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The Impact of Vegan Diet in the Prevention and Treatment of Type 2 Diabetes: A Systematic Review.
Pollakova, D, Andreadi, A, Pacifici, F, Della-Morte, D, Lauro, D, Tubili, C
Nutrients. 2021;13(6)
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Associations between vegan diets and better health outcomes have been shown in previous studies yet impacts on diabetes are still not fully understood. The aim of this systematic review of 15 observational and randomised control trials looks at the effects of a vegan diet on risk for type 2 diabetes (T2D), blood sugar balance and T2D related complications. The results showed that risk for T2D is lower in vegans than in omnivores, even though the difference in BMI between the two groups was low. The occurrence of T2D was low amongst the studies reviewed and in those already diagnosed with T2D, blood sugars were better controlled amongst those following a vegan diet. It was concluded that the vegan diet is associated with lower T2D prevalence, incidence and better blood sugar control. This study could be used by healthcare professionals to make dietary recommendations of the use of a vegan diet to reduce the risk for T2D and achieve better blood sugar control in those who already have T2D.
Abstract
A protective effect of vegan diets on health outcomes has been observed in previous studies, but its impact on diabetes is still debated. The aim of this review is to assess the relationship between vegan diets and the risk for type 2 diabetes (T2D) along with its effect on glycemic control and diabetes-related complications. In accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, Pubmed and Cochrane library databases were systematically searched for all relevant studies. Seven observational and eight randomized controlled (RCTs) studies were included. The methodological quality of studies was assessed using the National Institutes of Health quality assessment tool for observational cohort and cross-sectional studies and the Cochrane Risk of Bias Tool for RCTs. We found that a vegan diet is associated with lower T2D prevalence or incidence and in T2D patients decreases high glucose values and improves glucose homeostasis, as reported from the majority of included studies. This approach seems to be comparable to other recommended healthful eating models, but as it may have potential adverse effects associated with the long-term exclusion of some nutrients, appropriate nutritional planning and surveillance are recommended, particularly in specific groups of diabetic patients such as frail elderly, adolescents, and pregnant or breastfeeding women.
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Vegan Diet Health Benefits in Metabolic Syndrome.
Marrone, G, Guerriero, C, Palazzetti, D, Lido, P, Marolla, A, Di Daniele, F, Noce, A
Nutrients. 2021;13(3)
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Plant-based diets (PBD) have grown in popularity in recent years and have been associated with better health outcomes especially with heart disease, however poorly planned PBD’s can result in nutrient deficiencies like vitamin B12. This review aimed to summarise the health benefits of PBD’s, especially vegan diets, compared to omnivorous diets when looking at risk factors associated with heart disease. The authors started by summarising three PBD’s obvious in the literature; vegan diet with no animal products, lacto-ovo-vegetarian (LOV) with dairy products and eggs, and fish-vegetarian including fish and seafoods. The study then highlighted the strengths and weaknesses of the vegan diet, highlighting that although the vegan diet represents a healthy way of eating rich in carbohydrates, omega-6 fats, fibre, vitamin C, vitamin E and magnesium it can be low in protein, omega-3 fats, vitamin B12, vitamin D, calcium, iron, zinc and iodine if not properly planned. Heart disease incidence was reported to be lower in individuals on a PBD, especially vegans, when compared to omnivorous diets possibly due to their improvement on risk factors associated with the disease. Metabolic syndrome, blood pressure, fat production, and blood sugar balance were all shown to be improved and reasons such as their high fibre content reducing energy intake and causing feelings of satiety and their low saturated fat content impacting cholesterol production were listed as possible mechanisms behind the improvements. It was concluded that a nutritionist led, vegan diet can improve risk factors for heart disease resulting in better health outcomes. This study could be used by healthcare practitioners to understand where vegan diets may lack certain nutrients and the Importance of a well-planned vegan diet in the prevention of heart disease in those at an increased risk.
Abstract
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.
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Vegan diet in young children remodels metabolism and challenges the statuses of essential nutrients.
