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The present study compared the effects of diets rich in stearic acid (C18:0) versus one high in lauric and myristic acid (C12:0, C14:0) on platelet phospholipid fatty acid levels and concentrations of urinary thromboxane B2 (TXB2) and 6-keto-PGF1 alpha, which are stable metabolites of thromboxane A2 (TXA2) and PGI2 and indicators of cardiovascular hemostasis. A diet high in dairy butter (B) was the source of C12:0 and C14:0; C18:0 was provided by diets high in cocoa butter (CB), milk chocolate (CHOC) or CB+B in a 4:1 ratio (MIX). A randomized, crossover double-blind experimental design was used. Experimental subjects (n = 15) consumed each diet for 26 days, with a 1-month washout period between each experimental period. Urine and blood were collected from each subject at the beginning and end of each dietary period. Urinary TXB2 and 6-keto-PGF1 alpha were analyzed by radioimmunoassay (RIA). There were no effects of diet on the 24-hour excretion of either metabolite or on the ratio of 6-keto-PGF1 alpha/TXB2, even though there were significant changes in the eicosanoid precursor, arachidonic acid (C20:4n-6), in platelet phospholipids. C20:4n-6 levels increased (44.8% +/- 1.0% to 47.1% +/- 1.3%; P < .05) in the phosphatidylethanolamine phospholipid subclass in subjects on the B diet and decreased in the phosphatidylcholine subclass on the CB diet (16.5% +/- 1.0% to 14.2% +/- 1.1%; P < .05) compared with baseline values.(ABSTRACT TRUNCATED AT 250 WORDS)

This article reviews the literature about the safety and benefits of two recombinantly derived proteins, bovine somatotropin (bST) and porcine somatotropin (pST), that likely will be used in animal agriculture in the future. When administered to dairy cows, bST increases milk production per cow approximately 15% to 20% and improves productive efficiency approximately 10%. Administration of pST to growing pigs reduces carcass fat content by as much as 70% to 80% and improves productive efficiency 15% to 35%. Because meat is a major source of total fat and saturated fatty acids in the diets of human beings, pST will allow consumers to include leaner, more nutrient-dense pork in their diets and still meet current dietary guidelines. Although these biotechnologies have not yet received regulatory approval from the Food and Drug Administration (FDA) for commercial use, information published by the FDA, the National Institutes of Health, the US Congress Office of Technology Assessment, and the American Academy of Pediatrics, as well as an extensive body of scientific evidence, indicate that these products are safe for the consumer. Nonetheless, it is important that consumers understand the benefits and safety of these biotechnologies. Dietitians can play an important role in providing information to consumers about the safety and benefits of bST and pST.

Regression analyses were performed on individual data from our two previous clinical investigations to establish the cholesterolemic effects of individual fatty acids. Our principal objective was to determine the effects of stearic acid on plasma total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol levels. Our second objective was to determine the variation in the cholesterolemic response of individuals to changes (delta) in the major dietary fatty acids. The best-fitting linear regression equations relating delta TC and delta LDL (mg/dL) were as follows: delta TC = 2.3 delta C14:0 + 3.0 delta C16:0 - 0.8 delta C18:0 - 1.0 delta polyunsaturated fatty acids (PUFA) and delta LDL = 2.6 delta C14:0 + 2.9 delta C16:0 - 0.5 delta C18:0 - 0.7 delta PUFA, where delta fatty acid = change in intake expressed as percent of calories. Based on these equations, in which stearic acid has a significant, negative regression coefficient, and the other regression models analyzed, it appears that stearic acid has an independent cholesterol-lowering effect. Using the equation we developed, 75% of the actual cholesterolemic responses were within +/- 10 mg/dL of the predicted response. In summary, we have developed a predictive equation (similar to those developed by both Keys and Hegsted) to estimate changes in plasma TC and LDL cholesterol levels of young men in response to changes in dietary fatty acids. However, our predictive equation separates stearic acid from the other long-chain saturated fatty acids (SFA) and indicates that it has an independent cholesterol-lowering effect. Thus, stearic acid is a unique long-chain SFA because of its effect on plasma cholesterol level.

