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'''Vegetarian nutrition''' is the set of health-related challenges and advantages of [[Vegetarianism|vegetarian]] [[diet (nutrition)|diets]]. |
'''Vegetarian nutrition''' is the set of health-related challenges and advantages of [[Vegetarianism|vegetarian]] [[diet (nutrition)|diets]]. |
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Appropriately planned vegetarian diets are healthful and [[nutrition]]ally adequate for all stages of the human life cycle, including during pregnancy, lactation, infancy, childhood, and adolescence.<ref name="ada">{{cite journal |doi=10.1053/jada.2003.50142|pmid=12778049|title=Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets|journal=Journal of the American Dietetic Association|volume=103|issue=6|pages=748–65|year=2003|last1=American Dietetic|first1=Association|last2=Dietitians Of|first2=Canada}}</ref> However, vegetarian diets deficient in [[Vitamin B12|vitamin B<sub>12</sub>]] or calories may compromise children's health and development.<ref name="ada"/><ref>{{cite journal|last=Black|first=Maureen|title=Effects of vitamin B12 and folate deficiency on brain development in children|journal= Food and Nutrition Bulletin|pmc=3137939|pmid=18709887|volume=29|issue=2 Suppl|date=June 2008|pages=S126–31|doi=10.1177/15648265080292S117}}</ref> The UK [[National Health Service]] recommends that vegetarian diets should also follow the general recommendations for healthy diets, such as low fat, salt and sugar intakes and [[5 A Day|5 fruits or vegetables a day]].<ref>{{Cite web|date=2018-04-27|title=The vegetarian diet|url=https://www.nhs.uk/live-well/eat-well/the-vegetarian-diet/|access-date=2021-05-22|website=nhs.uk|language=en}}</ref> [[Qatar]]'s public health ministry states, "One cannot be a healthy vegetarian by going to a fast food restaurant and ordering french fries and soda!".<ref>{{Cite web|date=2015|title=Qatar Dietary Guidelines|url=https://www.moph.gov.qa/_layouts/download.aspx?SourceUrl=/Admin/Lists/PublicationsAttachments/Attachments/68/MOPH_DIETARY_BOOKLET_ENG.PDF |
Appropriately planned vegetarian diets are healthful and [[nutrition]]ally adequate for all stages of the human life cycle, including during pregnancy, lactation, infancy, childhood, and adolescence.<ref name="ada">{{cite journal |doi=10.1053/jada.2003.50142|pmid=12778049|title=Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets|journal=Journal of the American Dietetic Association|volume=103|issue=6|pages=748–65|year=2003|last1=American Dietetic|first1=Association|last2=Dietitians Of|first2=Canada}}</ref> However, vegetarian diets deficient in [[Vitamin B12|vitamin B<sub>12</sub>]] or calories may compromise children's health and development.<ref name="ada"/><ref>{{cite journal|last=Black|first=Maureen|title=Effects of vitamin B12 and folate deficiency on brain development in children|journal= Food and Nutrition Bulletin|pmc=3137939|pmid=18709887|volume=29|issue=2 Suppl|date=June 2008|pages=S126–31|doi=10.1177/15648265080292S117}}</ref> The UK [[National Health Service]] recommends that vegetarian diets should also follow the general recommendations for healthy diets, such as low fat, salt and sugar intakes and [[5 A Day|5 fruits or vegetables a day]].<ref>{{Cite web|date=2018-04-27|title=The vegetarian diet|url=https://www.nhs.uk/live-well/eat-well/the-vegetarian-diet/|access-date=2021-05-22|website=nhs.uk|language=en}}</ref> [[Qatar]]'s public health ministry states, "One cannot be a healthy vegetarian by going to a fast food restaurant and ordering french fries and soda!".<ref>{{Cite web|date=2015|title=Qatar Dietary Guidelines|url=https://www.moph.gov.qa/_layouts/download.aspx?SourceUrl=/Admin/Lists/PublicationsAttachments/Attachments/68/MOPH_DIETARY_BOOKLET_ENG.PDF|website=Qatar MOPH|page=18}}</ref> |
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Vegetarian diets tend to be rich in [[carbohydrates]], [[omega-6 fatty acids]], [[dietary fibre]], [[carotenoids]], [[folic acid]], [[vitamin C]], [[vitamin E]], [[potassium]] and [[magnesium]]. They are possibly low in [[saturated fat]], [[cholesterol]], and animal protein. |
Vegetarian diets tend to be rich in [[carbohydrates]], [[omega-6 fatty acids]], [[dietary fibre]], [[carotenoids]], [[folic acid]], [[vitamin C]], [[vitamin E]], [[potassium]] and [[magnesium]]. They are possibly low in [[saturated fat]], [[cholesterol]], and animal protein. |
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[[File:Red_Beans_and_Rice.jpg|thumb|Red beans and rice]] |
[[File:Red_Beans_and_Rice.jpg|thumb|Red beans and rice]] |
