Vegetarian Diets
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FROM THE ACADEMY Position Paper Position of the Academy of Nutrition and Dietetics: Vegetarian Diets ABSTRACT POSITION STATEMENT It is the position of the Academy of Nutrition and Dietetics that appropriately planned It is the position of the Academy of Nutrition vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide and Dietetics that appropriately planned fi vegetarian, including vegan, diets are health bene ts for the prevention and treatment of certain diseases. These diets are healthful, nutritionally adequate, and may appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, provide health benefits in the prevention childhood, adolescence, older adulthood, and for athletes. Plant-based diets are more and treatment of certain diseases. These environmentally sustainable than diets rich in animal products because they use fewer diets are appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, natural resources and are associated with much less environmental damage. Vegetar- childhood, adolescence, older adulthood, ians and vegans are at reduced risk of certain health conditions, including ischemic and for athletes. Plant-based diets are more heart disease, type 2 diabetes, hypertension, certain types of cancer, and obesity. Low environmentally sustainable than diets rich intake of saturated fat and high intakes of vegetables, fruits, whole grains, legumes, soy in animal products because they use fewer fi natural resources and are associated with products, nuts, and seeds (all rich in ber and phytochemicals) are characteristics of much less environmental damage. vegetarian and vegan diets that produce lower total and low-density lipoprotein cholesterol levels and better serum glucose control. These factors contribute to reduc- tion of chronic disease. Vegans need reliable sources of vitamin B-12, such as fortified foods or supplements. J Acad Nutr Diet. 2016;116:1970-1980. EGETARIAN AND VEGAN VEGETARIAN DIETS IN intake from vegetables, fruits, whole dietary patterns can be quite PERSPECTIVE grains, and beans.3 In the 2015-2020 diverse because of the vari- Trends among Vegetarians Dietary Guidelines for Americans, ety of food choices available vegetarian diets are recommended as V According to a nationwide poll in 2016, and the different factors that moti- one of three healthful dietary patterns, vate people to adopt such patterns. approximately 3.3% of American adults and meal plans are provided for those People choose to adopt a vegetarian are vegetarian or vegan (never eat following lacto-ovo-vegetarian and fi diet for many reasons, such as meat, poultry, or sh), and about 46% of vegan diets.4 The National School 1 compassion toward animals, a desire vegetarians are vegan. The same poll Lunch Program, while not requiring to better protect the environment, to revealed that 6% of young adults (18 to vegetarian options per se, requires lower their risk of chronic diseases, or 34 years) are vegetarian or vegan, schools to increase availability of fruits, to therapeutically manage those dis- while only 2% of those 65 years or older vegetables, and whole grains in current eases. A well-planned vegetarian diet are vegetarian. Sales of alternative meal patterns in the school menu. containing vegetables, fruits, whole meat products reached $553 million in Those following a vegetarian diet now grains, legumes, nuts, and seeds can 2012, an 8% increase in 2 years. It was have technological support. To date, provide adequate nutrition. Vege- observed that 36% of survey responders while no online nutrition food tracker tarian diets are devoid of flesh foods sought vegan meat alternatives, largely exists strictly for vegetarian diets, some (such as meat, poultry, wild game, from among the 18- to 44-year-old age allow clients to select vegetarian and 1,2 seafood, and their products). The group. While whole plant foods serve vegan plans. These applications for mo- most commonly followed vegetarian best as dietary staples, some processed bile devices allow vegetarians to discover fi diets are shown in Figure 1.The and forti ed foods, such as nondairy nutritional needs, track intake, and adoption of a vegetarian diet may beverages, meat analogs, and breakfast locate restaurants and markets where cause a reduced intake of certain cereals, can contribute substantially to vegan foods are available. The online nutrients; however, deficiencies can the nutrient intake of vegetarians. tracking tool at www.SuperTracker.usda. be readily avoided by appropriate Plant-based diets, including vege- gov is a part of the US Department of planning. tarian and vegan diets, are becoming Agriculture Choose My Plate program.5 well accepted, as further evidenced by fi many nonpro t and government NUTRITION CONSIDERATIONS institutions highlighting this dietary FOR VEGETARIANS choice. The American Institute for 2212-2672/Copyright ª 2016 by the Cancer Research