Vegan for Life - Jack Norris [7]
SUPPLEMENTS IN VEGAN DIETS
With the exception of vitamin B12, it’s possible to get all of the vitamins and minerals you need from plant foods. Depending on individual circumstances, though, vitamin supplements can provide an important way to meet nutrient needs, especially for vitamin D, iodine, calcium, and DHA.
While it’s possible to purchase vitamin supplements that are food concentrates, many are synthetic—that is, they are synthesized in a laboratory. As long as they are well-digested, synthetic vitamins and minerals will do their job. In fact, in some cases they are a better source of nutrition than the food concentrates. For example, some “natural” vitamin B12 supplements are produced by companies that have not used proper testing standards and therefore, the B12 is not a reliable source of that nutrient.
The United States Pharmacopeia (USP) verifies the quality, purity, and potency of dietary supplements for companies that take part in their certification program. Supplements that display the “Dietary Supplement USP Verified” mark on labels have been tested to verify that they dissolve properly. (Vitamin and mineral supplements that don’t carry the USP symbol may still be of high quality; it just means they haven’t been certified.)
The supplements we recommend are for nutrients that can be low enough in vegan diets to lead to a deficiency. While a multivitamin can provide a number of these nutrients all at once, taking them as separate supplements will allow you to take only the supplements you need. A few things to keep in mind regarding supplements: First, most of us have sufficient stomach acid to dissolve supplements for thorough digestion. But if you have reason to believe that your stomach acid isn’t strong, it’s a good idea to crush or chew vitamin and mineral supplements. Also, supplements sometimes require a bit of attention to balance. For example, high doses of zinc can inhibit copper absorption. Taking 50 milligrams of zinc per day (the RDA is 8 to 11 milligrams) can cause a copper deficiency in just a few short weeks. This is one reason to rely on a well-balanced diet to provide enough nutrients and use supplements just to make up for any shortfall.
KEEPING NUTRITION SIMPLE
Humans require more than forty essential nutrients. Most people know that they need nutrients like vitamin C, protein, and calcium. But they may never have heard of the B vitamin biotin or the mineral vanadium and have no idea that they need to consume foods that provide these nutrients. And it’s definitely not something you need to worry about. Most nutrients are so readily available in all different types of diets that we don’t need to think about how to get them.
In this book, we’re going to focus on just nine nutrients—protein, calcium, iron, zinc, iodine, alpha-linolenic acid, and vitamins B12, A, and D. We’ll briefly mention a handful of others and talk about DHA, an omega-3 fat that doesn’t have essential nutrient status (meaning that, while a growing body of evidence suggests that it’s important, it hasn’t been established as a dietary essential). These are the nutrients that are of special interest to vegans and are the center of vegan nutrition. Getting enough of them isn’t difficult. You just have to know how to do it.
Nutrient Recommendations: Some Terminology
Depending on the available research, determining precise needs is easier for some nutrients than for others. If researchers don’t have enough data, or the findings are conflicting, it can be difficult to reach conclusions about optimal intakes. Therefore, current recommendations fall into several different categories, which are collectively known as the DRI (Dietary Reference Intakes):
Recommended Dietary Allowance (RDA): The amount of a nutrient that is believed to be sufficient to meet the