Riboflavin is important for energy production, enzyme function, and normal fatty acid and amino acid synthesis. It is necessary for the reproduction of glutathione, a free radical scavenger. Water-soluble Vitamin B-2 is not stored in ample amounts, with only minute reserves in the liver, kidneys, and heart. Consequently, a constant supply is needed. Deficiency in this vitamin does not occur in isolation, but is part of a multiple-nutrient deficiency.
Severe riboflavin deficiency is rare, except in alcoholics. Hazardously low levels of this nutrient are common among the elderly. Thirty-three percent of the elderly population are considered deficient. Research from 1992 indicated exercising women between the ages of 50 and 67 may have increased riboflavin requirements.1
Because riboflavin can boost cellular energy production, it is thought to offer prevention against migraine headaches. Migraines are believed to be caused by a diminished amount of energy produced in blood vessels. Research as recent as 1994 has shown that a high dosage of riboflavin can be an effective treatment for these headaches.2
Because a deficiency in riboflavin also results in a decrease in available glutathione, it has been speculated that such a deficiency may be a factor in the development of cataracts. Varied results concerning the association of riboflavin and cataracts emerged from research in the late 1970s and early 1980s. A study conducted in 1993 found supplemental riboflavin to improve iron and glutathione levels in patients with sickle cell anemia.3 A study from 1983 found a combination of iron and riboflavin supplements to be a more effective treatment for microcytic anemia than iron supplements alone.4
As a photosynthesizing agent, riboflavin is destroyed by light. The combination of light, oxygen, and riboflavin can lead to the formation of free radicals, and, consequently, cataracts. Cataract patients are advised to use no more than 10 mg of riboflavin daily, as too much can likely do just as much harm as not enough.
Riboflavin is a water-soluble vitamin and is considered to be nontoxic with no known side effects. Because of the light sensitivity of this vitamin, fruits and vegetables stored in clear glass or uncovered produce will lose the riboflavin content rather quickly. This vitamin should be taken with food since only about 15% is absorbed when taken alone on a empty stomach. Excess riboflavin is excreted in urine, giving the urine a fluorescent yellow-green tint in urine.
1 Winters L, Yoon J, Kalkwarf H, et al., Riboflavin requirements and exercise adaptation in older women. Am J Clin N 1992; 56:526-532.
2 Schoenen J, Lenaerts M, and Bastings E, High-dose riboflavin as a prophylactic treatment of migraine: Results of an open pilot study. Cephalalgia 14, 328, 329, 1994.
3 Ajayi OA, George BO, and Ipadeola T, Clinical trial of riboflavin in sickle cell disease. East Afr Med J 70, 418-421, 1993.
4 Powers J, Bates C, Prentice A, et al., The relative effectiveness of iron and iron with riboflavin in correcting a microcytic anemia in men and children in rural Gambia. Hum Nutr Cl 1983; 37:413-425.
VITAMIN B-2: SOURCES
Available as:
VITAMIN B-2: PROVEN BENEFITS
What this vitamin does:
1 From Griffith HW, Vitamins, Minerals, and Supplements.
VITAMIN B-2: UNPROVED SPECULATED BENEFITS
1 From Griffith HW, Vitamins, Minerals, and Supplements.
VITAMIN B-2: SPECIAL CONSIDERATIONS
Miscellaneous information:
1 From Griffith HW, Vitamins, Minerals, and Supplements.
VITAMIN B-2: DEFICIENCY SYMPTOMS
1 From Griffith HW, Vitamins, Minerals, and Supplements.
VITAMIN B-2: LAB TESTS TO DETECT DEFICIENCY
1 From Griffith HW, Vitamins, Minerals, and Supplements.
VITAMIN B-2: OPTIMAL LEVELS
5-100 mg.
VITAMIN B-2: MINIMUM DOSAGE
Recommended Dietary Allowance (RDA):
The optimum dosage for migraine headaches is 400 mg daily. In cases of cataracts, dosage should not exceed 10 mg daily. While riboflavin is considered to be relatively nontoxic, it is thought that less than 20 mg may be absorbed from one oral dose.
Estimate of adequate daily intake by the Food and Nutrition Board of the National Research Council, 1989.
Age RDA
0-6 months 0.4mg
6-12 months 0.5mg
1-3 years 0.8mg
4-6 years 1.1mg
7-10 years 1.2mg
MALES
11-14 years 1.5mg
15-18 years 1.8mg
19-50 years 1.7mg
51+ years 1.4mg
FEMALES
11-50 years 1.3mg
51+ years 1.2mg
Pregnant 1.6mg
Lactating 1st 6 mos 1.8mg
2nd 6 mos 1.7 mg
VITAMIN B-2: WARNINGS AND PRECAUTIONS
Don't take if you:
Over age 55:
Pregnancy:
Effect on lab tests:
Storage:
Others:
1 From Griffith HW, Vitamins, Minerals, and Supplements.
Signs and symptoms:
What to do:
1 From Griffith HW, Vitamins, Minerals, and Supplements.
Reaction or effect What to do
1 From Griffith HW, Vitamins, Minerals, and Supplements.
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