Write N/A if it was not labeled
You can list vitamins and minerals, but also include any information on how it helps us (i.e. good for circulation)
Usually risks are associated with over consumption, but if you aren't able to find any "N/A" is an acceptable answer.
If you have chosen fresh produce this will often be listed on the price sign in the grocery store. If you have chosen a packaged food it may list the origin or might say the distributor. Attempt to find where the company sources their product.