Reevaluating riboflavin

Some health experts suspect that riboflavin deficiency may impair the body’s ability to absorb and use iron, and to further clarify the relationship between these nutrients, researchers invited 256 women, aged 19 to 25, to undergo screening for riboflavin deficiency and identified 123 women who were deficient.

The riboflavin-deficient women were randomly selected to receive one of three supplements daily for eight weeks:

• No riboflavin (placebo)
• mg riboflavin (2 mg group)
• mg riboflavin (4 mg group)

Intake of iron did not change throughout the study.

Blood levels of riboflavin and hemoglobin, a marker of anemia, were measured at the start of the study and at 4, 8, and 12 weeks after supplementation began. The researchers found that:

• Riboflavin supplements significantly improved riboflavin levels in deficient women.
• Compared with the placebo group, the 2 mg group had improved riboflavin levels but the 4 mg group had the greatest increase in riboflavin levels.
• In the women taking riboflavin, hemoglobin levels increased. Since iron deficiency is the most common cause of low hemoglobin levels, this finding suggests that the riboflavin improved iron status.
• Among the women taking riboflavin supplements, bigger increases in blood riboflavin levels were associated with bigger improvements in hemoglobin.
• Among the women taking riboflavin supplements, hemoglobin levels improved the most in those with the lowest riboflavin levels at the beginning of the study.

Riboflavin riches

This study suggests that even among healthy adults, low intake of riboflavin may be common. And for people who don’t get enough riboflavin, improving intake may help reduce the risk of iron deficiency, another common nutrition issue. Use our tips to ensure you are getting enough:

• Focus on food. The best food sources of riboflavin include dairy products and fortified cereals and breads. Almonds and legumes, especially soybeans, also pack plenty of riboflavin.
• Think about supplements. Multivitamins and B-complex supplements can supply riboflavin. Ask your doctor or dietitian which supplement is right for you.
• Consider connections. This study points to the multiple connections between various nutrients in our diet. If you’ve been diagnosed with iron deficiency or low hemoglobin levels, you may need more iron, but don’t overlook possible benefits of other health-improving nutrients, including riboflavin.
• Ask for evaluation. If you suspect your diet isn’t up to snuff, talk to your doctor about a complete nutritional evaluation, including blood work, to figure out where you may be coming up short and how to address the issue.

(Am J Clin Nutr 2011; 93:1274–84)