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Eating Green: Meeting Nutritional Needs on Vegetarian Diet Dr Kate Marsh BSc, MNutrDiet, PhD, Grad Cert Diab Edn & Mgt Advanced Accredited Practising Dietitian Credentialled Diabetes Educator Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Introduction A vegetarian is someone who consumes a diet consisting mostly of plant-based foods including fruit, vegetables, legumes, nuts, seeds and grains. Some vegetarians also consume eggs and dairy products. While not true vegetarians, others follow a ‘semi-vegetarian’ diet where they restrict only certain animal foods or a ‘pesco-vegetarian’ diet where they eat fish but no other animal flesh. Main types of vegetarian diets: Lacto-ovo-vegetarian – eats dairy foods and eggs but no meat, poultry or seafood. This is the most common type of vegetarian diet. Lacto-vegetarian – eats dairy foods but not eggs, meat, poultry or seafood Ovo-vegetarian – eats eggs but no dairy foods, meat, poultry or seafood. Vegan – doesn’t eat any animal products including meat, poultry, seafood, eggs and dairy foods. Most vegans also won’t use honey or other animal products. While we don’t have any good data on the number of vegetarians and vegans in Australia, A 2010 national Newspoll survey of 1200 adults indicated seven out of 10 Australians are eating some plant based meals in the belief that eating less meat and more plant foods improves overall health. The popularity of the Meat-Free Mondays movement, which began in 2003 and has been adopted in many countries including the US, UK, Canada, Israel and Australia, also reflects the increasing awareness of the health and environmental benefits of eating less meat and adopting more plant-based meals. If you are not already aware of the Meat-Free Monday’s movement, take a look at the website now to find out more. Why not join up and receive regular emails and tasty meatfree recipe to try every Monday? http://foodwise.com.au/meat-free-mondays/homepage/ Dr Kate Marsh Page | 2 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet The reasons for choosing a vegetarian diet are varied but include: Health – there is now a significant body of evidence to demonstrate the health benefits of vegetarian and plant-based diets and this is a common reason someone might choose to become vegetarian Environment – there is increasing awareness of the environmental benefits of eating more plant foods and less meat for the environment, and this is becoming an increasingly common reason for people choosing a vegetarian diet or eating more plantbased meals. Animal rights – many people choose to follow a vegetarian diet as they believe that killing animals for food is inhumane, and there is an increased awareness of the questionable treatment of farm animals in factory farming. Watch this video to understand more about animal welfare. Religion – many religions advocate a vegetarian diet including Seventh-day Adventists, Hindus, Jains and Buddhists. Others avoid certain meats or only allow the consumption of meats which have been slaughtered in a particular way. Food safety - outbreaks of food-borne disease (eg food poisoning, mad-cow disease) from meat products, as well as increased concern over the additives in meat such as hormones and antibiotics have led some people to be concerned over the safety of eating meat. Ethics – this ties in with animal rights, with many vegetarians and vegans believing that it is not ethical to unnecessarily kill another living creature for food. There is also the issue of environmental ethics and food sustainability due to the fact that the production of animal foods is far less efficient than the harvesting of plant-foods. “Not everyone needs to or wants to become vegetarian, but reducing our dependence on meat is a good recipe for our own health and also that of our planet. Diets dominated by plant foods are almost certainly the way of the future”. Rosemary Stanton (Source: Stanton. A plant-based diet – good for us and good for the planet (editorial). MJA Open 2012; 1 Suppl 2: 5-6. Read the full paper here Dr Kate Marsh Page | 3 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Health Benefits of a Vegetarian Diet Improved health is one of the many reasons people choose to adopt a vegetarian diet and there is now a wealth of evidence to support the health benefits of a vegetarian diet. Vegetarians have been found to have lower rates of a number of health problems including overweight and obesity, cardiovascular disease, hypertension, type 2 diabetes and some cancers[1, 2]. A number of studies have also shown increased longevity among vegetarians[3, 4]. While vegetarians generally have a lower body mass index (BMI) and tend to be more health conscious than non-vegetarians[5], health outcomes remain better even when these factors are taken into account. It is likely that the benefits of a vegetarian diet are the result of both a reduced consumption of potentially harmful dietary components and an increased consumption of beneficial dietary components as outlined below[6]. Vegetarians generally eat less…. Saturated fat Vegetarians generally eat more….. Dietary fibre/cereal fibre Red meat Nuts Processed meats Legumes Animal protein Fruit and vegetables Haem iron Wholegrains Refined grains Soy products High GI carbs Low GI carbs As you can see above, vegetarian diets differ from non-vegetarian diets in many respects, but the most significant difference is the absence of red meat intake in a vegetarian diet. Research has linked higher intakes of red meat and processed meat with an increased risk of obesity, type 2 diabetes, gestational diabetes, cardiovascular disease and some types of cancer. A large study investigating the association of a wide range of meat intakes with