Vegan diet during pregnancy and first years of life

Table of contents

Note

1 Introduction and question

2 Methodology

3 Pregnant and breastfeeding women
3.1 Recommendations for nutrient intake
3.2 Nutritional evaluation of vegan diet in pregnant and breastfeeding women
3.3 Breast milk from vegans
3.4 Example of practical implementation
3.5 "Vegan- Vegetarian diets in pregnancy: danger or panacea? A systematic narrative review"
3.6 "A maternal vegetarian diet in pregnancy is associated with hypospadias"

4 Infants and young children
4.1 Recommendations for nutrient intake
4.2 Nutritional evaluation of vegan nutrition in infants and children
4.3 Soy-based infant formula
4.4 Nutrient supplementation in infants
4.5 Weaning and complementary food
4.6 Example of practical implementation
4.7 "The Growth of vegetarian children: The Farm Study"
4.8 "Growth and Development of British vegan children"
4.9 Macrobiotic nutrition in infants

5 Expert opinions
5.1 Position of the German Nutrition Society
5.2 Position of the American Dietetic Association: Vegetarian Diets

6 Reviews

7 Discussion

Summary

Bibliography

Appendix

Note

In the entire bachelor thesis, the male noun was used for both female and male persons due to the better readability.

1 Introduction and question

In this work, the main focus is placed on the nutritional evaluation of vegan nutrition in pregnancy and lactation, as well as in infants and toddlers up to the age of three. Vegan nutrition is characterized by the renunciation of any animal products in all possible variants. Reasons for this decision are usually ethical, health, religious or ecological in nature. The number of people who opt for a vegan lifestyle is growing. Unfortunately, there is no detailed study of the number of vegans worldwide, but it is assumed that about 1% of the world's population [vegan world. Internet: http://www.veganwelt.de/inhalt/vegan/v-faq.html].

The vegan diet is often criticized, as it is suspected that the restriction of animal foods significantly increases the risk of nutrient deficiency, especially in people with an increased need for macro- and micronutrients. Many vegan women also opt for the vegan lifestyle during pregnancy and also feed their child without animal foods. Opinions on this topic are controversial. The various professional societies, for example, do not hold the same views on this issue. The German Nutrition Society (DGE) does not consider the vegan diet to be recommended in these special phases of life, as they assume that this type of diet is not appropriate to cover the need for all nutrients [Richter et al., 2016]. In contrast, the American Dietetic Association (ADA) believes that a well-planned vegan diet at all stages of life is able to adequately provide a person with macro- and micronutrients [Craig & Mangels, 2009]. The number of recent studies investigating the effect of vegan diets on pregnant women, breastfeeding women, infants and young children and their supply status is limited. In many areas, insufficient research has been carried out and there is a lack of long-term studies with significant results. Taking into account the existing literature, the question should be clarified whether a vegan diet in these phases of life is recommended from a nutritional point of view, or whether it can cause health damage to the child or mother. At the beginning, the reference values for pregnant women, breastfeeding women, infants and young children, as well as certain risk nutrients and the practical implementation of the diet are discussed. Subsequently, some studies that have examined the effect of vegan nutrition on pregnant women, breastfeeding women, infants or young children, as well as the statements of the DGE and the ADA are cited. At the end, five questionnaires, answered by mothers who follow a vegan diet, are summarized as experience reports.

2 Methodology

In september 2016, the systematic literature search on the topic of vegan nutrition in pregnancy and lactation, as well as in infancy and infancy, was started. For the most part, the search interfaces Google Scholar and Pubmed were used. English literature was preferred. The search was made with the terms "vegan diet", "pregnancy", "pregnancy outcome", "lactation", "infants" and "children". In addition, the book "Vegetarian Nutrition" by Leitzmann and Keller was used as a supplement.

3 Pregnant and breastfeeding women

3.1 Recommendations for nutrient intake

Life phases such as pregnancy and lactation are characterized by a partially increased need for nutrients. From the fourth month onwards, the demand for proteins, minerals and vitamins in particular increases considerably [Leitzmann & Keller, 2013]. The following table shows which reference values for nutrient intake are generally recommended for pregnant and breastfeeding women.

