g. December 18, 2021 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 7

Diary products Diary product Milk Yogurt American cheese Cheddar cheese Cottage cheese Ice cream December 18, 2021 Riboflavin mg/100 g 0, 17 0, 16 0, 43 0, 46 0, 28 0, 21 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 8

Meats Meat Liver, beef Beef Chicken Lamb Pork Ham, cured December 18, 2021 Riboflavin mg/100 g 3, 50 0, 24 0, 19 0, 22 0, 27 0, 19 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 9

Cereals Wheat, whole Rye Oat meal Rice December 18, 2021 Riboflavin mg/100 g 0, 11 0, 08 0, 02 0, 01 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 10

Vegetables Riboflavin mg/100 g Asparagus 0, 18 Broccoli 0, 20 Cabbage 0, 06 Carrots 0, 06 Cauliflower 0, 08 Corn 0, 06 Lima beans 0, 10 Potatoes 0, 04 Spinach 0, 14 Tomatoes 0, 04 December 18, 2021 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 11

Fruits Apples Bananas Oranges Peaches Strawberries December 18, 2021 Riboflavin mg/100 g 0, 01 0, 04 0, 03 0, 04 0, 07 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 12

Other Eggs: 0, 30. December 18, 2021 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 13

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. • • December 18, 2021 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 14

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. December 18, 2021 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 15

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. December 18, 2021 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 16

Hindgut microflora Riboflavin is synthesized by the bacteria populating the hindgut. December 18, 2021 Microfloral riboflavin can be absorbed across the colon to contribute to nutritional riboflavin status of the host. Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 17

Literature • Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. December 18, 2021 18