chronic disease mortality found that both red and processed meat intakes were associated with modest increases in total mortality, cancer mortality and cardiovascular disease mortality. Low meat intake, on the other hand, has been associated with greater longevity. Dr Kate Marsh Page | 4 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Overweight and Obesity Research has consistently shown that vegetarians, and particularly vegans, are leaner than non-vegetarians. The European Prospective Investigation in Cancer and Nutrition (EPIC) Oxford study compared weight gain over 5 years in almost 22000 meat-eating, fish-eating, vegetarian, and vegan men and women. Weight gain was lowest in the vegan group and those who, during follow-up, had changed to a diet containing fewer animal foods. The study found that the mean BMI of participants was highest in the meat-eaters and lowest in the vegans. Fisheaters and vegetarians had a mean BMI which fell between the meat-eaters and vegans. The Adventist Health Study-2 similarly found that mean BMI was lowest in vegans and incrementally higher in lacto-ovo vegetarians, pesco-vegetarians, semi-vegetarians, and nonvegetarians. See Figure 1. Figure 1: Association between BMI and vegetarian diet status 29 28.2 28 26.8 27 25.9 25.6 26 25 24 23.8 23 22 21 Vegan LOV Pesco-vegetarian Semi-vegetarian Non-vegetarian Tonstad et al; Diabetes Care 2009; 32(5): 791-6. There are a number of possible explanations for this association including the lower fat intake, higher intake of dietary fibre, and lower energy density typical of a vegetarian diet. Foods such as wholegrains and nuts are more regularly consumed by vegetarians and have been independently associated with a reduced risk of obesity and weight gain. A higher intake of red meat, on the other hand, has been associated with an increased risk of weight gain. Dr Kate Marsh Page | 5 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Cardiovascular Disease The most consistent evidence for the health benefits of a vegetarian diet is for a reduced risk of coronary heart disease (CHD) and coronary disease mortality. A combined analysis of 5 prospective studies reported a 24% lower risk of mortality from ischaemic heart disease (IHD) in vegetarians compared to meat-eaters. Lacto-ovo vegetarians had a 34% reduced risk and vegans a 26% reduced risk. The benefit was apparent in those who had followed their diet for at least 5 years and was greater in younger age groups. These findings are not surprising considering that vegetarians generally have a better cardiovascular risk profile than non-vegetarians with lower total and low density lipoprotein (LDL) cholesterol levels, a lower body weight, and a lower incidence of diabetes and hypertension all of which contribute to CVD risk. Specific aspects of a vegetarian diet likely to contribute to its cardiovascular benefits include: A lower intake of saturated fat and greater proportion of unsaturated fats A higher intake of wholegrains. Several studies have demonstrated an association between wholegrain intake and cardiovascular disease risk and a recent meta-analysis estimated that a greater intake of wholegrains was associated with a 21% lower risk of CVD events. A higher intake of legumes. The National Health and Nutrition Examination Survey (NHANES) 1 Epidemiologic Follow-up Study found that consuming legumes at least 4 times per week, compared to less than once per week, was associated with a 22% reduced risk of CHD and an 11% reduced risk of CVD. A higher intake of nuts. Regular nut consumption has been found to protect against CHD in both epidemiological and clinical trials. Nuts may protect against CHD through effects on lipids, lipid oxidation, inflammation and vascular reactivity. A higher intake of soy foods. Soy protein has been shown to reduce total and LDL cholesterol levels and a meta-analysis of thirty studies demonstrated a small but significant reduction in both total and LDL cholesterol with the consumption of 25g of soy protein per day. While individual components of a vegetarian diet may provide benefits for CVD risk, the combination of these foods is likely to provide the greatest effect. For example a vegetarian diet incorporating soluble fibre, soy protein, almonds and plant sterols (the ‘Portfolio diet’) has been shown to reduce LDL cholesterol to a similar extent to a low dose of statins (the most commonly prescribed cholesterol-lowering medication) over 4 weeks. While some studies have linked red meat intake with coronary heart disease risk a recent meta-analysis found that processed meat intake, but not red meat intake, was associated with a higher risk of coronary heart disease. Several studies have demonstrated the benefits of a Mediterranean diet, a mostly plant-based diet with low meat intake, with a reduced risk of coronary heart disease. Dr Kate Marsh Page | 6 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Hypertension Evidence suggests that a vegetarian diet may help in both the prevention and management of hypertension. The EPIC-Oxford study found that non-meat eaters had a lower prevalence of hypertension and lower systolic and diastolic blood pressures than meat eaters but this was largely due to differences in body mass index. The age-adjusted prevalence of self-reported hypertension was significantly different between the four diet groups, ranging from 15.0% in male meat eaters to 5.8% in male vegans, and from 12.1% in female meat eaters to 7.7% in female vegans. Fish eaters and vegetarians had a similar, intermediate prevalence of hypertension. In the Adventist Health Study-2, a significant, graded association with blood pressure was also observed. Compared with non-vegetarians, the odds ratio for hypertension (defined as a systolic BP > 139 mmHg