Vegetarianism adequate

WEAVER c M, PROULX w R and HEANEY R (1999) Choices for achieving adequate dietary calcium with a vegetarian diet. Am J Clin Nutr. 70 (3 Suppl) 543S-548S. 

Vitamin B12 (cobalamine) is one of the most complex low-molecular-weight substances occurring in nature. The core of the molecule consists of a tetrapyrrol system (corrin), with cobalt as the central atom (see p. 108). The vitamin is exclusively synthesized by microorganisms. It is abundant in liver, meat, eggs, and milk, but not in plant products. As the intestinal flora synthesize vitamin B12, strict vegetarians usually also have an adequate supply of the vitamin. 

Intramuscular injection of as little as 3-6 pg of crystalline vitamin B12 is sufficient to bring about a remission of pernicious anemia and 1 pg daily provides a suitable maintenance dose (often administered as hydroxocobalamin injected once every 2 weeks). For a normal person a dietary intake of 2-5 pg / day is adequate. There is rarely any difficulty in meeting this requirement from ordinary diets. Vitamin B12 has the distinction of being synthesized only by bacteria, and plants apparently contain none. Consequently, strict vegetarians sometimes have symptoms of vitamin B12 deficiency. 

Vegetarians can achieve an adequate intake of the essential amino acids if they eat many different plant foods. Plant proteins can be chosen to be complementary, with some foods supplying amino acids that others lack. An alternative is to supplement the vegetarian diet with a rich source of complete protein such as milk or eggs. 

From the results of these studies it would appear that diets of both vegetarian and omnivore women tend to contain less than recommended total amounts of iron. Furthermore, the iron in vegetarian diets tends to come from foods of suspected low iron bioavailability. However, on the basis of biochemical indices of iron status, most seemed to be in adequate nutritional status. Recently, Bergan and Brown (29), reported results of a study involving new vegetarians. Results indicated that 50% had non-acceptable hematocrit levels 23% had non-acceptable hemoglobin levels, 18% had non-acceptable serum iron levels,... 

Administration. Most children and adults do not ingest sufficient dietary calcium and require supplements (see Tables 88-5 and 88-6). Individuals with certain characteristics or conditions—such as lactose intolerance nondairy vegetarian diet malnutrition low-fat diets and glucocorticoid, antiresorptive, or parathyroid therapy—also require evaluation for calcium supplementation. To ensure adequate calcium absorption, 25(OH) vitamin D concentrations should be maintained in the normal range." ... 

Why is it necessary to mix vegetable proteins to provide an adequate vegetarian diet ... 

Protein intake for adults should be approximately 0.8 g/kg ideal body weight per day. The protein should be of high quality and should be obtained from sources low in saturated fat (e.g., fish, lean poultry, and dry beans). Vegetarians should eat a mixture of vegetable proteins that ensures the intake of adequate amounts of the essential amino acids. 

Nutritional studies suggest that the iodine content of vegetarian diets may be inadequate, but adherence to a vegetarian diet need not lead to iodine deficiency. As diets become increasingly restrictive, assurance of adequate iodine intake increasingly depends on the appropriate use of iodized salt and other dietary supplements. Fortunately, the actual number of individuals who follow strictly vegan diets is small, and therefore so are public health risks of resulting iodine deficiency. 

Seaweeds are a good source of some water- (Bj, B2, B,2, C) and fat-soluble (P-carotene with vitamin A activity, vitamin E) vitamins. To ensure that the adequate intake of all vitamins is received in the diet, people (especially peopleon specialdiet, strict vegetarians, and vegans) can consume foods enriched with vitamins, for example, in the form of functional foods with vitamins as nutraceuticals, extracted from natural sources such as seaweeds. Seaweed vitamins are important not only due to their biochemical functions and antioxidant activity but also due to other health benefits such as decreasing of blood pressure (vitamin C), prevention of cardiovascular diseases (P-carotene), or reducing the risk of cancer (vitamins E and C, carotenoids). 

It is adequate to provide the population with a nutritionally acceptable, but mainly vegetarian, diet. If the populace were given the free choice of the types of food they would tike to consume, including some animal proteins, this may not be entirely tme. 

Babies are born with a limited hepatic reserve of vitamin B12. The content of vitamin B12 in breast milk is important to maintain adequate supplies. Infants of vegetarian mothers or mothers with unrecognized pernicious anaemia may therefore develop vitamin B12 deficiency. Vitamin B12 deficiency may have detrimental neurological effects such as psychomotor retardation and epilepsy. 

Observations at Hopewood House (1952-1956), a children s home in Australia which maintained a nutritionally adequate but mainly vegetarian diet in which refined carbohydrates... 

Vitamin B is found only in foods of animal origin, although it is also formed by some yeasts and bacteria. There are no plant sources of this vitamin. This means that strict vegetarians (vegans), who eat no foods of animal origin, are at risk of developing dietary vitamin B deficiency. The small amounts of vitamin B formed by bacteria on the surface of fruits may be adequate to meet requirements. Preparations of vitamin Bj2 made by bacterial fermentation, which are ethically acceptable to vegans, are readily available. 

The omission of cow s milk or goat s milk from a strict vegetarian diet is also likely to lead to deficiencies of calcium and vitamin D since few other foods contain adequate quantities of these nutrients in forms that are utilized readily. Hence, supplements containing them should be taken. 

Vegetarian athletes have a limited choice of protein sources, especially if they are vegan. These athletes would almost require the inclusion of soy protein in their diet to be able to consume an adequate protein intake. While it appears that soy protein may not be the ideal choice for maximal muscle PS, it has been shown to be viable as a sole source of dietary protein. Studies have been conducted where soy protein was used to replace other protein sources without negative effects on the subjects. However, these tests were conducted in nonexercising individuals. As shown by Phillips, soy protein may not be the optimal choice for athletes and those seeking increased muscle mass. Additionally, because both resistance and cardiovascular exercise alone can decrease cardiovascular risks, " the benefits of including soy in the diet of an athlete may not be worth the potential decrease in attained muscle mass. However, sedentary persons may notice less of the diminished effect of soy protein intake than highly trained and competitive athletes. 

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