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Despite the long-standing, widespread belief that vegetarians must consume grains and beans within a short time to make a ''[[complete protein]]'' that contains all 9 [[essential amino acid]]s that must be supplied through diet, this has never been substantiated by research. The protein-combining theory was brought to popular attention after being promoted in [[Frances Moore Lappé]]'s 1971 bestselling book ''[[Diet for a Small Planet]]''. In later editions of the book, starting in 1981, Lappé withdrew her contention that ''protein combining'' is necessary.<ref>{{cite book |author-link=Frances Moore Lappé |last=Lappé |first=Frances Moore |year=1981 |title=Diet for a Small Planet |page=162 |isbn=978-0-345-32120-6|title-link=Diet for a Small Planet }}</ref> |
Despite the long-standing, widespread belief that vegetarians must consume grains and beans within a short time to make a ''[[complete protein]]'' that contains all 9 [[essential amino acid]]s that must be supplied through diet, this has never been substantiated by research. The protein-combining theory was brought to popular attention after being promoted in [[Frances Moore Lappé]]'s 1971 bestselling book ''[[Diet for a Small Planet]]''. In later editions of the book, starting in 1981, Lappé withdrew her contention that ''protein combining'' is necessary.<ref>{{cite book |author-link=Frances Moore Lappé |last=Lappé |first=Frances Moore |year=1981 |title=Diet for a Small Planet |page=162 |isbn=978-0-345-32120-6|title-link=Diet for a Small Planet |publisher=Ballantine Books }}</ref> |
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Plant foods rich in protein include [[soy bean]]s and soy products such as [[tofu]], [[veggie burger]]s, and [[soy milk]]; other [[legume]]s; [[nut (fruit)|nuts]] and [[seed]]s; and [[cereal|cereal grains]].<ref>{{cite book |first1=Winston J. |last1=Craig |first2=Laura |last2=Pinyan |chapter=Nutrients of Concern in Vegetarian Diets |pages=299–332 |chapter-url=https://books.google.com/books?id=f_XKBQAAQBAJ&pg=PA299 |editor1-first=Joan |editor1-last=Sabate |year=2001 |title=Vegetarian Nutrition |publisher=CRC Press |isbn=978-1-4200-3683-1}}</ref> |
Plant foods rich in protein include [[soy bean]]s and soy products such as [[tofu]], [[veggie burger]]s, and [[soy milk]]; other [[legume]]s; [[nut (fruit)|nuts]] and [[seed]]s; and [[cereal|cereal grains]].<ref>{{cite book |first1=Winston J. |last1=Craig |first2=Laura |last2=Pinyan |chapter=Nutrients of Concern in Vegetarian Diets |pages=299–332 |chapter-url=https://books.google.com/books?id=f_XKBQAAQBAJ&pg=PA299 |editor1-first=Joan |editor1-last=Sabate |year=2001 |title=Vegetarian Nutrition |publisher=CRC Press |isbn=978-1-4200-3683-1}}</ref> |
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[[File:Huehnereier 2989.jpg|right|thumb|[[Egg (food)|Eggs]] are a source of vitamin B<sub>12</sub> for vegetarians.]] |
[[File:Huehnereier 2989.jpg|right|thumb|[[Egg (food)|Eggs]] are a source of vitamin B<sub>12</sub> for vegetarians.]] |
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Generally, humans need 2.4 to 3 [[microgram]]s of vitamin B<sub>12</sub> each day.<ref name=ODS>{{cite web|title=Dietary Supplement Fact Sheet: Vitamin B12|url=http://ods.od.nih.gov/factsheets/vitaminb12/|work=USA.gov|publisher=Office of dietary supplements|access-date=14 March 2012}}</ref> There are cases to suggest that vegetarians and vegans who are not taking vitamin B<sub>12</sub> supplements or food fortified with B<sub>12</sub> do not consume sufficient servings of B<sub>12</sub> and have abnormally low blood concentrations of vitamin B<sub>12</sub>.<ref>{{cite journal |
Generally, humans need 2.4 to 3 [[microgram]]s of vitamin B<sub>12</sub> each day.<ref name=ODS>{{cite web|title=Dietary Supplement Fact Sheet: Vitamin B12|url=http://ods.od.nih.gov/factsheets/vitaminb12/|work=USA.gov|publisher=Office of dietary supplements|access-date=14 March 2012}}</ref> There are cases to suggest that vegetarians and vegans who are not taking vitamin B<sub>12</sub> supplements or food fortified with B<sub>12</sub> do not consume sufficient servings of B<sub>12</sub> and have abnormally low blood concentrations of vitamin B<sub>12</sub>.<ref>{{cite journal|author=Pawlak, Roman; Parrott, Scott James; Raj, Sudha; Cullum-Dugan, Diana; Lucus, Debbie|year=2013|title=How prevalent is vitamin B12 deficiency among vegetarians?|volume=71|issue=2|pages=110–117|journal=Nutrition Reviews|doi=10.1111/nure.12001|pmid=23356638 |doi-access=free}}</ref> This is because, unless fortified, plant foods do not contain reliable amounts of active [[Vitamin B12|vitamin B<sub>12</sub>]].<ref name="ada"/> |
