Unconventional Eating Practices and Their Health Implications

Symposium on Nutrition

Unconventional Eating Practices and Their Health Implications

Rhona M. Hanning, B.A.Sc.,* and Stanley H. Zlotkin, M.D., Ph.D.t

The terms "health foods, stress tabs, organic, megavitamin, orthomolecular, macrobiotic, and natural foods," are all part of the nutritional vocabulary of the 1980's. The diets and food choices that were considered to be fads 10 years ago continue to be popular, thus the term "fad" is no longer applicable. The routine use of unconventional foods and inappro"priate supplements is, however, associated with a number of nutritionally related problems, many of which are of direct relevance to the pediatrician. Vitamin D deficiency rickets has reappeared along with other nutrient deficiencies, including growth retardation, in strict vegetarian children. Incidences of vitamin overuse and resulting toxicity are increasing. Even infants have not been spared the health food movement. Many parents place high expectations on extravagant claims for the role of food and nutrients in the prevention and treatment of disease. Their unfounded faith is not surprising, since the many self-proclaimed nutritionists are only too willing to offer nutritional counsel. Even individuals with impeccable credentials, including Nobel prize winners and academic scientists, have promulgated faddist schemes. Some of these claims are not only unfounded, but may be harmful to children if carried out. Physicians can no longer take a passive role when children are being fed inappropriate foods or food supplements. They must be able to provide their patient with sound nutritional advice in order to avert potentially harmful practices. This review will provide an overview of unconventional foods and feeding practices and their health implications. *Ph.D. candidate, Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada t Assistant Professor of Pediatrics and Nutrition, Department of Nutritional Sciences, University of Toronto, and the Division of Clinical Nutrition and the Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada

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VEGETARIANISM

Vegetarianism itself is not an unconventional eating practice. In fact, much of the world's population exists almost exclusively on vegetarian diets with few ill effects. In North America, some immigrant groups and specific populations, such as the Seventh Day Adventists, routinely follow wellestablished vegetarian regimens. In the 1960's and 1970's, however, a new group of vegetarians emerged. Individuals who previously were omnivorous began to adopt vegetarian diets. Their reasons for adopting vegetarianism included perceived health benefits, and ethical, philosophical, religious, ecological, and occasionally economic reasons. 40 Adolescents seemed to be particularly attracted to meat-free diets, perhaps because of their reaction to animal slaughter or a desire to be slender.47 The extent of the dietary practices of the "new vegetarians" varied. Some ate fish or poultry, others avoided foods that were processed or grown using chemical fertilizers and pesticides, and still others adhered to extremely strict regimens such as Zen macrobiotic diets. As the food choices varied, so did the nutritional merit of the diets. 16 Vegetarian diets fall into three categories: 32 . 67 lacto-ovo diets, in which meat, fish, and poultry are not consumed, but milk, dairy products and eggs are allowed; lacto-vegetarian diets, which resemble the lacto-ovo pattern except that eggs are not used; and total, pure, or strict vegetarian diets, in which no animal products are ingested. The term "vegan" is also used to described total vegetarian diets, but has philosophical and life-style connotations for its adherents. 4 Well-balanced vegetarian diets potentially offer a number of nutritional benefits. The diets tend to be high in fiber and polyunsaturated fatty acids and low in cholesterol and energy.l While the diet offers clear advantages for the obese or hypercholesterolemic individual, the health benefits for the normocholesterolemic, nonobese individual are less apparent. 4. 59 For better or for worse, vegetarianism may impose a shorter and lighter stature on the growing child. 54 A well managed lacto-ovo or lacto-vegetarian diet, however, can meet the nutritional needs of an infant or small child. Even total vegetarian diets can meet the needs of children. Careful planning is necessary to accomplish this goal, however, and many nutritionists discourage total vegetarian diets, particularly in infancy, when physiologic needs are highest and the impact of nutritional deficiencies most severe. 32 The nutritional problems that have been associated with vegetarian diets in the pediatric population are summarized in Table 1, and will be examined individually. Low Energy The energy content of vegetarian diets is low in comparison to the average North American diet. This is particularly true of total vegetarian diets, which are low in fat because of the absence of animal products. 32 Vegeterian staples, such as rice or beans, have low energy density. A cup of either would provide approximately 200 calories, or about one sixth of the energy requirements of a 1 to 3 year old. It may be difficult, therefore,

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Table 1. Nutritional Hazards of Vegetarian Diets in Infants and Children DIET CLASSIFICATION

