A clinical trial to selectively change dietary fat and/or energy intake in women: the Women's Diet Study.

Dietary fat and energy intake have been implicated in breast cancer etiology. To examine the relative importance of these dietary factors on markers of cancer risk in women, we designed an intervention trial to selectively decrease fat and/or energy intake in free-living, premenopausal women who were somewhat overweight. The study used a 2 x 2 factorial design to evaluate the independent and interactive effects of dietary fat and energy. The diets were nonintervention, low fat (15% of energy from fat, maintenance of energy intake), low energy (25% energy reduction), and combination low fat and low energy. We utilized an individualized counseling approach with self-selection of foods. Women on the low-fat and combination diets were asked to meet given daily goals for fat grams and food group exchanges, while women on the low-energy diet used only food group exchanges. Of the 113 premenopausal women randomized who were eligible for analysis, 43% were African-American. A total of 88 women completed the 12-week program, and adherence to the dietary goals was similar in both racial groups. Women on the low-fat diet were able to reduce dietary fat intake to 19% of energy by 4 weeks and to 17% by 12 weeks with a slight decrease in energy intake. Women on the low-energy diet met their energy reduction goals by four weeks while maintaining percentage of energy from fat. Women on the combination diet largely met their goals by four weeks as well. These data indicate that it is possible to selectively manipulate dietary fat and energy intake in women over a short period of time, which makes clinical studies on the relative effects of these two dietary variables on cancer risk biomarkers readily feasible.     

Dietary intervention in breast cancer patients: effects on food choice.

Effects of dietary intervention on food choice were studied in 240 women aged 50-65 years who had been operated for a stage I-II breast cancer. Following surgery, the women participated in a dietary history interview and were then randomized to one of two groups. The intervention group (n = 121) received individual dietary counselling aimed at reducing dietary fat intake to 20-25% energy (E%), whereas no dietary advice was given to women in the control group (n = 119). For the 52% of the women in the intervention group that completed the study the total fat intake decreased from 36 to 23 E% (P less than or equal to 0.01) and from 37 to 34 E% (P less than or equal to 0.01) for the control group. There were significant reductions in the intake of table fat, high-fat milk products, pork and sausages (containing greater than 11% fat), eggs, rice, pasta, cakes and chocolate for the intervention group. Concurrently the intake of vegetables, fruits, potatoes, bread, cereals, low-fat milk products, low-fat meat, sausages and fish increased significantly. For the control group there was a significant decrease in the consumption of total milk products, total meats, rice, pasta, cakes, and butter intake while the consumption of vegetables, fruits, cereals and fish increased (P less than or equal to 0.01). Reduction of high-fat foods and increases of carbohydrate-rich foods were more pronounced for the intervention group than for the control group. Formal education influenced dietary changes, and dietary counselling should therefore ideally be adapted to education level. This study showed that dietary counselling can bring about significant changes in consumption of high-fat foods for at least a 2-year period for women operated for breast cancer.     

Comparison of dietary assessment methods in a low-fat dietary intervention program

The food frequency questionnaire (FFQ) is commonly utilized for assessment of dietary fat intake, but its validity among individuals following a low-fat diet is unclear. We evaluated the agreement of nutrient estimates derived from FFQ, 24-h recall, and 3-day food records obtained from 104 participants in a randomized trial of a low-fat dietary intervention for women at elevated breast cancer risk. Comparisons were made for total calories, percent calories from fat, and total fat after 1 yr. Correlation was assessed using standard methods based on a null hypothesis of no agreement between instruments as well as by a methodology based on a null hypothesis that the instruments should be in agreement. With the use of standard methods, FFQ estimates for women on the low-fat diet were significantly correlated to records only for percent calories from fat (r = 0.39), whereas recall and record estimates were significantly correlated for all three dietary variables. Using the new method, we found no significant correlation between FFQ and either recalls or records for women following a low-fat diet but significant correlation between recall and record estimates for total calories (r = 0.67). Traditional correlation testing may overestimate the extent of agreement in dietary instruments among women on a low-fat diet. We found empirical support for the nontraditional method.     