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It is essential, therefore, that vegetarians consume adequate amounts of dietary supplements or foods that have been fortified with B<sub>12</sub>, such as vegetable [[stock (food)|stock]], [[veggie burger]] mixes, [[textured vegetable protein]], [[soy milk]]s, vegetable and sunflower [[margarine]]s, and [[breakfast cereal]]s.<ref name=b12>The Vegetarian Society. ''[http://www.vegsoc.org/info/b12.html Information Sheet: Vitamin B{{ssub|12}}] {{Webarchive|url=https://web.archive.org/web/20080822090753/http://www.vegsoc.org/info/b12.html |date=22 August 2008 }}''. Retrieved 26 April 2007.</ref> B<sub>12</sub> used in these foods or supplements is typically grown from vegan sources (such as [[bacteria]]). Soybeans and barley seeds from plants grown in soils amended either with cow dung (which is rich in B<sub>12</sub>) or with pure B<sub>12</sub> had a higher B<sub>12</sub> content than those grown without this supplementation.<ref>{{cite journal |doi=10.1007/BF00007957|title=Enrichment of some B-vitamins in plants with application of organic fertilizers|journal=Plant and Soil|volume=167|issue=2|pages=305–311|year=1994|last1=Mozafar|first1=A.|s2cid=44300067}}</ref> |
It is essential, therefore, that vegetarians consume adequate amounts of dietary supplements or foods that have been fortified with B<sub>12</sub>, such as vegetable [[stock (food)|stock]], [[veggie burger]] mixes, [[textured vegetable protein]], [[soy milk]]s, vegetable and sunflower [[margarine]]s, and [[breakfast cereal]]s.<ref name=b12>The Vegetarian Society. ''[http://www.vegsoc.org/info/b12.html Information Sheet: Vitamin B{{ssub|12}}] {{Webarchive|url=https://web.archive.org/web/20080822090753/http://www.vegsoc.org/info/b12.html |date=22 August 2008 }}''. Retrieved 26 April 2007.</ref> B<sub>12</sub> used in these foods or supplements is typically grown from vegan sources (such as [[bacteria]]). Soybeans and barley seeds from plants grown in soils amended either with cow dung (which is rich in B<sub>12</sub>) or with pure B<sub>12</sub> had a higher B<sub>12</sub> content than those grown without this supplementation.<ref>{{cite journal |doi=10.1007/BF00007957|title=Enrichment of some B-vitamins in plants with application of organic fertilizers|journal=Plant and Soil|volume=167|issue=2|pages=305–311|year=1994|last1=Mozafar|first1=A.|s2cid=44300067}}</ref> |
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Vegetarian diets can be low in [[omega-3 fatty acid]]s (O3FAs). Major vegetarian O3FA sources include [[algae]], [[hemp|hempseeds and hempseed oil]], [[walnut]]s, [[flax|flaxseeds and flaxseed oil]], [[olive oil]], [[canola oil]], [[avocado]], and [[salvia hispanica|chia seeds]].{{Citation needed|date=May 2021}} |
Vegetarian diets can be low in [[omega-3 fatty acid]]s (O3FAs). Major vegetarian O3FA sources include [[algae]], [[hemp|hempseeds and hempseed oil]], [[walnut]]s, [[flax|flaxseeds and flaxseed oil]], [[olive oil]], [[canola oil]], [[avocado]], and [[salvia hispanica|chia seeds]].{{Citation needed|date=May 2021}} |
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A potential problem is that vegetarian diets lacking eggs or generous amounts of [[edible seaweed]] generally lack a direct source of [[Fatty_acid#Length_of_fatty_acids|long-chain]] O3FAs such as [[ |
A potential problem is that vegetarian diets lacking eggs or generous amounts of [[edible seaweed]] generally lack a direct source of [[Fatty_acid#Length_of_fatty_acids|long-chain]] O3FAs such as [[docosahexaenoic acid]] (DHA) and [[eicosapentaenoic acid]] (EPA). Vegetarian diets may also have a high ratio of [[omega-6 fatty acids]] to O3FAs, which inhibits the conversion of short-chain fatty acids such as [[alpha-Linolenic acid]] (ALA), which is found in most vegetarian O3FA sources, to EPA and DHA.<ref name="ada"/> Short-term supplemental ALA has been shown to increase EPA levels but not DHA levels, suggesting poor conversion of the intermediary EPA to DHA.<ref name="dha">{{cite journal |doi=10.1016/j.plefa.2009.05.013|title=DHA status of vegetarians|journal=Prostaglandins, Leukotrienes and Essential Fatty Acids|volume=81|issue=2–3|pages=137–141|year=2009|last1=Sanders|first1=Thomas A.B.|pmid=19500961}}</ref> To remedy this, DHA and EPA supplements derived from microalgae are available.<ref name="ada"/><ref name="Lane 2022">{{cite journal|author=Lane KE, Wilson M, Hellon TG, Davies IG.|year=2022|title=Bioavailability and conversion of plant based sources of omega-3 fatty acids – a scoping review to update supplementation options for vegetarians and vegans|journal=Critical Reviews in Food Science and Nutrition|volume=62|issue=18|pages=4982–4997|doi=10.1080/10408398.2021.1880364|pmid=33576691|s2cid=231899843 |doi-access=free}}</ref> |
