Myths vs facts: Folsäure and allergy

The claim that folic acid causes or prevents allergies is a common myth. Observational studies suggest that high folic acid intake during pregnancy may slightly increase the risk of asthma and allergies in offspring, but the evidence is inconsistent and not causal. For adults, there is no robust evidence that folic acid from supplements affects allergy risk. Importantly, folic acid is essential for cell division and blood formation, especially before and during early pregnancy to prevent neural tube defects. The recommended daily intake is 300 µg (adults) and 550 µg during pregnancy. Excessive intake (>1 mg/day) may pose risks, such as masking vitamin B12 deficiency. Those prone to allergies should focus on a balanced diet rich in natural folate from vegetables and legumes rather than relying on supplements. Genetic testing for MTHFR variants (e.g., C677T) can influence folate metabolism, but no official guidelines exist for allergy prevention based on genetics. Bottom line: folic acid is neither a cause nor a cure for allergies. The evidence is weak and conflicting.