Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Low-carbohydrate diet wikipedia , lookup
Gastric bypass surgery wikipedia , lookup
Obesity and the environment wikipedia , lookup
Food studies wikipedia , lookup
Raw feeding wikipedia , lookup
Food coloring wikipedia , lookup
Food politics wikipedia , lookup
Vegetarianism wikipedia , lookup
RESEARCH Research and Professional Briefs Young Swedish Vegans Have Different Sources of Nutrients than Young Omnivores CHRISTEL L. LARSSON, PhD; GUNNAR K. JOHANSSON, DDS ABSTRACT The aim of this study was to identify sources of nutrients in diets of young Swedish vegans and omnivores. Three months of dietary intakes were investigated by diet history interviews. Volunteers were recruited through advertising and visits to schools in the city of Umeå, Sweden. Thirty vegans, 15 female and 15 male, aged 17.5⫾1.0 years, were compared with 30 sex-, age-, and heightmatched omnivores. Vegans had different sources of nutrients than young omnivores and relied to a great extent on dietary supplements as a source of vitamin B-12, vitamin D, calcium, and selenium. Dietary intake of vegetables, fruits, and berries exceeded 500 g/day for 21 of the 30 vegans, whereas the same held true for only 1 of the 30 omnivores. Instead of animal products, young vegans rely on dietary supplements, legumes, vegetables, fruits, and berries as sources of nutrients. J Am Diet Assoc. 2005;105:1438-1441. I n the mid-1990s, an increasing number of young people became vegans in Sweden (1). People eating a vegan diet consume food products from the plant kingdom only and exclude meat, fish, eggs, and dairy products (2). The young vegans were eating vegan food mainly for ethical reasons rather than health considerations. Because of this, there was apprehension that they excluded animal products from their diet without replacing them with nutritionally equivalent products from the plant kingdom. This concern was based on speculations rather than on scientific knowledge and, in order to obtain more information, a study was conducted to gather data on the food intake of young vegans. Dietary intake of 30 vegans was investigated by diet history interview and compared with that of 30 omnivores. Intake for the female group of vegans showed that contributions from diet alone of vitamin B-12, vitamin D, calcium, and selenium were below average requirements (3). When consumption of dietary supplements was in- C. L. Larsson is a senior lecturer and G. K. Johansson is a professor, Department of Food and Nutrition, Umeå University, Umeå, Sweden. Address correspondence to: Christel Larsson, Department of Food and Nutrition, Umeå University, SE-901 87 Umeå, Sweden. E-mail: [email protected] Copyright © 2005 by the American Dietetic Association. 0002-8223/05/10509-0012$30.00/0 doi: 10.1016/j.jada.2005.06.026 1438 Journal of the AMERICAN DIETETIC ASSOCIATION cluded, however, intakes of vitamin B-12, vitamin D, and calcium were above average requirements. Selenium obtained from both diet and supplements provided 79% of the average requirement. For female omnivores at group level the dietary intake from diet alone was above average requirements for all nutrients except selenium. Intake at group level of male vegans showed that the contribution from diet alone of vitamin B-12, riboflavin, calcium, and selenium was below average requirements (3). Calcium and selenium obtained from both diet and supplements provided 98% and 65% of the average requirement, respectively. Intake of vitamin B-12 and riboflavin was above average requirements when intake from dietary supplements was included. For male omnivores, the dietary intake at group level was above average requirements for all nutrients. It is of interest to further analyze the dietary data collected to identify sources of nutrients and choice of vegetables and fruits in diets of young Swedish vegans and omnivores. The method of analysis and sources of nutrients are presented and discussed in this article. SUBJECTS AND METHODS Subjects Volunteers, who had to be 16 to 20 years old and in good health with no chronic diseases, were recruited through