When it comes to fruits and vegetables, deep color is often a good indicator of high nutritional content, especially in vegetables. For example, the best sources of beta-carotene, which the body converts into vitamin A, can be found in orange and yellow plants like carrots and sweet potatoes, and dark-leafed greens. Romaine contains about eight times as much beta-carotene as iceberg lettuce, while kale has about 27 times as much.

Freshly harvested produce generally packs the most nutrients. Store most greens and broccoli in plastic bags or in a vegetable crisper at temperatures just slightly above freezing. Canned foods should be stored at about 65 degrees to minimize vitamin loss.

If you don’t live where fresh-caught fish and seafood is sold or if you local market doesn’t stock fresh looking produce, check out a grocer’s freezer case. The vitamin contents of well wrapped frozen meats; fish ad poultry are almost the same as that of the fresh varieties. Keep your own freezer set at a temperature of 0 degrees or below. Some foods are even better frozen than fresh. For example, a package of frozen broccoli, which contains mostly nutrient-rich florets, or buds, can have more beta-carotene than the same weight of fresh broccoli that has been in the refrigerator for a few days. Frozen foods should be used within several months of purchase. It’s a good idea to keep a grease pencil hand to mark on the package the date of purchase.