Lacto-ovo vegetarian Lacto-vegetarian Total vegetarian/vegan

NUTRITIONAL PROBLEM

Low energy Low energy and iron Low energy, B12 , Fe, protein, Ca, vitamin D, riboflavin

for children, with their small stomachs, to consume adequate volumes of mch foods to meet their energy needs. 32 In addition, poorly digestible plant foods may not be fully absorbed, thus contributing to inadequate energy intake in the child. 40 It is the energy, rather than the protein, content of vegetarian diets that is of greatest concern to the pediatrician, since inadequate energy intake will lead to delayed growth. Dwyer et al. 16 reported growth data on 142 vegetarian and 229 nonvegetarian children (age 3 weeks to 6 years) in the Boston area. They measured the length and weight of the children and then matched the results to appropriate growth curves. The growth of the vegetarian subjects was only slightly below that of the control population. Weight was 0.5 to 1.0 kg less and length was 1 to 2 cm lower depending on age, sex, and diet. Relative growth retardation was particularly significant at the time the children were weaned to a vegetarian diet (~ 12 to 35 months of age). In the same study it was noted that the growth of vegetarian children with more extreme dietary habits (for example, macrobiotic) was the most retarded, especially for length, and specifically at 2 to 3 years of age. The energy content of the diets of the growth-retarded children was below that recommended for age, while the protein content was appropriate. The lower energy intake, shorter stature, and lighter body weight of total vegetarian children has been noted, as well, in other studies. 54 For example, 25 infants from a religious "black Hebrew" vegan community were hospitalized with signs of protein-calorie malnutrition, while an additional 47 infants from the same community were noted to be growth retarded. 58 Although these infants had been exclusively breastfed until 3 months of age, analysis of samples of the breast milk that they had received showed low levels of protein, carbohydrate, and fat. Mter weaning, their diet consisted mainly of a combination of dilute soy milk (13.7 kcal/dl) with some fruits and vegetables. Clearly the growth failure observed in these infants was due to the inadequate energy content of their diet. Protein Although most vegetarian diets contain adequate quantities of protein, when energy intake is insufficient, the carbon skeleton of protein will be used as an energy source. The amino acids in the diet, therefore, will be unavailable for protein synthesis and growth. Vegetarian diets must concurrently provide adequate amounts of both protein and energy. Protein quality is defined in terms of its essential amino acid composition relative to the essential amino acid needs of the human. Infants and

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children are relatively more sensitive to protein quality than are adults. The diet of an infant must contain 37 per cent of total amino acids as essential amino acids, compared with 32 per cent in children and 16 per cent in adults. 50 Protein from animal sources is of high quality, and therefore lacto-ovo and lacto-vegetarian diets can easily meet protein needs. 32 Proteins from plant sources are all relatively deficient in one or more amino acids. Cereal grains, for example, are limited in the amino acids lysine, and legumes are limited in the amino acid methionine. When cereal grains and legumes are eaten in combination, each compensates for the limitation of the other,4 and the result is a protein source of comparable quality to animal protein. There are several reported cases of protein malnutrition in the infants of new vegetarians and macrobiotics. These infants were weaned onto poorly balanced foods at an early age. 32 Thus, it is essential that vegetarians have a good knowledge of complementing protein sources. Lappe's Diet for a Small Planet 36 provides a useful reference. The poor digestibility of some plant sources may also decrease the amount of protein absorbed. 40 The protein recommendations set out in American 24 and Canadian50 Dietary Guidelines are based on the digestibility of the average diet and should be adjusted upward if less digestible protein sources are used. Vitamin B12 Normally, a fetus is born with sufficient stores of vitamin B12 to last for the first year of life. 32 During pregnancy, however, maternal stores of B12 cannot be readily mobilized, and both fetal stores and breast milk supply must come directly from dietary B12 that has been ingested by the mother. Vitamin B12 is not found in plant foods, and the amount found in fermented soy products, tempura, and seaweed is inconsistent. 32 Therefore, vitamin B12 deficiency can occur in infants who are exclusively breastfed by totally vegetarian mothers who do not take B12 supplements. 13. 32, 40 Vitamin B12 supplementation is strongly recommended for pregnant and lactating vegan women, and infants, children, and adolescents who are not consuming animal products. 32 Minerals Mineral deficiency may be a problem for the vegetarian child for two reasons. First, phytates, which are found primarily in cereal grains, bind calcium and zinc, thereby limiting their absorption. In addition, vegetarian diets have 2.5 times more fiber than nonvegetarian diets,31 The fiber also decreases mineral bioavailability. Second, typicallacto-ovo, lacto, and vegan diets all contain low quantities of zinc. 35 Not surprisingly, low serum zinc levels have been reported in vegan children58 likely due to both the low dietary zinc content and the high phytate level in the diet. In addition, pure vegan diets contain only limited amounts of calcium primarily because of the absence of milk and milk products. Vitamin D Infants of vegetarian mothers may be born with low vitamin D stores. Breast milk contains only 20 IV of antirachitic activity per liter and therefore