Feasibility of a randomized trial of a low-fat diet for the prevention of breast cancer: dietary compliance in the Women's Health Trial Vanguard Study

The Women's Health Trial Vanguard Study was conducted to examine the feasibility of a nationwide, randomized multicenter intervention trial to test the hypothesis that a low-fat diet followed for a period of 10 years will reduce breast cancer risk. Women ages 45-69 years at increased risk of breast cancer were randomized into intervention (low-fat diet, n = 184) and control (usual diet, n = 119) groups. On the basis of 4-day food records, baseline fat intakes were comparable in the two groups, averaging 1,718 kcal with 39% of energy as fat. Intervention women reported substantially lower fat intake at 6 (20.9% kcal), 12 (21.6%), and 24 months (22.6% kcal). In contrast, control women reported only slight reductions in fat intake (37.3% kcal at 12 months and 36.8% kcal at 24 months). Evidence that these women were indeed complying with the low-fat dietary intervention comes from (a) the reasonable nature of reported nutrient changes within food groups in the intervention women and (b) agreement between observed and expected differences in plasma total cholesterol between the control and the intervention groups. At 12 months, the observed control - intervention plasma cholesterol difference was 13.1 +/- 4.6 mg/dl while the expected difference based on the Keys equation was 15.1 +/- 1.1 mg/dl; at 24 months, the observed difference was 15.5 +/- 4.3 mg/dl and the expected difference was 12.0 +/- 1.2 mg/dl. These analyses indicate that the intervention women made substantial dietary changes and have successfully maintained these changes over a 2-year period. This study thus demonstrates the feasibility of a randomized trial with an intensive low-fat dietary intervention.     

Nutrient and food intake in obese women on a low-fat or low-calorie diet

The low-fat group consumed significantly fewer calories from fat and more calories from carbohydrate at both 6 and 12 months than the low-calorie group, but their fat intake was still about twice their goal at both 6 months (39 gm per day) and 12 months (46 gm per day). The low-calorie group achieved their fat goal of 30% of calorie intake, but they consumed from 300 to 700 kcal more than their calorie goal. Caloric intake, physical activity, palatability, satiety, quality of life, and weight loss were not significantly different by treatment. Two studies, which gave patients hypocaloric diets of varying fat and carbohydrate content (fat calories 10% to 45%) for from 10 to 12 weeks, found no effect of diet composition on weight loss. In addition, one study, which gave patients a low-fat, energy-unrestricted diet (fat calories 19%), reported a weight loss of 10.1 lb at 16 to 20 weeks and 5.7 lb at 9 to 12 months, which is similar to that seen in the low-fat group in the this study. Most of the decrease in fat intake (90%) in the low-fat group resulted from a reduction in intake of fat from fat and oils; meat, fish, and poultry; dairy products; and sweets. The dietary changes in the low-fat group are consistent with those found in one study, which prescribed a 15% fat calorie diet to women with breast cancer. Intake of vitamin C increased in the low-fat group and decreased in the low-calorie group. This difference was significant and was caused by an increased intake of fruits and vegetables in the low-fat group and a decreased consumption of fruits in the low-calorie group. Calcium intake decreased significantly more in the low-calorie group because of a decreased intake of dairy foods.     

Long-term maintenance of a low-fat diet: durability of fat-related dietary habits in the Women's Health Trial.

The Women's Health Trial (WHT) was a feasibility study for a randomized trial of a low-fat diet for the prevention of breast cancer. One year after the WHT was terminated, a random sample of 894 participants who had been active in the WHT for an average of 16 months (range = 5 to 37) completed questionnaires about their dietary habits (a 21-item instrument that measures five dimensions of low-fat dietary habits) and food intake (a food frequency questionnaire). Women who participated in the intervention program maintained most of the low-fat dietary habits adopted during the study: mean total fat intake increased from 37.8 g to 41.0 g and scales describing substitution of specially manufactured low-fat foods and modification of meats to be lower in fat increased only slightly (by 0.11 and 0.14, respectively, on a scale of 1 = always to 4 = never). Scales describing avoiding meat and avoiding fats as a flavoring increased by 0.23 and 0.22, respectively, which suggests some recidivism. Women in the control group lowered their dietary fat intake from 65.0 to 57.5 g, but all differences in fat intake and fat-related dietary habits scales between women in the control and intervention groups remained highly statistically significant. In multiple regression models, all five low-fat dietary habits scales were independently associated with percentage of energy from fat, but the strongest association was for avoiding fats as flavorings. These results suggest that substitutions of specially manufactured low-fat foods are easily adopted and maintained dietary changes, but that maintenance of new habits related to avoiding fats as flavorings and avoiding meat will require long-term reinforcement strategies.(ABSTRACT TRUNCATED AT 250 WORDS)     