or diastolic BP > 89 mmHg or use of antihypertensive medications) 0.37 for vegans, 0.57 for lacto-ovo vegetarians and 0.92 for partial vegetarians. The relationship remained but was attenuated after adjustment for BMI (see figure 2). Figure 2: Risk of hypertension according to vegetarian diet status 1.4 1.22 1.2 1 0.86 0.92 1 1 0.8 0.53 0.6 0.4 0.57 0.37 0.2 0 Vegan LOV Partial vegetarian Non-vegetarian Petterson; Public Health Nutr. 2012; 15(10): 1909–1916. (note: hashed bars are after additional adjustment for weight) A number of randomised clinical trials have shown that a vegetarian diet can lower blood pressure in both normotensive and hypertensive individuals. While it is well accepted that both weight loss and reducing sodium intake can lower blood pressure , the effect of a vegetarian diet on blood pressure appears to be independent of these, suggesting that other components of the diet are responsible. These findings are consistent with the results of the DASH (Dietary Approaches to Stopping Hypertension) trial which found that a diet high in fruit, vegetables, wholegrains, and low fat dairy products significantly reduced blood pressure in those with normal blood pressure or mild hypertension. Dr Kate Marsh Page | 7 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Diabetes Observational studies have demonstrated a significantly lower risk of type 2 diabetes in individuals following a vegetarian diet compared to non-vegetarians. The original Adventist Health Study found that vegetarians had approximately half the risk of developing diabetes while in the more recent Adventist Health Study-2, involving more than 60 000 men and women, those following a vegan diet were found to have a diabetes prevalence approximately one-third that of non-vegetarians, while the lacto-ovo vegetarians, pescovegetarians and semi-vegetarians had an intermediate diabetes prevalence. After adjusting for confounding factors, those following a vegan diet had almost a 50% reduction in the risk of developing type 2 diabetes compared to non-vegetarians and the risk reduction became incrementally smaller as more animal products were consumed as shown in Figure 3. Figure 3: Risk of diabetes according to vegetarian diet status 1.2 1 1 1 0.8 0.7 0.6 0.76 0.56 0.54 0.51 0.69 0.43 0.4 0.32 0.2 0 Vegan LOV Pesco-vegetarian Semi-vegetarian Non-vegetarian Tonstad et al; Diabetes Care 2009; 32(5): 791-6. (note: hashed bars are after additional adjustment for weight) Whether the reduction in risk of diabetes in vegetarians can be attributed to the absence of meat or the higher intake of plant foods such as wholegrains, legumes and nuts is unclear. However several studies have shown a positive association between dietary heme iron intake and heme iron intake from red meat and the risk of type 2 diabetes. A positive association between the intake of red meat, processed meats and animal protein and the incidence of type 2 diabetes has also been shown. A recent systematic review and metaanalysis of cohort studies of meat consumption and type 2 diabetes risk estimated the relative risk comparing high versus low intake was 1.17 for total meat, 1.21 for red meat and 1.41 for processed meat. The authors predict that a 120g per day increase in red meat consumption increases the risk of diabetes by 20% and a 50g per day increase in processed meat consumption increases the risk by 57%. Dr Kate Marsh Page | 8 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet There are only a few intervention studies assessing the effects of a vegetarian diet in people with diabetes, and weight loss has generally been greater on the vegetarian diets, making it difficult to determine the independent effect of the diets. However, greater weight loss may be one of the advantages of a vegetarian diet as even small amounts of weight loss can help in both the prevention and management of type 2 diabetes. One study comparing a low fat vegan diet with a diet based on the American Diabetes Association (ADA) guidelines found that the vegan diet reduced HbA1c levels significantly more than the ADA diet (1.23 versus 0.38 percentage points in those who didn’t change medication). Furthermore, 43% of subjects were able to reduce their medication compared to only 26% in the ADA group. Earlier studies of low fat vegan diets in patients with type 2 diabetes have also demonstrated significant improvements in blood glucose control and blood fats, as well as considerable reductions in medication use although the larger of these studies was not controlled. Dr Kate Marsh Page | 9 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Cancer Overall, cancer rates in vegetarians appear to be moderately lower than non-vegetarians, and life expectancy appears to be greater. However, results for specific cancers are less convincing and require more study. Most of the research conducted on vegetarian diets and cancer has involved lacto-ovo-vegetarians. Of the studies looking at vegan groups, most only cover a short period of time or a small group. The health benefits of protective compounds in a plant-based diet have been linked to the prevention of cancer initiation and a reduction in cancer cell growth. Foods that are central to vegetarian diets such as wholegrains, legumes, fruits, and vegetables are rich in fibre, folic acid, phytochemicals and antioxidants which may protect against cancer. On the other hand, eating red meat may contribute to cancer formation. The consumption of red meat cooked at high temperatures, diets rich in animal fat and cholesterol or diets high in animal protein have been associated with an increased risk of developing cancer. The World Cancer Research Fund released their second expert report in 2007 Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective, which