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Table 1: Recommendations for nutrient intake for pregnant and breastfeeding women, 19-50 years [DACH, 2015] (mod. after [Leitzmann and Keller, 2013])

3.2 Nutritional evaluation of vegan diet in pregnant and breastfeeding women

3.2.1 Food energy

The energy requirement increases in pregnant women in the second trimester by 250kcal/day, in the third by 500kcal/day [s. Tab. (1).Foods with a high nutrient density should be consumed to meet the increased nutrient requirements without drastically changing energy intake. Vegan women often have a lower BMI compared to omnivorous women [Tonstad et al., 2009]. If body weight is too low, the risk of low birth weight and the risk of miscarriage increases [Leitzmann & Keller 2013]. Pregnant vegans should therefore pay attention to a sufficient energy intake. For exclusive breastfeeding in the first four to six months, there is also an additional requirement of 500kcal/day [s. Tab. (1). However, the need for partial breastfeeding, after the introduction of complementary foods, depends on the intensity and duration of breastfeeding, so no guideline for additional calorie intake is given [EFSA, 2013].

3.2.2 Protein

From the fourth month of pregnancy, the protein requirement increases by about 20%, which leads to an increase of 10g/day. The additional requirement results from the tissue formation of the fetus and the multiplication of hemoglobin stores. Breastfeeding women should consume 63g/day of protein [DACH, 2015]. The protein intake of vegans is usually lower than that of mixed dieters and lacto-ovo vegetarians. However, they often come very close to the recommendations for intake, as protein intake in most people is well above the reference values [Davey et al., 2003]. In a study by Haddad et al., however, the intake was too low [Haddad et al., 1999]. When insufficient energy is absorbed, the body uses dietary and body protein to provide energy, which can lead to deficiency symptoms in the mother and fetus. A sufficient intake of proteins is therefore essential. Vegetable protein sources such as legumes, nuts, seeds and whole grains should be consumed.

3.2.3 Essential fatty acids

The formation of membrane lipids, blood lipids and eicosanoids requires an adequate intake of essential fatty acids. Arachidonic and docosahexaenoic acid (DHA) help in the development of the brain and eyes. Alpha-linolenic acid can be converted to DHA in the body. DHA occurs naturally in microalgae and fish oils. Through an increased intake of a-Linolenic acid can increase the conversion rate [Brenna, 2002]. Linoleic acid inhibits the conversion of linolenic acid to DHA. Vegans absorb virtually no DHA through food, as it is mostly found in animal foods. However, the vegan diet is usually rich in linoleic acid.

The recommended daily amount (2-4g/day) of linolenic acid, for example, is contained in half a teaspoon of linseed oil. However, there is evidence that supplementation with alpha-linolenic acid has no effect on the DHA status of omnivorous mothers or children [De Groot et al., 2004]. For vegans, however, microalgae oils can play an important role in meeting demand.

3.2.4 Vitamin D

The need for vitamin D does not change during pregnancy and lactation. Studies showed very low vitamin D intake in vegans who did not consume vitamin D supplements or fortified foods [Dunn- Emke et al., 2005]. Only a few foods contain significant amounts of the vitamin, but these are of animal origin (e.B. fatty fish, cheese). It is possible to meet the need through sun exposure, this becomes problematic in northern latitudes and in winter. The consumption of fortified foods or the intake of preparations is therefore recommended for pregnant and breastfeeding vegans.

3.2.5 Riboflavin

In a study by Majchrzak et al., riboflavin status was not satisfactory in 30% of vegans, while it was only 10% of vegetarians and mixed dieters [Majchrzak et al., 2006]. Other studies showed similar images in vegans and omnivores [Sanders and Manning, 1992; Sanders and Purves, 1981]. If the mother absorbs too little riboflavin in the last trimester, the riboflavin content in breast milk is significantly lower [Ortega et al., 1999]. Good sources of riboflavin include nutritional yeast, soybeans, wheat germ, mushrooms, green leafy vegetables, algae, avocado, almonds, and fortified grains.

3.2.6 Vitamin B6

Due to the increased need for protein, the need for vitamin B also increases6 by about 60%. Breastfeeding people should also absorb more pyridoxine to replenish stores after pregnancy and compensate for losses from breast milk. Waldmann et al. reported marginal B6 status in vegans, although the intake was adequate [Waldmann et al., 2006]. In contrast, another study conducted by Majchrzak et al. showed that deficiency was equally common in both vegans and vegetarians and non-vegetarians [Majchrzak et al., 2006].

