Nuevo estudio de la Asociación Americana de Dietética

Se ha publicado un nuevo estudio de la Asociación Americana de Dietética, en el que se vuelve a confirmar que las dietas veganas bien planificadas son saludables y nutricionalmente adecuadas en cualquier momento de la vida, y también para atletas.

http://www.vrg.org/nutrition/2009_AD...tion_paper.pdf

El estudio incluye referencias a otros estudios recientes. Por eso sería conveniente que, a la hora de citar un estudio de la ADA, citemos este.

La referencia es:

Craig WJ, Mangels AR. Position of the American Dietetic Association: Vegetarian Diets. J Am Diet Assoc. 2009 Jul; 109(7):1266-1282.

Estos son los documentos que a veces hecho en falta tener a mano. A ver si me lo leo...

estaria bien que alguien lo tradujera, aunque solo fuera las partes más destacadas :rolleyes:

tremendo... ahora mismo me lo empapo. Muchas gracias Dani.

Buenas, propongo que, al menos, la gente del foro que sepa y pueda, nos traduzca para todos la sección de la posición de la ADA sobre los nutrientes considerados "de riesgo" en una dieta veg-etari-ana.
Copio y pego, al menos ésto, estaria muy muy bien que entre quienes controláis lo tradujerais.

MIL GRACIAS
* En el PDF de la ADA anterior, quienes lo tradujeron no tradujeron las notas a pie de página y son muy importantes, tenedlo en cuenta.



n-3 Fatty Acids

Whereas vegetarian diets are generally rich in n-6 fatty acids, they may be marginal in n-3 fatty acids. Diets that do not include fish, eggs, or generous amounts of algae generally are low in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), fatty acids important for cardiovascular health as well as eye and brain development. The bioconversion of#-linolenic acid (ALA), a plant-based n-3 fatty acid, to EPA is generally less than 10% in humans; conversion of ALA to DHA is substantially less (14).
Vegetarians, and particularly vegans,tend to have lower blood levels of EPA and DHA than nonvegetarians (15).DHA supplements derived from microalgae are well absorbed and positively influence blood levels of DHA, and also EPA through retroconversion(16). Soy milk and breakfast bars, fortified with DHA, are now available in the marketplace.
The Dietary Reference Intakes recommend intakes of 1.6 and 1.1 g ALA per day, for men and women, respectively(17). These recommendations may not be optimal for vegetarians who consume little if any DHA and EPA (17) and thus may need additional ALA for conversion to DHA and EPA. Conversion rates for ALA tend to improve when dietary n-6 levels are not high or excessive (14). Vegetarians should include good sources of ALA in their diet, such as flaxseed, walnuts, canola oil, and soy. Those with increased requirements of n-3 fatty acids, such as pregnant and lactating women, may benefit from DHA-rich microalgae (18).

Iron

The iron in plant foods is nonheme iron, which is sensitive to both inhibitors and enhancers of iron absorption. Inhibitors of iron absorption include phytates, calcium, and the polyphenolics in tea, coffee, herb teas, and cocoa.
Fiber only slightly inhibits iron absorption (19). Some food preparation techniques such as soaking and sprouting beans, grains, and seeds, and the leavening of bread, can diminish phytate levels (20) and thereby enhance iron absorption (21,22). Other fermentation processes, such as those used to make miso and tempeh, may also improve iron bioavailability (23).
Vitamin C and other organic acids found in fruits and vegetables can substantially enhance iron absorption and reduce the inhibitory effects of phytate and thereby improve iron status (24,25). Because of lower bioavailability of iron from a vegetarian diet, the recommended iron intakes
for vegetarians are 1.8 times those of nonvegetarians (26).
Whereas many studies of iron absorption have been short term, there is evidence that adaptation to low intakes takes place over the long term, and involves both increased absorption and decreased losses (27,28). Incidence of iron-deficiency anemia among vegetarians is similar to that of nonvegetarians (12,29). Although vegetarian adults have lower iron stores than nonvegetarians, their serum ferritin levels are usually within the normal range (29,30).

Zinc

The bioavailability of zinc from vegetarian diets is lower than from nonvegetarian diets, mainly due to the higher phytic acid content of vegetarian diets (31). Thus, zinc requirements for some vegetarians whose diets consist mainly of phytate-rich unrefined grains and legumes may exceed the Recommended Dietary Allowance (26). Zinc intakes of vegetarians vary with some research showing zinc intakes near recommendations (32) and other research finding zinc intakes of vegetarians significantly below recommendations (29,33).
Overt zinc deficiency is not evident in Western vegetarians. Due to the difficulty in evaluating marginal zinc status, it is not possible to determine the possible effect of lower zinc absorption from vegetarian diets (31). Zinc sources include soy products, legumes, grains, cheese, and nuts. Food preparation techniques, such as soaking and sprouting beans, grains, and seeds as well as leavening bread, can reduce binding of zinc by phytic acid and increase zinc bioavailability (34). Organic acids, such as citric acid, can also enhance zinc absorption to some extent
(34).

