Presentation on theme: "Nathan D. Wong, Ph.D., F.A.C.C. Professor and Director"— Presentation transcript:
1 Dietary Intervention and Recommendations in the Prevention of Obesity and Heart Disease Nathan D. Wong, Ph.D., F.A.C.C.Professor and DirectorHeart Disease Prevention Program, University of California, Irvine
2 Dietary Effects on Lipids Seven Countries study showed significant correlation between saturated fat intake and blood cholesterol levelsMeta-analysis of randomized controlled trials shows lowering saturated fat and cholesterol to reduce total and LDL-C 10-15%For every 1% increase in intake of saturated fat, blood cholesterol increases 2 mg/dlSoluble fiber intake may provide additional LDL-C response over that of a low-fat diet
3 Dietary Effects on Thrombosis Omega-3 fatty acids have antithrombogenic and antiarrhythmic effects, decreased platelet aggregation, and lower triglyceridesEskimos’ cold water fish diet associated with prolonged bleeding times and lower rates of MI; similar findings in Japan, Netherlands, and EnglandLyon Diet-Heart Study reported increased survival following Mediterranean diet with fish and high in linolenic acid (no lipid differences seen).
4 Associations between the percent of calories derived from specific foods and CHD mortality in the 20 Countries Study*Food Source Correlation Coefficient†ButterAll dairy productsEggsMeat and poultrySugar and syrupGrains, fruits, and starchyand nonstarchy vegetables*1973 data, all subjects. From Stamler J: Population studies. In Levy R: Nutrition, Lipids, and CHD. New York, Raven, 1979.†All coefficients are significant at the P<0.05 level.
5 Men participating in the Ni-Hon-San study* ResidenceJapan Hawaii CaliforniaAge (years)Weight (kg)Serum cholesterol (mg/dL)Dietary fat (% of calories)Dietary protein (%)Dietary carbohydrate (%)Alcohol (%)5-yr CHD mortality rate(per 1,000)*Data from Kato et al. Am J Epidemiol 1973;97:372. CHD, coronary heart disease.
6 Epidemiologic studies* Populations on diets high in total fat, saturated fat, cholesterol, and sugar have high age-adjusted CHD death rates as well as more obesity, hypercholesterolaemia, and diabetesThe converse is also trueWhat is the evidence for dietary intervention studies?*Results from Seven Countries, 18 countries, 20 countries, 40 countries,and Ni-Hon-San Studies
7 Oslo Diet Heart Study 412 men with CHD, 5 year study Treatment group randomized to low saturated fat (8.4% of calories), low cholesterol (264 mg/day), high polyunsaturated fat (15.5%) dietSerum cholesterol reduced 14%33% reduction in MI, 26% decrease in CHD mortalityDietary counseling every 3 monthsLeren et al. Acta Med. Scand 1966; 466:1.
8 Los Angeles VA study 846 men in Veterans Home, 5-8 years Groups randomized to diets in which 2/3 of fat given either as vegetable oil (corn, cottonseed, safflower, soybean) or animal fatSaturated fat 11% vs. 18%, polyunsaturated fat 16% vs. 5% of calories31% decrease in CVD endpointsDayton et al. Circulation 1969; 40:1.