Dairy food intake is positively associated with cardiovascular health: findings from Observation of Cardiovascular Risk Factors in Luxembourg study

Conflicting findings have been reported about dairy food consumption and risk for cardiovascular disease. Furthermore, few studies have examined dairy food intake in relation to cardiovascular health and the incorporation of lifestyle factors such as diet and physical activity. This study examined whether dairy food consumption was associated with cardiovascular health, recently defined by the American Heart Association. Data were analyzed from 1352 participants from the Observation of Cardiovascular Risk Factors in Luxembourg survey. A validated food frequency questionnaire was used to measure intakes of milk, yogurt, cheese, dairy desserts, ice cream, and butter. Seven cardiovascular health metrics were assessed: smoking, body mass index, physical activity, diet, total cholesterol, blood pressure, and fasting plasma glucose. A total cardiovascular health score (CHS) was determined by summing the total number of health metrics at ideal levels. It was hypothesized that greater dairy food consumption (both low fat and whole fat) would be associated with better global cardiovascular health, as indicated by a higher CHS. Total dairy food intake was positively associated with the CHS. Higher intakes of whole fat milk, yogurt, and cheese were associated with better cardiovascular health. Even when controlling for demographic and dietary variables, those who consumed at least 5 servings per week of these dairy products had a significantly higher CHS than those who consumed these products less frequently. Higher total whole fat dairy food intake was also associated with other positive health behaviors, including being a nonsmoker, consuming the suggested dietary intakes of recommended foods, and having a normal body mass index. Increased dairy food consumption was associated with better cardiovascular health.     

Response to a diet low in total fat in women with postmenopausal breast cancer: a pilot study

A feasibility study was instituted to determine if women with postmenopausal breast cancer would follow a low-fat diet (20% of kcal) for at least four months. Nineteen women, whose baseline food intake was 1,504 +/- 420 kcal with 56 +/- 16 g of fat, reported a decrease in fat intake to 21 +/- 6 g after two months of dietary intervention. Serum concentrations of cholesterol, HDL cholesterol, and estradiol were significantly reduced by the fifth month on the diet. We conclude that self-selected patients can adhere to a low-fat diet, and that serum cholesterol may serve as an indicator of dietary compliance.     

Changes in food sources of dietary fat in response to an intensive low-fat dietary intervention: early results from the Women's Health Initiative

OBJECTIVE: To evaluate changes in food sources of dietary fat made by participants in the Women's Health Initiative Low-Fat Dietary Modification Trial. DESIGN: This study compares sources of dietary fat intake, estimated by a food frequency questionnaire, between intervention and control participants at baseline, 1 year (year 1) and 2 years (year 2) after randomization. The outcome measure was intake of fat in grams per day. Results are given on consumption of fat from six food groups and the intervention effect, defined as mean change in the intervention group minus the change in controls, controlling for baseline fat intake. PARTICIPANTS: 5,004 intervention and 7,426 control postmenopausal women in 40 clinical centers across the United States. RESULTS: At baseline, the major sources of fat were added fats, such as butter, oils, and salad dressings (25%); meats (21%); and desserts (13%). From baseline to year 1, the intervention group reduced fat by 24.3 g/day compared with the control group. Reductions came primarily from added fats (9.1 g/day), meats (4.6 g/day), and desserts (3.9 g/day). White people reduced added fats more than other race/ethnicity groups did, white and Hispanic people were more likely to reduce fat intake from milk and cheese compared with other groups, and Hispanics reduced fat from mixed dishes more than did other race/ethnicity groups (P<.05 for all). APPLICATIONS/CONCLUSIONS: These data indicate that women in the Women's Health Initiative dietary change intervention made substantial changes in food choices. These results can facilitate future low-fat interventions, and also offer clinical applications, by identifying foods that may be refractory to change.     

