Recommended Daily Intake of Vitamin B2 (Riboflavin)
The recommended daily allowance (RDA) of riboflavin is 1.3 mg for adult males and 1.1 mg for adult females, with increased requirements of 1.4 mg during pregnancy and 1.6 mg during lactation. 1
Riboflavin Requirements by Population Group
Riboflavin requirements vary by age, sex, and physiological state:
Adults
Pediatric Population
- Preterm and term infants up to 12 months on parenteral nutrition: 0.15-0.2 mg/kg/day 1
- Older children: 1.4 mg/day 1
Special Populations
- Elderly: May require up to 1.6 mg/day due to decreased absorption and altered metabolism 1
Biological Significance and Functions
Riboflavin plays critical roles in:
- Energy metabolism through redox reactions 1
- Antioxidant functions and protection against oxidative stress 1
- Metabolism of other B vitamins (niacin, B6, B12, and folate) 1
- Immune function and antibody production 1
- Iron handling and prevention of anemia 1, 2
- Fatty acid oxidation 1
Riboflavin is converted to its active coenzyme forms:
- Flavin mononucleotide (FMN)
- Flavin adenine dinucleotide (FAD)
These coenzymes function in numerous metabolic pathways and are essential for mitochondrial energy production 3.
Dietary Sources
The main dietary sources of riboflavin include:
- Dairy products (milk, yogurt, cheese) - primary source in Western diets 2
- Meat and fish 1, 2
- Eggs 1
- Enriched and fortified grains, cereals, and bakery products 1
- Dark green vegetables 1, 2
Clinical Implications of Deficiency
Riboflavin deficiency manifests as:
- Oral-buccal lesions (cheilosis, glossitis, angular stomatitis) 1
- Seborrheic dermatitis of face, trunk, and scrotum 1
- Ocular symptoms (itching, burning, dryness, corneal inflammation, photophobia) 1
- Normochromic, normocytic anemia 1
- Compromised iron handling 1, 2
High-Risk Populations for Deficiency
- Patients with malabsorption (short bowel syndrome, celiac disease) 1
- Individuals with thyroid dysfunction or diabetes 1
- Patients with renal disease 1
- Individuals with alcoholism 1
- Elderly populations 1
- Patients recovering from surgery, trauma, burns, or fractures 1
- Individuals taking psychotropic drugs, tricyclic antidepressants, or barbiturates 1
Safety and Upper Limits
No tolerable upper intake level has been established for riboflavin due to insufficient data on adverse effects 1. Riboflavin consumed orally from diet or most supplements rarely causes side effects, though high doses may result in yellow-colored urine 1.
Pharmacologic doses (>100 mg) repeatedly consumed may potentially:
- React with light to form peroxides
- Form tryptophan-riboflavin adducts with potential hepato- and cytotoxic effects 1
Clinical Pearls
- Riboflavin is not stored in the body in ample amounts, making constant dietary supply necessary 1
- All flavins are light-sensitive and decompose after irradiation 1
- Plasma riboflavin levels decrease during inflammation by 30-40%, making erythrocyte assays more reliable for assessment during inflammatory states 1
- Riboflavin deficiency is frequently associated with deficiencies of pyridoxine, folate, and niacin 1
- Emerging research suggests riboflavin supplementation may benefit patients with MTHFR 677 TT genotype by lowering blood pressure 1
In summary, maintaining adequate riboflavin intake is essential for optimal metabolic function, energy production, and prevention of deficiency symptoms that can impact quality of life and overall health.