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Although research on the role of single nutrients in immune function is extensive, this is not the case for multiple nutrients and subsequent nutrient-nutrient interactions. After presenting a brief overview of immune function, the authors consider reports that examine imbalance of more than one nutrient and interactive effects on immunocompetence. Availability of one nutrient may impair or enhance the action of another in the immune system, as reported for nutrients such as vitamin E and selenium, vitamin E and vitamin A, zinc and copper, and dietary fatty acids and vitamin A. Nutrient-nutrient interactions may negatively affect immune function. For example, excess calcium interferes with leukocyte function by displacing magnesium ions, thereby reducing cell adhesion. Because of consumer interest in supplementation to improve immune function, the potential for harm exists. Research is needed to improve knowledge in this area so that recommendations can be made with more confidence.

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OBJECTIVE: To identify and compare the presence of coronary heart disease (CHD) risk factors among 14- and 15-year-old boys and girls. DESIGN: For this cross-sectional study of 54 subjects, a blood sample taken after subjects fasted was used to determine total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglyceride concentrations. Dietary intake was estimated using a 24-hour recall and a 2-day food record. Height, weight, and skinfold thicknesses were measured to identify obese and severely obese subjects. Cardiovascular fitness, blood pressure, and cigarette use also were measured. TC, HDL-C, LDL-C, fitness, blood pressure, and smoking are modifiable risk factors, for CHD. SUBJECTS: Adolescents were selected by random sampling from lists of students attending public schools in two central Texas cities. Adolescents who were 14 or 15 years old; were not pregnant; and had no history of high blood pressure, diabetes, or heart disease were eligible to participate. STATISTICAL METHODS: Data were analyzed using Student's t and chi square tests. RESULTS: Of the subjects, 25% demonstrated two or more risk factors for CHD. A significantly higher percentage of girls than boys had a TC concentration greater than 5.2 mmol/L. Boys (n=29) had a mean fitness score that indicated a higher level of cardiovascular fitness than girls (n=25); however, the mean score for both groups was below average. CONCLUSION: Data provide support for increased interventions targeted toward lowering the risk factors for CHD and other chronic diseases in adolescents.

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A number of studies have found that health beliefs and social influences predict changes in dietary intake, including red meat. These studies have not determined what kinds of individuals are more likely to change their diets due to the advice of physicians, the advice of significant others, or because of mass-media exposure. We obtained data from 424 elderly Houstonians regarding whether they had attempted to reduce red meat consumption and if so, why. Social network, health status, food attitude and demographic variables are used to differentiate those who have made physician-induced changes from other sources of influence/information for change. Elderly subjects with smaller abdominal girth measurements are more likely to make red meat reductions regardless of the source of influence/information; those who believe in the efficacy of health foods are more likely to give physicians and mass media as sources of influence/information for red meat reductions. Men are more likely than women to report red meat reductions because of mass media and physician influences. Women who receive a greater amount of companionship from their social networks are more likely to change because of friends/relatives influences.

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Factors that influence tissue copper concentration include age, diet, hormones, and pregnancy. In this study we altered diet independently, hormone (estrogen) independently, and various combinations of diet and hormone in animals of the same age to study the effects of ovariectomy complicated with dietary copper deficiency; a deficiency that has been demonstrated to cause bone defects. Sprague-Dawley rats were placed on various combinations of copper deficient or enriched diets before and/or after ovariectomy to determine if copper deficiency aggravated osteoporosis and if return to a copper-adequate diet alleviated it. In this study, ovariectomy did induce an osteopenia that was characterized by decreased trabecular bone. This osteopenia was slightly more severe with copper deficiency, but was not necessarily alleviated by the return of normal copper levels to the diet.

