Vegetarian diets need planning

Press, 30 March 1989, Page 10

Vegetarian diets need planning

YOUR FOOD STYLE

JANICE BREMER DIETITIAN

The first International Congress on Vegetarian Nutrition held in Washington was organised to bring together scientists to examine the risks and benefits of vegetarian diets. Janice Bremer

continues her report from the congress.

All vegetarians exclude animal flesh from their diets. Beyond this common exclusion, some groups exclude milk products and/or eggs; some go further and even restrict some plant foods. . A diet oriented toward plant foods excludes some of our most valuable sources of essential nutrients.

One of the present nutritional concerns about vegetarian diets is with respect to low-fat diets and absorption of minerals. Excessive consumption of fibre, phytates and oxalates may interfere with absorption of some minerals.

Minerals The reported studies give conflicting results about the mineral adequacy of vegetarian diets. Vegetarian populations apparently have no gross mineral deficiencies so it was concluded at the congress that most vegetarians probably have adequate mineral status. This could be due either to an adapation to low mineral availability, or to wise food choices.

Studies do suggest precautionary recommendations against diets extremely high in substances that may inhibit mineral absorption. When we eat a varied and liberal diet these concerns are not a problem. But we do not yet know the optimal mix of amount and type of fibre and fat. When we start a low-fat diet programme it is important to have an adequate nutrient intake and an adequate calorie intake. Among the more common nutrient problems associated with vegetarianism are low intakes and availability (adequate absorption) of the minerals iron and calcium, and also possibly zinc, magnesium, and manganese. Other mineral deficiencies are also a possibility.

Among vegans — those who eat no meat, fish or dairy products — vitamin D deficiency, rickets, and poor growth in infancy, iron deficiency anaemia, and vitamin 812 deficiency anaemia may occur. Vitamins

Sources of vitamin 812 in vegetarian diets that exclude all dairy products are an ongoing concern. Vitamin 812 is present in our plant foods only in a random fashion as a contaminant from the environment. The congress highlighted that Bl 2 estimations by the food industry.did not always use reliable methods, and claims for 812 content were often not accurate. Fibre is estimated to reduce the availability of the vitamin B 6 we eat in our food by five to 10 per cent. While this is not a problem, increasingly research finds that B 6 in the form of pyridoxine (the name for B 6) glucoside is not absorbed very well at all. Interestingly, foods containing vitamin B 6 in this form are otherwise healthpromoting plant foods. The richest sources are the crucifers — such as cauliflower. Other rich sources include soybeans, carrots, and orange juice. This does not mean we need" to avoid these foods. We just cannot rely on their vitamin B 6 to be well absorbed. Research continues in this area. Those most at risk from a low B 6 status are pregnant and breast feeding women, infants, and the elderly. The observations about vitamin B 6 and vegetarianism highlight the importance of a varied diet for everyone. Children

One of the major concerns for vegetarian families is the nutrition of children. Although within normal limits, macrobiotically fed children and vegan

Check the

nutrient quality

(5) Include vitamin C-rich foods with meals containing wholegrains, but no rich source of protein (more next article);

children are reported to grow more slowly and be shorter than their meateating counterparts. A very important consideration for vegetarian diets for children is the total amount of food they can actually eat. Children’s stomachs are small and require foods that are relatively dense in calories without an over-abundance of low-calorie, excessively bulky foods. This does not mean children cannot eat fibre-rich wholesome foods, but it requires careful planning for them to live on plant foods alone. The efficiency of their protein intake may be decreased by dietary fibre, food processing, and storage but probably most importantly by inadequate calories. Soy bean products are critical to the nutrition of vegan children. But the congress brought warnings to not eat soy products to excess either. They contain a good source of protein and soy milk substitutes contain added minerals, but the whole beans are rich in fibre. They take a long time to eat, and may contain inhibitors of some of our digestive enzymes if they are not adequately cooked. So rather than providing nutrition, they may disturb the body’s digestion of other nutrient-rich foods. Raw foods

Diets containing too many raw foods can be very deficient in essential nutrients. Many foods need to be cooked to be digestible. An over-emphasis on raw foods depletes an already limited diet of valuable foodstuffs — for example, the starchy foods, which are critical to the energy intakes of non-meat-eaters.

It is impossible for children to live on a raw diet.

Be sure your vegetarian meals are: (1) Highly varied in content, using many different foods; (2) Enough to eat to satisfy appetite and calorie needs — if you are left hungry within two hburs of the meal, the meal was not dense enough;

(3) Enough to eat of nutrient dense foods — all foods should not be of the low-calorie, watery varieties, even weight watchers need some starchy and some protein-rich foods; (4) Contain multiple sources of dietary fibre — some wholegrain cereals, some wholegrain breads, some fruits, and plenty of the different varieties of vegetables;

(6) Contain milk or at least one daily milk product, if not then add some soy products; (7) Are not overloaded with raw foods at the expense of foods that are needed as well — especially for children.

The nutritional health of vegetarians depends on many factors. The restrictiveness of the eating pattern, the vegetarian’s use of health services, other aspects of lifestyle and personal idiosyncracies all play a part. Vegetarian diets can be nutritionally adequate and promote health when they are well planned. Unfortunately many vegetarians do not plan their diets in line with modern principles of nutrition, and many are starving because of unsuitable food choices.

How to plan a nutrient-rich vegetarian foodstyle — in my next column.