Hovinen, T, Korkalo, L, Freese, R, Skaffari, E, Isohanni, P, Niemi, M, Nevalainen, J, Gylling, H, Zamboni, N, Erkkola, M, et al
EMBO molecular medicine. 2021;13(2):e13492
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As vegan diets gain popularity amongst families, there is little known about the impact of strict plant-based diets on metabolism and micronutrient status in children, apart from reduced average growth within the norm. This small study looked at 40 Finnish children from one day centre, and compared children following an omnivore or vegetarian diet to those raised on a vegan diet. The diets were analysed, and biomarkers and metabolites were measured. The metabolic profile and nutrient status of children who followed a vegan diet from birth were distinctively different to other diet patterns, including vegetarians. The authors suggest that little animal source foods are enough to shift the metabolism of children. Dietary analysis showed that vegan children had higher folate consumption and lower protein and saturated fats intake. Despite intake appearing adequate, serum markers for fat-soluble vitamins A and D were low. While the fatty acid ALA was higher compared to omnivores, DHA and overall cholesterol were decreased. The authors concluded that the bodies own cholesterol production does not seem to compensate for a lack of dietary cholesterol in this case and it remains to be established whether lower cholesterol in vegan children are negative to health. Furthermore, the circulating amino acids pool was decreased in vegan children, particularly branch chained amino acids. The most distinct difference, however, was seen in the variance of bile acid patterns. The physiological functions of bile acids go beyond digestion, yet the consequences of diverging bile acid profiles in children’s health are unknown. In conclusion, the data shows that a strict vegan diet affects the metabolism of healthy children, but much of the long-term impact on health is currently still unclear. This article highlights some of the differences, risks and uncertainties that come with raising young children on a strictly vegan diet.
Abstract
Vegan diets are gaining popularity, also in families with young children. However, the effects of strict plant-based diets on metabolism and micronutrient status of children are unknown. We recruited 40 Finnish children with a median age 3.5 years-vegans, vegetarians, or omnivores from same daycare centers-for a cross-sectional study. They enjoyed nutritionist-planned vegan or omnivore meals in daycare, and the full diets were analyzed with questionnaires and food records. Detailed analysis of serum metabolomics and biomarkers indicated vitamin A insufficiency and border-line sufficient vitamin D in all vegan participants. Their serum total, HDL and LDL cholesterol, essential amino acid, and docosahexaenoic n-3 fatty acid (DHA) levels were markedly low and primary bile acid biosynthesis, and phospholipid balance was distinct from omnivores. Possible combination of low vitamin A and DHA status raise concern for their visual health. Our evidence indicates that (i) vitamin A and D status of vegan children requires special attention; (ii) dietary recommendations for children cannot be extrapolated from adult vegan studies; and (iii) longitudinal studies on infant-onset vegan diets are warranted.
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Effects of a Low-Fat Vegan Diet on Gut Microbiota in Overweight Individuals and Relationships with Body Weight, Body Composition, and Insulin Sensitivity. A Randomized Clinical Trial.
Kahleova, H, Rembert, E, Alwarith, J, Yonas, WN, Tura, A, Holubkov, R, Agnello, M, Chutkan, R, Barnard, ND
Nutrients. 2020;12(10)
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Gut bacteria composition can have an important role in health. Long-term adherence to a plant-based diet can lead to altered gut bacteria compared to omnivores, however how this association is linked to body metabolism is not entirely understood. This randomised control trial of 168 overweight individuals on a vegan diet compared to a control group where individuals followed their usual diet containing animal products, aimed to assess gut microbiota changes and how this may be related to body weight, body composition and the body’s ability to balance blood sugars, over 16 weeks. The results showed that body weight was decreased in the vegan group compared to control group, mainly due to reduced fat mass. Measures of the body’s ability to balance blood sugars was significantly improved in the vegan group. Gut microbiota diversity remained unchanged in the vegan group yet increased in the control group. Several species changes were observed in the vegan and control groups. Faecalibacterium prausnitzii increased in the vegan group and this was related to decreases in body weight and fat mass. A smaller decrease in Bacteroides fragilis compared to control was observed with a low-fat vegan diet and this was also associated to decreased body weight, fat mass and increased blood sugar control. It was concluded that changes in body weight, body composition and the body’s ability to balance blood sugars in overweight adults following a vegan diet are related to gut microbiota changes. This study could be used by healthcare professionals to recommend a vegan diet to overweight adults to aid weight loss and understand how this diet may affect those changes.
