This case-sensitive code system http://terminology.hl7.org/CodeSystem/diet defines the following codes:
| Code | Display | Definition |
| vegetarian | Vegetarian | Food without meat, poultry or seafood. |
| dairy-free | Dairy Free | Excludes dairy products. |
| nut-free | Nut Free | Excludes ingredients containing nuts. |
| gluten-free | Gluten Free | Excludes ingredients containing gluten. |
| vegan | Vegan | Food without meat, poultry, seafood, eggs, dairy products and other animal-derived substances. |
| halal | Halal | Foods that conform to Islamic law. |
| kosher | Kosher | Foods that conform to Jewish dietary law. |