3.2.7 Folate

Folate is involved in DNA synthesis and thus has an influence on the division and formation of new cells. The additional demand of 550mg/day in pregnancy results from increased erythropoiesis of the mother, fetal growth and increased renal excretion. The folate requirement for breastfeeding people increases to 450mg/day as a result of losses caused by breast milk. If folate is undersupply in the first month, the fetus can lead to malformations, especially neural tube defects. Various professional societies (e.g. DGE) recommend women who wish to have children an additional folate intake of 400mg/Day [DACH, 2015]. Studies show that vegans often exceed recommendations due to high consumption of folate-rich leafy greens, legumes, and whole grains [Davey et al., 2003; Majchrzak et al., 2006]. 90% of the amount of folate contained can be lost when heated, so a third of the vegetables should be eaten raw.

3.2.8 Vitamin B12

A lack of vitamin B12 can lead to anemia and irreversible neurological defects. In some studies, undersupply of the mother during pregnancy increased the risk of too low birth weight, neural tube defects, preeclampsia, spontaneous abortions, a congenital heart defect of the child and other complications [Lopez-Quesada et al., 2003; Verkleij et al., 2006]. Breastfeeding women do not take enough vitamin B12 , the content in breast milk is lower and the risk of a B12deficiency in infants increases [Specker et al., 1990]. For this reason, it is especially important for pregnant vegans to ensure an adequate intake of vitamin B12 to respect. The only ways to adequately meet needs are fortified foods or nutrient preparations.

3.2.9 Calcium

If the mother does not absorb enough calcium, this has no effect on the calcium supply of the child, but the mineral is mobilized from the mother's bone tissue, which can lead to demineralization [Leitzmann and Keller, 2013]. Often there were deficiencies in the calcium supply, both in pregnant women and in the general population. Vegans consumed significantly less calcium in studies than vegetarians and mixed dieters [Haddad et al., 1999; Davey et al., 2003]. Vegan women should consume calcium-rich or fortified foods and take supplements if necessary.

3.2.10 Magnesium

Research showed that vegans ined more magnesium than non-vegans, mainly due to the increased consumption of tofu, which is rich in magnesium. Covering the additional demand for breastfeeding should therefore not be a problem. [Davey et al., 2003]

3.2.11 Iron

According to the DACH reference values, the recommendation for the intake of iron during pregnancy doubles from 15mg/day to 30mg/day. When breastfeeding itself, there is no further additional need. The increased recommendation of 20mg/day is intended to compensate for the losses of pregnancy [s. Tab. (1). Adequate care is important to reduce the risk of iron deficiency anemia, which is associated with spontaneous abortions, premature births, maldevelopment and low birth weight. Women, regardless of their diet, tend to be deficient. The recommended 30mg/day of iron for pregnant women is set very high and is therefore difficult to achieve in practice [Leitzmann & Keller, 2013]. In contrast to the DACH reference values, however, the European Food Safety Authority assumes that pregnant and breastfeeding women have sufficient iron stores and that absorption is increased in pregnant women. Therefore, no additional intake is recommended, the recommended intake remains at 15mg/day [EFSA NDA Panel, 2015]. 15mg/day is much easier to achieve than 30mg/day, especially with a plant-based diet. Vegans absorb a lot of vitamin C and organic acids. These substances can significantly improve iron absorption, as they reduce the effect of phytates.

Supplementation with iron is only recommended in the case of an existing deficiency [Scholl, 2005].

3.2.12 Iodine

Iodine intake increases from 200 to 230 during pregnancymg/day. Chronic iodine deficiency in the mother during pregnancy can lead to fetal hypothyroidism, stunted growth, mental retardation and cretinism in the fetus, increasing the risk of stillbirth or miscarriage. With existing deficiency, there may be a manifestation of iodine deficiency goiter, both in the mother and in the newborn. In a study by Shaikh, the intake of many vegan women was far below the recommendations. The low intake led to increased goiter formation or thyroid dysfunction [Shaikh, 2003]. The iodine status in milk and the supply of the infant depends on the iodine status of the mother. To meet the needs of the child, the milk must have an iodine concentration of 100-120mg/L [Zimmermann, 2007]. Pregnant and breastfeeding vegans should have their iodine status checked regularly. The use of iodized salt and the occasional consumption of algae can improve iodine status. If necessary, nutrient preparations can also be taken additionally.