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will not furnish the 100 IV/day necessary to prevent rickets. 13 In addition, infants born in temperate climate regions may not receive enough sunlight exposure, particularly during winter months, for adequate endogenous vitamin D production. Vitamin D supplementation is recommended for breast-fed infants, particularly if the sunlight exposure is limited. 13 Since vitamin D fortified milk or formula is not consumed by the totally vegetarian child after weaning from breast milk, older vegan infants who are not given vitamin supplements are also at risk of vitamin D deficiency rickets. Three cases of vitamin D deficiency rickets have been reported at The Hospital for Sick Children in Toronto. 13 In all cases the mothers were strict vegetarians and infants were entirely breast-fed during the first year of life. On weaning, the infants were given purely vegetarian diets without milk, eggs, or vitamin supplements. Dwyer et al. 18 reported 4 preschool children on macrobiotic diets who developed roentgenographic evidence of rickets, and Shinwell and Gorodisher also found rickets in a group of vegan infants. 58 These reported cases likely represent only a small fraction of infants who have developed vitamin D deficiency rickets due to faulty dietary practice. Once weaned from the breast, young infants who are not fed cow's milk based formulas, cow's milk, or dairy products should be given fortified soy formula, which will provide vitamin D, calcium, and vitamin B12 .59 If they are not receiving adequate amounts of vitamin D or calcium through the diet, then supplements are warranted. Iron Iron deficiency anemia is commonly observed in vegan children. 58 The etiology of the anemia is not difficult to explain. Iron in foods is either heme iron of animal origin, which is well absorbed, or non-heme iron whose absorption is poor and is influenced by other dietary components. While the iron in milk is well absorbed, it is present in low amounts (1 mg/L).4O Eggs contain more iron but also contain a factor that interferes with non-heme iron absorption. Phytates also decrease the bioavailability of food iron by binding with it, thus making it unavailable for absorption. The presence of phytates may therefore explain the poor iron absorption associated with legume ingestion. 38 Ascorbic acid (vitamin C), on the other hand, effectively increases the absorption of non-heme iron. Vegetarians, therefore, who consume foods rich is ascorbic acid together with iron containing foods may increase iron absorption and decrease their risk of iron deficiency anemia. 32 ZEN MACROBIOTIC DIETS

The goals of this very strict dietary regimen are largely spiritual. Followers of the Zen macrobiotic regimen progress through 10 dietary stages. In the first stage is elimination of animal products, followed by the elimination of fruit and vegetables, until, at the highest level, only brown rice and water are consumed. 4 Even water is limited to one glass per day, since urine and sweat are considered unclean.

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For young infants on macrobiotic diets, a formula called Kohoh is used as a substitute for milk. It is a composite of ground sesame seeds, brown rice, aduki beans, wheat, oats, soybeans, and water. The mixture is overly dilute and inadequate in vitamin D and B12 and calcium. 59 Extreme growth retardation has been reported in infants on this regimen 4. 53 as well as rickets, kwashiorkor, and marasmus. 52 The inclusion of honey, in order to increase the energy density of the vegan diet, is common practice. Botulism, however, has been reported in infants fed honey contaminated with botulin in spores; thus, honey is not considered an appropriate food for infants.40 Nut butters are also commonly included in vegan diets. Although nut butters are nutritionally acceptable, extreme caution is urged, since young children may aspirate on nuts and seeds if they are not very finely ground. Many of the followers of the Zen macrobiotic regimen are reluctant to seek orthodox medical care 4. 32 and may refuse nutrient supplementation or processed foods, including soya formulas. 40 It has been suggested, however, that parents may be more receptive of nutritional counselling for their children then for themselves. 4 Since the first few stages of the Zen regimen include foods of animal origin, moving children to lower levels may improve their nutritional intake. 40 Unfortunately, legal action has been necessary in some cases to achieve an acceptable diet for these children. 52 Guidelines for the Physician Perhaps the most important step a pediatrician can take in order to avoid the nutritional problems associated with vegetarianism is to ask about diet as part of the patient history. Pure vegetarians should be encouraged to breast-feed their infants for the first six months of life. During this time the diet of the mother should be nutritionally adequate, including a source of vitamin B12 , and the infant should receive a vitamin D supplement. If desired, soy protein isolate formulas are an appropriate alternative to breast milk. For the older vegan infant and child, vitamin D and B12 supplements should be prescribed as well as iron. 40 If children do not receive fortified soy milk, calcium supplements may be necessary as well. Since energy intake may be limited, height and weight should be routinely followed. Children should optimally receive a variety of foods, including a mixture of plant protein sources, so as to improve protein quality. If parents are not aware of the potential limitations of a vegetarian diet, they should receive counselling either by a qualified physician or a trained dietitian or nutritionist. Since many "new vegetarians" may have an inherent mistrust of the health establishment, it is imperative that physicians or nutrition counsellors approach the parent or patient with a great deal of sensitivity in order to maximize the chances that their nutritional advice will be followed.