Methods to increase fruit and vegetable intake with and without a decrease in fat intake: compliance and effects on body weight in the nutrition and breast health study

Dietary patterns that involve a decrease in fat and an increase in fruit and vegetable (FV) intake have been suggested to decrease cancer risks. In this study, intervention methods to selectively modify dietary fat and/or FV intakes were developed. Compliance to the diets and the effects on body weight are shown, because both of these dietary changes can impact on and be confounded by changes in energy intake. A total of 122 women with a family history of breast cancer were randomized onto one of four diets for 12 mo. Counseling methods were devised to increase amount and variety of FV consumed with or without a decrease in fat intake using modified exchange list diets. Women on the low-fat and combination low-fat/high-FV diet arms decreased their fat intakes to approximately 16% of energy. Women on the high-FV and the combination low-fat/high-FV diet arms increased FV intakes to approximately 11 servings/day. Despite counseling efforts to maintain baseline energy intakes, mean body weight increased significantly by 6 pounds in women in the high-FV diet arm and decreased significantly by 5 pounds in women in the low-fat diet arm. Percent body fat also was increased in the high-FV diet arm and decreased in the low-fat diet arm. Body weight and percent body fat in the combination diet arm did not change significantly. Control of energy intake, therefore, appears to have been achieved only when the addition of FV to the diet was balanced by a decrease in fat intake and both dietary components were enumerated daily. Maintenance of energy intake, therefore, did not appear to be attained intrinsically when individuals were counseled to make changes in the composition of their diets.     

Dietary intake and changes in lipoprotein lipids in obese, postmenopausal women placed on an American Heart Association Step 1 diet

BACKGROUND: Dietary intake and changes in lipoprotein lipids in obese, postmenopausal women placed on an American Heart Association Step 1 diet. OBJECTIVE: The purpose of this study was to determine the specific dietary factors associated with the commonly observed decrease in HDL-C concentration in obese, postmenopausal women placed on a low-fat diet. DESIGN/SUBJECTS/INTERVENTION: Dietary intake, lipoprotein lipid concentrations, and body weight were measured before and after 10 weeks of instruction in the principles of the American Heart Association (AHA) Step 1 diet in 55 overweight and obese (body mass index=33+/-4 kg/m2), sedentary, postmenopausal women (mean age 59+/-5 years). RESULTS: The percent of energy obtained from total fat, monounsaturated, polyunsaturated, saturated fat, and dietary cholesterol decreased significantly after dietary intervention, while the polyunsaturated:saturated ratio and the percent of energy obtained from total carbohydrate, complex carbohydrate, and simple carbohydrate increased. On average, the women lost a small, but significant, amount of body weight (2%+/-3%, P<.0001). Adherence to the AHA diet reduced total cholesterol (-8%+/-8%), LDL-C (-6%+/-11%), and HDL-C (-16%+/-10%). The only dietary change that predicted decreases in HDL-C concentrations was the increase in the percent of energy from simple sugar (r=-0.32, P<.05). There were no relationships between changes in HDL-C and changes in percent of energy from fat (r=0.16), saturated fat (r=0.07), polyunsaturated fat (r=0.04), or monounsaturated fat (r=0.09). APPLICATIONS/CONCLUSIONS: In postmenopausal women, a dietary reduction in total fat, saturated fat, and cholesterol reduces body weight, total cholesterol, and LDL-C, but substitution of simple sugar for dietary fat may lead to a reduction in HDL-C. Further research is needed to determine which specific simple sugars are contributing to diet-induced reductions in HDL-C in older women placed on a low-fat diet.     

US dietary patterns associated with fat intake: the 1987 National Health Interview Survey.

