- Alcohol use
- Cancer radiation therapy or chemotherapy
- Corticosteroid use
- Excessive simple sugar consumption
- Excessive stress
- Fasting
- Food allergens
- Gastrointestinal infections
- NSAIDs (non-steroidal anti-inflammatory drugs) such as aspirin and ibuprofen
- Nutrient deficiencies
- Premature birth
- Whole food exposure prior to 46 months of age