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A 2022 review found that [[Seaweed oil|microalgal oil]] supplementation is consistent in increasing DHA and EPA levels, whilst high dose [[Linseed oil|flaxseed]] or [[Echium|echium seed]] oil supplements provide no increase despite significant increases in ALA levels.<ref name="Lane 2022"/> |
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[[Image:English Walnuts.jpg|thumb|right|[[Walnuts]] are a source of [[omega-3 fatty acid]]s.]] |
[[Image:English Walnuts.jpg|thumb|right|[[Walnuts]] are a source of [[omega-3 fatty acid]]s.]] |
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There is only weak evidence that O3FAs benefit [[cardiovascular]] health,<ref>{{cite journal |vauthors=Colussi G, Catena C, Novello M, Bertin N, Sechi LA |title=Impact of omega-3 polyunsaturated fatty acids on vascular function and blood pressure: Relevance for cardiovascular outcomes |journal=Nutr Metab Cardiovasc Dis |volume= 27|issue= 3|pages= 191–200|year=2016 |pmid=27692558 |doi=10.1016/j.numecd.2016.07.011 |type=Review}}</ref> and although O3FAs have been thought useful for helping to alleviate [[dementia]], {{asof|2016|lc=yes}} there is no good evidence for their effectiveness in this regard.<ref>{{cite journal |vauthors=Burckhardt M, Herke M, Wustmann T, Watzke S, Langer G, Fink A |title=Omega-3 fatty acids for the treatment of dementia |journal=Cochrane Database Syst Rev |volume=4 |pages=CD009002 |year=2016 |pmid=27063583 |doi=10.1002/14651858.CD009002.pub3 |type=Systematic review|pmc=7117565 }}</ref> |
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While there is little evidence of adverse health or cognitive effects caused by DHA deficiency in adult vegetarians, fetal and breast milk levels remain a concern for pregnant or lactating mothers.<ref name="dha" /> EPA and DHA supplementation has been shown to reduce blood [[platelet aggregation]] in vegetarians, but a direct link to [[cardiovascular morbidity]] and mortality, which is already lower for vegetarians, has yet to be determined {{as of|2000|lc=yes}}.<ref>{{cite journal |doi=10.1016/S0049-3848(00)00313-3 |title=Cardiovascular Risk Factors in Vegetarians: Normalization of Hyperhomocysteinemia with Vitamin B<sub>12</sub> and Reduction of Platelet Aggregation with n-3 Fatty Acids |year=2000 |last1=Mezzano |first1=Diego |last2=Kosiel |first2=Karin |last3=Martínez |first3=Carlos |last4=Cuevas |first4=Ada |last5=Panes |first5=Olga |last6=Aranda |first6=Eduardo |last7=Strobel |first7=Pablo |last8=Pérez |first8=Druso D |last9=Pereira |first9=Jaime |last10=Rozowski |first10=Jaime |last11=Leighton |first11=Federico |journal=[[Thrombosis Research]] |volume=100 |issue=3 |pages=153–60 |pmid=11108902|display-authors=9 |hdl=10533/172391 |hdl-access=free }}</ref> |
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===Calcium=== |
===Calcium=== |
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In general, lacto-ovo-vegetarians have a relatively high intake of calcium that meet or exceed calcium recommendations.<ref name="Vesanto 2016">{{cite journal | last1=Melina | first1=Vesanto | last2=Craig | first2=Winston | last3=Levin | first3=Susan | title=Position of the Academy of Nutrition and Dietetics: Vegetarian Diets | journal=Journal of the Academy of Nutrition and Dietetics | volume=116 | issue=12 | |
In general, [[Lacto-ovo vegetarianism|lacto-ovo-vegetarians]] have a relatively high intake of [[calcium]] that meet or exceed calcium recommendations.<ref name="Vesanto 2016">{{cite journal |date= 2016| last1=Melina | first1=Vesanto | last2=Craig | first2=Winston | last3=Levin | first3=Susan | title=Position of the Academy of Nutrition and Dietetics: Vegetarian Diets | journal=Journal of the Academy of Nutrition and Dietetics | volume=116 | issue=12 | pages=1970–1980 | pmid=27886704 | doi=10.1016/j.jand.2016.09.025| s2cid=4984228 | url=https://higherlogicdownload.s3.amazonaws.com/THEACADEMY/859dd171-3982-43db-8535-56c4fdc42b51/UploadedImages/VN/Documents/Position-of-the-Academy-of-Nutrition-and-Dietetics-Vegetarian-Diets.pdf}}</ref> |
