Over 1.5 million people in Britain are vegetarian and a further 1.5 million avoid all red meat. Many are opting instead for a wide range of different foods including some of the novel protein sources on offer such as tofu, quorn (myco-protein) etc. Analysing the nutritional status of this group, be they lactovegetarian, demi-vegetarian or vegan, is difficult because they tend to vary their eating patterns.
It was thought by some researchers that the calorie intake of vegetarians may be lower than their meat-eating counterparts and that this may lead to a deficiency in certain micronutrients. It is now generally believed this may not be the case. A study by Draper et al 1990 actually showed no significant difference in calorie intake between people following a demi-vegetarian, lacto-ovo vegetarian or vegan diet. What this means is that vegetarians are often at less risk, calorie-wise than groups such as slimmers who may be drastically reducing their calorie intake and at the same time, eating a very limited number of foods.
A Question of Protein
Just as calorie intake can vary from one individual to another, so too will protein requirements. The UK’s NRV suggests 60-84g for men and 54-62g for women depending on their level of activity i.e., equivalent to 10% of the total calorie intake. The Department of Health however suggests a lower level which is set at 44g for men and 36g for women. It is often assumed therefore that vegans and vegetarians are at risk of protein deficiency because such a high level of protein can only be derived from meat sources.
Of course in reality this is not true, particularly since most vegetarian diets contain a range of protein from pulses, nuts, dairy, grains and soya products. Contrary to popular belief, foods such as seeds, nuts, pulses and dairy products are rich in protein. Whilst each protein source may contain a different amino acid profile, eating a wide source of proteins over the course of a day ensures that the diet provides a plentiful supply.
The average diet supplies far more protein than is actually needed. There are in fact indications that there may be certain health benefits associated with a lower protein intake, because the diet is usually associated with less saturated fat intake.
A View of Vitamins
Researchers looking at the vitamin intake of vegetarian and vegan diets have been unable to produce clear-cut results, largely because of the variation in the diets consumed. Those less well informed groups such as teenagers who simply cut out meat without replacing it with suitable nutrient-dense alternatives such as eggs, nuts and pulses are likely to suffer from long term low level deficiencies.
Vegans should ensure that they use a vitamin B12 supplement, since vegetable sources of this nutrient (such as chlorella, a blue-green algae available in supplement form) are not compatible in humans and of little use for this particular nutrient.
A study undertaken by Millet et al (1989) found that in a group of middle-aged vegetarians living in France, intake of many vitamins, notably thiamin (Vitamin B1) and riboflavin (Vitamin B2), exceeded that of non-vegetarians. As a whole, B12 and D intakes were generally lower in the vegetarian group indicating a higher risk for deficiency in this group. In another trial the mineral and trace mineral content of vegetarian diets, lacto-ovo, lacto vegan and vegetarian diets were analysed. Diets containing diary products had a high calcium and phosphorous content and the magnesium content of all three types of diet was adequate or high. The zinc content in all three diets was lower than that of the NRV (15mg/day) whilst the iron content varied from 12mg to 22mg (Lois B Kramer et al (1984).
It has been suggested that this variation in mineral content of food could be due to a high phytate content of some diets. This substance is found in many cereal-based products such as whole-wheat bread, pasta and cakes.
In conclusion, it does seem as though the hypothesis concerning adequate proteins in vegetarian diets is unfounded. Nevertheless as researchers have demonstrated, there is a need to ensure adequate levels of trace minerals in the diet and groups such as teenagers, pregnant women and the elderly who follow a vegetarian diet are advised to take a high potency multi vitamin and mineral supplement to guard against deficiency of any micronutrients.
Which Vegetarian are You?
A person who will eat no food of animal origin
Vegetarians who include milk, eggs and poultry in their diet
A person who will eat only milk and eggs but no other food derived from animals