Abstract
Diet modulates gut microbiota and plays an important role in human health. The aim of this study was to test the effect of a low-fat vegan diet on gut microbiota and its association with weight, body composition, and insulin resistance in overweight men and women. We enrolled 168 participants and randomly assigned them to a vegan (n = 84) or a control group (n = 84) for 16 weeks. Of these, 115 returned all gut microbiome samples. Gut microbiota composition was assessed using uBiome Explorer™ kits. Body composition was measured using dual energy X-ray absorptiometry. Insulin sensitivity was quantified with the predicted clamp-derived insulin sensitivity index from a standard meal test. Repeated measure ANOVA was used for statistical analysis. Body weight decreased in the vegan group (treatment effect -5.9 kg [95% CI, -7.0 to -4.9 kg]; p < 0.001), mainly due to a reduction in fat mass (-3.9 kg [95% CI, -4.6 to -3.1 kg]; p < 0.001) and in visceral fat (-240 cm3 [95% CI, -345 to -135 kg]; p < 0.001). PREDIcted M, insulin sensitivity index (PREDIM) increased in the vegan group (treatment effect +0.83 [95% CI, +0.48 to +1.2]; p < 0.001). The relative abundance of Faecalibacterium prausnitzii increased in the vegan group (+5.1% [95% CI, +2.4 to +7.9%]; p < 0.001) and correlated negatively with changes in weight (r = -0.24; p = 0.01), fat mass (r = -0.22; p = 0.02), and visceral fat (r = -0.20; p = 0.03). The relative abundance of Bacteroides fragilis decreased in both groups, but less in the vegan group, making the treatment effect positive (+18.9% [95% CI, +14.2 to +23.7%]; p < 0.001), which correlated negatively with changes in weight (r = -0.44; p < 0.001), fat mass (r = -0.43; p < 0.001), and visceral fat (r = -0.28; p = 0.003) and positively with PREDIM (r = 0.36; p < 0.001), so a smaller reduction in Bacteroides fragilis was associated with a greater loss of body weight, fat mass, visceral fat, and a greater increase in insulin sensitivity. A low-fat vegan diet induced significant changes in gut microbiota, which were related to changes in weight, body composition, and insulin sensitivity in overweight adults, suggesting a potential use in clinical practice.
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Low Intakes of Iodine and Selenium Amongst Vegan and Vegetarian Women Highlight a Potential Nutritional Vulnerability.
Fallon, N, Dillon, SA
Frontiers in nutrition. 2020;7:72
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Plant-based food sales have grown in recent years, driven by consumers who are cutting down or cutting out meat and animal products. Avoiding animal products can mean differing nutrient intakes to those that eat meat and the consequences of not meeting nutritional requirements in women of child- bearing age can affect future generations. This cross-sectional study of 62 females aimed to determine the nutrient intakes of omnivorous, vegan, and vegetarian diets. The results showed substantial variability in the intakes of nutrients between the diets. Omnivorous and vegetarian diets were lacking in fibre, with the vegan group being the only group to reach adequate intakes. Omnivorous diets exceeded government recommended intakes of sugar. Fat intake was higher in the omnivorous and vegetarian diets compared to the vegan diet, but none of the groups exceeded recommended daily intakes. Several vitamins and minerals differed between the groups with vegans not reaching daily recommended intakes of iodine, vitamin B12, and calcium and both vegetarians and vegans failing to reach recommended intakes of selenium. Omnivores and vegetarians failed to reach recommended intakes of vitamin K. It was concluded that nutrient intakes vary with diet type and that vegans may be vulnerable to inadequate intakes of key vitamins and minerals. However vegan diets are lower in protein and fat, and high in fibre. Despite differences, it appears that all three diets are considered healthy by government standards. This study could be used by healthcare professionals to understand areas of concern in vegan diets and that some vegans may need additional advice to meet nutritional requirements, especially when considering vitamins and minerals.