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⚫ | A 2022 review found no significant difference in calcium intake between vegetarians and omnivores.<ref>{{Cite journal |last1=Bickelmann |first1=Franziska V. |last2=Leitzmann |first2=Michael F. |last3=Keller |first3=Markus |last4=Baurecht |first4=Hansjörg |last5=Jochem |first5=Carmen |date=2022-06-06 |title=Calcium intake in vegan and vegetarian diets: A systematic review and Meta-analysis |url=https://doi.org/10.1080/10408398.2022.2084027 |journal=Critical Reviews in Food Science and Nutrition |pages=1–19 |doi=10.1080/10408398.2022.2084027 |s2cid=249441078 |issn=1040-8398}}</ref> Vegetarians can obtain calcium from [[dairy product]]s, calcium-fortified [[plant milk]]s, almonds, figs, oranges, calcium-set tofu as well as low-oxalate vegetables such as bok choy, kale and turnip greens.<ref name="Vesanto 2016"/> |
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Compared with omnivores, vegetarians tend to have a lower [[Bone density|bone mineral density]] (BMD) but not a higher fracture rate.<ref>{{cite journal|author=Iguacel I, Miguel-Berges ML, Gómez-Bruton A, Moreno LA, Julián C.|year=2019|title=Veganism, vegetarianism, bone mineral density, and fracture risk: a systematic review and meta-analysis|journal=Nutr Rev|url=https://academic.oup.com/nutritionreviews/article/77/1/1/5146363|volume=77|issue=1|pages=1–18|doi=10.1093/nutrit/nuy045|pmid=30376075|doi-access=free}}</ref><ref>{{cite journal|author=Ogilvie AR, McGuire BD, Meng L, Shapses SA.|year=2022|title=Fracture Risk in Vegetarians and Vegans: the Role of Diet and Metabolic Factors|journal=Curr Osteoporos Rep|volume=20|issue=6|pages=442–452|doi=10.1007/s11914-022-00754-7|pmid=36129610|s2cid=252405392 }}</ref> |
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⚫ |
A 2022 review found no significant difference in calcium intake between vegetarians and omnivores.<ref>{{Cite journal |last1=Bickelmann |first1=Franziska V. |last2=Leitzmann |first2=Michael F. |last3=Keller |first3=Markus |last4=Baurecht |first4=Hansjörg |last5=Jochem |first5=Carmen |date=2022-06-06 |title=Calcium intake in vegan and vegetarian diets: A systematic review and Meta-analysis |url=https://doi.org/10.1080/10408398.2022.2084027 |journal=Critical Reviews in Food Science and Nutrition |pages=1–19 |doi=10.1080/10408398.2022.2084027 |s2cid=249441078 |issn=1040-8398}}</ref> Vegetarians can obtain calcium from [[dairy product]]s, calcium-fortified [[plant milk]]s, almonds, figs, oranges, calcium-set tofu as well as low-oxalate vegetables such as bok |
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=== Iron === |
=== Iron === |
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{{main|Iron deficiency}} |
{{main|Iron deficiency}} |
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Vegetarians are more likely to have lower iron stores compared with non-vegetarians and have a higher risk of iron deficiency anemia.<ref>{{cite journal|author=Pawlak R, Berger J, Hines I.|year=2016|title=Iron Status of Vegetarian Adults: A Review of Literature|journal=Am J Lifestyle Med|url=|volume=12|issue=6|pages= |
Vegetarians are more likely to have lower iron stores compared with non-vegetarians and have a higher risk of iron deficiency anemia.<ref>{{cite journal|author=Pawlak R, Berger J, Hines I.|year=2016|title=Iron Status of Vegetarian Adults: A Review of Literature|journal=Am J Lifestyle Med|url=|volume=12|issue=6|pages=486–498|doi=10.1177/1559827616682933|pmid=30783404|pmc=6367879 }}</ref><ref>{{cite journal|author=Haider LM, Schwingshackl L, Hoffmann G, Ekmekcioglu C.|year=2018|title=The effect of vegetarian diets on iron status in adults: A systematic review and meta-analysis|journal=Crit Rev Food Sci Nutr|volume=58|issue=8|pages=1359–1374|doi=10.1080/10408398.2016.1259210|pmid=27880062|s2cid=25792199 }}</ref><ref name="Oussalah 2020">{{cite journal|author=Oussalah A, Levy J, Berthezène C, Alpers DH, Guéant JL.|year=2020|title=Health outcomes associated with vegetarian diets: An umbrella review of systematic reviews and meta-analyses|journal=Clinical Nutrition|url=https://hal.archives-ouvertes.fr/hal-03492615/document|volume=39|issue=11|pages=3283–3307|doi=10.1016/j.clnu.2020.02.037|pmid=32204974|s2cid=213892045 |doi-access=free}}</ref> Lacto-ovo-vegetarians that overly rely on dairy consumption may lead to an elevated calcium intake which can affect iron absorption.<ref>Bray, George A; Temple, Norman J; Wilson, Ted. (2022). ''Nutrition Guide for Physicians and Related Healthcare Professions''. Springer. p. 182. {{ISBN|978-3-030-82515-7}}</ref> |
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[[Image:Tofu-beijingchina.jpg|thumb|right|upright|[[Tofu]], a soy product, can be a valuable source of not only iron, but also protein, zinc and calcium for vegetarians.]] |
[[Image:Tofu-beijingchina.jpg|thumb|right|upright|[[Tofu]], a soy product, can be a valuable source of not only iron, but also protein, zinc and calcium for vegetarians.]] |