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Table eggs enriched with n-3 fatty acids may provide an alternative to fish as a source of these proposed healthful fatty acids. Successful marketing of this product may be influenced, however, by consumer perceptions of the egg as an unhealthful food. Therefore, the objectives of the current study were to assess consumer perceptions of table egg health quality and to determine the potential consumer acceptability of an n-3 fatty acid-enriched table egg. A survey was conducted in five major Texas cities; over 500 consumers completed the survey. Data were analyzed using the chi-square procedure. The majority of consumers surveyed considered eggs healthful and reported purchasing eggs at least once monthly and consuming an average of three whole eggs per week, as compared with an average reported fish consumption of only one serving per week. Sixty-five percent of the consumers reported willingness to purchase an n-3 fatty acid-enriched table egg and of these, 71% were willing to pay an additional $.50 per dozen. These data indicate that n-3 fatty acid-enriched table eggs represent a viable means of incorporating n-3 fatty acids into the diet of health-conscious consumers.

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A mailed survey of 239 Texas physicians selected by a stratified random sample was completed in 1990 (response ratio = 39.5%) concerning physician's background in nutrition, nutrition knowledge, and recommended treatments to patients with hypercholesterolemia. Twenty-one percent reported taking a nutrition seminar and 41 percent read a nutrition text during the past year. Less than a third had taken a nutrition course after medical school; half had taken such a course during medical school. Over 46 percent achieved a perfect score on nine knowledge questions regarding dietary fat. Only 35 percent identified the latest American Heart Association nutrition education effort. Seventy-four percent said they ate chicken or fish instead of red meat three or more times a week. Over 80 percent selected exercise, weight reduction, and low fat diets as the most important treatment types. Physicians continue to have limited knowledge of nutrition and should be encouraged to make greater use of dietitians as consultants.

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One hundred ninety-two elderly men and women were investigated to determine the effects of recent life events, psychological adjustment, and social support on lymphocyte count, controlling for nutritional status, age, education, income, and the presence of lymphocyte-altering drugs. Effects of specific recent life events were found. For elderly males, recent sexual dysfunction lowers lymphocyte count, while psychological adjustment and percentage kin in the intimate network elevates it. For elderly females, the experience of either family or legal problems elevates lymphocyte count as does frequent interaction with members of the intimate network. These results suggest that life events have very different effects on elderly men and women's immune systems. Social support has direct but mediating effects on lymphocyte count for both genders.

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Meat from such monogastric animals as swine can be modified to substitute monounsaturated fatty acids for saturated fatty acids. Because monounsaturated fatty acids have a beneficial effect on serum lipids as compared with saturated fatty acids, the objective of this study was to assess the effect of modified pork as compared with regular pork on serum and hepatic lipids. Guinea pigs were fed diets containing pork from control diet-fed hogs or from hogs fed a diet containing high oleic acid sunflower oil. The pork provided almost all of the fat in the diets at the level of 4 and 15 g/100 g diet, 10 or 34% energy. The high oleic pork muscle and fat contained 26 and 46% less palmitic and stearic acids (the primary saturated fatty acids), respectively, and 31 and 29% more oleic acid (the primary monounsaturated fatty acid) than the regular pork muscle and fat, respectively. Cholesterol concentration of diets ranged from 0.06 to 0.08% of the diet. Although total serum cholesterol, HDL cholesterol and triglyceride concentrations did not differ due to type of pork, results indicated that serum LDL cholesterol was lower (15%) and hepatic cholesterol was greater (15%) in the high oleic pork, 15% fat group as compared with the control pork 15% fat group. Also, serum LDL cholesterol concentration was higher in the groups fed 15% fat compared with those fed 4% fat. In this study pork modified to have more oleic acid and less saturated fatty acids had a positive effect on tissue lipids when fed to animals.

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Measurements of height, weight, skinfold thicknesses, and circumferences were obtained along with data on health practices and disease from 424 independent-living elderly in the Houston area. The objectives of the study were to examine anthropometric measurements of younger (58 through 74 years) and older (75 through 100 years) elderly individuals and to assess relationships between these measurements and health behaviors and disorders. Results demonstrated differences in anthropometric indexes due to aging and sex. Individuals who considered themselves to be more active than peers or who smoked had lower values for some anthropometric variables such as body mass index and waist circumference. Those who drank alcoholic beverages had lower values for some variables than those who stated that they did not drink alcohol. Diabetes and hypertension in the younger elderly were associated with higher values of some measurements, including waist circumference and body mass index. Anthropometric measurements in the elderly varied with sex, age, health practices, and the presence of certain disorders.

