Worlds largest verified nutrition database.
Nutritionix API is a free Health API that requires apiKey authentication, is served over HTTPS and has unconfirmed CORS support.
Details from developer.nutritionix.com.

Unified API suite · now live
Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
The Nutritionix API is provided by Nutritionix API (developer.nutritionix.com).
Yes. The Nutritionix API is listed in the Health category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
Yes. The Nutritionix API uses apiKey authentication, so you need to register for credentials before making requests.
CORS support for the Nutritionix API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The Nutritionix API is served over HTTPS, so it's safe to use in production.