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The impact of vegan diet on B-12 status in healthy omnivores: Five-year prospective study

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There are no long-term prospective studies assessing the impact of the vegan diet on vitamin B-12 (B-12) status. Many vegans take B-12 supplements irregularly or refuse to adopt them at all, considering them to be "unnatural" products. The use of B-12 fortified food may be an alternative. Therefore, we aimed to estimate the long-term effect of a vegan diet on serum B-12 concentrations in healthy omnivore adults, comparing the influence of natural products consumption and B-12 fortified food. A five year prospective study was carried out comprising 20 omnivore healthy adult subjects, who moved to strict vegan diet for 5 years. Ten volunteers followed vegan diet based entirely on natural products, while the remaining ten subjects consumed food fortified in B-12. In all subjects serum vitamin B-12 concentration was determined before and 6, 12, 24 and 60 months after the implementation of the diet. A significant decrease (p < 0.0002) of serum B-12 concentrations in the whole studied group was noted after 60 months of vegan diet. However, observed changes were in fact limited to the subgroup consuming exclusively natural products (p < 0.0001). Transition from omnivore to vegan diet is associated with the risk of vitamin B-12 deficiency. B-12 fortified products might constitute a valuable alternative in vegans refusing to take vitamin supplements.
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© Copyright by Wydawnictwo Uniwersytetu Przyrodniczego w Poznaniu
Acta Sci. Pol., Technol. Aliment. 11(2) 2012, 209-213
pISSN 1644-0730 eISSN 1889-9594 www.food.actapol.net/
edytamadry@poczta.onet.pl
INTRODUCTION
Western societies are witnessing during last the
decades a rising popularity of all types of vegetarian
diet. According to the Mintel survey the percentage of
vegetarians in Western Europe varies from 2% to 4%
of the population, with the United Kingdom being an
exception. Vegetarianism seems to be more frequent in
British females as 7% of them declare to follow a strict
diet (in comparison to 2% of British males) [Mintel...
2006]. Swan documented that 12% of women aged
19-24 years and 11% aged 25-34 years are vegetarians
[Swan 2004]. As a comparison, a poll conducted in the
United States in 2006 estimated that 6.8% of adults
aged 18 years or older never eat meat while 1.4% de-
clare to follow consistently vegan diet [Stahler 2006].
Vegetarians do not eat meat (including fowl) and
seafood, or products containing these foods. The ve-
gan eating pattern additionally excludes eggs and
dairy. Vegetarians tend to have lower body mass index
(BMI) and cholesterol level among other health ben-
e ts linked to the diet. They typically enjoy a lower
THE IMPACT OF VEGAN DIET ON B-12 STATUS IN HEALTHY
OMNIVORES: FIVE-YEAR PROSPECTIVE STUDY
Edyta Mądry1, Aleksandra Lisowska2, Philip Grebowiec2, Jarosław Walkowiak2,3
1Department of Physiology, Poznań University of Medical Sciences
Święcickiego 6, 60-572 Poznań, Poland
2Department of Pediatric Gastroenterology and Metabolism, Poznań University of Medical Sciences
Szpitalna 27/33, 60-572 Poznań, Poland
3Department of Human Nutrition and Hygiene, Poznań University of Life Sciences
Wojska Polskiego 31/33, 60-624 Poznań, Poland
ABSTRACT
Background. There are no long-term prospective studies assessing the impact of the vegan diet on vitamin
B-12 (B-12) status. Many vegans take B-12 supplements irregularly or refuse to adopt them at all, consider-
ing them to be “unnatural” products. The use of B-12 forti ed food may be an alternative. Therefore, we
aimed to estimate the long-term effect of a vegan diet on serum B-12 concentrations in healthy omnivore
adults, comparing the in uence of natural products consumption and B-12 forti ed food.
Material and methods. A ve year prospective study was carried out comprising 20 omnivore healthy adult
subjects, who moved to strict vegan diet for 5 years. Ten volunteers followed vegan diet based entirely on nat-
ural products, while the remaining ten subjects consumed food forti ed in B-12. In all subjects serum vitamin
B-12 concentration was determined before and 6, 12, 24 and 60 months after the implementation of the diet.
Results. A signi cant decrease (p < 0.0002) of serum B-12 concentrations in the whole studied group was
noted after 60 months of vegan diet. However, observed changes were in fact limited to the subgroup con-
suming exclusively natural products (p < 0.0001).
Conclusions. Transition from omnivore to vegan diet is associated with the risk of vitamin B-12 de ciency.
B-12 forti ed products might constitute a valuable alternative in vegans refusing to take vitamin supplements.
Key words: vegan diet, vitamin B-12, risk of de ciency, vegetarianism
Mądry E., Lisowska A., Grebowiec P., Walkowiak J., 2012. The impact of vegan diet on B-12 status in healthy omnivores: fi ve-year
prospective study. Acta Sci. Pol., Technol. Aliment. 11(2), 209-213.
