D. Czajka-Narins

Serum and liver lipids in rats fed diets containing corn oil, cottonseed oil, or a mixture of corn and cottonseed oils

Previous research has demonstrated that the total replacement of corn oil (CO) with cottonseed oil (CSO) in the diets of growing male rats results in a lowering of the total cholesterol (TC) concentration in the serum. It is not, however, known if a partial replacement of dietary CO with CSO would be sufficient to lower TC levels, nor is the effect of replacing dietary CO with CSO on other indices of cholesterol status (e.g., the levels of high-density lipoprotein cholesterol [HDL-C], non-HDL-C [i.e., very-low and low-density lipoprotein-cholesterol], or the TC/HDL-C ratio). Growing male rats were fed diets having CO, CSO, or a CO/CSO (1:1, w/w) oil mixture (OM) as the source of dietary oil (diet groups CO, CSO, and OM, respectively). There were no differences between CO and OM groups for TC, HDL-C, non-HDL-C, or the TC/HDL-C ratio. However, TC was significantly lower (p≤ 0.05)for the CSO group than the CO group (2.85 vs. 3.23 mmol/l, or 110 vs. 125 mg/dl, respectively) as was HDL-C (1.83 vs. 2.13 mmol/l, or 71 vs. 82 mg/dl, respectively), but there were no differences between these groups for non-HDL-C or the TC/HDL-C ratio. Diet had no effect on serum triglycerides (TGs) or on total liver content of either cholesterol or TGs. Thus, partial (50%) replacement of CO with CSO was without effect on any of these serum indices of cholesterol status, but total replacement resulted in lower TC and HDL-C, without affecting non-HDL-C or the TC/HDL-C ratio. Because, relative to CO, CSO has higher levels of saturated fatty acids but lower levels of monounsaturated and polyunsaturated fatty acids, the cholesterol-lowering effect of CSO appears to be unrelated to its fatty acid composition, and may be caused by a component of its nonsaponifiable fraction.

Body Composition, Dietary Intake, and Energy Expenditure in Nonobese, Prepubertal Children of Obese and Nonobese Biological Mothers

OBJECTIVE To determine differences in dietary intake, resting energy expenditure, activity level, fat-free mass, and percentage body and abdominal fat in nonobese children of obese mothers compared with nonobese children of nonobese mothers. DESIGN Cross-sectional comparison study. Childrens food diaries were analyzed to determine average energy and nutrient content. Resting energy expenditure of children was measured by means of indirect calorimetry. Childrens activity levels were estimated through questionnaires administered during interviews. Dual-energy x-ray absorptiometry was used to estimate body composition of children. SUBJECTS Mothers of subjects responded to advertisements and were recruited as nonobese (body mass index = 20 to 25) or obese (body mass index > or = 30). Offspring included in the study were prepubertal and nonobese (10th to 90th percentile of weight for height by gender). Twelve pairs of children could be matched for weight, gender, and age. STATISTICAL ANALYSIS PERFORMED Wilcoxon signed rank tests were used to determine differences between the 2 groups of children. RESULTS Percentage abdominal fat was greater (median difference = 3.15, P = .001) and fat-free mass was lower (median difference = 1.19, P = .04) in children of obese mothers compared with children of nonobese mothers. No statistically significant differences between the 2 groups of children were found for dietary intake, resting energy expenditure, activity level, or percentage body fat. APPLICATIONS/CONCLUSIONS The significantly higher percentage of abdominal fat and lower fat-free mass in children of obese mothers may contribute to obesity onset. Use of dual-energy x-ray absorptiometry as a screening tool for nonobese, prepubertal children with an obese parent will help to identify those at risk. Education and lifestyle changes can then be implemented to help prevent the onset of obesity.

Use of arginine to reduce the severity of retinoid-induced hypertriglyceridemia.

Abstract: Previous research with an animal model of retinoid-induced hypertriglyceridemia, rats fed a 13-cis retinoic acid-containing diet in which casein was the dietary protein, has demonstrated that replacement of dietary casein with soy protein isolate can reduce the severity of this condition. A depressant action of soy protein vs. that of casein on serum triglyceride concentration has also been demonstrated in rats fed purified diets without supplemental retinoid. Because this action of soy protein appears to be due to its having a higher arginine-to-lysine ratio than casein, a study was done to determine how feeding a casein-containing diet supplemented with sufficient arginine, to give a dietary arginine-to-lysine ratio equivalent to that of soy protein, would affect the development of retinoid-induced hypertriglyceridemia. Groups of five-week-old male Fischer 344 rats (n = 7/group) were fed a control diet containing casein or one of three 13-cis retinoic acid-containing diets in which dietary nitrogen was provided as casein, casein + arginine, or soy protein. Incorporation of dietary 13-cis retinoic acid resulted in hypertriglyceridemia, with serum triglyceride concentrations of 2.00 and 7.23 mmol/l, or 177 and 640 mg/dl, for groups fed the control and casein + 13-cis retinoic acid diets, respectively. For animals fed the 13-cis retinoic acid-containing diets, serum triglyceride levels for the casein + arginine and soy protein diet groups (4.75 and 2.92 mmol/l, or 421 and 258 mg/dl, respectively) were significantly lower than for the casein group (p < 0.05); however, the value was significantly lower for the group fed the soy protein diet than for the group fed the casein + arginine diet. Serum and dietary arginine-to-lysine ratios were highly correlated (r = 0.93, p < 0.0001). Thus, supplementing dietary casein with arginine reduced the severity of retinoid-induced hypertriglyceridemia, but not as effectively as replacing casein with soy protein.