Iodine

Some studies suggest that vegans who do not consume key sources of iodine, such as iodized salt or sea vegetables, may be at risk for iodine deficiency, because plant-based diets are typically low in iodine (12,35). Sea salt and kosher salt are generally not iodized nor are salty seasonings such
as tamari. Iodine intake from sea vegetables should be monitored because the iodine content of sea vegetables varies widely and some contain substantial amounts of iodine (36).
Foods such as soybeans, cruciferous vegetables, and sweet potatoes contain natural goitrogens. These foods have not been associated with thyroid insufficiency in healthy people provided iodine intake is adequate (37).

Calcium
Calcium intakes of lacto-ovo-vegetarians are similar to, or higher than, those of nonvegetarians (12), whereas intakes of vegans tend to be lower than both groups and may fall below recommended intakes (12). In the Oxford component of the European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford) study, the risk of bone fracture was similar for lacto-ovo-vegetarians and meat eaters, whereas vegans had a 30% higher risk of fracture possibly due to their considerably lower mean calcium intake (38). Diets rich in meat, fish, dairy products, nuts, and grains produce a high renal acid load, mainly due to sulfate and phosphate residues. Calcium resorption from bone helps to buffer this acid load, resulting in increased urinary losses of calcium. A high sodium intake can also promote urinary calcium losses.
On the other hand, fruits and vegetables rich in potassium and magnesium produce a high renal alkaline load which slows bone calcium resorption,and decreases calcium losses in the urine. In addition, some studies show that the ratio of dietary calcium to protein is a better predictor of bone
health than calcium intake alone.
Typically, this ratio is high in lactoovo-vegetarian diets and favors bone health, whereas vegans have a ratio of calcium to protein that is similar to or lower than that of nonvegetarians(39). Many vegans may find it is easier to meet their calcium needs if calcium-fortified foods or dietary supplements are utilized (39).
Low-oxalate greens (eg, bok choy,broccoli, Chinese cabbage, collards, and kale) and fruit juices fortified with calcium citrate malate are good sources of highly bioavailable calcium(50% to 60% and 40% to 50%, respectively),while calcium-set tofu, and cow’s milk have good bioavailability
of calcium (about 30% to 35%), and sesame seeds, almonds, and dried beans have a lower bioavailability (21% to 27%) (39). The bioavailability of calcium from soy milk fortified with calcium carbonate is equivalent to cow’s milk although limited research has shown that calcium availability is substantially less when tricalcium phosphate is used to fortify the soy
beverage (40). Fortified foods such as fruit juices, soy milk, and rice milk, and breakfast cereals can contribute significant amounts of dietary calcium for the vegan (41). Oxalates in some foods, such as spinach and Swiss chard, greatly reduce calcium absorption, making these vegetables
a poor source of usable calcium. Foods rich in phytate may also inhibit calcium absorption.

Vitamin D

Vitamin D has long been known to play a role in bone health. Vitamin D status depends on sunlight exposure and intake of vitamin D–fortified foods or supplements. The extent of cutaneous vitamin D production following sunlight exposure is highly variable and is dependent on a number
of factors, including the time of day, season, latitude, skin pigmentation, sunscreen use, and age. Low vitamin D intakes (42), low serum 25- hydroxyvitamin D levels (12), and reduced bone mass (43) have been reported in some vegan and macrobiotic groups who did not use vitamin D
supplements or fortified foods. Foods that are fortified with vitamin D include cow’s milk, some brands of soy milk, rice milk, and orange juice, and some breakfast cereals and margarines. Both vitamin D-2 and vitamin D-3 are used in supplements and to fortify foods. Vitamin
D-3 (cholecalciferol) is of animal origin and is obtained through the ultraviolet irradiation of 7-dehydrocholesterol from lanolin. Vitamin D-2 (ergocalciferol) is produced from the ultraviolet irradiation of ergosterol from yeast and is acceptable to vegans.
Although some research suggests that vitamin D-2 is less effective than vitamin D-3 in maintaining serum 25-hydroxyvitamin D levels (44) other studies find that vitamin D-2 and vitamin D-3 are equally effective (45). If sun exposure and intake of fortified foods are insufficient to meet
needs, vitamin D supplements are recommended.

