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Authors: Jack Norris,Virginia Messina

Tags: #Health & Fitness

Vegan for Life (3 page)

BOOK: Vegan for Life
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The recommendations are set at levels that are believed to meet the needs of the vast majority of Americans. Therefore, for any given nutrient, many Americans will need less than the recommended amount while others might need more. There can be exceptions, though. For example, many experts believe that current recommendations for vitamin D are far too low. And the debate about calcium recommendations is ongoing. We’re also starting to hear questions from world experts about protein requirements; some think that they may fall short of actual needs.
1
VEGANS AND THE RDAS
The dietary recommendations are aimed at omnivores and, in a few cases, nutrient needs might be higher for vegetarians and vegans. Protein requirements are believed to be slightly higher because plant protein isn’t digested quite as well as protein from animals. It’s a small difference and it’s easily satisfied with vegan diets as long as calorie needs are met and your diet includes high-protein plant foods. Zinc needs may also be higher, and it’s possible that some vegans have intakes that are less than optimal.
The situation for iron is a little more controversial. We’ll see that vegans have higher requirements but how much higher is a subject of some debate. We’ve included the FNB recommendations for iron in the chart below, but we don’t think that vegans should worry too much about getting this much iron. We’ll talk much more about this issue in Chapter 6.
NUTRIENT INTAKE OF VEGANS: HOW DOES IT COMPARE TO RECOMMENDATIONS?
There isn’t much available information about nutrient intakes of vegans, but a few studies show that vegans are likely to consume more of certain nutrients—vitamin C, thiamin, riboflavin, niacin, vitamin B
6
, folate, and sometimes iron—than omnivores.
2
In contrast, many vegans have intakes of calcium and zinc that are lower than the recommendations. In the chart on pages 4 and 5, we’ve compared FNB recommendations to actual intakes of a group of British vegans.
GOOD DIETS ARE GOOD ADVOCACY
Whether you are already vegan or just starting to take steps in that direction, eliminating animal products from your lifestyle is an effective way to make a difference. It reduces animal suffering, removes your financial support for factory farming, and represents a stance against the use of animals. But in order to have the greatest impact possible, most of us who care about animals hope to influence others to go vegan as well.
Those who work for the meat, dairy, and egg industries would like to portray vegan diets as inadequate. So the last thing we want to do is give them any ammunition. Some vegans balk at the idea of taking vitamin B
12
supplements, because they think it makes vegan diets appear inadequate. But taking a chance with nutrient deficiencies is the worst thing we can do for the image of vegan diets. For example, arguing that vegans have lower calcium needs than omnivores can cause some vegans to make poor choices for their bone health. Taking every precaution to make sure that we are healthy is one way to help others feel confident about going vegan.
Promoting veganism as a lifestyle that is practical, easy, and realistic is important, too. Time, convenience, and taste are primary factors in people’s food choices. That’s why overly restrictive diets can create the wrong kind of image for veganism. Current trends among some vegans to give up more and more foods—added fats, cooked foods, and gluten—are counterproductive, especially because these dietary restrictions have few health benefits for most people. It’s true that some people might have better success with weight control when they eat very little fat, but research suggests that diets containing small amounts of added fats or higher-fat foods can be even more beneficial for long-term weight control. And we’ll look at why a little bit of unsaturated fat in the diet, especially monounsaturated fat, can be good for controlling and preventing chronic diseases.
 
NUTRIENT RECOMMENDATIONS FOR OMNIVORES AND VEGANS COMPARED TO INTAKES OF BRITISH VEGANS
3
Likewise, the idea behind a raw foods diet is based on a few scientific principles that are shaky at best. There is really no good evidence to suggest that eating all raw food is any better for you than eating a mix of raw and cooked whole plant foods. In fact, some of the beneficial compounds in foods, such as lycopene (an antioxidant in tomatoes that protects against prostate cancer), are available only when foods are cooked. The vitamin A precursor beta-carotene is more readily available from cooked foods as well and is also better absorbed in the presence of some fat. A raw foods diet can be helpful for weight control, since it has a lower caloric density, but this also means that it isn’t appropriate for children.
A gluten-free diet is an absolute necessity for those who have celiac disease, a permanent intolerance to gluten. But this autoimmune disease affects only 1 percent of the population. That means that most vegans have no reason to eliminate gluten from their diets. In fact, some research suggests that gluten-free diets are associated with reductions in levels of beneficial gut bacteria and increased levels of harmful microbes. For those who don’t have celiac disease, it may be beneficial to include some gluten in their diet. (Of course, those who have allergies, including non-celiac wheat allergy, need to adjust their diets accordingly.)
Promoting these additional restrictions that have
no known health advantage
for most people doesn’t do anything to help animals or promote vegan diets. To the contrary, it creates an image of vegan diets
that makes them look more difficult and less appealing. If we want others to follow our lead in adopting more compassionate food choices, it makes sense to avoid unnecessary restrictions and make vegan diets as accessible as possible.
The nutrition recommendations in this book, which are based on solid, current science, are aimed at making your vegan diet healthful and realistic. You’ll see that it’s easy to meet nutrient needs by eating a variety of cooked and raw plant foods, and it’s also reasonable to plan some family meals using convenience products without compromising your health.
SUPPLEMENTS IN VEGAN DIETS
With the exception of vitamin B
12
, 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 B
12
supplements are produced by companies that have not used proper testing standards and therefore, the B
12
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 B
12
, 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 needs of 97 to 98 percent of the population. It varies for different age groups and between men and women.
 
Adequate Intake (AI)
: When there isn’t enough data to establish an RDA, the Institute of Medicine sets an AI, which is based on both studies and observations of what healthy populations consume. The recommendation for calcium, for example, is an AI because the data regarding calcium needs is conflicting.
 
Tolerable Upper Intake Level (UL)
: This is the maximum daily intake of a nutrient that is likely to be safe. Some nutrients can be extremely toxic at higher than normal levels, although excessive intakes are almost always associated with supplements.
 
Daily Values (DV)
: These are values used strictly for food labeling purposes and they are based on much older RDAs. The amounts of vitamins and minerals in a food are listed as a percent of the DV. For example, the DV for calcium is 1000 milligrams, so if a food contains 10 percent of the DV for calcium per serving, it provides 100 milligrams of calcium. The problem is that without knowing what the DV is for a specific nutrient—and the food label doesn’t tell you—it’s hard to know exactly what these numbers mean. As we discuss the nutrients that are especially relevant to vegans in the next several chapters, we’ll give you the information you need to decipher food labels.
UNDERSTANDING NUTRITION RESEARCH
The amount of nutrition information in the media and on the Internet is staggering. Much of it is conflicting and often studies looking at the same question come up with completely different answers.
In fact, for essentially all heavily researched areas, you can build a case for just about anything by picking and choosing the studies that support your point. Some advocates do this to make vegan diets look more beneficial. And some vegan detractors pick a completely different set of studies to make vegan diets look bad.
The key to understanding nutrition research is to look at the
entire body of evidence
and see what
most studies
say. Rarely can a single study provide a definitive answer to a question. There are always inconsistencies and there are always study flaws. In addition, different types of studies carry different weight. So the strengths and weaknesses of certain types of studies have to be balanced against the strengths and weaknesses of others.
BOOK: Vegan for Life
9.8Mb size Format: txt, pdf, ePub
ads

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