210 www.food.actapol.net/
risk of cardiovascular disease, obesity, type 2 diabetes,
hypertension and some cancers [Key et al. 1999, 2009,
Appleby et al. 2002, Vang et al. 2008, American...
2006]. However, it is also well known that eliminating
all animal products from the diet increases the risk of
certain nutritional de ciencies. Micronutrients of spe-
cial concern for the vegetarians include vitamin B-12
(B-12) and D, calcium, long-chain n-3 fatty acids and
zinc [Sanders 2009, Craig and Mangels 2009, Mądry
et al. 2009]. With many forti ed products and dietary
supplements available today a great improvement of
vegetarians key-micronutrients status has been noted
as compared to vegetarians 1-2 decades ago [Craig
2009]. Nonetheless B-12 status of some vegetarians is
less than adequate due to the lack of its reliable dietary
sources and/or of regular supplementation.
Severe clinical symptoms of B-12 de ciency
which include ataxia, psychoses, paresthesia, disori-
entation, dementia, mood or motor disturbances, may
appear with or without obviously known hematologi-
cal symptoms (megaloblastic anemia, macrocytosis)
[Reynolds 2006]. There are no long-term prospective
studies assessing the impact of the vegan diet on vita-
min B-12 status. Many vegans take B-12 supplements
irregularly or refuse to adopt them at all, considering
to be “unnatural” products. The use of B-12 forti ed
food may be an alternative. Therefore, we aimed to
estimate the long-term effect of a vegan diet on serum
B-12 concentrations in healthy omnivore adults, com-
paring the in uence of natural products consumption
and B-12 forti ed food.
MATERIAL AND METHODS
The prospective study was carried out comprising
20 healthy adult omnivores (14 females, 6 males,) who
intentionally declared to follow strict vegan diet for
at least 5 years. The studied group was divided into
2 subgroups. First subgroup (10 subjects; 7 females,
3 males) followed vegan diet based entirely on natu-
ral products, while the second (10 subjects; 7 females,
3 males) consumed B-12 forti ed food, widely avail-
able in health food stands. The participants were ran-
domly assigned to the subgroups and there were no
drop-outs during the study. All subjects adhered to the
vegan style diet over the ve-year period and they did
not take B12-containing supplements in the course of
the study. Fasting serum B12 levels were determined
in all participants before and 6, 12, 24 and 60 months
after the implementation of the diet. B-12 concentra-
tions were assessed with the use of chemilumines-
cence immunoassay. (Immunolite-Vitamin B-12 test,
Diagnostic Products Corporation; IMX Foliate Cali-
bration, Abbott). Values lower than 193 pg/ml were
considered as abnormal. The differences in B-12 con-
centrations were analysed with the use of Friedman
test and the post-hoc multiple comparison performed
using the Dunn test (dependent samples). The level of
statistical signi cance was set at p < 0.05.
Ethical considerations. The protocol of the inves-
tigation was approved by the Ethical Committee of
the Poznań University of Medical Sciences, Poznań,
Poland.
RESULTS
A signi cant decrease (p < 0.0002) of serum B-12
concentrations in the whole studied group was noted
(Fig. 1). However, the observed changes were in fact
limited to the subgroup consuming exclusively natural
products (p < 0.0001). None of the subjects consuming
B-12 forti ed food demonstrated the decline of B-12
concentration below cut-off level during the whole
studied period. Nevertheless, in a subgroup following
Table 1. Basic characteristics of the studied subjects
Characteristics
Studied group
whole group
(N = 20)
FD
(N = 10)
ND
(N = 10)
Age, years
Median
(mean ±SEM)
23
(23.0 ±0.2)
23
(22.9 ±0.2)
23
(23.0 ±0.2)
Range 21-25 21-24 22-25
BMI, kg/m2
Median
(mean ±SEM)
21.2
(21.4 ±0.4)
21.2
(21.3 ±0.3)
21.4
(21.4 ±0.4)
Range 18.5-24.7 18.5-24.6 19.0-24.7
ND – vegan diet based upon natural products, FD – vegan diet
comprising B-12 forti ed products, N – number of participants.
211
Mądry E., Lisowska A., Grebowiec P., Walkowiak J., 2012. The impact of vegan diet on B-12 status in healthy omnivores: fi ve-year
prospective study. Acta Sci. Pol., Technol. Aliment. 11(2), 209-213.
www.food.actapol.net/
diet based entirely on natural products, abnormal B-12
level was detected in 2 out of 10 (20%) subjects (166
and 178 pg/ml after 60 months of vegan diet).
DISCUSSION
Vegans typically have lower plasma B-12 concen-
trations and higher prevalence of its de ciency than
other vegetarians and omnivores [Craig 2009, Elmad-
fa and Singer 2009]. However, according to PubMed
search to date, there are no long-term prospective
studies documenting the dynamics of B-12 declining
in subjects who moved from omnivore to vegan diet.