poster advertising and visits to schools in the Umeå area. Vegans were defined as people eating food of plant origin only, and they were included in the study if they had consumed a vegan diet for at least 6 months and were planning to continue. Omnivores were defined as people eating food of both plant and animal origin. They were considered for participation in the study if they had consumed an omnivorous diet through their entire life and were planning to continue to do so. No lacto-ovo-vegetarians or individuals with dietary restrictions of special diets for weight loss, lactose intolerance, or other conditions were included among the group of omnivores. In total, 65 self-described vegans and 272 omnivores were interviewed regarding food habits, age, and height. Thirty vegans were eligible for inclusion according to the above-mentioned inclusion criteria. Thereafter, 30 omnivores were matched by sex, age (⫾6 months), and height (⫾3.5 cm). Background data for the subjects have been published previously (4). Each participant gave written informed consent and the study was approved by the research ethics committee of the Medical Faculty, Umeå University, Umeå, Sweden. © 2005 by the American Dietetic Association Figure. Contribution to nutrient intake of different food categories eaten by 30 vegans and 30 omnivores in Umeå, Sweden. Categories are presented in order from dietary supplements on the right in the stack bar to miscellaneous on the left. The miscellaneous category includes: mixed dishes that could not be subdivided into food components, alcoholic drinks, oil, dressing, coffee, tea, salt, and spices. The animal product category includes meat, fish, seafood, dairy products, and eggs. Dietary Assessment Each respondent was asked about usual food intake during two separate 1- to 2-hour diet history interviews 1 to 2 weeks apart during the period August 1997 to June 1998. The aim was to construct a typical eating pattern for the preceding 3 months. No food records or food frequency questionnaire was used. Rather, the subjects reported in the first interview what type of food they usually ate and how often. During the second interview, portion sizes of foods were described in terms of household measures, standard weights of food items, three-dimensional food models, or portion photographs of known weights (5). The reported food, beverage, and dietary supplement intakes were entered in the dietary analysis program Stor MATs 4.03e (Rudans Lättdata, Västerås, Sweden), which uses the Swedish Food composition database (version 2.97). Composite foods (eg, casseroles) were split into ingredients (food items). Each food item has a unique “food item code” in the database and food items also have a “food category code.” The program provides weight reports (in grams) of various food categories. Recipes and information on nutritional content of composite foods and dietary supplements not listed in the food database were added. Further information about the dietary assessment, the validity of the method, and information about energy and nutrient intakes of the 60 subjects, has been published previously (3,4). RESULTS Sources of Nutrients Sixteen percent of the vegan energy intake came from low-nutritious food (such as candy, pastry, chips, and soft drinks) compared with 22% of the omnivore energy intake (Figure). Vegans obtained 53% of protein intake from bread, cereals, pasta, and rice; 24% from legumes; and 14% from vegetables and potatoes, while the corresponding figures for omnivores were 19%, 0%, and 3%, respectively (Figure). A large amount (62%) of protein intake in the omnivorous diet came from animal products. All vitamin B-12 in the vegan diet came from dietary supplements (Figure). The greatest food source of vitamin D in the vegan diet was margarine (50%), while in the omnivorous diet it was animal products (51%). The three best food sources of iron in the vegan diet were the food categories consisting of bread, cereals, pasta, and rice (29%); vegetables and potatoes (16%); and legumes (15%); the best sources for omnivores were bread, cereals, pasta, September 2005 ● Journal of