COMPENDIUM ON FUNCTIONAL MEDICINE - Flipbook - Page 215
DAO (Diamine Oxidase)
Function: The DAO gene (AOC1) encodes the primary enzyme
responsible for breaking down histamine in the digestive tract [40].
Key Variant:
DAO rs10156191
Associated with reduced enzyme activity and decreased
capacity to break down dietary histamine.
Impact: People with DAO variants often experience:
● Symptoms consistent with histamine intolerance (headaches,
digestive issues, skin problems)
● Reactions to high-histamine foods (fermented foods, aged
cheeses, cured meats)
● Potential benefit from low-histamine diets and DAO
supplementation
● Possible probiotic sensitivities
GST (Glutathione S-Transferase)
Function: GST genes encode enzymes involved in detoxification
processes, particularly the conjugation of toxins with glutathione
for elimination [41].
Key Variants:
GSTM1 and GSTT1 deletion variants
Complete deletions of these genes result in absence of enzyme
activity.
GSTP1 rs1695
Affects the activity of the GSTP1 enzyme.
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