Despite a number of surveys evaluating the health
status of vegetarians, all dietary guidelines are based
on cross-sectional studies. This is the rst evaluation
showing long-term changes in B12 status in vegans,
comparing diet based upon natural and B12-forti ed
products. We documented that 60 months of the vegan
diet based exclusively on natural products can lead in
healthy adult omnivores to B-12 de ciency. It makes
particularly important the recommendation of regular
consumption of B-12 forti ed food or B-12 supple-
ments, what may attenuate a potential decline in serum
B-12 concentrations in individuals adhering to vegan-
type diets. However, it has been shown by Asok that
such recommendations are not easily implemented
[Asok 2003]. The studies on unique groups in the West
such as Seventh-Day Adventists showed the extent of
poor cobalamin status and highlighted the dif culty
of persuading even highly educated subjects that they
are at risk of B-12 de ciency and that they should rou-
tinely take cobalamin supplements [Hokin and Butler
1999].
The world authorities in the eld of nutrition rec-
ommended “appropriately planned vegetarian diets as
healthful and nutritionally adequate for all stages of the
life cycle” [Craig and Mangels 2009]. In the decade of
obesity, it is indisputable that vegetarian diets, associ-
ated with the low supply of calories per unit volume,
may be bene cial for the health, provided however,
that we can avoid certain dangers, from which no diet
is free. Vegan diet is nowadays growing in popularity
among adolescents and young adults, especially fe-
males [Mintel... 2006, Swan 2004]. Proper monitoring
of vegan’s B-12 status appears to be substantial, espe-
cially since they do not receive suf cient supervision
of medical or nutritional professionals. It may allow
for early detection of B-12 declining/de ciency, and
possible early introduction of dietary/pharmacological
intervention. It should be underlined that in vegans bi-
ochemical expression can precede clinical symptoms
by many years, and that dietary B-12 de ciency is eas-
ily reversible [Carmel 2008].
The obtained data should be interpreted with cau-
tion because of the study limitations. The major draw-
back is the small number of participants, what seems
understandable given the restrictiveness of the diet and
length of the testing period. What needs to be pointed,
is that the dietary B-12 intake was not assessed in the
present study. However, the reliability of B12 intake is
limited [FAO/WHO... 2005]. The obtained data point
to the need of developing an effective attitude to the
diet planning in vegans.
In conclusion, transition from omnivore to ve-
gan diet is associated with the risk of vitamin B-12
de ciency. B-12 forti ed products might be a valu-
able alternative in vegans refusing to take vitamin
supplements.
Authors’ contribution: Jarosław Walkowiak and
Aleksandra Lisowska designed the study. Jarosław
Walkowiak, Aleksandra Lisowska and Edyta Mą-
dry collected the data. Edyta Mądry and Jarosław
200
250
300
350
Meadian B-12, pg/ml
0
Months
400
p < 0.0001
FD
all
ND
p < 0.0002
612 24 60
Fig. 1. Serum vitamin B-12 concentrations in healthy adult
omnivores consuming vegan diet for 60 months. The im-
pact of natural diet and B-12 forti ed food: FD – vegan diet
comprising B-12 forti ed products (N = 10), all – all sub-
jects (N = 20), ND – vegan diet based upon natural products
(N = 10)
Mądry E., Lisowska A., Grebowiec P., Walkowiak J., 2012. The impact of vegan diet on B-12 status in healthy omnivores: fi ve-year
prospective study. Acta Sci. Pol., Technol. Aliment. 11(2), 209-213.
212 www.food.actapol.net/
Walkowiak and Philip Grebowiec wrote the draft of
the manuscript. Edyta Mądry prepared table and g-
ure. All undersigned authors are responsible for search
of literature, analysis and interpretation of the data,
drafting and/or revising of the manuscript.
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N.E., Thorogood M., Mann J.I., 2009. Cancer incidence
in British vegetarians. Br. J. Cancer 7, 192-197.
Key T.J., Davey G.K., Appleby P.N., 1999. Health bene ts
of a vegetarian diet. Proc. Nutr. Soc. 58, 271-275.
Mądry E., Lisowska A., Chabasińska M., Przysławski J.,
Schlegel-Zawadzka M., Walkowiak J., 2009. Effect of
lacto-ovo-vegetarian diet on serum vitamin B12 con-
centrations– ve-year prospective study. Acta Sci. Pol.,
Technol. Aliment. 8 (4), 71-76.
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etarianism – UK- September 2006. [on line] https://aca-
demic.mintel.com/sinatra/oxygen_academic/search_re-
sults/show&&sort.RCItem.=recent&type=RCItem&sor
t=a2z&mode=inaccessible&list=search_results/display/
id=173806 [accessed: 28 December 2010].
Reynolds E., 2006. Vitamin B12, folic acid, and the nervous
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Sanders T.A., 2009. DHA status of vegetarians. Prostagl.