encourages a plant- Protein Academy of Nutrition and Dietetics. based diet, suggesting Americans Vegetarian, including vegan, diets http://dx.doi.org/10.1016/j.jand.2016.09.025 consume two-thirds of their dietary typically meet or exceed recommended 1970 JOURNAL OF THE ACADEMY OF NUTRITION AND DIETETICS ª 2016 by the Academy of Nutrition and Dietetics. FROM THE ACADEMY nonvegetarians, blood and tissue levels Concerns about the iron status of Type of diet Nature of diet (all are of EPA and DHA can be significantly vegetarians have led to questions of fl devoid of esh foods) lower.10,11 bioavailability of non-heme iron from The clinical relevance of reduced EPA plant foods. Non-heme iron absorption Vegetarian May or may not include and DHA status among vegetarians and depends upon physiological need and egg or dairy vegans is unknown.11,12 Long-chain n-3 is regulated in part by iron stores. Its products. fatty acids are important for the absorption can vary greatly, depending development and maintenance of the upon both the meal composition and Lacto-ovo- Includes eggs and dairy brain, retina, and cell membranes and the iron status of the individual. vegetarian products. favorably impact pregnancy outcomes Bioavailability of non-heme iron is and risk for cardiovascular disease impacted by the ratio of inhibitors, Lacto- Includes dairy (CVD) and other chronic diseases.6,13,14 such as phytates and polyphenolics, vegetarian products, but not Yet, vegetarian and vegan children do and enhancers, such as vitamin C, citric egg products. not appear to experience impairment acid, and other organic acids.19 in visual or mental development, and In a recent review, non-heme iron Ovo- Includes eggs and egg vegetarian and vegan adults experi- absorption was seen to vary from 1% to vegetarian products, but no ence reduced risk for CVD.10,11,15 23%, depending upon iron status and dairy. ALA is endogenously converted to dietary enhancers and inhibitors.20 EPA and DHA, but the process is A newly developed regression equa- Vegan Excludes eggs and somewhat inefficient and is affected by tion enables iron absorption to be dairy products, and sex, dietary composition, health status, predicted from serum ferritin levels may exclude honey. and age. High intakes of linoleic acid and dietary modifiers. Diet had a 11,13 Raw vegan Based on vegetables, (LA) may suppress ALA conversion. greater effect on iron absorption when A ratio of LA/ALA not exceeding 4:1 serum ferritin levels were low.20 fruit, nuts and seeds, has been suggested for optimal Nonheme iron absorption can be as legumes, and conversion.7,10,14 much as 10 times greater in iron- sprouted grains. The The Dietary Reference Intake for ALA deficient individuals compared with amount of uncooked are 1.6 g/day and 1.1 g/day, for men and iron-replete individuals. food varies from 75% women, respectively.4 For vegetarians The Dietary Reference Intake to 100%. and vegans, it may be prudent to assigned to iron for vegetarians in 2001 ensure somewhat higher intakes of was 80% more than that for non- Figure 1. Types of vegetarian diets. ALA.8,10 The most concentrated plant vegetarians. This derives from the sources of n-3 fatty acids are seeds assumption that the bioavailability of (flax, chia, camelina, canola, and iron from a vegetarian diet is 10%, protein intakes, when caloric intakes 8,10 6-8 hemp), walnuts, and their oils. Evi- whereas that from a nonvegetarian diet are adequate. The terms complete dence suggests that n-3 needs of is 18%.21 These assumptions were and incomplete are misleading in rela- healthy individuals can be met with based on very limited data using tion to plant protein. Protein from a ALA alone, and that endogenous syn- single-meal absorption studies variety of plant foods, eaten during the thesis of EPA and DHA from ALA is involving meals that were atypical of course of a day, supplies enough of all sufficient to keep levels stable over what most vegetarians consume in indispensable (essential) amino acids 11,14 7 many years. Low-dose micro- Western countries. when caloric requirements are met. algae based DHA supplements are We now know that individuals can À The regular use of legumes and soy available for all vegetarians with adapt and absorb non-heme iron more products will ensure an adequate pro- increased needs (eg, pregnant or effectively.22 The magnitude of the tein intake for the vegetarian, as well as 9 lactating women) or with reduced effect of enhancers and inhibitors of providing other essential nutrients. conversion ability (eg, those with iron absorption can diminish with Fruitarian diets are normally low in hypertension or diabetes).10 time.23 Individuals are able to adapt to protein and other nutrients. Protein low intakes of iron over time and can needs at all ages, including those for reduce iron losses.24 In one study, total athletes, are well achieved by balanced Iron fi 7,8 iron absorption signi cantly increased vegetarian diets.