Do patients with Glucose-6-phosphate dehydrogenase (G6PD) deficiency need to avoid blue food coloring and certain fruits?

Blue Food Coloring and Fruits in G6PD Deficiency

There is no evidence that blue food coloring needs to be avoided in patients with G6PD deficiency, but certain fruits, particularly fava beans, should be strictly avoided due to risk of severe hemolysis. 1, 2

Foods to Avoid in G6PD Deficiency

Definitively Avoid:

• Fava beans (broad beans): The only food with conclusive clinical evidence linking it to hemolytic anemia in G6PD deficiency 2
  • Can cause both acute hemolytic anemia and methemoglobinemia 3
  • Symptoms typically appear 24-72 hours after consumption 4

Potentially Concerning Foods (Based on Case Reports):

• Blueberries: A case report documented probable blueberry-induced hemolysis in a G6PD-deficient child 5
• Other legumes: Some reports suggest caution with:
  • Falafel (19.4% of hemolytic cases in one study) 4
  • Chickpeas (10.8%) 4
  • Green peas (4.4%) 4
  • Lentils (2.8%) 4

Food Additives and Coloring

• Blue food coloring: No evidence in the guidelines or literature suggests that blue food coloring needs to be avoided in G6PD deficiency 2
• Food additives: At permitted levels in North America, can be consumed safely by most patients with G6PD deficiency 2

Important Clinical Considerations

Methylene Blue Contraindication

• Methylene blue (a blue dye used medically) is strictly contraindicated in G6PD deficiency as it can:
  • Cause significant hemolytic anemia 6
  • Worsen methemoglobinemia 6
  • Be ineffective in treating methemoglobinemia in G6PD-deficient patients 1

Screening Recommendations

• Screening for G6PD deficiency is recommended upon entry into care or before starting therapy with an oxidant drug in patients with predisposing racial or ethnic backgrounds 1
  • Most common in Black men and women (10-15% with GdA- variant) 1
  • Also common in men from Mediterranean regions, India, and Southeast Asia (Gdmed variant) 1

Clinical Presentation of Hemolysis

• Patients typically present with:
  • Pallor (100% of cases in one study) 4
  • Dark red urine (89.6%) 4
  • Jaundice (87.8%) 4
  • Symptoms appearing 24-72 hours after exposure 4

Management of Hemolytic Crisis

• If hemolysis occurs:
  • Provide supportive care with hydration and oxygen supplementation 6
  • Monitor hemoglobin levels and renal function 1
  • Do not use methylene blue for treatment of any associated methemoglobinemia 1, 6
  • Consider exchange transfusion for severe cases 1

Patient Education

• Provide clear dietary counseling:
  • Emphasize absolute avoidance of fava beans
  • Consider recommending caution with other legumes, particularly if there's a personal history of reaction
  • Reassure that most foods, including those with blue food coloring, are safe
  • Educate about medications to avoid, including dapsone, nitrofurantoin, and methylene blue 7

The evidence clearly shows that while fava beans pose a significant risk, there is no need to restrict blue food coloring in the diet of G6PD-deficient individuals.