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WPŁYW DIETY WEGAŃSKIEJ NA STĘŻENIE WITAMINY B-12 U ZDROWYCH DOROSŁYCH:
PIĘCIOLETNIE BADANIE PROSPEKTYWNE
STRESZCZENIE
Wstęp. Nie ma długofalowych badań prospektywnych oceniających wpływ diety wegańskiej na zawartość
witaminy B-12 (B-12) w surowicy. Wielu wegan sięga po suplementy B-12 nieregularnie lub odmawia ich
przyjmowania, uznając je za produkty „nienaturalne”. Spożywanie żywności wzbogaconej B-12 można trak-
tować jako alternatywę suplementacji. Celem przeprowadzonego badania była ocena długofalowego sto-
sowania diety wegańskiej na stężenie B-12 w surowicy u zdrowych dorosłych osób będących dotychczas
na diecie zwykłej oraz porównanie wpływu diety wegańskiej opartej wyłącznie na produktach naturalnych
z dietą zawierającą żywność wzbogaconą.
213
Mądry E., Lisowska A., Grebowiec P., Walkowiak J., 2012. The impact of vegan diet on B-12 status in healthy omnivores: fi ve-year
prospective study. Acta Sci. Pol., Technol. Aliment. 11(2), 209-213.
www.food.actapol.net/
Materiał i metody. Prospektywne badanie 5-letnie zostało przeprowadzone na 20 zdrowych dorosłych
ochotnikach, którzy zdecydowali się przejść na ścisłą dietę wegańską. W grupie 10 osób stosowało dietę
wyłącznie opartą na produktach naturalnych, natomiast pozostałe 10 – spożywało żywność wzbogaconą
w B-12. U wszystkich badanych oceniano stężenie B-12 w surowicy przed dietą oraz 6, 12, 24 i 60 miesięcy
po wprowadzeniu diety wegańskiej.
Wyniki. W całej badanej grupie zaobserwowano statystycznie znamienne (p < 0,0002) zmniejszenie stęże-
nia B-12 w surowicy po 60 miesiącach stosowania diety wegańskiej. Jednakże obserwowane zmiany były
de facto ograniczone do podgrupy spożywającej wyłącznie produkty naturalne (p < 0,0001).
Wnioski. Przejście na dietę wegańską wiąże się z ryzykiem wystąpienia niedoboru witaminy B-12. Żywność
wzbogacana w B-12 może być cenną alternatywą dla wegan odmawiających przyjmowania suplementów
witaminowych.
Słowa kluczowe: dieta wegańska, witamina B-12, ryzyko niedoboru, wegetarianizm
Received – Przyjęto: 6.12.2011 Accepted for print – Zaakceptowano do druku: 17.01.2012
For citation – Do cytowania
Mądry E., Lisowska A., Grebowiec P., Walkowiak J., 2012. The impact of vegan diet on B-12 status in healthy omnivores: fi ve-year
prospective study. Acta Sci. Pol., Technol. Aliment. 11(2), 209-213.
... Reduction in systemic inflammation [49,50,52,76] Increased risk of vitamin B12 deficiency [35,36,107] Reduced risk of developing obesity [34] and type II diabetes [59] Increased risk of vitamin D deficiency [70,108,109] Reduction in TMAO levels in plasma and urine [92,93] Insufficient intake of DHA and EPA [70] Lower caloric intake and saturated fat intake compared to other types of diets [35,70] Decreased pro-inflammatory bacteria in the gut [77,84] Increased production of beneficial bacterially produced metabolites [76,81] TMAO: Trimethylamine N-Oxide; DHA: docosahexaenoic acid; EPA: eicosapentaenoic acid. ...
... An unsupplemented vegan diet will inevitably result in a B12 deficiency. In a five-year prospective study, transitioning from an omnivore to a vegan diet was linked to vitamin B-12 deficiency [107]. Nonetheless, only the participants that did not take any supplements became deficient. ...
... Nonetheless, only the participants that did not take any supplements became deficient. In contrast, the group that consumed food fortified with B12 did not exhibit any signs of deficiency [107], confirming that foods fortified with B12 and B12 supplements are the only reliable vegan sources of B12. ...
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... In a cross-sectional study performed in Germany entitled "The Risks and Benefits of a Vegan Diet", the authors stated that vitamin B12 status was similar in vegans and omnivores, even though vegans assumed a lower amount [88]. This data can be explained by the high oral supplementation rate in these subjects, according to previous studies [85,87]. In addition to the fortified foods, which are able to counteract vitamin B12 deficiency contained in vegetables, milk, yeast and cereals [89], the market offers oral food supplements namely (i) methyl-cobalamin, (ii) adenosyl-cobalamin, and (iii) hydroxy-cobalamin [90]. ...