is a is a comprehensive analysis of the literature on food, nutrition, physical activity and cancer. One of the 10 recommendations they make for reducing cancer risk relates to animal foods and is to limit intake of red meat and avoid processed meats. They recommend that individuals who eat red meat should to consume less than 500g per week, with very little, if any, being processed. They refer to 'red meat' as beef, pork, lamb, and goat from domesticated animals including that contained in processed foods, and 'processed meat' as meat preserved by smoking, curing or salting, or the addition of chemical preservatives, including that contained in processed foods. More details can be found here: http://www.dietandcancerreport.org/expert_report/recommendations/recommendation_a nimal_foods.php Other diseases Limited research has suggested that a vegetarian diet may also reduce the risk of other health conditions including diverticular disease, gallstones, rheumatoid arthritis, gout and kidney disease. While these findings are positive and add to the evidence of the health benefits of a vegetarian diet, the small number of studies mean that further research is required to confirm these benefits. Dr Kate Marsh Page | 10 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Meeting nutritional needs on a vegetarian diet. In addition to their health benefits, well planned vegetarian diets, including vegan diets, are nutritionally adequate and are appropriate for individuals during all stages of life. Some nutrients can be more difficult to obtain on a vegetarian diet, but careful planning and in some cases the use of fortified foods or supplements, can ensure that an individual’s nutrition needs are met while maximising the health benefits of a vegetarian or vegan diet. The following table shows the main food sources of key nutrients in a vegetarian diet and these are discussed in more detail in the following pages. Food sources of important nutrients on a vegetarian diet Dr Kate Marsh Protein Legumes, tofu, soy milk, tempeh, gluten, wholegrains (particularly amaranth and quinoa) nuts, seeds, eggs, milk, yoghurt. Iron Legumes/soybeans, wholegrains (particularly amaranth and quinoa), iron fortified cereals, tofu, tempeh, dried fruit, nuts, seeds, green leafy vegetables. Zinc Whole grains, legumes, tofu, nuts, seeds, tempeh, eggs, milk, yoghurt. Calcium Milk, yoghurt, cheese, calcium-fortified soy, rice, almond or oat milk, calcium set tofu, unhulled tahini, kale, Asian green vegetables, almonds. Vitamin B12 Milk, yoghurt, cheese, eggs, B12 fortified soy or rice milk, B12 fortified meat analogues (e.g. sausages and burgers). Note – mushrooms are not a reliable source as they provide only very small amounts. Omega-3 fats Flaxseed oil, linseeds/flaxseeds, chia seeds, walnuts, soy foods, omega-3 eggs, DHA-fortified foods (eg breads, yoghurts, orange juice). Vitamin D Milk, eggs, vitamin D fortified soy milk. Page | 11 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Protein Protein is an essential nutrient that is required for many vital roles in the body. Proteins are made up of amino acids – some of these can be made by the body while others (known as “essential” amino acids) must be supplied by the diet. A vegetarian can obtain of all the essential amino acids they need by eating a variety of different types of protein-rich plant foods each day. It was once thought that certain combinations of plant foods had to be eaten at the same meal but it is now known that strict protein combining is not necessary as long as a variety of protein-rich foods are eaten from day to day. Food sources of protein on a vegetarian diet: legumes including chickpeas, lentils and dried or canned beans soy foods including tofu, tempeh, textured vegetable protein (TVP) mycoprotien (Quorn) seitan (gluten) grains (particularly quinoa, amaranth) nuts and seeds soy milks and yoghurt eggs and dairy products (for lacto-ovo vegetarians) Daily protein requirements Men under 70 years Men over 70 years Women under 70 years Women over 70 years 64g 81g 46g 57g Pregnancy Breastfeeding 58-60g 63-67g Practical tips for meeting protein needs: Include a variety of protein foods each day Don’t just cut out the meat at meals – replace it with alternatives including legumes, tofu, tempeh or Quorn Choose more wholegrains such as quinoa and amaranth in place of refined grains Snack on nuts & seeds or add these to meals. Nut and seed spreads are also good choices. Soy milk has similar protein content to dairy but rice, oat and almond milk are low in protein (and for this reason are not suitable alternatives for young children) Dr Kate Marsh Page | 12 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Iron Iron is an essential mineral which plays a vital role in forming haemoglobin, which transports oxygen around the body, and assisting in energy-producing chemical reactions and maintaining a healthy immune system. Low iron levels lead to anaemia. There are two types of iron in food - haem iron is found in animal foods while non-haem iron is found in eggs and plant foods such as legumes, cereal grains, nuts, seeds and dark green leafy vegetables. Non-haem iron is not as well absorbed by the body but including foods high in vitamin C at the same meal can improve absorption. Phytates (in wheat bran) and polyphenols (in tea, coffee, cocoa and red wine) can inhibit the absorption of iron. Food sources of iron on a vegetarian diet: legumes wholegrains (especially amaranth and quinoa) iron fortified cereals tofu, tempeh dried fruit nuts & seeds dark green leafy vegetables Daily iron requirements for vegetarians* Men under 70 years 14mg Women 19-50 years 32mg Women over 51 years 14mg Pregnancy Breastfeeding 48mg 16-18mg * set at 180% higher than RDI for