The ABCs of nutrition: will a vegetarian diet provide all the vitamins and minerals you need? - includes related information on pumpkin and vitamins

Vibrant Life, May-June, 1992 by Patricia K. Johnston

Pumpkin: High in Beta-Carotene

The best source of beta-carotene, the vitamin-a compound believed to help fight heart disease and prevent some forms of cancer, is pumpkin. According to research by Charles Hennekens of Harvard University Medical School, about one-third cup of canned pumpkin contains some 20 milligrams, nearly four times as much as a large carrot.

Riboflavin niacin, pantothenic acid, cobalamin, folate-exotic words? No, simply B vitamins. And in nutrition B, isn't a supersonic bomber, ifs thiamine, also a B vitamin. Of course, there's A, C, D, E, K, biotin, pyridoxine and a host of minerals.

But what about vegetarian diets? Do they provide all the vitamins and minerals you need?

First let's consider what vitamins are and what they do. The dictionary defines them as organic substances; that is, they contain carbon. They also contain hydrogen, oxygen, and sometimes nitrogen and sulfur. Vitamins are needed in minute quantities to help control the metabolic processes that go on in our bodies. They do not, however, provide energy, as people often mistakenly think. They do help to change the energy in the food we eat to forms the body can use, and they help maintain our vision and our nervous tissue, and protect against damage from oxygen.

Water-soluble vitamins are the eight B vitamins and vitamin C, and fat-soluble vitamins are A, D, E, and K. it is often thought that water-soluble vitamins must be eaten every day, but the body stores enough of some to last for a few weeks and others for months or longer. ft is important, though, that the average intake over a week or two provides all the vitamins.

The body contains even larger stores of fat-soluble vitamins than water-soluble. Fat-soluble vitamins can be toxic. And just as children are especially susceptible to inadequate intake of nutrients, they are especially susceptible to overdoses. Supplements should be used only under a physician's care. However, toxicity is unlikely to occur from the diet.

Minerals. Minerals work with vitamins to control the various metabolic processes in the body. They provide the structural support in our skeleton and form the enamel of our teeth. They help our blood to clot, carry oxygen to all our cells, regulate our heart beat, and maintain proper fluid balance.

Like vitamins, minerals are divided into two categories: major and trace minerals. The major minerals are needed in larger amounts and include calcium, phosphorus, and magnesium. Trace minerals are needed in much smaller amounts. Some minerals, essential in very small amounts, are toxic at higher intakes.

Nutrient sources. The foods we eat carry the nutrients we need. Since no one food contains all the essential nutrients, we need to eat a variety of foods.

In general, the same kinds of foods contain similar nutrients. So if a group of foods is eliminated from the diet, care must be taken to ensure that the nutrients usually found in that food group are obtained from other sources. The potential for deficiency becomes greater as more foods are excluded from the diet. This is of special interest to vegetarians who do not use various animal foods products.

Vitamin B12- Vitamin B12 (cobalwnin) is of special interest in a vegetarian diet because the practical sources for this vitamin are animal products, such as meat, fish, poultry, eggs, milk, and other dairy products. B12 is manufactured by bacteria. The process occurs in the digestive tract of cud-chewing animals. B12 can then be absorbed and incorporated into their tissues or milk. The vitamin is not made by any plants.

Lacto-ovo- or lactovegetarians obtain adequate amounts of B12 from milk and dairy products and/or eggs. A total vegetarian diet would not contain this vitamin unless it had been added to a particular food product, and thus total vegetarians could develop a deficiency.

Labels on some fermented soy products, such as tempeh, state that they are good sources of this vitamin. And spirulina is touted by health food stores as being a rich source. However, these claims are misleading, and such products are not reliable sources of vitamin B12.

Confusion persists because the common method for analyzing vitamin B12 content does not distinguish between forms of the vitamin that are active for humans and those that are active for bacteria but not for humans. The latter forms are called B12 analogues, whereas the form that is active in humans is called cobalwnin. If a label simply says vitamin B12"' substantial amounts may be the analogue form.

Important for infants and seniors. The status of this vitamin is of particular concern because a deficiency can mean irreversible neurological damage. in the past few years several cases of vitamin B,2 deficiency in infants have been reported in the medical literature. The infants were all exclusively breast-fed by mothers who used no animal products. They developed normally for several months and then began to regress. Their activity progressively decreased, as did their socialization. They lost muscle control and became increasingly irritable and fretful. Two became comatose.