FAST FOODS Fast foods are foods that are prepared quickly and uniformly in one of a number of fast food outlets. Junk foods, on the other hand, are those

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foods that have no nutritional value other than as a source of calories. In Canada, for example, there are probably 20,000 fast food places. Not only have they increased in number, but the variety of fast foods offered has also increased. Besides the ubiquitous hamburger, the bill of fare now includes roast beef, chicken, fish, and such ethnic offerings as pizza, chili, and tacos. Much of the appeal of these meals is in their convenience. There is no shopping, no preparation, no clean-up; ordering requires a minimum of decision-making, and service is usually fast. Consistency is another key to the fast food chain success. A Big Mac may not be gourmet fare, but it's a Big Mac whether you order it in Boston or Bobcaygeon. Another part of the fast food appeal is economy. It is a cheap way to eat out. The average price of a fast food meal for one person is probably about $3.00. At a conventional restaurant, the average price would certainly be more than double that amount. A survey recently completed indicated that at least 33 per cent of adults eat out everyday, and that, of these adults, 28 per cent do so at fast food places. 21 An impression that most people have about fast foods is that they are made up of processed materials and are basically less good for you than "natural foods." A common misconception about processed foods is that they are devitalized, robbed of nutrients, and inferior in nutritional quality to natural foods. An examination of the nutritional content of some of the more commonly eaten fast foods shows that this is not the case. Salt and caloric content, however, are high relative to recommended allowances. The McDonald's quarter-pounder with cheese and a vanilla shake contains 770 calories, 36 g of protein, 38 g of fat, and 970 mg of sodium as salt. As a percentage of the RDA (Recommended Dietary Allowance, USA), this meal contains 60 per cent of the protein RDA, 5 per cent of the vitamin A RDA, 25 per cent of the vitamin C, 35 per cent of the calcium, and 25 per cent of the iron. A typical meal of a Big Mac, regular French fries and 2 per cent milk would contain 900 calories, 1240 mg salt, and a similar percentage of the U.S. R.D.A. for protein and vitamins. Finally, in order to be fair to Burger King, one typical meal contains 900 calories, 1230 mg salt, and once again a similar percentage of the U.S. R.D.A. for protein and vitamins. The Significance of the high salt and caloric content of the various fast food meals is the potential danger of developing or potentiating hypertension from too much salt in the diet, or obesity from a high energy diet. Yet high salt and high caloric content are not unique to the fast foods. 22 The caloric and salt content of a McDonald's hamburger versus a tuna fish salad sandwich verus a peanut butter and jelly sandwich (three commonly eaten children's lunches) are very similar. Therefore, one has to be very careful in putting specific blame on the fast foods as major contributors to either increased energy intake or increased salt intake. What is the final conclusion? First, fast foods are not junk foods. Any of the fast food entrees plus French fries and a shake would prOVide about one-third of all the nutrients an adult male should have in a day. But the meal would also provide more than half the daily calories recommended for a women or child. Although teenagers generally have a little more leeway, obesity is the most common nutritional problem found in this

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group,48 and excessive caloric intakes should be avoided. In addition, the meal would provide as much as 1000 to 2000 mg of sodium. It would seem more prudent to advise patients with high blood pressure or obesity to limit their intake of foods containing high amounts of salt and high amounts of energy. For all others, however, although the fast foods are high in calories, fat, and sodium and low in fiber, they are certainly not entirely off limits. They are acceptable nutritionally when consumed judiciously, and as part of a well-balanced diet. If fast foods are eaten often, one might think about skipping the fries and shakes, since the fries provide a lot of fat and calories, some are high in sodium, and certainly the milkshakes are sugar-laden and high in calories. Certain nutrients may be low in fast food meals if no fruits and vegetables are selected, such as vitamin A and C and calcium if there are no milk products. 21 All individuals should be encouraged to eat a balanced diet, which includes adequate amounts of food from all the dietary groups including the bread-cereal group, vegetable-fruit group, meat group, and milk group. Many fast food chains are attempting to upgrade their selection by including salad bars, yogurt, and similar selections to appeal to the nutrition-minded consumer.