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The recommended iron intake for vegetarians is 180% that of nonvegetarians |
The recommended iron intake for vegetarians is 180% that of nonvegetarians due to the bioavailability of non-heme iron.<ref name="Vesanto 2016"/> Although a lower ''percentage'' of non-heme iron is absorbed by the body, greater total ''amounts'' of non-heme iron are concentrated in many non-meat sources of iron, and therefore breakfast cereals, eggs, nuts, seeds, and legumes (including soy foods, peas, beans, chickpeas, and [[lentils]]) are significant sources of iron, and a well-planned vegetarian diet should not lead to iron deficiency.<ref name="Vesanto 2016"/><ref>[https://www.bda.uk.com/resource/iron-rich-foods-iron-deficiency.html "Iron: Food Fact Sheet"]. bda.uk.com. Retrieved 2 January 2023.</ref><ref>[https://www.healthdirect.gov.au/vegetarian-and-vegan-diets "Vegetarian and vegan diets"]. healthdirect.gov.au. Retrieved 2 January 2023.</ref> |
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Non-heme iron is more sensitive to both ''inhibitors'' and ''enhancers'' of iron absorption: [[Vitamin C]] is an iron absorption enhancer; the main inhibitors for most people are [[phytates]] (e.g. [[legume]]s and [[cereal|cereal grains]]), but other inhibitors include [[tannins]] (from [[tea]] and [[wine]]), [[calcium]], and [[polyphenol]]s.<ref name="ada"/> |
Non-heme iron is more sensitive to both ''inhibitors'' and ''enhancers'' of iron absorption: [[Vitamin C]] is an iron absorption enhancer; the main inhibitors for most people are [[phytates]] (e.g. [[legume]]s and [[cereal|cereal grains]]), but other inhibitors include [[tannins]] (from [[tea]] and [[wine]]), [[calcium]], and [[polyphenol]]s.<ref name="ada"/> |
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{{further|Zinc deficiency}} |
{{further|Zinc deficiency}} |
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A 2013 review found that zinc intake and serum zinc concentrations were significantly lower in populations that follow vegetarian diets compared with non-vegetarians.<ref>{{cite journal|author=Foster M, Chu A, Petocz P, Samman S.|year=2013|title=Effect of vegetarian diets on zinc status: a systematic review and meta-analysis of studies in humans|journal=Journal of the Science of Food and Agriculture|url=|volume=93|issue=10|pages=2362–2371|doi=10.1002/jsfa.6179|pmid=23595983}}</ref> |
A 2013 review found that zinc intake and serum zinc concentrations were significantly lower in populations that follow vegetarian diets compared with non-vegetarians.<ref>{{cite journal|author=Foster M, Chu A, Petocz P, Samman S.|year=2013|title=Effect of vegetarian diets on zinc status: a systematic review and meta-analysis of studies in humans|journal=Journal of the Science of Food and Agriculture|url=|volume=93|issue=10|pages=2362–2371|doi=10.1002/jsfa.6179|pmid=23595983|s2cid=46474144 }}</ref> |
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[[Phytate]]s in many [[whole grain]]s, and [[dietary fiber]] in many plant foods may interfere with zinc absorption, and marginal zinc intake has poorly understood effects. Vegetarians may need more than the US [[Recommended Daily Allowance]] of 15 mg of zinc each day to compensate if their diet is high in phytates.<ref name="ada"/> Major plant sources of [[zinc]] include cooked [[dried bean]]s, [[edible seaweed]], fortified breakfast cereals, soy products, nuts, peas, and seeds.<ref name="ada"/> |
[[Phytate]]s in many [[whole grain]]s, and [[dietary fiber]] in many plant foods may interfere with zinc absorption, and marginal zinc intake has poorly understood effects. Vegetarians may need more than the US [[Recommended Daily Allowance]] of 15 mg of zinc each day to compensate if their diet is high in phytates.<ref name="ada"/> Major plant sources of [[zinc]] include cooked [[dried bean]]s, [[edible seaweed]], fortified breakfast cereals, soy products, nuts, peas, and seeds.<ref name="ada"/> |
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==Health effects== |
==Health effects== |
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Evidence suggests that vegetarian diets have beneficial effects on [[blood lipids]] and that vegetarians have a reduced risk of [[cancer]], [[cardiovascular disease]], [[hypertension]] and [[Diabetes mellitus type 2|type 2 diabetes]].<ref>{{cite journal|author=Wang F, Zheng J, Yang B, Jiang J, Fu Y, Li D.|year=2015|title=Effects of Vegetarian Diets on Blood Lipids: A Systematic Review and Meta-Analysis of Randomized Controlled Trials|journal=Journal of the American Heart Association |
