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Abbreviations: IU = International Unit (1 IU = 0.025 µg vitamin D); EPA = eicosapentaenoic acid; DHA = docosahexaenoic acid Nutritional support A wide range of products is currently available to support vegetarians and specifically vegans in their dietary choices and as such offers them the same level of safety and convenience enjoyed by non-vegetarians. Some examples are non-dairy milks, fortified foods such as breakfast cereals, juices and spreads, as well as supplements. Meat-free alternatives, including meat ‘analogues’, which resemble meat in texture, can be substituted for meat in recipes. Vegetarian ready-meals are widely available and many manufacturers voluntarily label their products as suitable for vegetarians or vegans. Otherwise, the list of ingredients, which is a mandatory labelling element on food and drink packages in Europe, provides all the information required to assess the suitability of a specific product in the context of a vegetarian or vegan diet. Soy, in its various forms (plain beans, tofu, etc.), is a useful addition to the vegetarian/vegan diet. It can meet protein needs as effectively as animal protein, and some preparations can be considered sources of the omega-3 fatty acid ALA (but not EPA and DHA).8 Soy is also rich in iron in a protein-bound form that appears to be readily absorbed. Some minor plant compounds in soy – referred to as phytochemicals – are also thought to have a protective effect against cardiovascular disease, osteoporosis and some cancers.2,8 Note that other beans and legumes are also good sources of protein and minerals, so check what is in season. Vegetarian sources of vitamin B12 include milk and dairy products as well as eggs, all at the same time good sources of high-quality protein. This list implies that vitamin B12 is one of the most critical nutrients for vegans, who may need to use supplements or rely on yeast extract spreads to meet their requirements. Potential health benefits If planned well, vegetarian diets are characterised by a relatively higher consumption of fruit, vegetables, legumes and nuts. Compared to omnivore diets, they tend to be lower in saturated fat and cholesterol but higher in fibre, vitamins C and E, magnesium, potassium and phytochemicals, such as flavonoids and carotenoids. Such diets are thought to confer a protective effect against a number of chronic diseases and may contribute to the lower body mass index (BMI) values that are seen in vegetarians, particularly vegans.2,9-13 It should be noted though that body weight or BMI alone are not suitable indicators of good health. Given the somewhat restrictive nature of vegan diets in particular, a lower body weight may be brought about merely from reduced and/or monotonous food intake. The cardiovascular benefits of low meat consumption may be due, in part, to improved blood lipid profiles and lower blood pressure levels that are typically seen in vegetarians, as well as the beneficial effects of certain phytochemicals on cardiovascular function. Vegetarians are at lower risk of developing type 2 diabetes than meat eaters.2 This is partly due to the lower BMI of vegetarians, but there is an additional risk associated with eating meat, particularly processed meat (e.g. bacon, ham, salami). Diets rich in whole grain foods, nuts and legumes can substantially reduce the risk of developing the condition and improve blood sugar control in those already affected. A recent study has also shown a benefit of a vegetarian diet for metabolic syndrome.12 It is worth pointing out that the risk of diet-related diseases in general is small with a well-balanced food intake, regardless of whether or not meat or other animal food is part of the menu. Therefore, reports of increases in risk of a certain disease by eating specific animal foods should be taken with a pinch of salt. Often results are presented as “relative risk”, e.g. that people eating 100 grams daily of red meat (such as beef, lamb, and pork) or 50 grams daily of processed meat may have an approximately 20% higher risk of developing bowel cancer than people not eating any such meats.10 If we assume that someone who does not eat red or processed meat has a lifetime “absolute risk” of contracting bowel cancer of 5%, this risk would increase to 6% if that person started eating 100 or 50 grams daily of red or processed meat, respectively. Therefore, presenting the results in terms of “relative risk” rather than “absolute risk” often makes the effects of the independent variable bigger than they actually are.14 Whilst a totally meat-free diet may not be appropriate or desirable for everyone, forgoing meat on one or more days a week would be an approach for those wishing to simply reduce overall intake. The World Cancer Research Fund currently recommends people to eat less than 500g red meat per week.9 Eating fish rather than meat, especially in the context of a dietary pattern rich in vegetables, fruits and wholegrain products could be another option associated with health benefits.15 Such patterns are observed for example in the traditional Nordic and Mediterranean diets. In summary For those wishing to eat less animal foods or cut them out altogether, careful meal planning is required to ensure nutritional needs are not compromised. The most critical nutrients in this respect are vitamin B12, vitamin D, calcium, iron, zinc and the omega-3 fatty acids EPA and DHA. If executed well, vegetarian diets can be a viable alternative, yet a higher fruit and especially vegetable intake remains an important goal for vegetarians and meat eaters alike. References
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Terms used in this article
Blood pressure
Carotenoids
Cholesterol
Fat
Fatty acids
Lipid
Oil
Osteoporosis
Prostaglandins
Quality
Relative risk
Risk factor
Vegan
Vitamin
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Many people choose to exclude meat and other animal products from their diet for a variety of reasons and to varying extents. Careful planning is needed to ensure adequate nutrient intakes.