THE TOXICITY OF VITAMINS Megavitamins In Canada and the United States, expert committees on nutrition have established the amounts of vitamins and other nutrients needed by healthy individuals of various age and sex categories not only to prevent deficiency, but to allow for optimal function and to maintain adequate stores. The American R.D.A. and the Canadian R.N.I.24,50 should be used as the working standard for optimal nutrition. 73 Self-proclaimed nutritionists suggest, however, that there is such wide biologic variability in an individual's daily requirements 70 that high doses of vitamins are needed as "nutritional insurance." Megavitamin ingestion is said to prevent colds, help cope with stress, increase energy levels, treat mental retardation, and may even lead to a longer life. 73 The megadoses of vitamins that are advocated refer to intakes of one or more vitamins in amounts 10 or more times the R. D.A. 29,59 Although the claims are largely unfounded, vitamin sales are now more than a billion dollar industry. Vitamins are organic compounds that are required in small amounts for normal human metabolism. When they are used in megadose amounts, however, they no longer act as vitamins, but as pharmacologic agents. Substances which are harmless in small doses may be harmful in large doses or may build up over a number of years. 73 It is well recognized that fat-soluble vitamins if taken in excess may be toxic. Recent studies have shown that high intakes of water-soluble vitamins are also associated with toxicity and complications. In addition, they may interfere with the actions of other vitamins or drugs. 3 Vitamin supplements are not needed by healthy individuals consuming balanced meals. Yet, it has been established that one third of the Canadian

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population takes vitamin supplements regularly, 24 per cent of them children. 65 There is a feeling that "more of a good thing is better." Pharmacies, department stores, and health food stores offer, without prescription, a tremendous range of vitamins, alone and in combinations, in small and massive doses. In addition, the doses can be manipulated by changing the frequency of intake. 15 It is perhaps not surprising that an increasing number of vitamin toxicity cases have been reported in recent years. 59 Vitamin A Vitamin A is a fat-soluble vitamin that is found in sufficient amounts in the diets of most children. It has been said that the hazards of toxicity from routine supplementation of children fed good diets is greater than the hazards of deficiency in children not given supplements. 4 In a study of the nutritional intake of over 300 healthy Canadian infants (from birth to 18 months of age), supplements accounted for 30 per cent of the daily vitamin A intake. Based on dietary intake records, however, dietary vitamin A was adequate in most infants; therefore, the supplements were largely unnecessary.71 Vitamin A deficiency is associated with visual impairment and eventually blindness. Vitamin A supplements have therefore been recommended, though never proved successful, in the treatment of childhood blindness and visual impairment. 15,65 Vitamin A has also been advocated along with other megavitamins to treat minimal brain dysfunction. Toxic reactions have been reported in a four-year-old child undergoing this therapy. 57 Vitamin A has also been recommended in large doses to treat acne. When vitamin A's therapeutic efficacy was compared with a placebo, it was found that doses of 10,000 and 20,000 IU vitamin Alday over 3 to 4 months were of no benefit. Treatment of acne with 30,000 IU/day, however, produced excellent results in 50 per cent of the subjects. 34 At this intake level, toxicity signs such as headaches and dry skin were reported. It should be noted that more than one third of the patients for whom vitamin A is prescribed to treat acne are adolescent females who are also at risk for pregnancy. 2 There have been case reports describing a high risk of spontaneous abortion 23 , 37 and malformations in the offspring of mothers taking high doses of vitamin A in pregnancy. Abnormal ears, cleft palate, congenital heart disease, and central nervous system malformations have been described. 23, 37 Because of the strong link between high-dose vitamin A therapy and teratogenicity in humans, physicians should exercise extreme caution when prescribing vitamin A preparations for women, including adolescents, of child-bearing potential. 62 The chronic ingestion of 50,000 IU vitamin Alday is toxic to adults, while children may experience toxicity with doses as low as 20,000 IU/day over a relatively short period of time. Aqueous vitamin A preparations are very well absorbed and are approximately six times more toxic than oilbased preparations. 59 Although the symptoms of toxicity vary from individual to individual, children generally experience a lack of appetite; dry, itchy,