non-vegetarians due to lower absorption of non-haem iron although there is some question around the evidence for this recommendation – read more about iron and vegetarian diets here. Practical tips for meeting iron needs: Include legumes and tofu or tempeh with meals daily Choose more wholegrains such as quinoa and amaranth in place of refined grains Eat plenty of dark green leafy vegetables Snack on dried fruit & nuts Include vitamin C-rich fruit & vegetables with all meals Limit intake of tea and coffee to between meals rather than with meals. Avoid large amounts of unprocessed bran Dr Kate Marsh Page | 13 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Zinc Zinc is needed for reproduction, growth, wound healing, sexual maturation and for maintaining a healthy immune system. While it is found widely in plant foods, its absorption is reduced by phytates found in wheat bran, wholegrains and legumes. Processing a food by soaking, fermenting or sprouting can reduce the phytate level and make zinc more readily available – for example, the leavening and fermenting of grains in bread-making and the soaking & sprouting of legumes and grains. Food sources of zinc on a vegetarian diet: legumes wholegrains tofu, tempeh nuts & seeds eggs dairy foods (eg. milk and yoghurt) Daily zinc requirements for vegetarians* Men under 70 years 21mg Women 19-50 years 12mg Women over 51 years 14mg Pregnancy Breastfeeding 15-16.5mg 16.5-18mg * set at 150% higher than RDI for non-vegetarians due to lower absorption of non-haem iron although there is some question around the evidence for this recommendation – read more about zinc and vegetarian diets here. Practical tips for meeting zinc needs: Include legumes, tofu and tempeh in meals regularly Choose wholegrain breads and cereals Snack on nuts & seeds or add these to meals. Nut and seed spreads can also be used. Use sprouted legumes (eg. mung beans) in salads and sandwiches Avoid excessive intake of unprocessed wheat bran Dr Kate Marsh Page | 14 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Calcium Calcium is important for healthy bones and teeth and also plays a role in muscle contraction and relaxation, blood clotting, nerve function and regulation of blood pressure. While dairy products can provide plenty of calcium for lacto-ovo vegetarians, there are also many plant sources of calcium. Vegans can obtain their calcium from fortified non-dairy milks (eg soy, rice, oat or almond milks) or other plant foods rich in calcium. Calcium absorption is improved in the presence of vitamin D but is reduced by sodium, caffeine, carbonated drinks and phytates. Food sources of calcium on a vegetarian diet: calcium-fortified soy, rice or oat milk hard tofu (particularly calcium-set) unhulled tahini kale, Asian green vegetables almonds milk yoghurt cheese Daily calcium requirements for vegetarians Men 19-70 years Men over 70 years Women 19-70 years Women over 70 years 1000mg 1300mg 1000mg 1300mg Pregnancy Breastfeeding 1000mg 1000mg Practical tips for meeting calcium needs: Consume calcium-rich foods daily including dairy products or calcium-fortified products (important to check labels as not all non-dairy milks are fortified with calcium) Include other plant-based sources of calcium regularly such as hard tofu, almonds, unhulled tahini (sesame seed paste), dried figs, kale, broccoli and Asian greens. Limit salt intake Limit caffeine found in tea, coffee, cola and ‘energy’ drinks Ensure adequate vitamin D from sensible sunlight exposure Dr Kate Marsh Page | 15 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Vitamin B12 (cobalamin) Vitamin B12 is an essential vitamin which is found almost exclusively in animal foods. We need it to form red blood cells and to maintain a healthy nervous system. Deficiency can cause a type of anaemia and may lead to irreversible nerve damage. It is particularly important for women who are pregnant or breastfeeding as newborn babies have very little of their own stores and rely on obtaining vitamin B12 from their mothers’ breastmilk. Vitamin B12 is found in red meat, poultry, seafood, milk, yoghurt, eggs and cheese. Plant foods are not a reliable source of this vitamin and some plant foods promoted as containing vitamin B12 (such as tempeh and miso) contain an inactive form of B12, which interferes with the normal absorption and metabolism of the active form in the body and will not prevent a deficiency. Food sources of vitamin B12 on a vegetarian diet Milk Yoghurt Cheese Eggs B12 fortified soy or rice milk (check labels as only a few Australian brands have added B12) B12 fortified vegetarian sausages/burgers B12 fortified yeast spread (eg Marmite) Note: mushrooms are not a reliable source as they provide only trace amounts. Daily vitamin B12 requirements for vegetarians Men Women 2.4mcg 2.4mcg Pregnancy Breastfeeding 2.6mcg 2.8mcg Tips for meeting vitamin B12 needs: For those who eat them, dairy products and eggs should be included in the diet regularly Those following a vegan diet should choose soy milk fortified with vitamin B12 (only a few brands currently have vitamin B12 added in Australia). Some vegetarian burgers, sausages and yeast extracts (eg Marmite) are also fortified with vitamin B12. For those who don’t eat foods containing vitamin B12, it is important that they take a vitamin B12 supplement Dr Kate Marsh Page | 16 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Omega-3 Fats Omega-3 fatty acids are essential fats which are important in maintaining cell membranes, and which help to regulate metabolism, reduce inflammation, lower blood pressure and cholesterol, and may protect against heart disease. Omega-3 fatty acids are particularly important during pregnancy and breastfeeding as they play a role in brain and eye development. As the