the AMERICAN DIETETIC ASSOCIATION 1439 Table. Comparison of Swedish vegans’ and omnivores’ choice of bread, cereals, vegetables, potatoes, fruits, and berries to identify sources of nutrients Bread, cereals, pasta, and rice (rank)a Vegans (nⴝ30) (g/d) %b Semi whole-wheat bread 93 Rice 71 White bread 68 Pasta 57 Porridge 46 Crisp bread 42 Breakfast cereals 15 Gruel 4 Total 396 a Omnivores (nⴝ30) Vegetable and potato intake (g/d) %b (rank)a 23 60 18 33 17 61 14 40 12 42 11 23 4 23 1 0 100 282 21 12 22 14 15 8 8 0 100 Vegans (nⴝ30) (g/d) %b Potatoes 137 Tomatoes 90 Cucumbers 40 Onions 37 Carrots 29 Iceberg lettuces 21 Peppers 20 Mushrooms 17 Zucchinis 13 Vegetable mixes 10 Leeks 10 Bean sprouts 9 Broccolis 8 Corn 8 Peas 7 Avocados 6 Cabbages 6 Aubergines 5 Chinese leaves 5 Beetroots 4 Pickled cucumbers 4 Asparagus 3 Cauliflowers – Lettuces – Spinach – Total 489 27 18 8 7 6 4 4 3 3 2 2 2 2 2 1 1 1 1 1 1 1 1 – – – 98 Omnivores Fruits and (nⴝ30) berries intake (g/d) %b (rank)a 109 29 13 12 15 8 5 2 – 3 1 – – – – 2 4 – 2 3 – – 2 2 2 214 50 14 6 5 7 4 3 1 – 1 1 – – – – 1 2 – 1 1 – – 1 1 1 100 Vegans (nⴝ30) Omnivores (nⴝ30) (g/d) %b (g/d) %b Apples 69 Bananas 36 Oranges 34 Pears 12 Melons 6 Grapes 5 Strawberries 3 Peaches 3 Raisins 2 Mangos 2 Plums 2 Figs 2 Blueberries 2 Apricots 1 Fruit cocktails 1 Kiwis 1 Pineapples – Raspberries – Total 181 38 20 18 6 3 3 1 1 1 1 1 1 1 1 1 1 – – 98 49 46 32 10 – 3 – – 2 – – – – 1 – 3 4 1 151 32 30 21 7 – 2 – – 1 – – – – 1 – 2 3 1 100 Food items are ranked by largest intake of vegans. Intake of a specific food item expressed as a percentage of the total amount of all food items in the present category. b and rice (26%) and animal products (25%). The largest sources of calcium, zinc, and selenium for vegans were dietary supplements, while animal products were the largest sources in the omnivorous diet. However, the best source of calcium from food in the vegan diet was vegetables and potatoes (15%), and 33% of the zinc intake and 14% of the selenium intake came from bread, cereals, pasta, and rice. Choice of Vegetables, Fruits, and Berries Intake of pasta, rice, and crisp bread was statistically higher (P⬍.05) among vegans than omnivores, while the intake of breakfast cereals was lower (Figure). For 21 of the 30 vegans, the dietary intake of vegetables (except potatoes), fruits, and berries was above 500 g/day, which conforms to the Swedish recommendation (6). The same held true for only one of the 30 omnivores. Vegans ate significantly more vegetables but not significantly more fruits and berries than the omnivores. Vegans and omnivores tended to choose similar types of vegetables, fruits, and berries in their diets, but vegans included a larger variety (Table). The most common vegetables eaten were tomatoes, cucumber, onions, carrots, and iceberg lettuce, 1440 September 2005 Volume 105 Number 9 accounting for 42% and 36% of the intake for each group, respectively. The most common fruits eaten by both vegans and omnivores were apples, bananas, oranges, and pears, which accounted for 82% and 90% of the fruit consumption, respectively. DISCUSSION Significantly lower intake of candy and chocolate was seen among vegans compared with omnivores in the present study. The same was found in Canadian and American studies (7-9). Legumes and bread were the greatest sources of protein for vegans in the present study and accounted for 11% and 24% of the protein intake, respectively. However, fruits, berries, and vegetables were also a great source and accounted for 12% of the protein intake. These results may be compared with findings of another study of lacto-ovo-vegetarians in which legumes, bread/cereals, and fruits/vegetables accounted for 39%, 19%, and 14% of protein intake, respectively (7). Similar to the results of other studies (10,11), the main food sources of iron were found to be bread (19%) and fruits, berries, and vegetables (14%). However, dietary supplements were also a major contributor to iron intake (22%), as well as to selenium, zinc, calcium, vitamin D, and vitamin B-12 intake (12). Both male and female vegans showed a statistically significant, higher