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The development of a 16-item nutritional risk index (NRI) is chronicled from its inception through its application in three studies designed to assess its reliability and validity. Study I involved a survey of 401 community-dwelling elderly in St. Louis, Missouri who were interviewed at baseline, 4-5 mo later, and 1 yr later. Study II involved a cross-sectional survey of 377 male outpatients attending two clinics at the St. Louis Veterans Administration Medical Center. Study III involved a cross-sectional survey of 424 community-dwelling elderly in Houston, Texas. Internal consistency reliability coefficients ranged between 0.47 and 0.60, and test-retest reliability coefficients ranged between 0.65 and 0.71. Validity was established by using the NRI to predict the use of health services, as well as by correlating it with a variety of anthropometric, laboratory, and clinical markers of nutritional status. The utility of the NRI for future applications is discussed.

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After the discovery of magnesium as an essential nutrient in 1926, research focused upon the identification of effects of an acute deficiency state and determination of the requirement for the mineral for normal growth and reproduction. In this early work, marginal intakes of magnesium were reported to result in alterations of tissue composition. Since the 1970s, research has shown that the ability to adapt to a marginal intake of magnesium, which is commonplace in developed countries, is limited. In fact, a low intake of the mineral for an extended period of time may be associated with abnormalities in reproduction, growth, and development and may be a factor in the pathogenesis of disorders of neuromuscular, cardiovascular, renal, and immune function. Problems related to the use of pharmacological agents or to trace metals, such as aluminium, may be worsened in the presence of a low intake of magnesium. Evidence presented illustrates that, although physical signs of magnesium deficiency may be absent, that is to say in cases of latent clinical forms, a marginal dietary inadequacy of the mineral over a long period of time could result in significant problems.

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Data were collected from home interviews of 424 noninstitutionalized individuals, 58 to 100 years old, in the Houston metropolitan area, to assess the relationships between dietary intake, socioeconomic variables, beliefs about nutrition, and use of nutritional supplements. Two-thirds of the subjects took nutritional supplements. The most common forms were vitamin C, calcium, and multivitamins. With the exception of vitamin B-6, magnesium, and dietary fiber, which were higher in diets of users of nutritional supplements than in diets of nonusers, nutrient density (amount of nutrient per 1,000 kcal) did not differ between the two groups. Attitudes toward the use of nutritional supplements, health foods, and/or nutritional quality of conventional foods differed with sex, age, income, and educational level. Nutrient intake of those with more positive feelings about nutritional supplements was higher, perhaps as a result of increased awareness of diet and health. Nutrition education that is targeted to issues of interest to people in this age group is needed; topics such as the role of nutrients in disease prevention and appropriate nutritional supplementation might be explored. This survey indicates that, although the practice of supplementation may be beneficial to augment nutritional quality of the diet for elderly people, use of nutritional supplements is not restricted to those whose dietary intake is of lower nutrient density than that of nonusers.

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Weanling rats were maintained on diets which were Mg-adequate (49 mmol Mg/kg), groups 1 and 3, or Mg-deficient (8 mmol Mg/kg), groups 2 and 4, for 8 weeks of growth. During breeding, gestation, and lactation, groups 3 and 4 received diets supplemented with 41 mmol Mg/kg. Femur and cardiac Mg in group 2 dams was reduced, confirming that Mg deficiency was present. Thymic weight from dams and pups and numbers of plaque-forming cells in pups in group 1 were higher than in other groups while splenic weight in pups was lowest in group 2. Results indicate that maternal magnesium deficiency impaired immunocompetence in offspring. Regardless of the presence or absence of pregestational magnesium deficiency, magnesium supplementation also was associated with depressed immune function.