3.2.13 Zinc

In the course of pregnancy, the zinc plasma level usually drops to 35% of the values of non-pregnant women, so it is recommended to take an additional 3mg/day [see Table 1]. Although phytates in plant foods reduce the absorption of zinc, the average zinc intake in vegans and omnivores was similar [Sanders, 1995]. There was no evidence of zinc deficiency in vegans in the Western world [Hunt, 2003]. For pregnant and breastfeeding women, it would be advisable to have their zinc status checked and supplement in case of an existing deficiency.

3.3 Breast milk from vegans

B vitamins, vitamins A, C and D in breast milk are highly dependent on the mother's diet [Lonnerdal, 1986]. The mineral content, total fat content and cholesterol content are hardly affected. The fat content in vegan mothers is similar to that of omnivorous breastfeeding mothers, but the fat composition may differ depending on the diet [Sanders et al., 1978]. In a study of British women, it turned out that the milk of vegan women had a lower content of saturated fatty acids and eicosapentaenoic acid and a higher content of linolenic and linolenic acid [Specker et al., 1987]. Infants can synthesize DHA. This ability is improved when breast milk contains a lot of linolenic acid. Nursing mothers should therefore consume more foods with a high content of linolenic acid and reduce the consumption of linoleic acid. Vitamin D content varied depending on the amount ingested with food and with the duration of sun exposure. In general, however, the vitamin D concentration in breast milk was low. The B12status also varied. Some studies have reported that vitamin B12 in breast milk was not accessible to the infant, but not all studies support this result [Specker et al., 1988]. Hughs and Sanders found that the riboflavin content in the breast milk of British vegans was lower than in omnivorous women [Hughs and Sanders, 1979]. The levels of taurine in the breast milk of vegan women were also lower [Rana and Sanders, 1986], but the values were comparable to the average content in the U.S. population. Although vegans consumed less carnitine, according to Lombard et al., plasma concentrations were similar or slightly lower than those of mixed foods [Lombard et al., 1989]. Vegans are able to synthesize carnitine themselves. Mangels and Messina assume that the carnitine concentration in the breast milk of vegan women is sufficient for the infant, but this has not been studied [Mangels and Messina, 2001]. In a study by Hergenrather et al., the levels of environmental pollutants such as DDT, chlordane and polychlorinated biphenyls in the breast milk of vegan mothers were lower [Hergenrather et al., 1981].

3.4 Example of practical implementation

Vegan, pregnant women should eat small meals with protein-rich foods several times throughout the day. The following table gives an example of a 1-day diet plan for pregnant vegans.

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Table 2: Example of a 1-day diet plan for a vegan, pregnant woman (mod. after [Wasserman & Mangels, 1999])

If in addition multivitamin preparations with iron, zinc, vitamin B12 and D, the sample plan can cover the nutrient needs. In total, the plan provides about 2500 kcal, 94g of protein, 70g of fat and 369g of carbohydrates [Wasserman & Mangels, 1999].

3.5 "Vegan- Vegetarian diets in pregnancy: danger or panacea? A systematic narrative review"

Piccoli et al. published a systematic, narrative review in January 2015 entitled "Vegan-Vegetarian diets in pregnancy: danger or panacea? A systematic narrative review" with the aim of examining the literature on the influence of vegan nutrition on the course of pregnancy. Although the vegan diet is becoming more and more popular, there has been no systematic review on the subject up to this point. Since the studies used were very heterogeneous, the design of a narrative review was chosen. 13 scientific publications on fetal outcomes and nine on nutrient deficiencies in vegan pregnant women met the inclusion criteria. Four of the studies were from North America, 14 from Europe and four from India. They came from the years 1977 to 2013. They had a different number of cases (studies with fewer than five cases were excluded) and had to include data on the course of pregnancy and birth, birth weight, gestational age, complications that occurred and certain nutritional parameters. Five studies showed a lower birth weight in the vegan-vegetarian diet compared to the mixed diet. The results were significant in one study, not significant in two studies. In two further investigations, significance was not reported. These studies provided insight into the duration of pregnancy, which was similar in vegan-vegetarian and omnivorous mothers.

