Include Vitamin A precursors and conversion rates in nutritional tables

I've noticed that information on Vitamin A precursors, such as beta-carotene, is missing from the nutritional tables, especially for foods like carrots. Currently, the Vitamin A entry shows 0 mcg for carrots, which can be misleading for those trying to track their Vitamin A intake. I suggest adding a section that lists Vitamin A precursors and provides the conversion rates of these into active retinol.

For example, carrots contain about 800 mcg of beta-carotene per 100g, which could theoretically convert into approximately 67 mcg of retinol, assuming a 12:1 conversion rate.

This update could significantly improve the accuracy and usefulness of the nutritional information provided. Thank you for your attention and continued commitment to improving the service.