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Plant-based diets (PBDs) are increasingly consumed by the Italian population and around the world. In particular, among PBDs, the vegan diet is a food pattern characterized by the exclusion of all animal-origin foods. What drives people to adopt this model are mainly ethical, health and environmental reasons. A vegan diet, if well-balanced and varied, can help in achieving and maintaining an optimal state of health. However, this nutritional approach, if not well-balanced, can cause deficiencies in proteins, ω-3 fatty acids, iron, vitamin D and calcium, zinc, iodine and, above all, vitamin B12. Oral food supplements especially fortified foods are recommended in these cases to restore the nutritional deficiencies. A vegan diet generally reduces the risk of developing chronic non-communicable degenerative diseases, such as metabolic syndrome (MetS) and, in addition, requires fewer natural resources for food production than an omnivorous diet. The aim of this review is to analyze the possible impact of the vegan diet on MetS onset and its treatment.
... Zonder B12-verrijkte voedingsmiddelen of B12-supplementen ontwikkelen alleseters, wanneer ze overschakelen op een veganistisch dieet dus vaak een vitamine B12-tekort [5]. Ja, het kan nodig zijn om te dalen tot ongeveer 150 picomol per liter om de tekenen van B12-tekort te ontwikkelen, zoals bloedarmoede en dat het ruggenmerg van binnenuit gaat rotten [6], maar lang voordat dat gebeurt kunnen mensen een verhoogd risico krijgen op cognitieve tekorten en hersenkrimp, beroerte, depressie en zenuw-en botbeschadiging, en ook dat de homocysteïne niveaus in het bloedernstig verhoogd worden [6]. ...
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Vitamine B12 cyano-cob-alamine continual meta-analysis 1 / 1 Vitamine B12 cyano-cob-alamine continual meta-analysis www.nutritionfactsnederlands.nl/videoscript/2022/3/29/vitamine-b12-cyano-cob-alamine-alomvattend-artikel Article: Vitamine B12 cyano-cob-alamine [Sources below] Source references
... 33 Some foods, like cheddar cheese, "veggie burgers," breakfast cereals, sunflower margarine, yeast extracts, vegetable stock, sausage mixes, and vegetable margarine are fortified with vitamin B 12 . 38,39 The US Institute of Medicine has recommended that adults older than 51 years consume most of their vitamin B 12 from fortified foods or supplements, bearing in mind that older adults are at higher risk of B 12 deficiency due to the physiological reduction in intrinsic factor secretion necessary for absorbing this vitamin, as well as due to the use of drugs that can reduce the bioavailability of cobalamin. 35 Vitamin B 12 has also been reported to be present in lower levels in nonanimal foods, including edible algae, some mushrooms, and fermented foods such as tempeh, kimchi, miso, and tea. ...
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This comprehensive review establishes the role of vitamin B12 as adjunct therapy for viral infections in the treatment and persistent symptoms of COVID-19, focusing on symptoms related to the muscle–gut–brain axis. Vitamin B12 can help balance immune responses to better fight viral infections. Furthermore, data from randomized clinical trials and meta-analysis indicate that vitamin B12 in the forms of methylcobalamin and cyanocobalamin may increase serum vitamin B12 levels, and resulted in decreased serum methylmalonic acid and homocysteine concentrations, and decreased pain intensity, memory loss, and impaired concentration. Among studies, there is much variation in vitamin B12 doses, chemical forms, supplementation time, and administration routes. Larger randomized clinical trials of vitamin B12 supplementation and analysis of markers such as total vitamin B12, holotranscobalamin, total homocysteine and methylmalonic acid, total folic acid, and, if possible, polymorphisms and methylation of genes need to be conducted with people with and without COVID-19 or who have had COVID-19 to facilitate the proper vitamin B12 form to be administered in individual treatment.
... En el grupo que consumió alimentos fortificados el nivel plasmático de vitamina B 12 se presentó dentro del rango adecuado, mientras que en dos sujetos que consumieron alimentos naturales los niveles se encontraron fuera del rango. En ambos grupos la concentración sérica de la vitamina B 12 disminuyó de manera significativa luego de cinco años de haberse iniciado la transición de una dieta omnívora a vegana 30 . Algunos investigadores refieren la importancia de re-definir los valores plasmáticos adecuados de esta vitamina, debido a que se observan efectos negativos (como neuropatías) aún con una concentración sérica de vitamina B 12 dentro del rango. ...
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A vegetarian diet is defined by the total or partial exclusion of foods of animal origin. When properly planned it can prevent and treat disease. However, a restrictive diet in certain foods must be evaluated. The purpose of this research wasto describe anthropometric parameters, eating and lifestyle habits of lacto-ovo-vegetarians and vegans, and to explore differences in critical nutrient intake between both groups. We conducted a descriptive cross-sectional study, carried out among lacto-ovo-vegetarians and vegans in the city of Asunción, Paraguay, during 2015. Anthropometric parameters, intake and healthy lifestyle habits were evaluated. Seventeen lacto-ovo-vegetarians and fourteen vegans participated. 67.7% (n= 21) were normal weight, 29.1% (n= 9) were overweight, and 3.2% (n= 1) were underweight. There was an intake lower than the requirements in terms of energy, carbohydrates, proteins and fats in both groups of vegetarians, and very limited intake of calcium and vitamin B12 in vegans. Women particularly had intake well below the recommendations for iron and calcium. No woman on a vegan diet met the dietary recommendation for vitamin B12. When comparing groups, significant differences were found in terms of protein and calcium, (lower consumption in vegans), fiber (lower in lacto-ovo-vegetarians). Vitamin supplementation was also very low. The results highlight the importance of constant evaluation of nutrient intake in a vegetarian diet in order to avoid deficiencies or excesses, and the very important work of the nutritionist for food and nutritional advice for individuals who express interest in adopting this type of diet.