The present studies were conducted to evaluate the cholesterolemic effects of whole-food diets high in stearic acid. In study no. 1, normocholesterolemic young men were fed diets high in stearic acid provided by cocoa butter (CB); oleic acid provided by olive oil (OO); linoleic acid provided by soybean oil (SO); and myristic acid (and lauric acid) provided by dairy butter (B). In study no. 2, different subjects with similar baseline characteristics were fed diets high in stearic acid provided by milk chocolate (C), CB, CB+B (4:1, MIX), and myristic (and lauric) acid provided by B. Both studies used a randomized, crossover, double-blind experimental design, and experimental subjects (n = 18 for study no. 1 and n = 15 for study no. 2) in each study consumed every diet for 26 days with a 1-month wash-out period between each experimental period. The diets provided 37% of calories from fat, of which 81% was provided by the test fat. Ten ounces (280 g) C was provided daily by the C diet. In study no. 1, the B diet was hypercholesterolemic, whereas the SO diet was hypocholesterolemic, compared with the other diets. The OO and SO diets were hypocholesterolemic compared with the CB diet. Low-density lipoprotein (LDL) cholesterol levels, in general, paralleled the changes in plasma total cholesterol levels. SO significantly decreased apolipoprotein (apo) B levels compared with the other diets. Plasma very-low density lipoprotein (VLDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and apo A-I levels were unaffected by the experimental diets.(ABSTRACT TRUNCATED AT 250 WORDS)

We studied 60 premenopausal women to identify the best predictors of plasma lipid levels. Eligible subjects gave one venous blood sample during menstruation, kept a 3-day food record, completed a demographic questionnaire, had their height and weight measured, and participated in a standardized physical activity interview. Dietary constituents, anthropometric measures, serum progesterone and estradiol concentrations, and leisure-time activity level were then examined for relationships to plasma lipids. Pearson correlations revealed associations among diet, adiposity, alcohol intake, and plasma lipids. Saturated fatty acid (SFA) intake was positively related to plasma total cholesterol, low-density-lipoprotein (LDL) cholesterol, and high-density-lipoprotein (HDL) cholesterol. Height and weight were significantly related to total triglycerides. Furthermore, in the multivariate analyses, dietary constituents and height or body weight explained more of the variance in plasma lipids than did physical activity level or sex hormones. The final models for each lipid are as follows: for plasma total cholesterol and LDL cholesterol, SFA intake was the only significant predictor, for HDL cholesterol, refined carbohydrate and SFA intake; and for total plasma triglycerides, body weight and crude fiber intake.

In this study, we used computer modeling to identify which techniques designed to achieve dietary fat reduction were the most effective in meeting the dietary recommendations of the American Heart Association Step-One diet. Menus were developed for men and nonpregnant, nonlactating women, 25 to 50 years old, according to the Continuing Survey of Food Intakes by Individuals (with 36% and 37% of energy from fat for men and women respectively). The menus were modified realistically using the Minnesota Nutrition Data System. The following five strategies were applied: skim milk replaced whole milk and 2%-fat milk (SKM); medium-fat meat exchanges replaced higher-fat ones (MMtEx); lean meat exchanges replaced higher-fat ones (LMtEx); fat-modified products were used (FMP); and 2%-fat milk replaced whole milk (LFM). For men, strategies LMtEx, SKM + LMtEx, SKM + LMtEx + FMP, LMtEx + FMP, LMtEx + FMP + LFM, and LMtEx + LFM reduced energy by 195 to 415 kcal and achieved the targeted level of energy from fat (less than or equal to 30 +/- 1%) and cholesterol (less than 300 mg) while maintaining 67% or more of the Recommended Dietary Allowances for other nutrients. For women, however, no single strategy achieved the goal. Certain combinations of strategies, SKM + LMtEx, SKM + FMP, SKM + MMtEx + FMP, reduced energy by 150 to 268 kcal and achieved the targeted dietary fat and cholesterol goals while maintaining 67% or more of the Recommended Dietary Allowances for other nutrients. All strategies led to a reduction in both saturated fatty acids (to 9% to 10% of energy) and monounsaturated fatty acids.(ABSTRACT TRUNCATED AT 250 WORDS)

A written case study--or patient management problem--was used to examine how the nutrition care planning process is influenced by increasing clinical experience. The sample consisted of 45 students in diet therapy courses, 46 dietetic interns, and 44 experienced clinical or generalist dietitians. The patient management problem tested data gathering, with sections containing information needed to assess nutritional status, and nutrition care planning, in which subjects identified and evaluated problems and selected short- and long-term goals. Performance was scored by comparing subjects' answers with those of five dietetic experts. Dietitians scored highest and students scored lowest on efficiency of data gathering. Dietitians and interns scored higher than students on proficiency of data gathering and nutrition care planning. Overall, dietitians and interns performed better than students. Only in tasks requiring the highest levels of information processing and/or confidence in clinical judgment were differences between dietitians and interns consistently found. These findings demonstrate that basic nutrition care planning skills are acquired during dietetic internships, but advanced skills are added with clinical experience.