OBJECTIVES. This research used food frequency data to investigate dietary patterns associated with fat intake. METHODS. Data from the 1987 National Health Interview Survey of 20,143 adults were used to determine correlations between fat (adjusted for kilocalories) and both nutrient and food group intakes. Median food and nutrient intakes were determined within quartiles of percentage of kilocalories from fat. RESULTS. Intakes of vegetables, fruits, cereals, fish/chicken, low-fat milk, alcoholic beverages, vitamin C, percentage of kilocalories from carbohydrates, carotenoids, folate, dietary fiber, carbohydrates, and vitamin A decreased as percentage of kilocalories from fat increased. Intakes of salty snacks, peanuts, processed and red meats, whole milk and cheese, desserts, eggs, fried potatoes, table fats, cholesterol, vitamin E, sodium, protein, and energy increased with percentage of kilocalories from fat. Results by demographic subgroups showed few differences from those found in the total population. CONCLUSIONS. Fat intake is consistently associated with specific dietary patterns. Such patterns need to be evaluated concurrently in studies of diet and chronic disease.     

How women''s adopted low-fat diets affect their husbands.

OBJECTIVES. One way of promoting a reduction in dietary fat intake is by changing the diet of family members. This study investigated the long-term effects of a low-fat dietary intervention on husbands of women who participated in the Women's Health Trial (WHT). METHODS. An average of 12 months after the end of the WHT, a randomly selected sample of participants' husbands was sent dietary and health questionnaires as part of a follow-up study of the maintenance of the low-fat diet among WHT participants. RESULTS. We found an absolute difference in fat intake between groups of 4 percentage points (32.9% energy from fat among intervention husbands [n = 188] vs 36.9% among control husbands [n = 180]). The wife's attitude and fat intake were among the most important predictors of her husband's fat intake, indicating that the effect of the WHT intervention on the husbands of participants was more likely due to their acceptance of lower-fat foods being served at home than to overt actions by the men. CONCLUSIONS. Our results suggest that a dietary intervention aimed at women can have an effect on their husbands and may be a cost-effective approach to healthy dietary change for both women and men.     

The impact of educational and environmental interventions in Dutch worksite cafeterias

Environmental interventions such as labeling and an increased availability of healthy foods may help consumers to meet guidelines for a healthy diet. This article describes a study into the effectiveness of two environmental programs to be used in worksite cafeterias along with an educational program. The aim of the interventions was to reduce fat intake, and to increase fruit and vegetable intake. In the labeling program, low-fat products were labeled. The food supply program comprised an increased availability of low-fat products and fruits and vegetables in worksite cafeterias. The educational program consisted of information about healthy nutrition through brochures, table tents, a self-help manual and posters. The design consisted of a pre-test-post-test experimental control group design, with four conditions: the educational program; the food supply program plus educational program; the labeling program plus educational program; and a control group. Seventeen worksites were randomly assigned to one of the four research conditions. Total fat, fruit and vegetable intake was measured with a quantitative, self-administered food frequency questionnaire (35 questions). Intake during lunch was measured by asking respondents to write down which food items they had purchased during their last lunch in the cafeteria. Furthermore, sales data for some targeted product categories were collected (milk, butter, cheese, meat products, desserts). For the whole study population, no significant effects on consumption data were found for any of the programs. The data showed a beneficial and significant treatment effect of the labeling program on total fat intake for respondents who believed they ate a high-fat diet. Sales data revealed a significant effect of the labeling program on desserts, but not for the other products.     

Monitoring Dietary Change in a Low-Fat Diet Intervention Study: Advantages of Using 24-Hour Dietary Recalls vs Food Records

Objective The purpose of the study was to evaluate two methods of dietary assessment for monitoring change in fat intake in a low-fat diet intervention study.Design The two dietary assessment methods were a 4-day food record (4DFR) and an unannounced 24-hour dietary recall conducted by telephone interview (referred to as a telephone recall [TR]). Subjects were assigned randomly to either a low-fat diet intervention group or a control group that received no counseling about fat intake. Dietary data were collected at baseline, 6 months, and 12 months.Subjects Two hundred ninety postmenopausal women with localized breast cancer were recruited at seven clinical centers in the United States.Statistical analysis Analysis of variance was used to test for significant differences in mean fat and energy intakes.Results Three sources of error were identified: (a) an instrument effect, suggesting underreporting at baseline of approximately 8% in mean energy intake and 11% in mean fat intake in the TR group compared with the 4DFR group (P=.0001); (b) a repeated measures effect observed for the 4DFR, suggesting underreporting of approximately 7% for energy intake and 14% for fat intake in the control group at 6 and 12 months compared with baseline values (P<.001); and (c) an adherence effect (or compliance bias), suggesting greater compliance to the low-fat intervention diet when subjects were keeping food records than when estimates were based on the unannounced TR. Compared with the TR, the 4DFR overestimated the extent of fat reduction in the low-fat diet intervention group by 41% (P=.08) and 25% (P=.62) at 6 and 12 months, respectively.Application Multiple days of unannounced 24-hour recalls may be preferable to multiple-day food records for monitoring dietary change in diet intervention studies. J Am Diet Assoc. 1996; 96:574-579.     