... Vegans are at risk of deficiency and must rely on consuming vitamin B12 fortified cereals which contain 6 μg of vitamin B12 per cup or plant or algae sources of vitamin B12 including fermented soybeans and edible red algae [47]. Vitamin B12 deficiency is uncommon in the USA in part due to mandatory food fortification with Vitamin B12 [48]. However, vegans that are not consuming an adequate amount of vitamin B12 or those taking proton pump inhibitor medications long-term may benefit from vitamin B12 supplementation, as achlorhydria can reduce absorption of protein-bound dietary vitamin B12 [49,50]. ...
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Purpose of Review Understand the current prevalence, health benefits, and health risks of vegetarian diets. Recent Findings Since the publishing of the Adventist Health Study 2 in 2013, there have been several prospective diet studies demonstrating and challenging the health benefits and risks of the vegetarian diet. Summary The definition of the vegetarian diet has become more specific over time and requires standardization for research purposes. Despite an uptrend in sales rates of plant-based foods per year, a 2018 Gallup poll showed overall stagnation of the percentage of self-reported vegetarians and vegans compared to percentages obtained 6 years prior. Compared to the Adventist Health Study, more recent vegetarian diet studies have demonstrated significant although smaller risk reductions for mortality in cardiovascular disease, cerebrovascular disease, diabetes mellitus, and chronic kidney disease. Recent studies have correlated certain food groups with early death or increased longevity. In addition, the vegetarian health risks of deficiencies of protein, omega-3 fatty acids, vitamin D, vitamin B12, iron, calcium, and zinc are explored.
... Earlier research shows that serum cobalamin concentrations are lower in vegetarians compared to omnivores, with vegans having even lower concentrations (Pawlak et al. 2014). Serum vitamin B 12 concentrations significantly decreased from 285 pg/mL to 230 pg/mL in healthy non-vegetarian adults who followed a strict vegan diet for 5 years (Madry et al. 2012). The regular intake of milk was also found to have a positive impact on vegetarians in India, decreasing blood homocysteine concentrations (Naik et al. 2018); however, milk consumption is seen to be avoided in ovo-vegetarians as well as vegans. ...
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Water-soluble vitamin B12 (cobalamin) plays a vital role in normal blood function and neurological functioning. Clinical and subclinical B12 deficiency has been notably reported in vegans, vegetarians, the elderly and metformin-treated diabetics. Currently, the prevalence of cobalamin deficiency among vegans and vegetarians in Australia is lacking; data on dietary intake including supplements and nutritional status are also limited. The increasing multiculturalism of Australia has seen an influx of imported foods, of which some may contain considerable vitamin B12. However, values for such foods are not included in the food composition databases. This review highlights the need to update the food composition database with culturally diverse foods containing vitamin B12. Moreover, the need for assessing dietary intakes and status using the most current best evidence and best practice on nutritional indicators (biochemical and functional biomarkers) to estimate the risk of deficiency and/or depletion is discussed.
Chapter
There is a continued increase in the global population, which has resulted in a concomitant increase in the demand for nutritious foods such as foods that are high in protein for human consumption. Animal-based proteins have been used in the food industry due to their functional properties such as gelation, foaming, and emulsification. Animal-based proteins however contribute to an increased carbon footprint and the resultant impact on the environment. In view of sustainability, there has been a gradual move from the consumption of animal-based foods to plant-based foods. Plant-based foods are associated with a myriad of health and nutritional benefits that include a reduction in obesity and several cancers in addition to the reduction in the risk for cardiovascular diseases. Some of these beneficial effects of plant-based foods are attributed to the presence of phytochemicals and phytonutrients in these foods. Plant-based foods can however contain several antinutritional factors that can impair the absorption of the health-promoting phytonutrients that are present in these foods. A number of factors such as attitudes and sensory perception do influence consumers' attitudes toward plant-based foods. This book chapter discusses the general consumer expectations, sensory perception, and attitude toward plant-based foods. The general health and nutrition of plant-based foods and ingredients are discussed, the antinutritional aspect of plant-based foods elucidated, and the impact of antinutrients on human health outlined.