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scaly skin; hair loss; subperiostal new bone growth and cortical thickening especially of small (hands and feet) and long bones; bone pain; enlargement of the liver and spleen; retarded growth; and occasionally papilledema, double vision, increased intracranial pressure, and symptoms mimicking brain tumor. 4, 41, 43, 54, 64, 73 With toxicity, plasma vitamin A levels are raised to over 200 fLg/dl; therefore, measurement of blood levels and a bone scan may provide early clues of toxicity. 57 Thankfully, all symptoms disappear upon withdrawal of the vitamin. Vitamin D Vitamin D is also a fat-soluble vitamin and is considered the most likely of all vitamins to cause overt toxicity.64 It is present in many multivitamin supplements, some calcium supplements, and most milk products. Vitamin D is also produced from the action of ultraviolet light on 7-dehydrocholesterol in the skin. An intake of 400 IV of vitamin D is adequate for a young child and 100 IV/day is sufficient for most infants. This level would be sufficient even without exposure to the sun.4 It is difficult to state a minimum toxic dose, since individual sensitivities vary. Doses of 3000 to 4000 IV/day used in Britain and Europe after World War II have been linked to idiopathic hypercalcemia, which was prevalent at the time. 4 There is even one report that implicates excessive sunlight exposure to hypercalciuria and kidney stone formation. 30 Vitamin D toxicity may be either acute or chronic. The symptoms result from deranged calcium metabolism. Toxicity symptoms include anorexia, nausea, weight loss, polyuria, muscle weakness, headache, hypercalcemia, metastatic calcification, bone pain, hypertension, and even kidney failure secondary to nephrocalcinosis. 64 , 70, 73 The toxicity symptoms will persist for months after exogenous vitamin D is discontinued;70 therefore, prevention of misuse must be emphasized. Vitamin E Vitamin E has been called the vitamin in search of a disease. Premature infants, because of low stores and inadequate dietary intake, may need supplemental vitamin E to prevent red blood cell hemolysis. 30 Most other healthy infants and children can easily meet their vitamin E needs through their diet. Yet, the popular press has promoted Vitamin E for everything from skin care to enhanced sexual prowess, thus inducing a large number of people to self-medicate with the vitamin. Surprisingly, no clear vitamin E toxicity picture has developed. Vague symptoms such as muscle weakness, headaches, nausea, and fatigue have appeared with doses of 300 to 800 IV/day. 64, 73 Excesses of vitamin E may interfere with vitamin K metabolism, resulting in a prolongation of prothrombin time and a bleeding tendency.4, II, 70 Vitamin E megadoses may also antagonize vitamin A73 and produce blurred vision. 73 Vitamin C Vitamin C came into the spotlight with the publication of Linus Pauling's book Vitamin C and the Common Cold. Dr. Pauling advocated large daily doses of ascorbic acid to prevent and treat colds. His theory

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prompted a large series of investigations. The consensus from the results of the many studies was that vitamin C is ineffective in preventing colds; however, it does lead to a modest reduction in the severity of symptoms associated with a cold. 6 The gram quantities used in early trials seem to be excessive. McLean et al. 44 found a similar reduction in the duration and number of symptoms associated with a cold using only 80 mg of vitamin C per day-the amount in an average-size grapefruit. Individuals who ingest large doses of vitamin C on a regular basis may exhibit deficiency symptoms on withdrawal of the vitamin. This is of particular concern to the pediatrician in the case of rebound scurvy of infancy. 10, 51 Scurvy was reported in two infants consuming seemingly adequate amounts of vitamin C (60 mg/day). It was found that their mothers had consumed a supplement of 400 mg vitamin C/day during pregnancy, 4 thus presumably promoting a dependency in the infants for a larger intake of the vitamin. At birth, although infants received adequate amounts of vitamin C by traditional standards, intakes were in fact suboptimal, with scurvy resulting, Certainly, large doses of vitamin C during pregnancy should be avoided. The use of megadoses of vitamin C is associated with other unfavorable side-effects: these include (1) kidney stone formation-the pH of urine may be lowered sufficiently to promote cysteine and oxalate precipitation and stone formation;3, 15, 64 (2) diarrhea-this has been reported with ascorbic acid doses as low as 1 gram per day; (3) hemolytic crisis in glucose-6phosphate deficiency;3,63 (4) interference with blood and urinary sugar determinations in diabetics; (5) vitamin B12 deficiency-ascorbic acid interferes with the absorption and metabolism of vitamin B12 and could produce B12 deficiency. 4 It should also be mentioned that claims regarding the effect of vitamin C on the prevention of sudden infant death syndrome have no scientific merit. 70 Vitamin B6 Vitamin B6 comprises three naturally occurring pyridine derivatives, pyridoxine, pyridoxal, and pyridoxamine. Large doses have been promoted in the treatment of depression, premenstrual tension (PMS), muscle fatigue, paresthesias, hyperkinesis, autism, and febrile convulsions. 3, 42, 56, 70 There is little evidence to support the use of megadoses of vitamin B6 in most of the conditions just mentioned. It has recently been established that vitamin B6, when ingested in large doses (> 2 gm/day) has toxic effects on the central nervous system, with nerve degeneration recorded at intakes of 5 gm/day.3, 55, 56 The symptoms were partially reversed with withdrawal of the vitamin; however, some degeneration persisted. Vitamin B6 is another example of a water-soluble vitamin that, when taken in large amounts by the mother, can induce dependency in the fetus. Three cases were reported of B6 responsive seizures in infants whose mothers had consumed large doses of B6 (5 to 300 mg/day) while pregnant. The positive response to B6 supplementation suggested that the infants had become acclimated to elevated blood levels of the vitamin and had seizures I