In two other studies, on the other hand, the birth weight and size of the infant were higher, of which the results of one study were not significant. The other study reported a significantly higher weight (on average over 99g higher).

No study showed unfavorable pregnancy courses (such as preeclampsia, HELPP syndrome) or serious malformations, with the exception of a large study of nearly 8,000 participating children that reported an increased risk of hypospadias in children of vegan-vegetarian mothers [aOR 4.99; 95% confidence interval, 9% CI 2.1-11.88]. One study showed that the incidence of hypertension with proteinuria in vegan-vegetarian women (4%) in contrast to omnivorous pregnant women (12%) could possibly be lower. The risk of eclampsia (a condition associated with seizures) was higher in vegans than in omnivorous pregnant women. However, this difference was not significant (2% vs. 0%).

Three other studies showed either lower or similar weight gain in pregnancy in the vegan-vegetarian women. In one report, there was evidence of an increased number of caesarean sections in vegan mothers (10.4% to 1.1%), but the reasons for this were not clarified. Nine studies examined nutrient deficiencies using various variables: Magnesium intake, vitamin B12-intake and deficiency, anemia and iron status, absorption, folate intake, the intake of free fatty acids and trace elements. The cohorts were relatively small (23-109 women), except for a cross-sectional study from India with 1150 women. Although the results and design of the nine studies on micronutrient supply showed high heterogeneity, the studies suggested an increased risk of vitamin B deficiency.12 and iron. Zinc status was similar in one study, in another it was impaired in vegan-vegetarian women. The intake of folic acid and magnesium was higher in vegan pregnant women. The free fatty acids were nearly comparable in the two groups. Unfortunately, according to the review, the data on vegan-vegetarian pregnancies is limited. In addition, there are no homogeneous control groups in the studies. There were few scientific papers that presented the same information in a similar way, so they were difficult to compare. In several studies, there was no insight into the protein and calorie intake of the women. A definition of negative pregnancy courses was also missing, this definition could possibly vary. Since there were virtually no randomized studies on this topic, it was difficult to distinguish the influence of diet from environmental influences or other lifestyle habits, such as smoking. Based on the scientific literature, Piccoli et al. came to the conclusion that vegan pregnancies are usually similar to those of omnivorous women. However, this conclusion only applies to women who have voluntarily made the decision to eat vegan and are not forced to do so out of poverty or limited access to food. Taking into account the limitations, a vegan-vegetarian diet is considered safe during pregnancy, with special caution in the supply of micronutrients, especially vitamin B12, iron, calcium and vitamin D. The increased risk of hypospadias, which has been proven in a large study, requires more detailed investigation to identify possible other co-factors [Piccoli et al., 2015].

3.6 "A maternal vegetarian diet in pregnancy is associated with hypospadias"

In the following, the study "A maternal vegetarian diet in pregnancy is associated with hypospadias", conducted by North et al., is discussed in more detail. The influence of diet in pregnancy on the development of hypospadias was investigated. In the clinical picture of hypospadias, the development of the urethra is disturbed, the mouth of the urethra is further down than in healthy people.

Above all, the effect of a vegetarian diet and a related increased consumption of phytoestrogens, which may be associated with the development of hypospadias, was considered. This study did not specifically look at whether the participating mothers ate a vegan diet. Since the consumption of soy is usually very much increased, especially in the vegan diet, it can be assumed that the results would be similar for vegan mothers. If soy is consumed in larger quantities, the estrogen content could disrupt the production of testosterone and thus the development of the male fetus. In this way, estrogen could play a role in the development of urethra malformations such as hypospadias.

The aim of the study was to identify the influence of maternal nutrition on the development of hypospadias. The study was conducted as a prospective cohort study with 7928 boys. The mothers were asked about their history of childbirth, pregnancy, hormonal contraception, lifestyle and diet using self-completed questionnaires. These questionnaires were answered at certain intervals in the eighth, 18th and 32nd weeks of pregnancy and after birth. In the 32nd week, the women were asked about their eating habits. They had to indicate which foods they consumed frequently and whether they followed a vegetarian diet, including the duration of the diet. The authors hypothesised that the questionnaire was most meaningful in the 18th week, as genital development is usually completed by this time.

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