Evidence suggests that vegetarian diets have beneficial effects on [[blood lipids]] and that vegetarians have a reduced risk of [[cancer]], [[cardiovascular disease]], [[hypertension]] and [[Diabetes mellitus type 2|type 2 diabetes]].<ref name="Oussalah 2020"/><ref>{{cite journal|author=Wang F, Zheng J, Yang B, Jiang J, Fu Y, Li D.|year=2015|title=Effects of Vegetarian Diets on Blood Lipids: A Systematic Review and Meta-Analysis of Randomized Controlled Trials|journal=Journal of the American Heart Association|volume=4|issue=10|pages=e002408|doi=10.1161/JAHA.115.002408|pmid=26508743|pmc=4845138 }}</ref><ref>{{cite journal|author=Dybvik, J.S., Svendsen, M. & Aune, D.|year=2022|title=Vegetarian and vegan diets and the risk of cardiovascular disease, ischemic heart disease and stroke: a systematic review and meta-analysis of prospective cohort studies|journal=European Journal of Nutrition|volume=62|issue=1|pages=51–69|doi=10.1007/s00394-022-02942-8|pmid=36030329|pmc=9899747 |s2cid=251866952 }}</ref><ref>{{cite journal|author=Gibbs J, Gaskin E, Ji C, Miller MA, Cappuccio FP. |year=2021|title=The effect of plant-based dietary patterns on blood pressure: a systematic review and meta-analysis of controlled intervention trials|journal=Journal of Hypertension|url=https://warwick.ac.uk/fac/sci/med/staff/cappuccio/newpublications/j_hypert_2020_pbds_and_bp.pdf|volume=39|issue=1|pages=23–37|doi=10.1097/HJH.0000000000002604|pmid=33275398|s2cid=225483653 }}</ref> |
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==See also== |
==See also== |
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* [[Vegetarian cuisine]] |
* [[Vegetarian cuisine]] |
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* [[Vegan nutrition]] |
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* The [[China–Cornell–Oxford Project]] in the 1980s |
* The [[China–Cornell–Oxford Project]] in the 1980s |
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* [[The China Study]] done 2005 |
* [[The China Study]] done 2005 |
Vegetarian nutrition is the set of health-related challenges and advantages of vegetarian diets.
Appropriately planned vegetarian diets are healthful and nutritionally adequate for all stages of the human life cycle, including during pregnancy, lactation, infancy, childhood, and adolescence.[1] However, vegetarian diets deficient in vitamin B12 or calories may compromise children's health and development.[1][2] The UK National Health Service recommends that vegetarian diets should also follow the general recommendations for healthy diets, such as low fat, salt and sugar intakes and 5 fruits or vegetables a day.[3] Qatar's public health ministry states, "One cannot be a healthy vegetarian by going to a fast food restaurant and ordering french fries and soda!".[4]
Vegetarian diets tend to be rich in carbohydrates, omega-6 fatty acids, dietary fibre, carotenoids, folic acid, vitamin C, vitamin E, potassium and magnesium. They are possibly low in saturated fat, cholesterol, and animal protein.
Despite the long-standing, widespread belief that vegetarians must consume grains and beans within a short time to make a complete protein that contains all 9 essential amino acids that must be supplied through diet, this has never been substantiated by research. The protein-combining theory was brought to popular attention after being promoted in Frances Moore Lappé's 1971 bestselling book Diet for a Small Planet. In later editions of the book, starting in 1981, Lappé withdrew her contention that protein combining is necessary.[5]
Plant foods rich in protein include soy beans and soy products such as tofu, veggie burgers, and soy milk; other legumes; nuts and seeds; and cereal grains.[6]
Vitamin B12 deficiency can be extremely serious and lead to megaloblastic anemia, nerve degeneration and irreversible neurological damage.[7]
Vegetarians may get vitamin B12 from eggs and dairy products (milk, cheese, etc.);[8] for some, this is adequate, while others may still remain B12-deficient.[1] More broadly, according to the Academy of Nutrition and Dietetics, even the form of vitamin B12 sourced from animal products is protein-bound and not as easily digested as supplements, especially as people age, and therefore B12 supplementation is recommended for everyone over the age of 50.[1] Pregnant and lactating vegetarian mothers—and breastfed infants if the vegetarian mother's diet is not supplemented—should also use supplements, whether B12-pills, B12-injections, or B12-fortified foods, if they don't get adequate vitamin B12 from animal products like eggs or dairy.