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upon withdrawal of the vitamin. Once again, pregnant women should be counselled not to ingest large amounts of vitamins during pregnancy. Nicotinic Acid The observation that patients with pellagra suffered from dementia led to the use of niacin in the treatment of mental illnesses such as schizophrenia. 15 The purveyors of orthomolecular therapy believe in "the treatment of mental disorders by the provision of the optimum molecular environment for the mind, especially the optimum concentrations of substances normally present in the body."49 The RDA for nicotinic acid (niacin) and nicotinamide (or niacinamide) is 20 mg/day in adults, but doses of up to 3 gm/day have been promoted. 3 Not only is there a lack of evidence that niacin is effective in treating schizophrenia, childhood psychoses, or learning disabilities, but the levels recommended are hazardous. As little as 100 mg of niacin per day may cause the release of histamine and thus severe flushing. Other symptoms of excess niacin intake include itching, skin disorders, and blood disorders.3. 70. 73 High doses (3 to 20 gm/day) are hepatotoxic and have caused cholestatic jaundice. 29, 47, 69 As niacin competes with uric acid for excretion, hyperuricemia and acute gouty arthritis have also been noted, 3, 15, 73 In addition, large doses of the vitamin may aggravate peptic ulcer disease or asthma and cause abdominal pain, nausea, and diarrhea, 3, 15, 70 The American Psychiatric Association does not recommend megavitamin therapy wih niacin in the treatment of mental illness. 15, 45 Megavitamins and Learning Disorders Dr. Alan Cott was one of the first to claim that megadoses of vitamins are useful in the therapy of behavior disorders and learning disabilities in children,12 Despite the fact that his studies were uncontrolled and not double-blinded, his work has received so much publicity that 20 per cent of the children referred to a pediatric neurology clinic at Yale had already been given megavitamins. 57 Controlled studies using vitamin dosages suggested by Cott have failed to detect differences between treatment and control groups of children with minimal brain dysfunction 7 or learning disabilities. 33 For example, in a double-blind crossover study in 41 children with attention deficit disorder, no benefit of the megavitamin regimen recommended by Cott was found. 28 This study also failed to confirm the finding that children with attention deficit disorders had low plasma pyridoxine and ascorbic acid levels. Both the American Psychiatric Association 45 and the American Academy of Pediatrics 46 have published statements to the effect that megavitamin therapy as a treatment for learning disabilities and psychoses in children, including autism, is not justified on the basis of documented clinical results. Megavitamins in Down Syndrome In 1981, Harrell et al. published results of a study claiming that large doses of vitamins and minerals improved the intellectual, educational, and language skills of a group of mentally retarded children. The results were particularly dramatic in four subjects with Down syndrome. 27 Although the

