Q I’ve been in a quandary about how to take vitamin C. Is one form better than another? Are there other nutrients that should be taken with it for optimal absorption and utility? There are probably more choices for this important nutrient than anything else. I’m confused!

Robbi, Tucson, AZ

A There are essentially two forms of vitamin C: water-soluble (ascorbic acid or a metallic salt of ascorbic acid, e.g., calcium ascorbate) and fat-soluble (an organic ester of ascorbic acid, e.g., ascorbyl palmitate). The latter is beneficial because it can provide the benefits of vitamin C to fatty tissues that do not receive them from the water-soluble forms. Because these tissues constitute a relatively small percentage of our body weight (in most cases), it’s unnecessary for more than a small proportion of our vitamin C intake to be in the fat-soluble form.

Also of great importance as an antioxidant is vitamin E, which ideally should be taken along with vitamin C in a ratio of roughly 1 part E for every 3 1/2 parts C. In long-lived wildlife, the ratios of these two antioxidants are typically found to be between 1:4 and 1:6. However, most animals have very low body fat—roughly 2–4%, which is far lower than that of humans. Hence the recommended ratio of 1:3 1/2. (It’s interesting to note that vitamin E and ascorbyl palmitate together constitute a good system for protecting foods from oxidation.)

One of vitamin C’s most important roles is as a participant in the body’s antioxidant network, a uniquely important set of interrelations among five antioxidants: lipoic acid, vitamin C, vitamin E, coenzyme Q10, and glutathione. Instead of being irreversibly destroyed by free radicals (as is the norm with antioxidants), these five molecules act through feedback loops of chemical reactions to regenerate each other (not entirely, but to a substantial degree) when they’ve been degraded. Apart from its own role as an antioxidant, vitamin C’s main role in the antioxidant network is to regenerate vitamin E (some scientists believe, in fact, that this is vitamin C’s most important role as an antioxidant). In so doing, vitamin C is degraded, but it’s regenerated by lipoic acid. (The latter is unique among the network antioxidants in being both water-soluble and fat-soluble, and it alone is capable of regenerating all four of the others.)

Also useful when taking vitamin C are certain antioxidant bioflavonoids, such as hesperidin, which is found with vitamin C in citrus fruits, and quercetin, which is found in various foods that are not good sources of vitamin C, such as apples, onions, red wine, and green tea. This is not to say that you should stop consuming fruits and vegetables that contain hesperidin or quercetin (or other bioflavonoids), because these vital and healthful foods contain many other constituents (antioxidants and others) that are protective against cancer and possibly cardiovascular disease.

Most of the ideas discussed above are embodied in Radical Shield Booster, a formulation designed by nutritional scientists Durk Pearson & Sandy Shaw. You might want to give it a try.