Effect of Preparation Methods on Total Fat Content, Moisture Content, and Sensory Characteristics of Breaded Chicken Nuggets and Beef Steak Fingers

In recent years, public concern has focused on the need to reduce the fat content of school lunches. This study was designed to determine the effects of three preparation methods (baking, deep-fat frying, and hot-air frying) on moisture, fat content, and sensory characteristics of chicken nuggets and beef steak fingers. Chicken nuggets and beef steak fingers that were hot-air fried had a higher moisture content (p < .01) than those that were deep-fat fried. Both hot-air frying and baking caused a lower fat content (p < .01) in chicken nuggets than deep-fat frying. However, fat content of beef steak fingers was not significantly affected by preparation methods. Paired preference sensory testing was conducted using 40 volunteer panelists for each test. These tests indicated that most panelists preferred (p < .05) the deep-fat fried products over baked or hot-air fried products for flavor, crispness, mouth feel, and overall likability.

Effect of Preparation Methods on Moisture Content, Fat Content and Sensory Characteristics of Breaded Food Items Served in School Lunches

Abstract LEARNING OUTCOME: To determine effects of three preparation methods on moisture content, fat content and sensory characteristics of chicken nuggets and beef steak fingers. Level of fat in school lunches is a current concern of many nutrition professionals. Purpose of this study was to determine effect of preparation methods on moisture content, fat content and sensory characteristics of convenience breaded food products commonly served to school children. Chicken nuggets and beef steak fingers were prepared by baking, deep fat frying and hot air frying. Hot air frying is an innovative variation of convection baking that uses a hot air fryer. Samples were dried in a vacuum oven to determine moisture content before fat was measured by Goldfisch fat extraction method. Preparation methods caused moisture content of products to decrease in an almost inverse proportion to increase in fat content. Fat content of chicken nuggets (initially 14.9g per 100g of dry sample) decreased to 12.6g after baking and 8.2g after hot air frying while deep fat frying caused an increase to 18.4g. Fat content of beef steak fingers (initially 19.8g per 100g of dry sample) decreased to 19.1g after hot air frying, but increased to 20.9g after baking and 22.4g after deep fat frying. Untrained panelists compared the appearance, flavor, crispness, mouthfeel and over-all likability of products using paired preference tests. A significant number of panelists preferred deep fat fried products over baked and hot air fried product for most attributes. However, tests comparing hot air fried and deep fat fried chicken nuggets showed no significant panelist preference for either product on over-all likability, flavor and appearance. Hot air frying can be recommended as a method which will reduce fat content of chicken nuggets without having a significant effect on consumer preferences.

Effects of two types of protein supplemented with retinyl acetate on mammary carcinogenesis in rats

Both retinoids and soy protein have the potential for reducing the incidence of mammary cancer. This study was designed to determine the effects of combining these two agents on N-nitroso-N-methylurea (NMU)-induced mammary carcinogenesis in the rat. One hundred and two 7-week-old female Sprague-Dawley rats were administered NMU at a dose of 50 mg/kg body weight. At 12 weeks of age, the rats were randomly assigned to one of the following four dietary groups: casein with placebo beadlets (CP; n=26); casein with retinyl acetate (1 mmol/kg diet) beadlets (CA; n=25); soy protein isolate (SPI) with placebo beadlets (SP; n=25); or SPI with retinyl acetate beadlets (SA; n=26). The rats were given free access to their respective diets until the termination of the study when they were 29 weeks old. Starting at six weeks post NMU administration, all the rats were palpated once weekly for palpable tumors. At the end of the study, the mammary tumor incidence was significantly lower in CA (32%) when compared to CP (73%) or to SA (65%), but not to SP (52%). The mean weight of the tumors/rat was significantly lower in CA and SP than in CP, but not significantly different from SA. The mean number of tumors/rat was significantly lower in CA than CP and SA, but not different from SP. The mean latency period among the four groups of rats was not significantly different. Thus, chronic feeding of retinyl acetate inhibited mammary tumor incidence when combined with casein, but the inhibitory effect of the retinoid was not present when SPI was the source of protein.