Vitamin B-12

The vitamin B-12 status of some vegetarians is less than adequate due to not regularly consuming reliable sources of vitamin B-12 (12,46,47). Lacto-ovo-vegetarians can obtain adequate vitamin B-12 from dairy foods, eggs, or other reliable vitamin B-12 sources (fortified foods and supplements),
if regularly consumed. For vegans, vitamin B-12 must be obtained from regular use of vitamin B-12-fortified foods, such as fortified soy and rice beverages, some breakfast cereals and meat analogs, or Red Star Vegetarian Support Formula nutritional yeast; otherwise a daily vitamin
B-12 supplement is needed. No unfortified plant food contains any significant amount of active vitamin B-12. Fermented soy products cannot be considered a reliable source of active B-12 (12,46).
Vegetarian diets are typically rich in folacin, which may mask the hematological symptoms of vitamin B-12 deficiency, so that vitamin B-12 deficiency may go undetected until after neurological signs and symptoms may be manifest (47). Vitamin B-12 status is best determined by measuring
serum levels of homocysteine, methylmalonic acid, or holotranscobalamin II (48).

(Notas correspondientes)

14. Williams CM, Burdge G. Long-chain n-3PUFA: plant v. marine sources. Proc Nutr Soc. 2006;65:42-50.
15. Rosell MS, Lloyd-Wright Zechariah, Appleby PN, Sanders TA, Allen NE, Key TJ. Longchain
n-3 polyunsatuurated fatty acids in plasma in British meat-eating, vegetarian, and vegan men. Am J Clin Nutr. 2005;82:327-334.
16. Conquer JA, Holub BJ. Supplementation with an algae source of docosahexaenoic
acid increases (n-3) fatty acid status and alters selected risk factors for heart disease in vegetarian subjects. J Nutr. 1996;126: 3032-3039.
17. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Energy,
Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington,
DC: National Academies Press; 2002.
18. Geppert J, Kraft V, Demmelmair H, Koletzko B. Docosahexaenoic acid supplementation
in vegetarians effectively increases omega-3 index: a randomized trial. Lipids. 2005;40:807-814.
19. Coudray C, Bellanger J, Castiglia-Delavaud C, Remesy C, Vermorel M, Rayssignuier Y.
Effect of soluble or partly soluble dietary fibres supplementation on absorption and balance
of calcium, magnesium, iron and zinc in healthy young men. Eur J Clin Nutr. 1997; 51:375-380.
20. Harland BF, Morris E R. Phytate a good or bad food component. Nutr Res. 1995;15:733- 754.
21. Sandberg AS, Brune M, Carlsson NG, Hallberg L, Skoglund E, Rossander-Hulthen L. Inositol phosphates with different numbers of phosphate groups influence iron absorption in humans. Am J Clin Nutr. 1999;70: 240-246.
22. Manary MJ, Krebs NF, Gibson RS, Broadhead RL, Hambidge KM. Communitybased
dietary phytate reduction and its effect on iron status in Malawian children. Ann Trop Paediatr. 2002;22:133-136.
23. Macfarlane BJ, van der Riet WB, Bothwell TH, Baynes RD, Siegenberg D, Schmidt U,
Tol A, Taylor JRN, Mayet F. Effect of traditional Oriental soy products on iron absorption. Am J Clin Nutr. 1990;51:873-880.
24. Hallberg L, Hulthen L. Prediction of dietary iron absorption: an algorithm for calculating
absorption and bioavailability of dietary iron. Am J Clin Nutr. 2000;71: 1147-1160.
25. Fleming DJ, Jacques PF, Dallal GE, Tucker KL, Wilson PW, Wood RJ. Dietary determinants of iron stores in a free-living elderly population: The Framingham Heart Study. Am J Clin Nutr. 1998;67:722-733.
26. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Vitamin
A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academies Press; 2001.
27. Hunt JR, Roughead ZK. Nonheme-iron absorption, fecal ferritin excretion, and blood
indexes of iron status in women consuming controlled lactoovovegetarian diets for 8 wk. Am J Clin Nutr. 1999;69:944-952.
28. Hunt JR, Roughead ZK. Adaptation of iron absorption in men consuming diets with
high or low iron bioavailability. Am J Clin Nutr. 2000;71:94-102.
29. Ball MJ, Bartlett MA. Dietary intake and iron status of Australian vegetarian women. Am J Clin Nutr. 1999;70:353-358.