Abstract
Vegan and vegetarian diets are becoming increasingly popular in the UK. Due to the avoidance of animal products there can be significant differences in nutrient intakes between meat-eaters and vegetarians, and especially vegans. Importantly, research has identified that both vegans and vegetarians may be vulnerable to low intakes of some micronutrients. The aim of this study was to investigate micronutrient intake in omnivorous, vegetarian and vegan women. In total, 62 women (26 omnivores, 16 vegetarians, 20 vegans, mean age 31.6 ± 12.4 y, mean BMI 24.1 ± 1.6 kg/m 2 ) completed 4-day diet diaries. Diet intake data was analyzed using Nutritics and nutrient intake levels were compared with national dietary recommendations (RNIs). Statistical analysis was performed using SPSS, with differences between the groups identified using ANOVA with post-hoc Bonferroni correction. All groups recorded intakes of vitamin D, iron, iodine and selenium below RNI. The vegan group had significantly lower intakes of vitamin D, vitamin B12, calcium, selenium and iodine than vegetarians and omnivores (p < 0.05), with particularly low intakes of selenium (24.7 ± 11.9 μg) and iodine (24.4 ± 12.7 μg). These results suggest that adult women in the UK are at risk of low intakes of several vitamins and minerals, with the exclusion of animal products conferring an additional vulnerability, particularly with respect to selenium and iodine, both of which play important roles in thyroid hormone production. This study highlights iodine and selenium intakes to be a concern amongst women who follow vegan diets, and the necessity of further research to identify if low intake translates to biochemical markers and functional status.
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Is a vegan diet detrimental to endurance and muscle strength?
Boutros, GH, Landry-Duval, MA, Garzon, M, Karelis, AD
European journal of clinical nutrition. 2020;74(11):1550-1555
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There is a common belief amongst the general population that a vegan diet leads to lower exercise performance due to the potential lack of dietary protein and nutrients. However, previous research that compared aerobic capacity and muscle strength between different diet groups only showed marginal variance, if any at all. But it is criticized that these studies did not always distinguish between the multiple subtypes of vegetarian or veganism. Hence this study sought to focus specifically on the comparison of strict plant-based eaters with omnivores. The participants involved were 56 active women, around their mid-twenties, with an average Body Mass Index of 22. Assessed were estimated VO2 max (an indicator of aerobic fitness), submaximal endurance performance and upper and lower body muscle strength. The 3-day food diaries of each participant was analysed and showed a similar intake of energy and fats in both groups. Vegans had higher carbohydrate, fibre, vitamin C, iron, and magnesium consumption and lower intake of protein, leucine, alanine, saturated fat, vitamin D, and vitamin B12, when compared to omnivores. Whilst upper body strength appeared to be marginally lower in the vegan group, higher levels of estimated VO2 max and significantly higher submaximal endurance levels were observed. The results contradict the common belief, demonstrating that a vegan diet appears to have no detrimental impact on endurance and muscle strength in healthy, young and lean women. In fact, the findings suggest that a vegan diet can be advantageous on endurance performance compared to omnivores. The authors propose that the higher intake of carbohydrates amongst vegans could be linked to better endurance performance and that such a plant-based diet can have favourable effects on oxidative stress and inflammatory profiles. The outcomes of this study may be of interest to those supporting the sports performance of strict plant-based eaters.