9 Lyon Diet Heart study 302 men and women with CHD Treatment group randomized to low saturated fat, high canola oil margarine (5% alpha linolenic, 16% linoleic, and 48% oleic acid, also 5% trans)46 month follow-up65% lower CHD death rate in treatment group (6 vs. 19 death)de Lorgeril et al. Circulation 1999; 99:
10 Stanford Coronary Risk Intervention Project (SCRIP) 300 men and woman with CHD, baseline and 4 year follow-up angiogramsRandomized to <20% fat, <6% saturated fat, <75 mg cholesterol/day, and exercise (Rx group) vs usual careLDL-C and TG decreased 22% and 20%, and HDL-C increased 20%Rx group had 47% less progression than control group, P<0.02Haskell et al. Circulation 1994; 89: Quinn et al. JACC 1994; 24:
11 U.S. Diabetes Prevention Project 3234 subjects with BMI > 34 kg/m2Placebo, metformin, and lifestyle modificationLifestyle modification goal > 7% weight loss with diet and exercise ( 150 min / week)New onset diabetes: 11% placebo, 7% metformin, 4.8% lifestyle groupNEJM 2002
12 Finnish Diabetes Prevention Study 522 overweight subjects; Intervention group - met with dietician 4 x /yr and supervised exercise vs control group (pamphlet)Goals: 1) 5 lb wt loss 2) 15gm of fiber/1000 cal 3) < 30% fat 4) < 10% saturated fat 5) 30 minutes of exercise /dayIntervention group met 4/5 goals 0% new diabetes, vs control group met 0 goals 32% new diabetesNEJM 2001
13 Cardiovascular Effects of Treating Overweight/Obesity (1998 NHLBI Obesity Guidelines) Lower elevated BP in overweight and obese persons with high blood pressure (45 trials)Lower elevated total and LDL-cholesterol and triglycerides and increase HDL-cholesterol (22 trials)Lower elevated blood glucose levels in overweight and obese persons with diabetes (17 trials)
14 Summary of Dietary Trials for Weight Loss (1998 NHLBI Obesity Guidelines) 48 acceptable RCTs showing an average weight loss of 8% of initial body weight can be obtained over 3-12 monthsWeight loss effects decrease in abdominal fat; low-fat diets with targeted caloric reduction promote greater weight lossVery low calorie diets promote greater initial weight loss, but similar effects after one yearNo improvement in CVD fitness measured by V02max in those not incorporating physical activity with dietary therapy
15 Homocysteine: Role in Atherogenesis Linked to pathophysiology of arteriosclerosis in 1969CVD patients have elevated levels of plasma homocysteineMay cause vascular damage to intimal cellsElevated levels linked to:genetic defectsexposure to toxinsdietIncreased dietary intake of folate and vitamin B6 may reduce CVD morbidity and mortalityMcCully KS. Am J Pathol. 1969;56:McCully KS. JAMA. 1998;279:Rimm EB et al. JAMA. 1998;279:
16 Benefits of fish oil supplementation In the Diet and Reinfarction Trial (DART) in 2033 men with CHD increased intake of fish or use of 2 fish oil caps/day reduced CHD mortality 29% over 2 yearsIn GISSI men and woman with CHD use of 1 gr. of n-3 PUFA decreased CVD events including mortality 15%Lancet 1989; 2; , and 1999; 345:
17 Nuts, Soy, Phytosterols, Garlic Nurses’ Health Study: five 1oz servings of nuts per week associated with 40% lower risk of CHD eventsMetaanalysis of 38 trials of soy protein showed 47g intake lowered total, LDL-C, and trigs 9%, 13%, and 11%Phytosterol-supplemented foods (e.g., stanol ester margarine) lowers LDL-C avg. 10%Meta-analysis of garlic studies showed 9% total cholesterol reduction (1/2-1 clove daily for 6 months).