Generally, humans need 2.4 to 3 micrograms of vitamin B12 each day.[8] There are cases to suggest that vegetarians and vegans who are not taking vitamin B12 supplements or food fortified with B12 do not consume sufficient servings of B12 and have abnormally low blood concentrations of vitamin B12.[9] This is because, unless fortified, plant foods do not contain reliable amounts of active vitamin B12.[1]
It is essential, therefore, that vegetarians consume adequate amounts of dietary supplements or foods that have been fortified with B12, such as vegetable stock, veggie burger mixes, textured vegetable protein, soy milks, vegetable and sunflower margarines, and breakfast cereals.[7]B12 used in these foods or supplements is typically grown from vegan sources (such as bacteria). Soybeans and barley seeds from plants grown in soils amended either with cow dung (which is rich in B12) or with pure B12 had a higher B12 content than those grown without this supplementation.[10]
Vegetarian diets can be low in omega-3 fatty acids (O3FAs). Major vegetarian O3FA sources include algae, hempseeds and hempseed oil, walnuts, flaxseeds and flaxseed oil, olive oil, canola oil, avocado, and chia seeds.[citation needed]
A potential problem is that vegetarian diets lacking eggs or generous amounts of edible seaweed generally lack a direct source of long-chain O3FAs such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Vegetarian diets may also have a high ratio of omega-6 fatty acids to O3FAs, which inhibits the conversion of short-chain fatty acids such as alpha-Linolenic acid (ALA), which is found in most vegetarian O3FA sources, to EPA and DHA.[1] Short-term supplemental ALA has been shown to increase EPA levels but not DHA levels, suggesting poor conversion of the intermediary EPA to DHA.[11] To remedy this, DHA and EPA supplements derived from microalgae are available.[1][12]
A 2022 review found that microalgal oil supplementation is consistent in increasing DHA and EPA levels, whilst high dose flaxseedorechium seed oil supplements provide no increase despite significant increases in ALA levels.[12]
In general, lacto-ovo-vegetarians have a relatively high intake of calcium that meet or exceed calcium recommendations.[13]
A 2022 review found no significant difference in calcium intake between vegetarians and omnivores.[14] Vegetarians can obtain calcium from dairy products, calcium-fortified plant milks, almonds, figs, oranges, calcium-set tofu as well as low-oxalate vegetables such as bok choy, kale and turnip greens.[13]
Compared with omnivores, vegetarians tend to have a lower bone mineral density (BMD) but not a higher fracture rate.[15][16]
Vegetarians are more likely to have lower iron stores compared with non-vegetarians and have a higher risk of iron deficiency anemia.[17][18][19] Lacto-ovo-vegetarians that overly rely on dairy consumption may lead to an elevated calcium intake which can affect iron absorption.[20]
The recommended iron intake for vegetarians is 180% that of nonvegetarians due to the bioavailability of non-heme iron.[13] Although a lower percentage of non-heme iron is absorbed by the body, greater total amounts of non-heme iron are concentrated in many non-meat sources of iron, and therefore breakfast cereals, eggs, nuts, seeds, and legumes (including soy foods, peas, beans, chickpeas, and lentils) are significant sources of iron, and a well-planned vegetarian diet should not lead to iron deficiency.[13][21][22]
Non-heme iron is more sensitive to both inhibitors and enhancers of iron absorption: Vitamin C is an iron absorption enhancer; the main inhibitors for most people are phytates (e.g. legumes and cereal grains), but other inhibitors include tannins (from tea and wine), calcium, and polyphenols.[1]
Iron is an integral part in the chemical structure of many proteins and enzymes, which maintain good health. In humans, iron is an essential component of proteins involved in the transport of oxygenofred blood cells. Iron also helps regulate cell growth and cellular differentiation.[23]
A 2013 review found that zinc intake and serum zinc concentrations were significantly lower in populations that follow vegetarian diets compared with non-vegetarians.[24]
Phytates in many whole grains, and dietary fiber in many plant foods may interfere with zinc absorption, and marginal zinc intake has poorly understood effects. Vegetarians may need more than the US Recommended Daily Allowance of 15 mg of zinc each day to compensate if their diet is high in phytates.[1] Major plant sources of zinc include cooked dried beans, edible seaweed, fortified breakfast cereals, soy products, nuts, peas, and seeds.[1]
One study reported a "potential danger of [iodine] (I) deficiency disorders due to strict forms of vegetarian nutrition, especially when fruits and vegetables grown in soils with low [iodine] levels are ingested."[25] Iodine, however, is usually supplied by iodized salt and other sources in first world countries. Other significant vegetarian sources of iodine include edible seaweed and bread made with dough conditioners.[1]
Evidence suggests that vegetarian diets have beneficial effects on blood lipids and that vegetarians have a reduced risk of cancer, cardiovascular disease, hypertension and type 2 diabetes.[19][26][27][28]
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