Abstract
BACKGROUND/OBJECTIVES In the general population, there is a popular belief that a vegan diet may be associated with a lower exercise performance due to the lack of certain nutrients in vegan individuals. Thus, the purpose of the present study was to examine endurance and muscle strength differences between vegan and omnivore participants. SUBJECTS/METHODS We studied 56 healthy young lean physically active women (age: 25.6 ± 4.1 years; body mass index: 22 ± 1.9 kg/m2). Participants were classified as vegan (n = 28) or omnivore (n = 28) based on their eating habits. All volunteers followed either a vegan or an omnivore diet for at least 2 years. Anthropometric measurements, body composition, estimated maximal oxygen consumption (VO2 max), a submaximal endurance test (70% of VO2 max), muscle strength (leg and chest press), and dietary factors were measured. RESULTS Both groups were comparable for physical activity levels, body mass index, percent body fat, lean body mass, and muscle strength. However, vegans had a significantly higher estimated VO2 max (44.5 ± 5.2 vs. 41.6 ± 4.6 ml/kg/min; p = 0.03, respectively) and submaximal endurance time to exhaustion (12.2 ± 5.7 vs. 8.8 ± 3.0 min; p = 0.007, respectively) compared with omnivores. CONCLUSIONS The results suggest that a vegan diet does not seem to be detrimental to endurance and muscle strength in healthy young lean women. In fact, our study showed that submaximal endurance might be better in vegans compared with omnivores. Therefore, these findings contradict the popular belief of the general population.
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Vegans, Vegetarians and Pescatarians Are at Risk of Iodine Deficiency in Norway.
Groufh-Jacobsen, S, Hess, SY, Aakre, I, Folven Gjengedal, EL, Blandhoel Pettersen, K, Henjum, S
Nutrients. 2020;12(11)
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Plant based diets, especially veganism have become increasingly popular all over the world. Changing from an omnivorous to a vegan or vegetarian diet has been associated with various health benefits; however, these dietary patterns are also linked to an increased risk of micronutrient deficiency. Iodine is a trace element which is needed to produce thyroid hormones and therefore maintain normal physiological functions of the body. In Norway, the main dietary sources of iodine are milk, seafood and eggs. The aim of this study was to evaluate iodine status, dietary intake of iodine, supplement use, macroalgae use and iodine knowledge of Norwegian vegans, vegetarians and pescatarian. Vegans, vegetarians and pescatarians in Norway are at risk of iodine deficiency and have limited knowledge of iodine. They were unable to reach recommended iodine intake from food sources alone. Data is needed on thyroid function in vegans, vegetarians and pescatarians to fully understand the consequences of iodine supplement use or macro algae use when adhering to a vegan, vegetarian or pescatarian diet in Norway.
Abstract
Low iodine intakes have been documented in different population groups in Norway. We aimed to assess iodine status, dietary intake, supplement and macroalgae use, and iodine knowledge in vegans, vegetarians and pescatarians. In this study, 115 vegans, 55 vegetarians and 35 pescatarians from the Oslo region of Norway, aged 18-60 years, participated. A spot urine sample was collected along with a dietary assessment of iodine intake, supplement and macroalgae use. The median urinary iodine concentration (MUIC) in vegans was 43 µg/L (moderate iodine deficiency), in vegetarians 67 µg/L and in pescatarians 96 µg/L (mild iodine deficiency). In multiple linear regression analysis, use of iodine supplements was one of the strongest predictors of UIC. About half of the participants had median 24-h iodine intakes below estimated average requirement (EAR) of 100 µg/day. Fifty percent had low knowledge score, while 27% had very low knowledge score. Vegans, vegetarians and possibly pescatarians in Norway, are unable to reach the recommended iodine intake merely from food and are dependent on iodine supplements. There is an urgent need for dietary guidance targeting vegans, vegetarians and pescatarians to avoid inadequate iodine intake in non-supplement users, as well as avoiding excess iodine intake in macroalgae users.
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Alpha-Linolenic and Linoleic Fatty Acids in the Vegan Diet: Do They Require Dietary Reference Intake/Adequate Intake Special Consideration?