26 Therapeutic Lifestyle Changes in LDL-Lowering Therapy: Major Features Saturated fats <7% of total caloriesDietary cholesterol <200 mg per dayPlant stanols/sterols (2 g per day)Viscous (soluble) fiber (10–25 g per day)Weight reductionIncreased physical activity
27 Therapeutic Lifestyle Changes Nutrient Composition of TLC Diet Nutrient Recommended IntakeSaturated fat Less than 7% of total caloriesPolyunsaturated fat Up to 10% of total caloriesMonounsaturated fat Up to 20% of total caloriesTotal fat 25–35% of total caloriesCarbohydrate 50–60% of total caloriesFiber 20–30 grams per dayProtein Approximately 15% of total caloriesCholesterol Less than 200 mg/dayTotal calories (energy) Balance energy intake and expenditure to maintain desirable body weight/ prevent weight gain
28 A Model of Steps in Therapeutic Lifestyle Changes (TLC) Visit 2Evaluate LDL responseIf LDL goal not achieved, intensify LDL-Lowering TxVisit 3Evaluate LDL responseIf LDL goal not achieved, consider adding drug TxVisit NVisit IBegin Lifestyle Therapies6 wks6 wksQ 4-6 moMonitor Adherence to TLCEmphasize reduction in saturated fat & cholesterolEncourage moderate physical activityConsider referral to a dietitianReinforce reduction in saturated fat and cholesterolConsider adding plant stanols/sterolsIncrease fiber intakeConsider referral to a dietitianInitiate Tx for Metabolic SyndromeIntensify weight management & physical activityConsider referral to a dietitian
29 Steps in Therapeutic Lifestyle Changes (TLC) First VisitBegin Therapeutic Lifestyle ChangesEmphasize reduction in saturated fats and cholesterolInitiate moderate physical activityConsider referral to a dietitian (medical nutrition therapy)Return visit in about 6 weeks
30 Steps in Therapeutic Lifestyle Changes (TLC) (continued) Second VisitEvaluate LDL responseIntensify LDL-lowering therapy (if goal not achieved)Reinforce reduction in saturated fat and cholesterolConsider plant stanols/sterolsIncrease viscous (soluble) fiberConsider referral for medical nutrition therapyReturn visit in about 6 weeks
31 Steps in Therapeutic Lifestyle Changes (TLC) (continued) Third VisitEvaluate LDL responseContinue lifestyle therapy (if LDL goal is achieved)Consider LDL-lowering drug (if LDL goal not achieved)Initiate management of metabolic syndrome (if necessary)Intensify weight management and physical activityConsider referral to a dietitian
32 Dietary Approaches to Stop Hypertension (DASH) Diet high in fruits and vegetables and low-fat dairy products lowers blood pressure (11 mmHg SBP/ 5 mmHg DBP lower than traditional US diet), including more than a sodium-restricted dietRecommends 7-8 servings/day of grain/grain products, 4-5 vegetable, 4-5 fruit, 2-3 low- or non-fat dairy products, 2 or less meat, poultry, and fish.NEJM 1997; 366:
33 Dietary fats* Fat SFA MUFA PUFA Cholesterol Canola oil† 6 62 31 0 Corn oilOlive oilPalm oilSafflower oilSoybean oil†Sunflower oil*Values for SFA, MUFA, and PUFA represent percentage of total fat calories, whereas those for cholesterolare expressed as mg per tablespoon. SFA is the sum of lauric, myristic, palmitic, and stearic acids.†Contain a considerable amount (>5%) of alpha-linolenic acid.‡Some are high in trans fatty acids: vegetable shortening>margarine fat>animal fat shortening>butter fat.SFA, saturated fatty acids; MUFA, monounsaturated fatty acids; PUFA, polyunsaturated fatty acids.
34 USDA FOOD PYRAMID Daily Food Intake Recommendations I servings of bread, cereal, rice or pasta1 serving is 1 slice of bread, 1 ounce of ready to eat cereal,or a ½ cup of cereal, rice, or pasta.II servings of vegetables1 serving is 1 cup of leafy vegetables, a ½ cupof other vegetables (cooked or chopped), or 3/4 cup of vegetable juice.III servings of fruit1 serving is 1 apple, banana, or orange, a ½ cup of chopped,cooked, or canned fruit, or 3/4 cup of fruit juice.IV servings of milk, yogurt, or cheese1 serving is 1 cup of low fat or skimmed milk or yogurt,1½ ounces of natural cheese, or 2 ounces of processed cheese.V servings of meat, poultry, fish, dried beans, or nuts1 serving is 2-3 ounces of lean meat,poultry (white meat without skin), or fish, or 1 cup of beans or nuts.VI. Use fats, oils, and sugars (including syrup) sparingly
35 Recommendations for CHD risk reduction and weight loss Decrease calories and increase energy expenditureDecrease saturated fat and cholesterol (animal fats)Increase essential fatty acids, especially n-3 (alpha-linolenic or fish oil-EPA/DHA)Decrease sugar intake and increase intake of vegetables, fruits and grainsDecrease hydrogenated fat and tropical oil intakeReplace butter with soft no trans margarine or oil (canola and soybean) or plant sterol margarineDecrease caloric density and increase fibre
36 Dietary Approaches: Dean Ornish Reversal Diet: 10% fat, 70-75% carbohydrate, 15-20% protein, 5 mg cholesterol/day, excludes all animal products (including seafood) except nonfat milk and yogurt, also excludes high-fat vegetarian foods, including oils, nuts, seeds, and avocados.Prevention Diet: Allows up to twice as much fat as the Reversal Diet, as long as blood cholesterol remains at 150 or less, allows meat and seafood, substitutes egg whites for yolks, use of canola oil.
