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| ==What is Vitamin B2 (Riboflavin)?== | | ==What is Vitamin B2 (Riboflavin)?== |
− | Vitamin B<sub>2</sub>, also called riboflavin, is an '''essential water-soluble vitamin'''. Riboflavin is absorbed across the intestinal mucosa primarily via [[Active Transport - Physiology|active transport]], with minimal [[Diffusion - Physiology|passive diffusion]]. Intracellular or plasma riboflavin is typically bound to protein. Riboflavin is '''not stored in the body''' and is freely filtered by the [[Nephron Microscopic Anatomy#Proximal Tubule|renal tubules]]. | + | Vitamin B<sub>2</sub>, also called riboflavin, is an '''[[Nutrition Glossary#Essential Nutrients|essential]] water-soluble vitamin'''. Riboflavin is absorbed across the intestinal mucosa primarily via [[Active Transport - Physiology|active transport]], with minimal [[Diffusion - Physiology|passive diffusion]]. Intracellular or plasma riboflavin is typically bound to protein. Riboflavin is '''not stored in the body''' and is freely filtered by the [[Nephron Microscopic Anatomy#Proximal Tubule|renal tubules]]. |
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| ==Why is it Important?== | | ==Why is it Important?== |
− | Riboflavin is a component of the co-enzymes flavin mononucleotide (FMN) and flavin adenine di-nucleotide (FAD)<ref>McCormick DB. Niacin, Riboflavin, and Thiamin. In Biochemical and physiological aspects of human nutrition. 2000 Philadelphia, PA: WB Saunders Company p.469-475.</ref>. It is also an essential component of the enzyme glutathione reductase. | + | Riboflavin is a component of the [[Nutrition Glossary#Coenzyme|co-enzymes]] flavin mononucleotide (FMN) and flavin adenine di-nucleotide (FAD)<ref>McCormick DB. Niacin, Riboflavin, and Thiamin. In Biochemical and physiological aspects of human nutrition. 2000 Philadelphia, PA: WB Saunders Company p.469-475.</ref>. It is also an essential component of the enzyme glutathione reductase. |
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| ==Roles in the Body== | | ==Roles in the Body== |
− | The [[Nutrition Glossary#Coenzyme|coenzymes]] FMN and FAD are play a catalytic role in redox reactions, such as the conversion of Vitamin A (Retinol) - Nutrition|retinol]] to the active metabolite retinoic acid, [[Tryptophan - Nutrition|tryptophan]] to [[Vitamin B3 (Niacin) - Nutrition|niacin]], and pyruvate to α-ketogluterate, and are cofactors in the electron transport chain. Riboflavin is also a component of the antioxidant enzyme, glutathione reductase. | + | The [[Nutrition Glossary#Coenzyme|coenzymes]] FMN and FAD are play a catalytic role in redox reactions, such as the conversion of [[Vitamin A (Retinol) - Nutrition|retinol]] to the active metabolite retinoic acid, [[Tryptophan - Nutrition|tryptophan]] to [[Vitamin B3 (Niacin) - Nutrition|niacin]], and pyruvate to α-ketogluterate, and are cofactors in the electron transport chain. Riboflavin is also a component of the antioxidant enzyme, glutathione reductase. |
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| ==Consequences of Riboflavin Deficiency== | | ==Consequences of Riboflavin Deficiency== |
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| Riboflavin deficiency impairs growth rate in puppies<ref>Axelrod AE, et al. The production of uncomplicated riboflavin deficiency in the dogs. Am J Physiol 1940;128:703-708.</ref><ref name="Noel">Noel PR, et al. Riboflavin supplementation in the dog. Res Vet Sci 1972;13:443-450.</ref>, and can result in anorexia, weight loss, weakness, ataxia, collapse, and death<ref>Street HR and Cowgill GR. Acute riboflavin deficiency in the dog. Am J Physiol 1939;125:323-334.</ref>. Bilateral corneal opacities have also been described in adult dogs fed riboflavin deficient diets<ref name="Noel"/>. | | Riboflavin deficiency impairs growth rate in puppies<ref>Axelrod AE, et al. The production of uncomplicated riboflavin deficiency in the dogs. Am J Physiol 1940;128:703-708.</ref><ref name="Noel">Noel PR, et al. Riboflavin supplementation in the dog. Res Vet Sci 1972;13:443-450.</ref>, and can result in anorexia, weight loss, weakness, ataxia, collapse, and death<ref>Street HR and Cowgill GR. Acute riboflavin deficiency in the dog. Am J Physiol 1939;125:323-334.</ref>. Bilateral corneal opacities have also been described in adult dogs fed riboflavin deficient diets<ref name="Noel"/>. |
| ====Cats:==== | | ====Cats:==== |
− | Riboflavin deficiency in cats can resulted in anorexia, weight loss, periauricular alopecia, bilateral cataracts, testicular hypoplasia, fatty accumulation in the liver, and death<ref>Gershoff SN, et al. The effect of the carbohydrate and fat content of the diet upon the riboflavin requirement of the cat. J Nutr 1959;68:75-88.</ref>. | + | Riboflavin deficiency in cats can resulted in anorexia, weight loss, periauricular [[alopecia]], bilateral cataracts, testicular hypoplasia, [[Hepatic Lipidosis|fatty accumulation in the liver]], and death<ref>Gershoff SN, et al. The effect of the carbohydrate and fat content of the diet upon the riboflavin requirement of the cat. J Nutr 1959;68:75-88.</ref>. |
− | Conditions associated with diuresis (e.g., chronic disease, such as renal disease or [[Diabetes Insipidus|diabetes]], or therapeutic intervention, such as intravenous fluids or increased water intake with management of [[Cystitis|lower urinary diseases]]) can result in increased loss of riboflavin and may increase daily requirements. Patients on chronic haemodialysis are also at an increased risk for developing a deficiency. | + | Conditions associated with diuresis (e.g. chronic disease, such as [[:Category:Kidney - Pathology|renal disease]] or [[Diabetes Insipidus|diabetes]], or therapeutic intervention, such as intravenous fluids or increased water intake with management of [[Cystitis|lower urinary diseases]]) can result in increased loss of riboflavin and may increase daily requirements. Patients on chronic haemodialysis are also at an increased risk for developing a deficiency. |
| Riboflavin deficiencies can also occur due to low dietary intake and vitamin degradation during cooking especially under alkaline conditions. | | Riboflavin deficiencies can also occur due to low dietary intake and vitamin degradation during cooking especially under alkaline conditions. |
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| ==Diagnosing Riboflavin Deficiency== | | ==Diagnosing Riboflavin Deficiency== |
− | Diagnosis of riboflavin deficiency is based on a finding of low erythrocyte glutathione reductase activity, although this is not routinely tested for in veterinary reference laboratories. A clinical suspicion arises when there are clinical signs consistent with a riboflavin deficiency and dietary analysis indicates a deficiency. | + | Diagnosis of riboflavin deficiency is based on a finding of low [[Erythrocytes|erythrocyte]] glutathione reductase activity, although this is not routinely tested for in veterinary reference laboratories. A clinical suspicion arises when there are clinical signs consistent with a riboflavin deficiency and dietary analysis indicates a deficiency. |
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| ==References== | | ==References== |
| <references/> | | <references/> |
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| + | <br> |
| + | {{Reviewed Nutrition 1 |
| + | |date = 22 May 2015}} |
| + | {{Waltham}} |
| + | {{OpenPages}} |
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| [[Category:Vitamins]] | | [[Category:Vitamins]] |
− | [[Category:To Do - Nutrition]]
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− | [[Category:To Do - Nutrition preMars]]
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