Effect of low-fat and/or low-energy diets on anthropometric measures in participants of the women's diet study

OBJECTIVE: To compare the effects of low-fat, low-energy and combination low-fat/low-energy intervention on changes in six anthropometric measures in Caucasian and African-American free-living women. METHODS: The effects of dietary counseling strategies for fat and/or energy reduction were examined on anthropometric measures in 86 pre-menopausal women, average BMI of 28 kg/m2, who participated in a 12-week intervention trial called the Women's Diet Study. The dietary goals were 15% of energy from fat and/or 25% reduction in energy intake, relative to reported baseline intake, using a 2 x 2 factorial design. Analysis of covariance models were constructed to evaluate changes in anthropometric measures over the 12 weeks of study. RESULTS: The biggest difference by race was in women who were relatively heavier at baseline, in which case African-American women lost significantly less weight but decreased their waist:hip ratio to a significantly greater extent than Caucasian women. With regard to the effects of diet arm, weight loss varied depending on baseline weight, and in women with higher baseline weights, the combination low-fat/low-energy diet resulted in the most weight loss (6.7 kg, p < 0.05). Decreases in the other anthropometric measures at week 12 were more uniform across diet arms and did not depend on baseline values. After controlling for previous weight history and race, the decreases in BMI, percent body fat and waist circumference after 12 weeks were statistically equivalent with the low-fat, low-energy or combination low-fat/low-energy diets. The relatively greater decreases in percent body fat and waist circumference with the combination diet versus the low-fat or low-energy diets were not statistically significant. CONCLUSION: The low-fat, low-energy and combination diets all resulted in similar and statistically significant decreases in BMI, percent body fat and waist circumference over 12 weeks of intervention. The extent of weight loss, however, varied depending on baseline weight, and the combination diet was the only intervention to result in significant weight loss for women who were heavier at baseline. This indicates that, although there may be an advantage for reducing dietary fat in initially heavier women, any of these counseling strategies could be effective for improving anthropometric predictors of health risks associated with overweight status. This is useful since flexibility in dietary choices may facilitate adherence to dietary counseling in some individuals.     

Correlates of maintenance of a low-fat diet among women in the Women's Health Trial.

BACKGROUND. The Women's Health Trial (WHT) was a feasibility study for a randomized controlled trial designed to test the hypothesis that a reduction in dietary fat reduces breast cancer incidence among women age 45 to 69. Between 1984 and 1988, 2,064 women participated in its two phases. METHODS. A follow-up study of 525 women who were randomized to receive the WHT dietary intervention program was conducted to assess maintenance of the diet 1 year on average after the trial ended. Among 448 participants, the mean percentage of energy from fat as measured by a food frequency questionnaire was 40.0% at baseline, 26.3% at the end of the trial, and 27.7% at follow-up. Based on 408 women with complete data, a recursive model was estimated, describing the influence of baseline characteristics of the women on attendance at intervention program sessions, adherence to the diet during the trial, and long-term maintenance of the diet after the trial ended. The effects of women's experiences during the trial on adherence and long-term maintenance were investigated as well. RESULTS. Attendance at the educational sessions was strongly related to adherence to the diet during the trial (P less than 0.001), and adherence was the most important predictor of long-term maintenance (P less than 0.001). The percentage of energy from dietary fat at baseline was an important correlate of both adherence (P less than 0.001) and long-term maintenance (P less than 0.001). College-educated women were more likely to adhere to the diet during the trial (P less than 0.001). Feelings of deprivation adversely affected long-term maintenance (P less than 0.01), primarily through their effect on adherence during the trial (P = 0.01). Costliness of the diet in time and money negatively influenced long-term maintenance (P less than 0.05). Development of a distaste for fat encouraged adherence (P = 0.06). CONCLUSIONS. The low-fat dietary pattern established during the WHT was maintained for as long as 20 months after the trial ended. A recursive model was useful in analyzing the process and correlates of long-term maintenance of dietary behavior change. Both predisposing variables and women's experiences while on a low-fat diet were associated with long-term maintenance. The results suggest that feelings of deprivation should be avoided, perhaps by use of low-fat substitutes, by those attempting to lower their dietary fat and that more research is needed on the development of a distaste for fat among individuals who adopt low-fat diets.     