Energy, CHO and possibly protein needs are higher for athletes than for typical persons. CHO supplementation during and after exercise is important for endurance athletes. A balanced diet, adequate in calories, can meet the vitamin and mineral needs of virtually all athletes. Athletes must be aware of maintaining an optimum hydration status. Intensive nutrition education efforts are needed to combat to combat quackery and fads that are targeted to athletes.

Pregnant rats were randomly allocated to one of 3 experimental dietary groups: Group 1 -- 15.5% butter, 2% cholesterol, 0.78% sodium cholate purified diet; Group 2 -- standard rat diet with the addition of 10% lard and 2% cholesterol, and Group 3 -- standard rat diet. Plasma and milk cholesterol at 10 days postpartum were significantly elevated in dams fed exogenous cholesterol. The rat of incorporation of [1-14C] acetate into digitonin-precipitable sterols of mammary tissue slices from dams in Group 1 and Group 2 was eight-fold and two-fold, respectively, less than controls. Mammary tissue cholesterol was greater in dams fed detary cholesterol. Thus, our data, for the first time, demonstrate that cholesterol synthesis in lactating rat mammary tissue is suppressed following cholesterol feeding. In a second experiment, the rate of incorporation of [1-14C] acetate into digitonin-precipitable sterols in kidney and lung tissue of Group 1 rats was suppressed; however, this response was not as marked as that observed in lactating mammary tissue. The concentration of cholesterol in kidney and lung was greater than controls. These results suggest that extrahepatic inhibition of cholesterol synthesis exists in the rat with a concomitant increase in tissue cholesterol.

The present study was conducted to determine if adipocyte diameter distributions of lean and obese Zucker rats were skewed (biphasic) and to quantify the extent to which skewed diameter distributions affect the accuracy of estimating average cell size. Diameter distributions were significantly biphasic for both lean and obese rats. The biphasic nature of the distributions was due to the presence of a large proportion of adipocytes 20-40 microns in diameter (30-60% of cell population). The proportion of these small cells was greater in obese than lean rats. The extent to which average diameter calculated from diameter distribution data underestimated cell size was a function of the extent to which diameter distributions were skewed.

Post myocardial infarct (MI) patients made significant dietary changed in accordance with the principles of the Prudent Diet. Patients reported changing their intake of selected food items; specifically, consumption of eggs, high-fat meat, whole milk, and butter significantly decreased. A number of food preparation techniques changes, leading to decreases in total fat and saturated fat consumption. Patients reported frying food less, trimming fat from meat, and using more polyunsaturated fat. These changes were unaffected by the length of time since the MI.

Plasma high-density and low-density lipoprotein cholesterol (HDL-C and LDL-C) and dietary intake were compared in female competitive swimmers (CS, n = 7), synchronized swimmers (SS, n = 11), and sedentary controls (C, n = 6). CS tended to be taller, heavier, and leaner than C; SS were intermediate. The caloric intake of CS was 21.5% greater than C (2468 +/- 534 versus 2030 +/- 668, p less than 0.001). Dietary composition for all groups was 49% carbohydrate, 35% fat, and 15% protein. Total plasma cholesterol (TC) and LDL-C were not significantly different among groups. HDL-C, and HDL-C/TC were increased in CS compared with SS and C. HDL-C was 17 and 22% higher for CS than SS or C (82.0 +/- 14.6 versus 70.0 +/- 10.9 versus 67.2 +/- 14.0 mg/dl, p less than 0.05, respectively). The results of the current study indicate that plasma HDL-C is significantly elevated in young women who participate in an intensive, but not moderate, exercise regimen.

Histological changes in the aorta were used as criteria to assess the effect of treadmill exercise on the development of atherosclerosis in rats consuming a moderately hyperlipemic diet. While grossly visible atherosclerotic plaques were absent, microscopic examination of sections of the abdominal aorta were distinctly different between exercised and sedentary rats. Aortas of sedentary rats fed a diet containing lard and cholesterol had a high degree of plaque development, fat accumulation, mineralization, erosion and necrosis. Aortas of exercised rats fed the same diet had considerably less atherogenic involvement. Both hyperlipemic groups had greater plaque formation than sedentary rats fed a normolipemic diet. In addition, there were marked differences in plasma lipids; exercise ameliorated the diet-induced changes in plasmatic atherogenic lipids. Our results indicate that exercise retards the development of atherosclerosis in rats fed a hyperlipemic diet.