main source of these fats in the diet is fatty fish, vegetarians generally have low intakes, however the implications of this is unclear particularly when vegetarians generally have lower risk of chronic disease. A number of plant foods contain omega-3 fats but in the short-chain form (known as alphalinoleic acid, or ALA) which must be converted to the longer chain fats that our body uses (DHA and EPA). This conversion process may be inefficient in some people but can be optimized by choosing the right balance of fats in the diet. Food sources of omega-3 fats on a vegetarian diet: Chia seed (ALA) Flaxseed (ALA) Canola oil (ALA) Walnut (ALA) Hempseed (ALA) Soybean (ALA) Wheatgerm (ALA) Green leafy vegetables (ALA) Eggs (DHA) Sea vegetables (DHA) Microalgae (DHA) Tips for optimizing omega-3 intake: Regularly include good sources of ALA – suggested intakes of at least 2.6g/d for men and 1.6g/d for women - this is double the recommended Adequate Intake (there is no RDI for omega-3 fats) for the general population. Limit intake of omega-6 (sunflower, corn, sesame and grapeseed oils and spreads) Use MUFA (olive, canola, avocado) in place of PUFA oils and spreads Limit alcohol and caffeine Women who are pregnant or breastfeeding might consider a vegan DHA supplement – the recommended Adequate Intake is 110-115mg long-chain omega-3 in pregnancy and 140-145mg/day while breastfeeding. Dr Kate Marsh Page | 17 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet For more details about the adequacy of vegetarian diets read this supplement to the Medical Journal of Australia: Is a vegetarian diet adequate? Concepts and controversies in plant-based nutrition. Written by Australian Accredited Practising Dietitians and leading researchers the supplement includes papers on protein, iron, zinc, vitamin B12, omega-3 fats and meeting the Australian Nutrient Reference Values (NRVs) on a vegetarian diet, as well as a paper on the practical aspects of a vegetarian diet. Activity: Look up the content of key nutrients in some of the vegetarian foods mentioned above and compare this to the current Recommended Dietary Intakes (RDIs) to get an idea of the amount of these key foods needed to meet nutritional requirements for different ages and genders. The following websites are good for looking up nutrient details: NUTTAB 2010 – the official Australian nutrient database (all nutrients apart from vitamin B12) http://www.foodstandards.gov.au/consumerinformation/nuttab2010/ Calorie King Australia – search function for Australian foods including brand-name items (protein and calcium) http://www.calorieking.com.au/ The papers in the supplement above also contain tables showing the amounts of key nutrients in commonly-eaten vegetarian foods (protein, iron, zinc, vitamin B12, omega-3) https://www.mja.com.au/open/2012/1/2 Dr Kate Marsh Page | 18 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Vegetarian athletes While some may question the adequacy of a vegetarian diet for athletes, there are plenty of well-known vegetarian and vegan athletes whose success would suggest otherwise. This includes Olympian Carl Lewis, ultra-marathon runner Scott Jurek, tennis legend Martina Navratilova, boxer Mike Tyson and football star Ricky Williams. The American Dietetic Association, in their position paper on vegetarian diets, say that a well-planned vegetarian diets, including total vegetarian or vegan diets, are appropriate for individuals during all stages of the life cycle, and for athletes. Read this interview from the New York Times with three experts (a professor of health and exercise science, an associate professor of human nutrition and author of Vegetarian Sports Nutrition, and a dietitian and the author of Nancy Clark’s Food Guide for Marathoners) about vegetarian diets for athletes. If you work with vegetarian athletes, the following resources might also be helpful. Australian Institute of Sport fact sheet on Vegetarian Eating The Vegetarian Resource Group Athlete & Vegetarian/Vegan Diet resources Vegetarian diets : nutritional considerations for athletes (Venderley & Campbell). Sports Med 2006; 36 (4): 293-305. Vegetarian Sports Nutrition by Enette Larson-Meyer Thrive Fitness by Brendan Brazier The No Meat Athlete – Matt Frazier Dr Kate Marsh Page | 19 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Vegetarian meal planning As for all healthy diets, meal planning for vegetarian diets should focus on incorporating a wide variety of minimally processed foods from each of the main groups to ensure a plentiful supply of nutrients and phytonutrients. The Vegetarian Healthy Eating Plate illustrated below provides a visual guide for planning vegetarian meals. Vegies and/or salads – should include a variety of colours and fill half of plate. Wholegrains – are preferred over refined grain foods (e.g. brown rice instead of white rice) and occupy about one quarter of your plate. Plant proteins – legumes, nuts, seeds, soy products or vegetarian convenience products should satisfy about one quarter of your plate. Dairy or fortified soy – these can be included as snack (eg a tub of yoghurt or fruit smoothie) or incorporated into meals (eg yoghurt or milk with cereal, grated cheese on pasta). Fruit – is best eaten mostly whole, rather than juiced, and enjoyed as a dessert or snack. While it’s important to try to include all these components in each meal, certain cooking styles and cuisines may determine how you plate up your food and whether it’s eaten at once or spread over the day. Activity: Using the information above on the key nutrients, and healthy eating plate guide above, design yourself a 1-day vegetarian eating plan to meet your nutritional needs. Click here to download some sample vegetarian meal plans for different age groups and genders. Dr