The effects of physical and emotional status on adherence to a low-fat dietary pattern in the Women's Health Initiative

OBJECTIVE: To examine whether the effects of physical and emotional status on adherance to a low-fat (20% energy) dietary pattern are mediated by participation in an intervention program (attending sessions and self-monitoring). DESIGN: The Baron and Kenny mediator model, a series of 4 regression analyses, was used to evaluate whether: a) physical and emotional status predicted program participation, b) program participation predicted dietary adherence, c) physical and emotional status factors predicted dietary adherence, and, ultimately d) the effects of physical and emotional status on dietary adherence were mediated by program participation. SUBJECTS/SETTING: Data from 13,277 postmenopausal women randomly assigned to the low-fat intervention arm of the Women's Health Initiative Dietary Modification Trial. INTERVENTION: The nutrition goals for women randomly assigned to the low-fat intervention were to reduce total fat intake to 20% or less of energy from fat and to consume 5 or more fruit/vegetable servings daily and 6 or more grain servings daily. MAIN OUTCOME MEASURES: Year 1 program participation (degree of attending group sessions and submitting fat scores) and adherence to the low-fat dietary pattern (percent energy from fat) as predicted by baseline physical and emotional status (eight SF-36 Health Survey subscales). RESULTS: Participating in the dietary intervention program reduced (mediated) the negative effect of poorer mental health on dietary adherence by 15%. Additional findings included that a 10% increase in physical functioning increased session attendance by 0.4% (P<.001) and a 10% increase in mental health predicted a decrease in percent energy from fat of 0.3% (P<.001). Program participation had a marked effect on dietary adherence: a 10% increase in session attendance predicted a 1.2% decrease in percent energy from fat (P<.001). APPLICATIONS/CONCLUSIONS: Understanding and using instruments to assess the physical and emotional status of a target population will help dietetic professionals promote healthful dietary change and maintenance.     

Reduced serum cholesterol with dietary change using fat-modified and oat bran supplemented diets

A low-fat, low-cholesterol diet and oat bran supplementation for treatment of hypercholesterolemia were studied for their effectiveness in lowering blood lipids and their impact on dietary intake. Seventy-one free-living men and women with hypercholesterolemia (serum cholesterol greater than 75th percentile) were randomly assigned to one of the following four groups: low-fat, low-cholesterol diet (LFLC); low-fat, low-cholesterol diet plus 50 gm/day oat bran (LFLC + OB); 50 gm/day oat bran supplemented diet (OB); or 42.5 gm/day processed oat bran (ready-to-eat cereal containing beta-glucan concentrated from oat bran) (POB). Subjects assigned to regimens OB and POB were requested to add the oat supplement without making additional changes in their diet. Serum cholesterol and high-density lipoprotein cholesterol analyses were performed at 4-week intervals, and diet records were assigned and analyzed. All groups experienced significant decreases in cholesterol from original levels (p less than .05). The average decrease in total serum cholesterol varied from 10% to 17%, with no significant differences among the four groups. High-density lipoprotein cholesterol concentrations decreased in all groups except group 4, in which there was a slight increase; however, no differences were found between groups. Energy, fat, and cholesterol intakes decreased in all groups, suggesting that displacement of higher fat foods from the diet may be one of the many mechanisms whereby oat supplements lower serum cholesterol. In addition, all groups reduced their intakes of calcium, copper, folic acid, and potassium from marginal levels at the beginning of the study.(ABSTRACT TRUNCATED AT 250 WORDS)