Continuing education has become increasingly important to the professions, including dietetics. There is some concern, however, that continuing education programs too seldom focus on practice-related problems and do not have a large enough impact on daily practice. A research and development endeavor is in progress to create an alternative approach to continuing education programming. Utilizing a process called the Practice Audit Model, this approach brings practitioners (or their representatives) and educators together to develop continuing education programs that focus on learning needs identified through an empirical assessment of practitioner performance.

Chronic exercise has been shown to alter plasma lipids in man and animals, but the mechanism(s) responsible for this phenomenon have not been clarified. In the present study we have examined the role of the liver in the production of lipoproteins following an intensive exercise regimen in lean and obese Zucker rats. Four-week-old lean and obese male Zucker rats were subjected to a vigorous exercise regimen of running on a motor-driven treadmill for 10 weeks. Hepatic lipoprotein cholesterol production was then assessed using liver perfusion techniques. Plasma cholesterol concentration was significantly lower in both lean and obese runners versus appropriate non-exercised controls. This decrease was due to a decline in both chylomicron and HDL cholesterol. Exercise had no affect on plasma VLDL and LDL cholesterol concentrations. Hepatic VLDL cholesterol production was elevated in obese rats versus lean rats and was not affected by exercise in runners of either phenotype. Hepatic HDL cholesterol production was higher in lean runners but was unchanged in obese runners. Plasma triglyceride was reduced by 50% in exercised obese rats. In summary, intense exercise decreased plasma triglyceride, cholesterol, and HDL cholesterol concentrations in lean and obese Zucker rats. Since hepatic HDL cholesterol production was increased and hepatic VLDL cholesterol production was unaffected by exercise, the changes in plasma lipid levels observed following exercise appear to be mediated by extrahepatic mechanisms.

Yorkshire (lean) and Ossabaw (obese) swine ca. one year of age were used to characterize the quantity and composition of plasma lipoproteins in animals with markedly different adiposity. While lean swine weighted more (175 vs 88 kg for obese), they had less backfat than obese swine (2.64 vs 5.97 cm; P < 0.05). Fasting plasma triacylglycerol (Tg) and cholesterol (CH) levels were elevated in obese swine. Swine plasma lipoproteins were fractionated into very low density lipoprotein (VLDL; d < 1.006), low density lipoprotein (LDL; d = 1.019-1.063), low density lipoprotein (LDL; d = 1.063-1.09), and high density lipoprotein (HDL; d = 1.09-1.21) by density ultracentrifugation. Obese VLDL-Tg, CH and protein (Pr) were elevated more than 2-fold. VLDL from obese swine were 2-fold larger than VLDL from lean swine. No alterations in LDL or LDL composition were observed. HDL-Tg, CH. Pr and phospholipid levels were significantly higher in obese swine. Plasma and VLDL-Tg levels were highly correlated with backfat thickness (r = 0.67 and r = 0.73, respectively). There was a positive correlation between adiposity and HDL-CH as well as VLDL-Tg and HDL-CH. These data indicate that (a) there are marked alterations in swine plasma lipoprotein composition between lean and obese swine; (b) that swine plasma lipoprotein levels may be useful parameters in estimating body composition; and (c) that HDL-CH is positively correlated with adiposity in swine.

A single education program for teaching principles of the Prudent Diet was assessed for its effectiveness in producing compliance to dietary recommendations. The study population consisted of 50 free-living adults between the ages of 20 and 75. Each adult was a member of a club or organization that had requested to view the program via a local chapter of the AHA. A pretest/post-test format was used for the study. Individuals completed a questionnaire prior to viewing the program and again eight weeks after viewing the program. The questionnaire was designed to measure attitudes, knowledge, and compliance to recommendations. Demographic data regarding age, sex, and exposure to heart disease were also obtained. Results indicated that the study population changed their beliefs about their perceived susceptibility to CHD, becoming more concerned after viewing the program. Attitudes toward diet and CHD became slightly more positive but not significantly so. An overall gain in knowledge occurred that was highly significant. The study group consumed skim milk, lean meats, and broiled meats more often after viewing the program. In addition, they reported trimming all visible fat from meat before preparation and/or consumption. It was concluded that this education program has potential for producing an attitude change and knowledge acquisition and for motivating positive changes in dietary habits toward the recommendations of the Prudent Diet.

