Extending the prudent diet to cancer prevention

The basis for the formulation of a “prudent diet” is briefly reviewed. Epidemiologic, clinical, and experimental studies related to cancer, coronary heart disease, obesity, diabetes, and hypertension support the position that it is prudent to limit consumption of fats, cholesterol, sugar, and salt, and increase the consumption of fruit, vegetables, and cereals. It is also prudent to limit consumption of products suspected to cause or promote cancer.     

Proceedings: Present and proposed regulations affecting the marketing of prudent diet foods

When the questions of the relationship of diet and heart disease are considered, even those most committed must admit a controversy. In the past, the Food and Drug Administration took a position specifically forbidding any kind of statements on fat and fatty acids. Although there are no definitive studies which have demonstrated beyond doubt that a diet modification in the general public with respect to fat and cholesterol is desirable, the Agency has modified its position so that patients may better identify such foods when a “prudent” diet has been recommended by their physicians. This product identification is achieved through labeling where the total fat content, the cholesterol, and saturated and polyunsaturated fatty acids may be stated. No other statements may be made that implicitly or explicitly claim a value in preventing or treating heart or artery diseases. Responsibility for the education and use of the information by the consumer will remain with the individual physician, health educator, and health organizations.     

Proceedings: The potential for vegetable proteins in prudent diet foods

A major problem in designing diets of any sort, be they the “prudent diet”, or for reducing weight, or otherwise, is that the participant is faced with many restrictions and few alternatives. But now it is possible, with the aid of modern food science, to fabricate foods with changed nutrient compositions which might make dieting easier. For example, protein foods are generally associated with a high degree of sensory satisfaction; this is true particularly of meats and the like. The problem is that the high degree of sensory satisfaction and the high quality of protein and micronutrient mix brings with it cholesterol and saturated fats, both of which are restricted in the prudent diet. The virtue of vegetable proteins is that it is now possible, because of the methods of texturizing, to fabricate analogs which approach the animal foods in sensory quality, yet contain a nutrient mix that is more satisfactory in terms of caloric intake and the nature and quantity of the lipids.     

Perceived palatability of the prudent diet: Results of a dietary demonstration for physicians

“Product sampling” is an effective marketing strategy which lowers consumer buying resistance by providing a free sample of the product for the consumer to test. We used this strategy to demonstrate the palatability of the prudent diet (30–35% of calories from total fats, <10% from saturated fats, <3 g sodium, and increased fiber) to physicians attending a 5-day family practice continuing medical education conference. The effect of the intervention was evaluated with pre- and postintervention questionnaires and a 20% random sample of participants was surveyed 1 year later. The proportion of physicians who reported that they considered the diet to be “very palatable” rose from 26% before the demonstration to 64% after the demonstration. Only 5% of the physicians did not report a favorable response to the demonstration. Sixty-two percent of the physicians reported that the diet was better than expected, and 82% reported that the demonstration encouraged them to recommend the diet to their patients. One year after the intervention 60% considered the diet “very palatable” and 55% reported that the demonstration stimulated them to increase their dietary intervention activities. These data suggest that serving the prudent diet at continuing medical education programs helps to remove prejudices about the diet and encourages physicians to recommend the diet to their patients.     

Influences of "normal" and "prudent" diets on biliary and serum lipids in healthy women

The differential effect of two diets, taken in synchrony with the menstrual cycles for 2 wk each, on serum and bile lipids was investigated in young healthy women. The "normal" diet was high in cholesterol and total fat, and low in polyunsaturated fat and fiber; the "prudent" diet contained a high proportion of polyunsaturated fat and fiber, but was low in cholesterol and total fat; there was little difference in energy content. Both in whole serum and in low-density lipoprotein the concentrations of cholesterol and apolipoprotein B were almost 30% lower with the "prudent" than with the "normal" diet; HDL-cholesterol was 16.3% lower. Triglycerides were increased, only in the very-low-density lipoproteins while cholesterol and apolipoprotein B did not change much in this fraction. The risk to acquire cholesterol gallstones was not less with the use of the "prudent" diet as originally expected. While using the "prudent" diet five of the women had slightly higher lithogenic indices, in two there were much higher values (greater than 25%), and only in three the lithogenic index was unchanged or slightly lower than with the "normal" diet.     

Cholesterol-lowering efficacy of a sitostanol-containing phytosterol mixture with a prudent diet in hyperlipidemic men.