Kate Marsh Page | 20 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Glossary of plant protein foods There are many varieties of plant protein foods to suit different tastes and cuisines. These include whole foods, such as legumes and nuts, traditional products like tofu and tempeh and even faux meats, which can provide an easier transition for meat lovers and extra convenience. Legumes – dry beans, peas or lentils available in many different varieties including chickpeas, borlotti beans, black beans, kidney beans, lima beans, cannellini beans and red, green or brown lentils. These can be purchased dried or canned. Tofu or bean curd, is made from soybeans, in a similar way that cheese is made from dairy milk. It comes in silken, soft and firm textures and can be cut to desired size depending on use. The firm variety is great for stir-fries and curries while the soft and silken varieties go well in burgers, creamy dressings or desserts. TVP (textured vegetable protein) is a great substitute for mince when making traditional meals like bolognaise, shepherd’s pie or tacos. Made from soy flour, TVP is dehydrated to resemble mince. It can be stored in the pantry for many months. Tempeh – is made from soybeans which are cooked and fermented and then formed into a patty or cake. It has a firm texture and can be can be grilled, baked or pan-fried, or diced and added into stir-fries. It can also be sliced and used in place of meat in a wrap. Gluten – also known as seitan, it has a meaty texture and can be used in stir fries, casseroles or crumbed and cooked as schnitzel. Buy it canned or fresh from Asian stores or make your own from gluten flour. Quorn is a protein derived from a fungus (mycoprotein), which is available as a cooking ingredient in mince or strips to replace meat. You can also buy Quorn sausages, schnitzels, fillets, burgers and meatballs. Note - people sensitive to moulds may have an allergic reaction. Dr Kate Marsh Page | 21 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Convenience vegetarian products including burgers, patties, sausages and schnitzels. These are generally made from soy, nuts, gluten and/or grains and are available in canned, chilled, frozen or shelf stable options. Most are ready to heat and serve or can be used as ingredients in various meals. Some are fortified with nutrients including iron, zinc and vitamin B12 (mainly the Sanitarium range) which can be a useful way to boost intake of these nutrients. However many are also high in sodium so not ideal for everyday use. Common brands readily available in Australia include: Sanitarium http://www.sanitarium.com.au/products/vegetarian Frys http://www.frysvegetarian.co.za/product-category/our-food/ Australian Eatwell http://www.australianeatwell.com.au/products.php Bean Supreme http://www.beansupreme.co.nz/ Syndian http://syndian.com.au/products/ Have a look at the products available from the companies above to get an idea of the range of vegetarian options now on offer. Consider trying some of these yourself to see what they taste like! Dr Kate Marsh Page | 22 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Supplements Vegetarians don’t need to take supplements routinely. Depending on their individual dietary restrictions, health, and stage of life however, certain supplements may be beneficial. Vitamin B12 - those who don’t consume at least 2 serves of a food rich in vitamin B12 each day should take a vitamin B12 supplement and have a blood test annually to check vitamin B12 levels. Omega 3 – A microalgae DHA supplement may benefit pregnant women, children or people with arthritis. Vitamin D – Those following a vegan diet and those who have little sun exposure may need a supplement. Iron – an iron supplement should only be taken on the advice of a doctor or dietitian if the individual has confirmed iron deficiency, as excess iron can cause harm. For those who do need a supplement, not all supplements are suitable for vegetarians as they can contain animal-derived ingredients including gelatine and lactose – this is most relevant for vegans. To determine whether they are suitable, individuals can check labels carefully, check with the supplement manufacturer or choosing brands specifically formulated for vegans (eg Deva Vegan, Available online at www.devanutrition.com). Dr Kate Marsh Page | 23 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Common myths about vegetarian diets Myth: it is difficult to get enough protein on a vegetarian diet Studies of Australian vegetarians have found that protein intakes are significantly lower than for omnivores, however intakes still easily meet the recommended dietary intakes (RDIs) as most omnivores eat much more protein than is required. Most plant foods contain some protein, with the best sources being legumes, soy foods (including soy milk, tofu and tempeh), nuts and seeds. Grains and vegetables also provide protein. Myth: vegetarians need to combine proteins at meals As most plant foods contain limited amounts of one or more essential amino acids it was once thought certain combinations had to be eaten at the same meal to ensure sufficient essential amino acids. It is now known strict protein combining is unnecessary, provided energy intake is adequate and a variety of plant foods are eaten each day including legumes, wholegrains, nuts and seeds, soy products and vegetables. Soy protein has a Protein Digestibility Corrected Amino Acid Score (PDCAAS) equivalent to egg white or dairy protein (casein), meaning it is considered a complete protein. Myth: vegetarians need to take an iron supplement Vegetarian diets can contain as much or more total iron (non-haem) compared to mixed diets, primarily from wholegrain breads and cereals. Iron deficiency is not more common in