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Background. Avoiding of meat is the basic principle of vegetarian diet with several variants existing.In the present study we have focused on lacto-ovo-vegetarian (LOV) diet which includes dairy products and eggs. We have aimed to assess its long-term effect on vitamin B12 status and intended to verify the influence of natural and vitamin B12-fortified food. Material and methods. The prospective study was carried out comprising 16 healthy omnivores (12 females, 4 males) who intentionally declared to follow strict LOV diet for at least 5 years. The studied group was divided into 2 subgroups. First subgroup followed LOV diet based entirely on natural products while the second consumed food fortified with B12 vitamin. Evaluation of vitamin B12 concentration was performed before and after 6, 12, 24 and 60 months from LOV diet implementation. Results. Five-years of LOV diet resulted in significant decrease of serum vitamin B12 concentrations in the whole studied group (p < 0.05). However, the significant drop of vitamin B 12 level was in fact limited to the subgroup consuming exclusively natural products (p < 0.05). In none of the subjects abnormal serum vitamin B12 levels were observed. Conclusions. Five-year lacto-ovo-vegetarian diet did not result in a risk of vitamin B12 deficiency in healthy subjects. However, the levels of serum vitamin B12 concentrations in a subgroup consuming natural diet tend to be significantly lower as compared with the group consuming fortified food. It confirms the need of follow-up (and potentially vitamin B12 fortification of food and/or its supplementation) in long-term lacto-ovo-vegetarians.
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Few prospective studies have examined cancer incidence among vegetarians. We studied 61,566 British men and women, comprising 32,403 meat eaters, 8562 non-meat eaters who did eat fish ('fish eaters') and 20,601 vegetarians. After an average follow-up of 12.2 years, there were 3350 incident cancers of which 2204 were among meat eaters, 317 among fish eaters and 829 among vegetarians. Relative risks (RRs) were estimated by Cox regression, stratified by sex and recruitment protocol and adjusted for age, smoking, alcohol, body mass index, physical activity level and, for women only, parity and oral contraceptive use. There was significant heterogeneity in cancer risk between groups for the following four cancer sites: stomach cancer, RRs (compared with meat eaters) of 0.29 (95% CI: 0.07-1.20) in fish eaters and 0.36 (0.16-0.78) in vegetarians, P for heterogeneity=0.007; ovarian cancer, RRs of 0.37 (0.18-0.77) in fish eaters and 0.69 (0.45-1.07) in vegetarians, P for heterogeneity=0.007; bladder cancer, RRs of 0.81 (0.36-1.81) in fish eaters and 0.47 (0.25-0.89) in vegetarians, P for heterogeneity=0.05; and cancers of the lymphatic and haematopoietic tissues, RRs of 0.85 (0.56-1.29) in fish eaters and 0.55 (0.39-0.78) in vegetarians, P for heterogeneity=0.002. The RRs for all malignant neoplasms were 0.82 (0.73-0.93) in fish eaters and 0.88 (0.81-0.96) in vegetarians (P for heterogeneity=0.001). The incidence of some cancers may be lower in fish eaters and vegetarians than in meat eaters.
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Recently, vegetarian diets have experienced an increase in popularity. A vegetarian diet is associated with many health benefits because of its higher content of fiber, folic acid, vitamins C and E, potassium, magnesium, and many phytochemicals and a fat content that is more unsaturated. Compared with other vegetarian diets, vegan diets tend to contain less saturated fat and cholesterol and more dietary fiber. Vegans tend to be thinner, have lower serum cholesterol, and lower blood pressure, reducing their risk of heart disease. However, eliminating all animal products from the diet increases the risk of certain nutritional deficiencies. Micronutrients of special concern for the vegan include vitamins B-12 and D, calcium, and long-chain n-3 (omega-3) fatty acids. Unless vegans regularly consume foods that are fortified with these nutrients, appropriate supplements should be consumed. In some cases, iron and zinc status of vegans may also be of concern because of the limited bioavailability of these minerals.
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It is the position of the American Dietetic Association that appropriately planned vegetarian diets, including total vegetarian or vegan diets, are healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain diseases. Well-planned vegetarian diets are appropriate for individuals during all stages of the life cycle, including pregnancy, lactation, infancy, childhood, and adolescence, and for athletes. A vegetarian diet is defined as one that does not include meat (including fowl) or seafood, or products containing those foods. This article reviews the current data related to key nutrients for vegetarians including protein, n-3 fatty acids, iron, zinc, iodine, calcium, and vitamins D and B-12. A vegetarian diet can meet current recommendations for all of these nutrients. In some cases, supplements or fortified foods can provide useful amounts of important nutrients. An evidence- based review showed that vegetarian diets can be nutritionally adequate in pregnancy and result in positive maternal and infant health outcomes. The results of an evidence-based review showed that a vegetarian diet is associated with a lower risk of death from ischemic heart disease. Vegetarians also appear to have lower low-density lipoprotein cholesterol levels, lower blood pressure, and lower rates of hypertension and type 2 diabetes than nonvegetarians. Furthermore, vegetarians tend to have a lower body mass index and lower overall cancer rates. Features of a vegetarian diet that may reduce risk of chronic disease include lower intakes of saturated fat and cholesterol and higher intakes of fruits, vegetables, whole grains, nuts, soy products, fiber, and phytochemicals. The variability of dietary practices among vegetarians makes individual assessment of dietary adequacy essential. In addition to assessing dietary adequacy, food and nutrition professionals can also play key roles in educating vegetarians about sources of specific nutrients, food purchase and preparation, and dietary modifications to meet their needs.