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Forty noninstitutionalized elderly subjects, ages 65-86 years, were recruited for a study to determine relationships between nutritional status, physical activity, and blood pressure. A 24-hour recall of dietary intake and activities, health history, skinfolds, circumferences, height, weight, and blood pressure were obtained. Obesity was associated with hypertension in this group of elderly subjects. Truncal skinfolds (abdomen and subscapula) were positively correlated (P less than .05) with systolic blood pressure while body mass index, dietary magnesium and dietary calcium to magnesium ratio were directly related (P less than .05) to diastolic blood pressure. Physical activity and energy expenditure were not correlated (P greater than .05) with blood pressure in this study; however, the level of activity did not include strenuous exercise.

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Weanling female Sprague-Dawley rats were fed purified diets to determine the influence of excess dietary calcium upon tissue content of magnesium and calcium, and reproductive outcome. Two levels of calcium (5000 and 16,000 ppm) and magnesium (200 and 1200 ppm) in a 2x2 factorial design (adequate magnesium and calcium = C; low magnesium adequate calcium = L; high calcium adequate magnesium = CHC; and high calcium low magnesium = LHC) were used during the study which included growth and breeding (10 weeks), and gestation and lactation (6 weeks). Depressed weight gain during growth and gestation occurred in response to calcium excess. Renal calcium accumulation was reduced in LHC dams as compared to L dams. In dams fed excess calcium, magnesium concentrations of bone, serum, and kidney were depressed while serum alkaline phosphatase activity increased. The adverse effects of high calcium seen in the dams were not apparent in LHC pups. These pups were heavier and more viable during lactation than pups in the L group. High dietary calcium in combination with low dietary magnesium during one reproductive cycle resulted in altered mineral levels in tissues and improved growth and viability of pups when compared to magnesium-deficient animals.

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Fitness- and weight-conscious students might be more interested in participating in feeding plans in colleges and universities if menus providing lower levels of energy, fat, and sodium, as well as nutrition information about the menus, were available. This study was done to determine the feasibility of developing a program that incorporated modified menus and nutrition information and that was based upon selections from existing menus. The modified menus planned for each day of the 5-week cycle provided approximately 1,200 kcal, 30% energy from fat, 250 mg cholesterol, and 3 gm sodium, as compared with 2,600 kcal, 35% energy from fat, 400 mg cholesterol, and 6 gm sodium in the original foodservice menus. Student response to the programs was assessed. Of the 97 students who responded, 35% reported regularly referring to information on the menus and displays, and 18% stated that they had followed the menus. Of the latter group, five (30%) attributed a weight loss to use of the program. Women were much more likely to use the program than were men. The prevalence of women who wanted to lose weight did not differ between those who were greater than 10% above desirable weight and those who were not. Three-fourths of the students wanted the program to continue. A nutrition program such as the one described might encourage students to eat in university foodservices.

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Eight-eight female weanling Sprague-Dawley rats were fed diets containing either 650 or 150 mg magnesium/kg diet and 7.0 or 3.5 mg pyridoxine-HCl/kg diet, in a 2 x 2 factorial arrangement, during growth, gestation, and lactation. The objective of the study was to determine whether concurrent dietary deficiencies of magnesium and pyridoxine were synergistic, additive, or antagonistic with regards to effects on reproductive performance, growth, and development of offspring, and tissue content of magnesium and calcium. Body weight of dams and pups was not different between groups until day 9 of lactation, at which point those animals in either low magnesium group weighed less than the other. Litter size and birth weight were not different. Development, as measured by timing of unfolding of the external ear, opening of both eyes, and clinical emergence of incisors, was delayed in pups from litters in the low magnesium groups. A synergistic effect on delay of onset of ear unfolding by deficiency of both magnesium and pyridoxine was observed. Calcium content of heart and kidney from dams was increased in the low magnesium groups. Renal calcium was not further increased by the level of pyridoxine deficiency in this study. The calcium to magnesium ratio in heart from pups was higher in those from litters in the low magnesium and pyridoxine group than in the others. Results indicate that simultaneous deficiencies of magnesium and pyridoxine may impair function synergistically. Because these two nutrients are often reported to be presented in inadequate amounts in diets of women in their reproductive years, the potential exists for impaired reproductive success.

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