This is a question I’m often asked by students studying food technology and nutrition because there are some distinct differences between the two diets. There are many divisions between those who follow a particular diet regime. Much of the decision to adopt a diet is based on a host of factors, principally nutritional but also political, moral, ethical, social, animal welfare, environmental, sustainability etc. There is some issue that an omnivorous diet confers considerable biological advantage over all other diets including the vegan diet because it is so wide ranging in nutritional content and availability.
A distinction between lacto-ovo vegetarians and vegans needs to be made before we look at how the diets differ. Firstly, lacto-ovo vegetarians will not eat dairy products but will consume eggs usually as long as they are free range. Vegans will simply not eat any animal derived produce including dairy and any egg, even honey.
Lifestyle trends have a major impact in food choice for many of us. Vegans and lacto-ovo vegetarians have strong preferences for the way food stuffs in general are produced and tend to purchase or grow organic and whole foods. Freetrade foods are an important consideration for all but especially those adopting these two diets. Vegans do not consume honey on the basis that in its production, bees are starved and killed in the process.
The nutritional value of the diets shows some variation. Vegans have a lower calorie consumption than lacto-ovo vegetarians because their diets often rely wholly on fruit and vegetables. The protein content of the vegan diet is about 75% that of the non-vegan diet on average although this is still high enough to be regarded as appropriate and acceptable. Vegans usually have to consume complementary proteins so that the full range of essential amino acids are available. On that basis, more LBV (low biological value) proteins are consumed given that meats which are treated as HBV (high biological value) proteins are deliberately avoided. For interest, the essential amino acids are isoleucine, leucine, valine, lysine, methionine, phenylalanine, tryptophan and histidine.
A number of vegans look to a variety of nutritional sources to obtain a wealth of amino acids. Soya and other legumes offer a great deal in terms of protein value and the presence of essential amino acids and some minerals, but obtaining certain vitamins can prove to be an issue. Products such as Vecon, a concentrated vegetable stock and Marmite provides vitamin B12 for example. This is one vitamin that is very often only obtained in sufficient quantity from meat sources and is of little concern to carnivores. Quorn, the trademarked fungal protein from Fusarium is accepted by lacto-ovo vegetarians but generally not by vegans because it often contains egg proteins as part of the product development.
Let’s take a look at those vitamins and minerals which can be problematic in supply for vegans rather than lacto-ovo vegetarians. Calcium comes from a wide variety of sources including, bread, leafy green vegetables, pulses and legumes, baked beans, nuts, muesli and various fortified nut milks and soya milk. Selenium which is important for immunity is most often derived from brazil and cashew nuts, sunflower seeds, wholemeal bread and lentils.
Iodine which is needed for the hormone, thyroxine is obtained from seaweed and kelp supplements. Vitamins as mentioned before can be an issue in terms of supply although some unique sources are available. We’ve mentioned that vitamin B12 (cobalamin) comes from various fortified breakfast cereals and breads, soya milks and Vecon. Vitamin D which is needed for immunity and protecting a range of cellular structures can be obtained from fortified variants of vegetarian margarine, cereals and soya milk. Another vitamin B2 (riboflavin) comes from similar fortified products especially soya milk but also Marmite as well as Vecon.
It is thought that vegans obtains more than the national average of various vitamins including vitamin C, magnesium, copper, folate, beta-carotene and mostly all the essential fatty acids. Having said that , the total fat intake is about 25% lower than the average and the saturated fat intake is about 25% lower than the average. The carbohydrate intake is about 55% higher as in fibre and this can be even higher than lacto-ovo vegetarians.