37 Lifestyle Heart Trial 41 male and female CHD patients Randomized to <10% fat diet, exercise and meditation (Rx group) vs. Step 1 dietAt one year 37% LDL-C reduction, 22% weight loss, and 1.8 % regression in Rx group vs 2.3% progression in control group (quantitative coronary angiography)At 5 years 20% LDL-C reduction, 3.1% regression in Rx group vs 11.8% progression in control group (n=35)Ornish et al. Lancet 1990; 336: , and JAMA 1998; 280:
38 Dietary Approaches: Zone/Soy Zone Premise is to reduce insulin levels and stabilize glucose control by limiting starchy carbohydrates, emphasize low-density carbohydrates.Emphasis on protein (avg. 75g/day for women and 100 g/day for men) (one-third of plate) (soy protein products for Soy Zone) and carbohydrates (primarily from vegetables, fruits to a lesser extent). Allows limited monounsaturated fats.Metaanalysis of clinical trial on soy protein (avg. 47g/day) showed reduction in total cholesterol of 9%, LDL-C 13%, and triglycerides 11% (NEJM 1995; 333: )
39 Dietary Approaches: Atkins Intended to correct unbalanced metabolism by restriction of carbohydrates to reduce insulin production and conversion of excess carbohydrates into stored body fatInduction diet limits carbohydrate intake to 20 gms/day (e.g., 3 cups of salad veg or 2 cups salad + 2/3 cup cooked vegs) to induce ketosis/ lypolysis. Maintenance diet gms/day.Pure proteins, fats, and protein/fat allowed (all meats, fish, foul, eggs, cheese, veg oils, butter)Most carbohydrates are not allowed--fruits, bread, grains, starchy vegs, or dairy products.
40 Data on Atkins and Zone diets Medline analysis 2001No large scale (>50 subjects) long term (>6months) follow-up studies could be identified with weight loss, cardiovascular risk assessment or clinical outcome data
41 Pritikin Lifestyle Program 3-week residential program with exercise and ad libitum low fat (<10% of calories) plant based diet4566 men and womanMean LDL-C reduction 25% in men and 20% in womanSignificant reductions in TG and HDL-CSignificant 3.2% reduction in body weightLimited long-term follow upBarnard et al. Arch Intern Med 1991;151:
42 Very Low Fat Diets: AHA Science Advisory (Circ. 1998; 98: 935-39) Diets <15% cal from fat, 15% protein, 70% carbohydrates; shown to be associated with lower CVD rates.Reducing fat intake from 35-40% to 15-20% reduces total and LDL-C 10-20%, but can increase TG and lower HDL-C. Long-term effects after weight stabilization not known.Effect on nutrient adequacy and density not well-known. Concern on meeting essential fatty acid requirements, esp. in youth (low-fat diets not recommended <2 yrs).Selected, high-risk persons with elevated LDL-C or CVD may benefit with proper supervision. Advice needed for optimal substitution of complex carbohydrates for fat.Clinical trials needed to show if there is added benefit
43 Barriers to Dietary Adherence Restrictive dietary patternRequired changes in lifestyle and behaviorSymptom relief may not be noticableInterference of diet with family/personal habitsCost, access to proper foods, preparation effortDenial or perceiving disease not seriousPoor understanding of diet/disease linkMisinformation from unreliable sources
44 Strategies for Maintaining Dietary Change Tailoring diet to patient’s needsUsing social support inside and outside healthcare settingProviding patient and caretaker with skills and trainingEnsuring an effective patient-counselor relationshipEvaluation, follow-up, and reinforcement