BACKGROUND: Dietary plant sterols (phytosterols) have been shown to lower plasma lipid concentrations in animals and humans. However, the effect of phytosterol intake from tall oil on cholesterol and phytosterol metabolism has not been assessed in subjects fed precisely controlled diets. OBJECTIVE: Our objective was to examine the effects of sitostanol-containing phytosterols on plasma lipid and phytosterol concentrations and de novo cholesterol synthesis rate in the context of a controlled diet. DESIGN: Thirty-two hypercholesterolemic men were fed either a diet of prepared foods alone or a diet containing 1.7 g phytosterols/d for 30 d in a parallel study design. RESULTS: No overall effects of diet on total cholesterol concentrations were observed, although concentrations were lower with the phytosterol-enriched than with the control diet on day 30 (P < 0.05). LDL-cholesterol concentrations on day 30 had decreased by 8.9% (P < 0.01) and 24.4% (P < 0.001) with the control and phytosterol-enriched diets, respectively. HDL-cholesterol and triacylglycerol concentrations did not change significantly. Moreover, changes in circulating campesterol and beta-sitosterol concentrations were not significantly different between phytosterol-fed and control subjects. In addition, there were no significant differences in fractional (0.091 +/- 0.028 and 0.091 +/- 0.026 pool/d, respectively) or absolute (0.61 +/- 0.24 and 0.65 +/- 0.23 g/d, respectively) synthesis rates of cholesterol observed between control and phytosterol-fed subjects. CONCLUSION: Addition of blended phytosterols to a prudent North American diet improved plasma LDL-cholesterol concentrations by mechanisms that did not result in significant changes in endogenous cholesterol synthesis in hypercholesterolemic men.     

Proceedings: Nutrition forum: Progress in developing the prudent diet. Summary of symposium and recommendations for food industry action

Diet and nutrition are important factors in the prevention and treatment of the commonest types of cardiovascular disease—coronary heart disease and stroke—both in the primary and secondary prevention.The most important aspect of diet and cardiovascular disease is that one can manipulate the diet with some ease. Many of the principles of nutrition that have preventive values relative to heart disease can actually be built into manufactured foods, and most of our foods today, and more in the future, will be manufactured foods. This, I think, is not only a challenge to the food industry but a responsibility. It is a challenge in which they should be helped by our regulatory agencies rather than hindered. No doubt those in the food industry who continue to make advances in this area will continue to be attacked by far out consumer activists who get such ego satisfaction by creating confusion and distrust in a gullible public that all is not well with the nation's food supply.Here are a few specifics for the food industry: design of foods with fewer calories, generally that means foods with less fat and more water; design of foods with less saturated fat, replacing part of the saturated fat with either mono- or polyunsaturated fat; the production of meat low in saturated fats and meat products (e.g., sausages, hot dogs, and cold cuts) low in saturated fats yet with an acceptable total fat, by the addition of polyunsaturated fats; the development of strains of animals that convert higher proportions of feed to protein rather than fat; a shift to range feeding with earlier slaughter of cattle to yield leaner animals; modernization of laws and regulations relating to the definition of meat products; further development and use of high-quality vegetable protein products; development of an intensive education program concerning the cooking of lean meats to assure their optimal palatability and acceptability without the use of added saturated fats; reduction in saturated fat and cholesterol content of dairy products; reduction of saturated fat, cholesterol, and calorie content of baked goods; reduction of use of egg yolk in foods. Lastly, it should be emphasized that diet is only one of the risk factors in our commonest type of ill health and death—cardiovascular disease—but it is a risk factor readily modified.     

Cholesterol-lowering effects of psyllium-enriched cereal as an adjunct to a prudent diet in the treatment of mild to moderate hypercholesterolemia.

Psyllium hydrophilic mucilloid, rich in soluble fiber, significantly lowers serum cholesterol concentrations. To investigate the lipid-lowering effects of a ready-to-eat cereal enriched with psyllium, we studied 44 hypercholesterolemic ambulatory individuals for 7 wk, using a randomized, double-blind, parallel design. After a 1-wk baseline period, subjects were randomly assigned to consume 114 g/d of a psyllium-flake or wheat-bran-flake cerearl for 6 wk adjunctive to an American Heart Association Step I diet. Serum high-density-lipoprotein cholesterol and triglycerides remained unchanged throughout the study; however, serum cholesterol and low-density lipoprotein (LDL) concentrations were significantly lower on psyllium than on wheat-bran cereal. Additionally, serum total and LDL cholesterol values were significantly lower than baseline values in the psyllium group. The dietary nutrient intake of the two groups did not differ except for soluble fiber. Adding psyllium-enriched cereal to a prudent low-fat diet may enhance dietary management of hypercholesterolemia.     

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.     