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study was criticized in scientific circles because it was only partially doubleblinded and the numbers were small, it received much public attention. Bennet et al. 8 attempted to replicate the study in a case-control trial of 20 home-reared children (age 5 to 13 years) with Down syndrome. For eight months the subjects received either a placebo or the identical supplement that Harrell had used in his original studies. The investigators found no significant differences between the groups in any behavioral or developmental areas examined, including IQ, school achievement, speech, language, and neuromotor function. Nor was there a difference between groups in appearance, growth, or general health. Smith et al. 60 also conducted a double blind trial of two groups of school-aged children with Down syndrome (n = 56). The groups were matched for cognitive intelligence, sex, and age. One group was given a megadose vitamin/mineral supplement and the other a placebo. A standard set of psychological tests, a physical examination, and blood tests were completed prior to, and four and eight months after, the supplements were started. Again there was no indication that megadoses of vitamins enhanced intellectual performance. At present, there is no scientific justification for supplementing children with mental retardation or Down syndrome with large and potentially hazardous levels of vitamins and minerals. Guidelines for Physicians Physicians should be aware of the vitamin supplementation practices of their patients. If patients are taking vitamins, the dosages should be evaluated in relation to normal recommendations. 23, 50 If multivitamin supplements are prescribed, it is important to be aware of the content of each vitamin within each preparation in order to avoid potentially toxic intake dosages. Patients should be instructed to take vitamin supplements with meals, to continue to eat well balanced meals, and to store the vitamins out of the reach of young children. 65 The Health Food Mystique The food faddists would have us believe that natural, organic, and health foods are safer, more nutritious, and somehow better for our health. However, there is no scientific evidence to support such assumptions, and in fact little agreement as to the exact meaning of the terms themselves. Natural foods are marketed as those that have received minimum refinement and minimum processing. Yet the term "natural" is very loosely used. A quick look around supermarket shelves will reveal such foods as natural ice creams and even natural potato chips! There are no universally acceptable standards to ensure that natural foods are, in fact, free of pesticides, additives, drugs, residual hormones, and the like. 59 "Natural" infers a wholesomeness that may be misleading. Raw, unpasteurized milk, for example, carries the hazards of bacterial contamination. 40 From the standpoint of nutrition, natural vitamins are indistinguishable from synthetic vitamins. "Organic" foods are grown without the use of chemical fertilizers or pesticides and are processed without the addition of chemicals. 54, 63 Food

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faddists and self-acclaimed nutritionists suggest that organically grown fruits and vegetables are nutritionally superior to the produce found in supermarkets. In fact, this is not so. The nutritional quality of a plant is determined by genetics and the processing to which it is subjected (for example, nutrient losses in cooking water), but not the quality of the soil. Plants absorb only inorganic nutrients. If the soil is deficient, the crop will be reduced. However, if inorganic nutrients are present, the plants will thrive regardless of whether the nutrients are derived from manure or chemicals.4, 61 Fad Diets in Infancy Even infants have not been spared the fad diet movement. A formula based on nondairy creamers was fed to four infants because of suspected cows' milk protein sensitivity. The low protein formula eventually lead to kwashiorkor in all four of the infants. 59 Growth retardation, failure to thrive, and hypochromic microcytic anemia were observed in five infants fed a formula of barley water, corn syrup, and whole milk. The mixture, which was described by a religious group as being "most like human milk," was, in fact, below the RDA for iron and vitamins A and C. 20 , 59 These cases demonstrate the hazards of prescribing supplements without having adequately considered their nutritional content. Elimination Diets Elimination diets are prescribed in order to determine whether or not a food, or foods, are responsible for allergic symptoms-for example, atopic eczema. 14 The extent and duration of the food restriction will determine the nutritional impact. If many foods are eliminated, then the remaining diet must be closely evaluated for its nutritional adequacy. For example, a study of food intake records of 23 children with eczema revealed low calcium intake (below 75 per cent RDA) in 57 per cent of the patients, although soy or caseine hydrolysate formulas had been prescribed to replace cow's milk in the children's diet.

CONCLUSIONS This paper has reviewed the use of unconventional diets and nutritional supplements and their effect on the health of children. With the current societal emphasis on natural, unprocessed foods, and the media's emphasis on "alternative disease therapy," physicians must be able to recognize health food misinformation and provide their patients with educated counsel on the specific hazards of unconventional foods and diets. Despite their best intentions, physicians may encounter strong resistance in their attempts to influence patients' dietary practices. A general management scheme for use when unconventional dietary practices are encountered would include: 1. Recognizing that they exist. This means asking patients specifically about what they eat and what supplements they take.

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2. Evaluating the nutrient content of the diet. Is it adequate to meet the nutritional needs of the child? 3. Determining the reasons for adopting the diet. 4. Counselling the patient on the nutritional quality and safe use of the diet. Physicians following these guidelines, who are aware of the dietary habits of their patients, can do much to avert the risks inherent in unconventional diets.

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