Can hyporiboflavinemia (low Riboflavin (B2)) cause hypervitaminosis B6 (elevated Vitamin B6 levels)?

From the Guidelines

Yes, low levels of vitamin B2 (riboflavin) can potentially cause elevated vitamin B6 levels in the body. This occurs because riboflavin is necessary for the conversion of vitamin B6 (pyridoxine) into its active form, pyridoxal 5'-phosphate (PLP), through enzymes that require riboflavin as a cofactor. When riboflavin is deficient, the body cannot properly activate B6, which may lead to an accumulation of inactive B6 in the bloodstream. This relationship is part of the complex interdependence within the B vitamin family.

Key Considerations

• Riboflavin deficiency can manifest with oral-buccal lesions, seborrheic dermatitis, and ocular symptoms, as well as normochromic, normocytic anemia and marrow aplasia 1.
• Patients at risk of deficiency include those with malabsorption, thyroid dysfunction, diabetes, renal disease, alcoholism, and in pregnancy, lactation, and in the elderly 1.
• The recommended dietary allowance (RDA) for riboflavin is 1.1 mg/day for women and 1.3 mg/day for men, with no established upper intake level 1.

Recommendations

• If you suspect a B2 deficiency, consider taking a riboflavin supplement of 1.1-1.3 mg daily for adults, along with consuming riboflavin-rich foods such as dairy products, eggs, lean meats, green vegetables, and whole grains.
• It's essential to address both vitamins together rather than supplementing with B6 alone, as increasing B6 without adequate B2 may not resolve the underlying metabolic issue.
• A healthcare provider can confirm these deficiencies through blood tests before starting any supplementation regimen, and may recommend higher doses of riboflavin, such as 5-10 mg/day orally in case of deficiency 1.

From the Research

Relationship Between Riboflavin and Vitamin B6

• The relationship between low riboflavin (B2) levels and high vitamin B6 levels is not directly addressed in the provided studies.
• However, it is mentioned in the study 2 that riboflavin deficiency may exert some of its effects by reducing the metabolism of other B vitamins, notably folate and vitamin B-6.
• This suggests that low riboflavin levels may have an impact on vitamin B6 metabolism, but it does not provide clear evidence of a direct link between low riboflavin and high vitamin B6 levels.

Riboflavin's Role in the Body

• Riboflavin is a water-soluble vitamin that plays important roles in various enzymatic reactions, including energy production, antioxidant protection, and metabolism of other B vitamins 3, 4, 5.
• It is essential for the conversion of oxidized glutathione to the reduced form and for the mitochondrial respiratory chain 3.
• Riboflavin deficiency has been linked to various health risks, including impaired iron handling, anemia, and increased risk of certain cancers 4, 2, 5.

Neuroprotective Effects of Riboflavin

• Riboflavin has been shown to have neuroprotective potential, particularly in relation to Parkinson's disease and migraine headache 6.
• It is thought to exert its neuroprotective effects by ameliorating oxidative stress, mitochondrial dysfunction, neuroinflammation, and glutamate excitotoxicity 6.
• Riboflavin-dependent enzymes also play essential roles in pyridoxine activation, tryptophan-kynurenine pathway, and homocysteine metabolism, which may contribute to its neuroprotective effects 6.