The role that diet plays in the management of plasma lipid levels is discussed in this review. It has long been recognized that saturated fatty acids and cholesterol raise the plasma cholesterol level whereas polyunsaturated fatty acids lower it. Recently, the effects of other dietary constituents in the management of plasma lipid levels have been established. In particular, monounsaturated fatty acids, soluble fiber, and vegetarian diets favorably affect plasma lipid levels. Overweight and obesity adversely affect plasma lipid levels. Omega-3 fatty acids are hypotriglyceridemic, and high carbohydrate diets low in saturated fatty acids are hypocholesterolemic. Further work is required to establish the long-term consequences of alcohol and coffee consumption on the plasma lipid response. A variety of alternative dietary strategies can be employed in conjunction with traditional dietary recommendations (i.e., reduce total fat, especially saturated fatty acids and dietary cholesterol) for the management of plasma lipid levels. The expected plasma total cholesterol (specifically low-density-lipoprotein cholesterol) reduction is approximately 10% to 20% when dietary saturated fatty acids and cholesterol are decreased to less than or equal to 7% of calories and less than or equal to 200 mg of cholesterol per day. Further dietary modifications, such as increasing soluble fiber, may lead to additional reductions of 1% to 10% in plasma total cholesterol.

Four-week-old male lean and obese Zucker rats were subjected to intense daily exercise for a 10-week period. The exercise regimen used (running 6 days/week for 90 min/day on a treadmill at 1.3 Km/h at an 8 per cent grade) was designed to maximize the amount of exercise performed. Lean and obese runners (LR and OR) gained significantly less weight than sedentary controls (LS and OS). Food intake was lower in LR and unchanged in OR compared with control animals. Exercise increased adrenal weight in runners of both phenotypes. Gastrocnemius muscle weight was significantly higher in OR compared to OS. Despite the intense exercise regimen, carcass fat of OR was reduced only 12 per cent versus OS. In contrast, exercise decreased carcass fat by 32 per cent in LR versus LS. This decrease in body fat of LR was due to smaller adipocytes. Exercise did not affect adipocyte size in obese rats. However, OR had fewer carcass adipocytes. These results indicate that exercise had substantially different effects on adipose tissue cellularity of lean and obese rats. The results of the present study indicate that a program of intense treadmill exercise initiated immediately post weaning only modestly reduced adipose tissue growth in obese Zucker rats. Furthermore, it did not normalize body composition.

This investigation assessed the effectiveness of two teaching strategies, dietary prescription (Diet-Directed [D-D]) and individual goal setting (Self-Directed [S-D]), on compliance with the U.S. Dietary Goals and Guidelines. College women, 18 to 30 years old, enrolled in a one-credit course that met for 1 hour and 15 minutes weekly for 10 weeks to learn the principles and application of the U.S. Dietary Goals and Guidelines. The D-D group received a prescribed diet; the S-D group learned goal-setting skills; and a Control group received no treatment. Caloric, total fat, and polyunsaturated fat (PUFA) intake decreased significantly in both treatment groups. The D-D group reduced caloric, fat, and PUFA intake by week 5 and maintained those changes for the remainder of the experiment. The S-D group decreased caloric intake by the eighth week and decreased fat and PUFA intake between weeks 5 and 8. Those changes, however, were not maintained for the duration of the experiment. The results demonstrate that the study population made dietary changes in the direction of the U.S. Dietary Goals and Guidelines. Further investigations are required to assess the effectiveness of various teaching strategies on long-term dietary compliance.

Exercise generally has been found to produce beneficial effects on plasma lipid and lipoprotein profiles, but the mechanisms involved and possible dietary interactions have not been well defined. Weanling male Fischer 344 rats were assigned to three groups: normocholesterolemic diet sedentary (NS), hypercholesterolemic diet sedentary (HS), and hypercholesterolemic diet exercised (HE). Exercise consisted of treadmill running at 1.2 to 1.4 km/h at a 9% grade, six days weekly, for a 10-week experimental period. Lipoproteins from plasma and from a recirculating in situ liver perfusion system were then isolated and analyzed. The values of several parameters for HE tended to fall intermediate between HS and NS. Final total plasma cholesterol and liver cholesterol concentrations were significantly different among all three groups (HS greater than HE greater than NS). Plasma HDL-cholesterol and phospholipids and perfusate HDL-cholesterol production rate per gram liver were all significantly lower in HS v NS, with HE lying in between. Plasma HDL protein was lower in HS than in both other groups. Plasma total triglyceride levels were significantly lowered by exercise, but neither plasma nor perfusate VLDL triglyceride levels differed significantly among the three groups. Food intakes of HE and HS rats were similar, but HE rats had significantly lower final body weights. The results suggest that (1) exercise may ameliorate many of the changes in lipoprotein and cholesterol metabolism induced by a diet containing lard and cholesterol, and (2) some of these changes may be mediated by changes in hepatic lipoprotein production.