intake of vegetables compared with omnivores. This result is similar to the findings of a study on 14- to 19-year-old Canadian adolescents in which 78 lacto-ovo-vegetarians had a higher intake of vegetables than 29 omnivores (7). In the present study, there was no significant difference in fruit and berry consumption among vegans compared with omnivores. This was also shown by Donovan and Gibson, but does not verify results of an American study of vegetarians aged 12 to 20 years (7-9), which showed that vegetarians were twice as likely to consume fruits (excluding juice). In this study, the vegans tended to consume the same types of vegetables and fruits as the omnivores; however, the vegans consumed a larger number of different fruits and vegetables than the omnivores. CONCLUSIONS The young Swedish vegans in the present study did not exclude meat and animal products without replacing them with nutritious alternatives. Rather, they had different sources of nutrients than the young omnivores, such as dietary supplements, vegetables, legumes, nuts, and seeds. For vegans, as well as omnivores, there may be very different food patterns. However, if the diet is well planned, both a vegan diet supplemented with vitamin B-12 and an omnivorous diet can offer an adequate nutritional intake. Meeting energy needs and limiting the intake of nutrient-poor foods are important considerations in the planning of a vegan diet. Also, a dietary supplement of vitamin B-12 is recommended and one needs to ensure that intake of iron, calcium, zinc, and selenium is sufficient. When planning menus for young vegetarians it is also important to consider that adolescents often consume a lot of food as snacks and meals away from home. Portable snacks (eg, dried and fresh fruits, nuts and almonds, hummus on pita bread, and juice) can make it easier for vegetarian adolescents to have access to nutritious food sources. The authors would like to thank all the adolescents who participated. The Faculty of Social Sciences at Umeå University and the Swedish Foundation for Healthcare Science and Allergy Research supported the present study. References 1. Larsson C, Johansson G. Prevalence of vegetarians in Swedish secondary schools. Scand J Nutr. 1997;41: 117-120. 2. ADA Reports. Position paper of the American Dietetic Association and Dietitians of Canada: Vegetarian diets. J. Am Diet Assoc. 2003;103:748-765. 3. Larsson C, Johansson G. Dietary intake and nutritional status of young vegans and omnivores in Sweden. Am J Clin Nutr. 2002:76:100-106. 4. Larsson C, Westerterp K, Johansson G. Validity of reported energy expenditure and energy and protein intakes of Swedish vegan and omnivore adolescents. Am J Clin Nutr. 2002;75:268-274. 5. Håglin L, Hagman U, Nilsson M. Evaluation of the meal model “Matmallen” a means of estimating consumed amounts of food. Scand J Nutr. 1995;39:79-83. 6. Becker W, Hagman U. In Swedish: Mer frukt och grönt bra för hälsan (More fruits and vegetables is good for the health). Vår Föda. 1999;6:24-28. 7. Donovan UM, Gibson RS. Dietary intakes of adolescent females consuming vegetarian, semi-vegetarian, and omnivorous diets. J Adolesc Health. 1996;18:292-300. 8. Neumark-Sztainer D, Story M, Resnich M, Blum R. Adolescent vegetarians. Arch Pediatr Adolesc Med. 1997;151:833-838. 9. Perry CL, McGuire MT, Neumark-Sztainer D, Story M. Adolescent vegetarians. How well do their dietary patterns meet the Healthy People 2010 objectives? Arch Pediatr Adolesc Med. 2002;156:431-437. 10. Waldmann A, Koschizke JW, Leitzmann C, Hahn A. Dietary intakes and lifestyle factors of a vegan population in Germany: Results from the German Vegan Study. Eur J Clin Nutr. 2003;57:947-955. 11. White R, Frank E. Health effects and prevalence of vegetarianism. West J Med. 1994;160:465-471. 12. Larsson C. Young vegetarians and omnivores—Dietary habits and other health-related aspects. Doctoral thesis, Department of Food and Nutrition, Umeå University, Sweden, 2001. Available at: http://www.divaportal.org/umu/theses/abstract.xsql?dbid⫽5. Accessed July 27, 2005. September 2005 ● Journal of the AMERICAN DIETETIC ASSOCIATION 1441