Burns-Whitmore, B, Froyen, E, Heskey, C, Parker, T, San Pablo, G
Nutrients. 2019;11(10)
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Fish and seafood are good sources of long-chain omega-3 fatty acids, like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). A vegan diet does not include animal-sourced foods and is therefore void of EPA and DHA, unless algae-derived omega-3 supplements are consumed. Thus, vegans rely on the body's own production of long-chain fatty acids from plant-derived alpha-linolenic acid (ALA). However, adequate conversion can have several limitations. Vegan diets are generally rich in linoleic acid (LA), an omega-6 fatty acid, which in high levels can impede the conversion of ALA to EPA and DHA. Furthermore, the efficiency of conversion is influenced by gender, age or health conditions like obesity. This review sought to discuss whether vegans require special dietary recommendations for fatty acids and what these suggestions could be. Most studies assessing biological indicators of fatty acid status showed that vegans had lower levels of EPA and DHA compared to omnivores. Thus, the authors concluded that special consideration should be given to ALA and LA intake in vegan diets. In the absence of a set recommendation for a fatty acid ratio, a ratio of 4:1 (omega-6:omega-3) was proposed for vegans and omnivores. A reduction in LA and an increased intake of ALA of 2.2–4.4 g/day (or 1.1 g/day/1000 Kcals) was suggested to achieve such. This article is a useful guide when considering adequate fatty acid balance and omega-3 conversion for individuals following a vegan diet.
Abstract
Good sources of the long-chain n-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) include cold-water fish and seafood; however, vegan diets (VGNs) do not include animal-origin foods. Typically, US omnivores obtain enough dietary EPA and DHA, but unless VGNs consume algal n-3 supplements, they rely on endogenous production of long-chain fatty acids. VGN diets have several possible concerns: (1) VGNs have high intakes of linoleic acid (LA) as compared to omnivore/non-vegetarian diets. (2) High intakes of LA competitively interfere with the endogenous conversion of alpha-linolenic acid (ALA) to EPA and DHA. (3) High somatic levels of LA/low ALA indicate a decreased ALA conversion to EPA and DHA. (4) Some, not all VGNs meet the Dietary Reference Intake Adequate Intake (DRI-AI) for dietary ALA and (5) VGN diets are high in fiber, which possibly interferes with fat absorption. Consequently, health professionals and Registered Dietitians/Registered Dietitian Nutritionists working with VGNs need specific essential fatty acid diet guidelines. The purpose of this review was: (1) to suggest that VGNs have a DRI-AI Special Consideration requirement for ALA and LA based on VGN dietary and biochemical indicators of status and (2) to provide suggestions to ensure that VGNs receive adequate intakes of LA and ALA.
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Associations between Dietary Patterns and Bile Acids-Results from a Cross-Sectional Study in Vegans and Omnivores.
Trefflich, I, Marschall, HU, Giuseppe, RD, Ståhlman, M, Michalsen, A, Lampen, A, Abraham, K, Weikert, C
Nutrients. 2019;12(1)
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Colorectal cancer is associated with higher intakes of meat and lower consumption of fibre. Fibre may alter cholesterol and bile acid production and high bile acids may cause changes in the cells of the colon. Vegan diets high in fibre and low in fat may affect bile acid production and this observational study of 72 people aimed to compare bile acids in the faeces and blood of vegans and omnivores. The results showed that vegans had higher fibre and lower fat intakes, compared to omnivores, and although bile acids in the faeces were lower in vegans, blood levels were higher. Fat intake was associated with increased bile acids in the faeces whereas fibre intake was associated with lower levels. Coffee, fish, margarine, fried potatoes, bread, and processed meat were all associated with increased bile acids in the faeces and muesli was associated with lower levels. It was concluded that high fibre, low-fat intakes characteristic of vegan diets, are associated with lower bile acids in the faeces and this could impact colorectal cancer incidence. This study could be used by healthcare professionals to recommend a vegan diet high in fibre and low in saturated fat to individuals with colorectal cancer or those who are at an increased risk.