vegetarians, although iron stores (serum ferritin levels) are often lower. Some studies have found lower iron stores are associated with reduced risk of chronic diseases (such as cardiovascular disease and type 2 diabetes), which may partly explain the lower risk of these diseases in vegetarians. Myth: dairy foods are the only good source of calcium. While a convenient source for many, dairy products are not the only, or best, source of calcium. Fortified soy milks, rice, oat and almond milks, unhulled tahini, Asian greens, almonds and calcium set tofu can all provide calcium for those who choose not to eat dairy. Myth: vegetarian diets are not suitable for pregnancy Vegetarian diets can be planned to supply the required levels of nutrients during pregnancy. Research shows there are no significant health differences in babies born to vegetarian mothers. The higher fibre content and lower energy density of many vegetarian diets may offer significant advantages, including a reduced risk of excess weight gain]. Further, some studies suggest that a lower intake of meat and dairy products reduces the pesticide content of breastmilk. Myth: vegetarian diets are not suitable for children Vegetarian diets are appropriate for children of all ages. The growth rate of vegetarian and vegan children is similar to non-vegetarian children if meals are planned well, according to the American Academy of Pediatrics and American Dietetic Association. Dr Kate Marsh Page | 24 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet Conclusion Well-planned vegetarian diets are not only nutritionally adequate, but also provide many health benefits, particularly in the prevention and treatment of many chronic diseases. In fact in Western countries, a vegetarian diet may present a significant advantage over meatbased diets and a number of studies have shown increased longevity in vegetarians. While potentially lower in some nutrients, careful planning can help to ensure that both a vegetarian or vegan diet meets all of the current recommended intakes for essential nutrients as well as maximising the intake of protective components present widely in plant foods. In fact, a vegetarian diet may well be one of the best ways to meet population dietary guidelines. Key Learning Points Vegetarian diets focus on fruits, vegetables, legumes, nuts, seeds and grains. Some vegetarian diets also include eggs and dairy foods. A varied and balanced vegetarian diet can provide all the nutrients needed for good health. Vegetarian diets may provide additional health benefits compared to non-vegetarian diets, such as reduced chronic disease risk. Vegetarian diets more closely match recommended dietary guidelines to eat plenty of fruits, vegetables, legumes, wholegrains and to limit saturated fats and sugars. A vegetarian diet doesn’t mean just cutting out meat. Careful planning along with knowledge of practical ideas for using a variety of plant foods is needed to ensure nutritional requirements are still met, particularly for the new vegetarian or those who wish to reduce their meat intake. Nutrients that may need more attention in a vegetarian diet include iron, zinc, calcium, vitamin B12, vitamin D and omega-3 fats. A minimally processed plant based diet with limited amounts of animal products eaten lower down the food chain, if at all, provides environmental advantages over a western style non-vegetarian diet. “Eat food. Mostly plants. Not too much.” Michael Pollan Dr Kate Marsh Page | 25 Eating Green: Meeting Nutritional Needs on a Vegetarian Diet References and Further Reading Appleby et al. (1999). "The Oxford Vegetarian Study: an overview." Am J Clin Nutr 70(3 Suppl): 525S-531S. Aune et al. (2009). "Meat consumption and the risk of type 2 diabetes: a systematic review and meta-analysis of cohort studies." Diabetologia 7: 7. Barnard et al. (2009). "A low-fat vegan diet and a conventional diabetes diet in the treatment of type 2 diabetes: a randomized, controlled, 74-wk clinical trial." Am J Clin Nutr. 89(5): 1588S-1596S. Barnard et al. (2009). "Vegetarian and vegan diets in type 2 diabetes management." Nutr Rev. 67(5): 255-263. Craig, W.J. and A.R. Mangels, Position of the American Dietetic Association: vegetarian diets. J Am Diet Assoc., 2009. 109(7): p. 1266-82. Fraser (2009). "Vegetarian diets: what do we know of their effects on common chronic diseases?" Am J Clin Nutr 89(5): 1607S-1612. Key et al. (2003). "Mortality in British vegetarians: review and preliminary results from EPICOxford." Am J Clin Nutr 78(3 Suppl): 533S-538S. Key, et al. (2006). "Health effects of vegetarian and vegan diets." Proc Nutr Soc 65(1): 35-41. Key et al. (1999). "Health benefits of a vegetarian diet." Proc Nutr Soc 58(2): 271-275. Key,et al. (1999). "Mortality in vegetarians and nonvegetarians: detailed findings from a collaborative analysis of 5 prospective studies." Am J Clin Nutr 70(3 Suppl): 516S-524S. Marsh K, Brand-Miller J. (2011). “Vegetarian Diets and Diabetes”. American Journal of Lifestyle Medicine 5(2):135-143. Marsh et al. (2012). "Health Implications of a Vegetarian Diet: A Review." American Journal of Lifestyle Medicine 6(3): 250-267. McEvoy et al. (2012). "Vegetarian diets, low-meat diets and health: a review." Public Health Nutrition 15(12): 2287-2294. Pan et al. (2011). "Red meat consumption and risk of type 2 diabetes: 3 cohorts of US adults and an updated meta-analysis." Am J Clin Nutr. 94(4): 1088-1096. Epub 2011 Aug 1010. Rizzo et al. (2011). "Vegetarian dietary patterns are associated with a lower risk of metabolic syndrome: the adventist health study 2." Diabetes Care. 34(5): 1225-1227. Sabate. (2003). "The contribution of vegetarian diets to health and disease: a paradigm shift?" Am J Clin Nutr 78(3 Suppl): 502S-507S. Dr Kate Marsh Page | 26