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Docosahexaenoic acid (22:6n-3; DHA) is absent from vegan diets and present in limited amounts in vegetarian diets. To review DHA status in vegetarians and vegans. To identify published studies and review their findings. Dietary analyses show that vegan diets are devoid of DHA and vegetarian diets that included dairy food and eggs only provide about 0.02 g DHA/d. Vegetarian and especially vegan diets supply more linoleic acid (18:2n-6) than omnivore diets. The intake of alpha-linolenic acid (18:3n-3) also tends to be similar or greater but depends on culinary oils used. The proportions of DHA in plasma, blood cells, breast milk, and tissues are substantially lower in vegans and vegetarians compared with omnivores. The lower proportions of DHA are accompanied by correspondingly higher proportions of the long-chain derivatives of linoleic acid, indicating that the capacity to synthesize long-chain polyunsaturated fatty acids is not limited. Short-term dietary supplementation with alpha-linolenic acid increases the proportion of eicosapentaenoic acid (20:5n-3) but does not increase the proportion of DHA in blood lipids. Small amounts of preformed DHA (as low as 200mg) result in a large increase in the proportion of DHA in blood lipids in vegetarians and vegans. There is no evidence of adverse effects on health or cognitive function with lower DHA intake in vegetarians. Preformed DHA in the diet of omnivores explains the relatively higher proportion of this fatty acid in blood and tissue lipids compared with vegetarians. The pathophysiological significance of this difference remains to be determined.
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Evidence exists that well-planned vegetarian diets provide numerous health benefits and are appropriate for all stages of the life cycle. It is also known that animal foods provide micronutrients that are nonexistent or available only in limited amounts in plant foods. Restriction or exclusion of all animal foods may therefore result in low intake of certain micronutrients such as vitamin B-12, thereby affecting vitamin B-12 status and elevating plasma homocysteine concentrations. Overall, the studies we reviewed showed reduced mean vitamin B-12 status and elevated mean homocysteine concentrations in vegetarians, particularly among vegans. Low vitamin B-12 intake may lead to decreased bioavailability and functional deficiency of cobalamin. Although early noticeable symptoms of vitamin B-12 deficiency are nonspecific (unusual fatigue, digestion problems, frequent upper respiratory infections), the best-known clinical manifestations of cobalamin malabsorption are hematologic (pernicious anemia) and neurologic symptoms. Hyperhomocysteinemia is associated with an increased risk of atherosclerosis and cardiovascular disease. Given these health concerns, vegetarians, particularly vegans, must be advised to carefully plan their diets, to monitor their plasma vitamin B-12 on a regular basis to facilitate early detection of low cobalamin status, and to use vitamin B-12-fortified foods or take vitamin B-12 supplements if necessary.
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Compared with non-vegetarians, Western vegetarians have a lower mean BMI (by about 1 kg/m2), a lower mean plasma total cholesterol concentration (by about 0.5 mmol/l), and a lower mortality from IHD (by about 25%). They may also have a lower risk for some other diseases such as constipation, diverticular disease, gallstones and appendicitis. No differences in mortality from common cancers have been established. There is no evidence of adverse effects on mortality. Much more information is needed, particularly on other causes of death, other morbidity including osteoporosis, and long-term health in vegans. The evidence available suggests that widespread adoption of a vegetarian diet could prevent approximately 40,000 deaths from IHD in Britain each year.
Article
As part of the Adventist Ministers' Health Study, a series of cross-sectional surveys conducted in 1992, 1994, and 1997, the serum vitamin B-12 status of 340 Australian Seventh-day Adventist ministers was assessed in 1997. The ministers in the study participated voluntarily. Of this group, 245 were either lactoovovegetarians or vegans who were not taking vitamin B-12 supplements. Their mean vitamin B-12 concentration was 199 pmol/L (range: 58-538 pmol/L), 53% of whom had values below the reference range for the method used (171-850 pmol/L) and 73% of whom had values <221 pmol/L, the lower limit recommended by Herbert. Dual-isotope Schillings test results in 36 lactoovovegetarians with abnormally low vitamin B-12 concentrations indicated that dietary deficiency was the cause in 70% of cases. Data from the dietary questionnaires supported dietary deficiency as the cause of low serum vitamin B-12 in this population of lactoovovegetarians and vegans, 56 (23%) of whom consumed sufficient servings of vitamin B-12-containing foods to obtain the minimum daily maintenance allowance of the vitamin (1 microg).