Abstract
Bile acids play an active role in fat metabolism and, in high-fat diets, elevated concentrations of fecal bile acids may be related to an increased risk of colorectal cancer. This study investigated concentrations of fecal and serum bile acids in 36 vegans and 36 omnivores. The reduced rank regression was used to identify dietary patterns associated with fecal bile acids. Dietary patterns were derived with secondary and conjugated fecal bile acids as response variables and 53 food groups as predictors. Vegans had higher fiber (p < 0.01) and lower fat (p = 0.0024) intake than omnivores. In serum, primary and glycine-conjugated bile acids were higher in vegans than in omnivores (p ≤ 0.01). All fecal bile acids were significantly lower in vegans compared to omnivores (p < 0.01). Processed meat, fried potatoes, fish, margarine, and coffee contributed most positively, whereas muesli most negatively to a dietary pattern that was directly associated with all fecal bile acids. According to the pattern, fat intake was positively and fiber intake was inversely correlated with bile acids. The findings contribute to the evidence that, in particular, animal products and fat may play a part in higher levels of fecal bile acids.
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Cardiometabolic risk factors in vegans; A meta-analysis of observational studies.
Benatar, JR, Stewart, RAH
PloS one. 2018;13(12):e0209086
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Healthy, balanced, plant-based diets have been associated with better health outcomes, however the role of dairy and meat products on heart disease and death due to heart disease is not fully understood. Vegan diets are strictly plant-based and could provide an opportunity to investigate the effect of eliminating animal products on heart disease risk. This meta-analysis of 40 observational studies aimed to evaluate the effect of a vegan diet on heart disease risk factors. The results showed that vegans in most countries had improved heart disease risk factors such as a small waist circumference, lower body mass index (BMI) and balanced blood sugars compared to omnivores, however studies from Taiwan failed to show this trend. It was concluded that a vegan diet in most countries is associated with better health outcomes compared to an omnivorous diet. This study could be use by healthcare practitioners to recommend a vegan diet to those at a higher risk of heart disease.
Abstract
BACKGROUND There is increasing evidence that plant based diets are associated with lower cardiovascular risk. OBJECTIVE To evaluate effects of a vegan compared to an omnivorous diet on cardio-metabolic risk factors. METHODS Meta-analysis of observational studies published between 1960 and June 2018 that reported one or more cardio-metabolic risk factors in vegans and controls eating an omnivorous diet were undertaken. Macro-nutrient intake and cardio-metabolic risk factors were compared by dietary pattern. The Newcastle Ottawa Scale (NOS) was used to assess the quality of each study. The inverse-variance method was used to pool mean differences. Statistical analyses were performed using RevMan software version 5•2 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen. RESULTS 40 studies with 12 619 vegans and 179 630 omnivores were included. From food frequency questionnaires in 28 studies, vegans compared to omnivores consumed less energy (-11%, 95% confidence interval -14 to -8) and less saturated fat (- 51%, CI -57 to -45). Compared to controls vegans had a lower body mass index (-1.72 kg/m2, CI -2.30 to -1.16), waist circumference (-2.35 cm, CI -3.93 to -0.76), low density lipoprotein cholesterol (-0.49 mmol/L CI -0.62 to -0.36), triglycerides (-0.14 mmol/L, CI -0.24 to -0.05), fasting blood glucose (-0.23 mmol/, CI -0.35 to -0.10), and systolic (-2.56 mmHg, CI -4.66 to -0.45) and diastolic blood pressure (-1.33 mmHg, CI -2.67 to -0.02), p<0.0001 for all. Results were consistent for studies with < and ≥ 50 vegans, and published before and after 2010. However in several large studies from Taiwan a vegan diet was not associated with favourable cardio-metabolic risk factors compared to the control diets. CONCLUSION In most countries a vegan diet is associated with a more favourable cardio- metabolic profile compared to an omnivorous diet.