Relationships Between Estimated Life Cycle Caffeine Intake, Serum Sex Hormone Levels and Bone Mineral Analyses in Post-Menopausal Women

Abstract The purpose of this study was to assess the influence of dietary caffeine intake and serum hormones (Estrone-Sulfate, Free Testosterone and Sex Hormone-Binding Globulin), on total bone mineral density (TBMD) and total bone mineral content (TBMC). Fifty-four healthy, postmenopausal women, age 57-84 years, completed the study. Subjects completed a questionnaire detailing family history, medical, menstrual and demographic information. Current caffeine intake was determined by analysis of a five-day food record using Nutritionist IV (mean = 183±20mg/day). Caffeine intake over the life cycle was calculated based on the reported frequency of consumption during various stages of life: 14–19,20–29, 30–39, 40–55 and previous year. Current caffeine intake, determined from the food record, was significantly correlated with the calculated intake value from the frequency survey (r=0.60, p 2 ±0.11 TBMC=2163g±330) compared to those who had been postmenopausal for 10 years or less (TBMD g/cm 2 =1.12±0.10, TBMC=2306g±358). There was a significant positive correlation between caffeine intake and both TBMD (r =0.32, p=0.011) and TBMC (r =0.46, p

Knowledge of Fats/Oils and Fat Content of Foods by Fast Food Restaurant Managers

Abstract A questionnaire was developed focusing on food preparation and types of fats/oils, knowledge of fats/oils and fat content of foods. The questionnaire was validated by a group of seven foodservice professionals and was pilot tested with ten local restaurant managers. A nationwide sample of 100 fast food restaurant chains located in the 100 largest metropolitan areas of the country was selected for a telephone survey. One manager was contacted from each restaurant. Results showed that 95 out of 100 managers used an oil for frying rather than a solid shortening. About one-third were using the same amount of oil for frying as three years ago while 1/3 were using more and 1/3 less. While 83 mangers agreed that consumers think low fat foods are important, 98 felt that customers were more concerned with taste than nutrition. A majority (64) knew that the recommended amount of total fat in the diet is 30% of calories or less. However, 41 selected sugar as containing more calories than vegetable oil or potatoes, and one-half did not realize that breaded convenience products such as chicken nuggets have been pre-fried by manufacturers. Sixty-five were not familiar with trans fatty acids. Results indicate that lack of knowledge may contribute to selection of food items and preparation methods that increase fat content of menus. To promote public health, fast food restaurant chains should provide more training for managers on nutrition and preparation methods that impact fat content of foods.

A Comparison of Bone Density and Dietary Intake in Postmenopausal Women who are Receiving and not Receiving Hormone Replacement Therapy

Abstract LEARNING OUTCOME: Identify dietary factors related to bone density in postmenopausal women receiving and not receiving hormone replacement therapy. Differences in bone density and dietary intake were examined in 38 postmenopausal women, aged 54 to 78 years. Fifteen were receiving hormone replacement therapy (HRT) and 23 were not (NHRT). Bone density in the lumbar spine (BDSP),femoral neck (BDN), Wards triangle (BDW) and trochanter (BDTR) were assessed using dual energy X-ray absorptiometry. Three day diet records were analyzed for average energy and nutrient intake. Average dietary intakes of calcium were adjusted for calcium content of supplements consumed. Analysis of variance was used to determine differences in bone density and dietary intake. No significant differences in bone density were found between the two groups. Mean calcium intake was significantly greater (p=0.007) in the HRT group than the NHRT group. No other significant differences in dietary intake were found. When grouped by calcium intake, eight women who consumed a daily mean of 1500mg or more of calcium had significantly lower BDW (p=0.03) than those consuming less. These women may have increased their calcium intake related to their perceived risk of osteoporosis. Pearson correlation coefficients showed calcium intake was significantly associated with BDN (p=0.02), BDW (p=0.04) and BDTR (p=0.02) but not BDSP for 30 women whose mean intake of calcium was below 1500mg.Identification of factors associated with bone density in postmenopausal women can assist in implementing education and lifestyle changes to prevent osteoporosis.

Linoleic and Linolenic Acid Concentrations of Milk of Women in Puerto Rico

Abstract LEARNING OUTCOME: To learn more about the fatty acid composition of human milk. Human milk represents the pattern of nutrients most suitable to meet the physiological requirements of infants. Knowledge of the composition of human milk is essential both to understand the needs of infants and to develop the best formula to be used as a substitute for human milk. About 50% of the energy in mature human milk comes from fat. Fat is also a source of essential fatty acids needed for the structural development of brain and other tissues. The total amount of fat in human milk is relatively constant, but the fatty acid composition varies depending on maternal diet. The purpose of the study was to determine the linoleic and linolenic acid content of milk produced by women in Puerto Rico. Mean age of mothers was 28.4 years; mean prepregnancy weight was 140.8 lbs. Mothers were asked to collect the first milk of the morning, before bating or nursing the infant. Instructions were given orally at time of recruitment, written in Spanish and again orally when called to remind them to collect the milk. Samples were collected in sterile vials on days 6 and 21 after parturition, stored frozen and analyzed in duplicate using high performance liquid chromatography. The mean ratios of linoleic to linolenic acids were 15.0 and 14.5 for days 6 and 21, respectively. Ranges for both fatty acids were broad for both days. Means values for linolenic were 375.5 nmol/ml for day 6 and 611.1 nmol/ml for day 21; mean values for linoleic acid were 5595 nmol/ml and 8698 nmol/ml, respectively. These results provide essential information on the composition of human milk.