30. Alexander D, Ball MJ, Mann J. Nutrient intake and haematological status of vegetarians
and age-sex matched omnivores. Eur J Clin Nutr. 1994;48:538-546.
31. Hunt JR. Bioavailability of iron, zinc, and other trace minerals from vegetarian diets. Am J Clin Nutr. 2003;78(suppl):633S-639S.
32. Davey GK, Spencer EA, Appleby PN, Allen NE, Knox KH, Key TJ. EPIC – Oxford: Lifestyle characteristics and nutrient intakes in a cohort of 33,883 meat-eaters and 31,546 non meat-eaters in the UK. Public Health Nutr. 2003;6:259-268.
33. Janelle KC, Barr SI. Nutrient intakes and eating behavior scores of vegetarian and
nonvegetarian women. J Am Diet Assoc. 1995;95:180-189.
34. Lonnerdal B. Dietary factors influencing zinc absorption. J Nutr. 2000;130(suppl): 1378S-1383S.
35. Krajcovicova M, Buckova K, Klimes I, Sebokova E. Iodine deficiency in vegetarians and vegans. Ann Nutr Metab. 2003;47:183- 185. 36. Teas J, Pino S, Critchley A, Braverman LE.
Variability of iodine content in common commercially available edible seaweeds. Thyroid. 2004;14:836-841.
37. Messina M, Redmond G. Effects of soy protein and soybean isoflavones on thyroid
function in healthy adults and hypothyroid patients: a review of the relevant literature. Thyroid. 2006;16:249-258.
38. Appleby P, Roddam A, Allen N, Key T. Comparative fracture in vegetarians and
nonvegetarians in EPIC-Oxford. Eur J Clin Nutr. 2007;61:1400-1406.
39. Weaver C, Proulx W, Heaney R. Choices for achieving adequate dietary calcium with a
vegetarian diet. Am J Clin Nutr. 1999;70(suppl):543S-548S.
40. Zhao Y, Martin BR, Weaver CM. Calcium bioavailability of calcium carbonate fortified
soymilk is equivalent to cow’s milk in young women. J Nutr. 2005;135:2379-2382.
41. Messina V, Melina V, Mangels AR. A new food guide for North American vegetarians.
J Am Diet Assoc. 2003;103:771-775.
42. Dunn-Emke SR, Weidner G, Pettenall EB, Marlin RO, Chi C, Ornish DM. Nutrient
adequacy of a very low-fat vegan diet. J Am Diet Assoc. 2005;105:1442-1446.
43. Parsons TJ, van Dusseldorp M, van der Vliet M, van de Werken K, Schaafsma G,
van Staveren WA. Reduced bone mass in Dutch adolescents fed a macrobiotic diet in early life. J Bone Miner Res. 1997;12:1486- 1494.
44. Armas LAG, Hollis BW, Heaney RP. Vitamin D2 is much less effective than vitamin D3 in humans. J Clin Endocrinol Metab. 2004;89:5387-5391.
45. Holick MF, Biancuzzo RM, Chen TC, Klein EK, Young A, Bibuld D, Reitz R, Salameh
W, Ameri A, Tannenbaum AD. Vitamin D2 is as effective as vitamin D3 in maintaining
circulating concentrations of 25-hydroxyvitamin D. J Clin Endocrinol Metab. 2008;93:677-681.
46. Donaldson MS. Metabolic vitamin B12 status on a mostly raw vegan diet with follow-
up using tablets, nutritional yeast, or probiotic supplements. Ann Nutr Metab. 2000;44:229-234.
47. Herrmann W, Schorr H, Purschwitz K, Rassoul F, Richter V. Total homocysteine,
vitamin B12, and total antioxidant status in vegetarians. Clin Chem. 2001;47:1094-1101.
48. Herrmann W, Geisel J. Vegetarian lifestyle and monitoring of vitamin B-12 status.
Clin Chim Acta. 2002;326:47-59.

No había visto este tema, asi que abrí otro...

Bueno, aquí lo dejo también:

Cita:

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Pues nada, aquí os dejo el informe de la ADA (American Dietetic Association - Asociación Americana de Dietética) del 2009 posicionándose a favor de las dietas vegetarianas y veganas, traducido al castellano.

veganismo_ada_09.pdf

Espero que os sea útil.
Un saludo.

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Cita:

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Iniciado por SkyPlooM

No había visto este tema, asi que abrí otro...

Bueno, aquí lo dejo también:

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pero tu aporte es en castellano así q suma un factor más y bien importante

gracias

Genial, mil gracias....a leer.

Yujuu gracias!!!

Me lo leí el mes pasado, poco a poco... Está bastante bien tenerlo de apoyo.