Dietary patterns and colon cancer in western New York

Seven dietary patterns were identified among control subjects in the Western New York Diet Study (1975–1986) by application of principal components analysis to data from a 95‐itemfood frequency interview. The results of case‐control analyses of colon cancer risk for these patterns are presented. Cases were matched with neighborhood controls on the bases of age and sex; 205 colon case‐control male and 223 female pairs were obtained. The dietary patterns and intakes of energy, total fat, and dietary fiber were examined with logistic regression for their individual contributions to risk. In males, three of these dietary patterns were associated positively with fat and energy consumption; they elevated risk for colon cancer and accounted for more risk than did the specific nutrients. Control for energy and fat intakes allowed the protective influences of additional dietary patterns to be expressed. No patterns elevated risk in women; two patterns were protective for colon cancer. Controlling for energy and fat intake enhanced the protection afforded by one of these patterns but had no influence on that of the other. Measures of foods rather than single nutrients may be more inclusive of dietary exposures to risk as well as being related more directly to underlying health behaviors. Therefore they may be better able to account for risk in diseases with multiple causation.     

Cholesterol-lowering effects of soluble-fiber cereals as part of a prudent diet for patients with mild to moderate hypercholesterolemia

Soluble-fiber breakfast cereals were examined for their cholesterol-lowering ability in 58 male patients with mild to moderate hypercholesterolemia in a randomized, double-blind, placebo-controlled study. Patients followed a step 1 diet for a minimum of 6 wk, then were randomly assigned to groups incorporating either corn flakes or one of two soluble-fiber cereals (pectin enriched or psyllium enriched) in the diet for an additional 6 wk. During the diet-only phase, total cholesterol dropped 3.8%. During the cereal-plus-diet phase, total and LDL cholesterol values of the pectin-enriched cereal group dropped an additional 2.1% (P = 0.243) and 3.9% (P = 0.16), respectively, and they dropped 5.9% (P = 0.005) and 5.7% (P = 0.034), respectively, in the psyllium-enriched cereal group. During the cereal-plus-diet phase, no significant effects on HDL cholesterol, triglyceride, or body weight were found within or between any cereal groups. These results support use of soluble-fiber cereals as an effective and well-tolerated part of a prudent diet in the treatment of mild to moderate hypercholesterolemia.     

Correlates of tobacco use among Native American women in western North Carolina.

OBJECTIVES: This study examined correlates of tobacco use among Cherokee women. METHODS: Prevalence rates were analyzed for 614 randomly selected Eastern Band Cherokee women. RESULTS: The prevalence rates for current smokeless tobacco use and smoking were 8% and 39%, respectively. Smokeless tobacco use correlates included lower education and having consulted an Indian healer. Smoking correlates included younger age, alcohol use, no yearly physical exam, separated or divorced marital status, and lack of friends or church participation. CONCLUSIONS: Smoking rates among these women were slightly above national rates. The association of smokeless tobacco use with having consulted an Indian healer may help in understanding Cherokee women's smokeless tobacco use.     

A case-control study of diet and rectal cancer in western New York

In three counties in western New York, a case-control study of incident, pathologically confirmed, single, primary cancers of the rectum was conducted from 1978 to 1986. Cases were matched with neighborhood controls on age and sex; 277 case-control pairs of males and 145 case-control pairs of females were interviewed regarding usual quantity and frequency of consumption of foods. Risk of rectal cancer increased with increasing intake of kilocalories, fat, carbohydrate, and iron. Risk decreased with increasing intake of carotenoids, vitamin C, and dietary fiber from vegetables. Fiber from grains, calcium, retinol, and vitamin E were not associated with risk. Associations of intake with risk were generally stronger for males than for females except for vitamin C. The association for carotenoids, vitamin C, and vegetable fiber persisted after stratification on intake of either kilocalories or fat.     

Dietary patterns and colon cancer in western New York.

Seven dietary patterns were identified among control subjects in the Western New York Diet Study (1975-1986) by application of principal components analysis to data from a 95-item food frequency interview. The results of case-control analyses of colon cancer risk for these patterns are presented. Cases were matched with neighborhood controls on the bases of age and sex; 205 colon case-control male and 223 female pairs were obtained. The dietary patterns and intakes of energy, total fat, and dietary fiber were examined with logistic regression for their individual contributions to risk. In males, three of these dietary patterns were associated positively with fat and energy consumption; they elevated risk for colon cancer and accounted for more risk than did the specific nutrients. Control for energy and fat intakes allowed the protective influences of additional dietary patterns to be expressed. No patterns elevated risk in women; two patterns were protective for colon cancer. Controlling for energy and fat intake enhanced the protection afforded by one of these patterns but had no influence on that of the other. Measures of foods rather than single nutrients may be more inclusive of dietary exposures to risk as well as being related more directly to underlying health behaviors. Therefore they may be better able to account for risk in diseases with multiple causation.