Healthcare in India

Healthcare in India

Nutrition and Cardiac Rehabilitation Heals Cardiovascular Disease: A Review

Considering the high mortality and morbidity rate associated with cardiovascular disease, nutritional strategy and cardiac rehabilitation are mandated for the prevention and management of cardiovascular diseases. Diet consisting of whole grain, vegetables (carrot, parsley, beetroot, cabbage, spinach and tomato; 400 to 500 gm per day), fresh fruits (apple, orange, pineapple, cranberry, cherry and peach; 300 to 500 gm per day); and low fat dairy products (milk, cheese, yogurt and dairy dessert; 30 to 50 gm per day) help to reduce, risk of cardiovascular disease. Cardiac rehabilitation scabbard exercise training program facilitates long term maintenance of cardiovascular fitness. Aerobic exercise training program including warm up, aerobic exercises and cool down period improves cardiovascular fitness in both healthy individual and cardiac patients. Aerobic exercises with intensity of approximately 60 to 70 % of the maximal heart rate; 30 to 60 minutes; 3 to 4 times a week, for 4 to 6 weeks enhances aerobic capacity. Well nourished diet pattern and incorporation of exercises in routine lifestyle prevent and treat cardiovascular disease, in turn reducing the cardiac risk factors, improving patients’ aerobic capacity and enhancing patients’ overall quality of life.
Cardiovascular disease (CVD) is the major cause of death world over.1 Regular exercises along with healthy nutrition is beneficial in increasing functional capacity, favorably modifying disease-related risk factors, decreasing symptoms, detecting signs and symptoms of disease before they become serious complications, improving quality of life.2 Proper diet should include almost all the necessary components of nutrition. Carbohydrate, protein and fat are considered to be essential parts of nutrient supplements.

Nutrition and cardiovascular disease
Effectiveness of dietary recommendations requires provision to patients in a manner that promotes implementation and long term adherence. Adequate nutrition plays an important role in managing risk for atherosclerotic cardiovascular disease. Numerous studies permit the general conclusion that lower risk for cardiovascular disease is promoted by emphasis on intake of fruits and vegetables, whole grains, nuts and legumes, fish, poultry and lean meat, low fat and fat free dairy products, and liquid vegetable oils. Major nutrient characteristics of these diets include high density of micronutrients and fiber; moderate amounts of unsaturated fats including omega-3 fatty acids; and lower content of saturated and trans fatty acids, sugars, and starches with a high glycemic effect.
Fruits and vegetables
Most of the fruits and vegetables contain lot of nutrient, high amount fiber are a source of low calorie. Several studies suggest that fruits (apple, orange, pineapple, cranberry, cherry and peach) and vegetables (carrot, parsley, beetroot, cabbage, spinach and tomato) help in the prevention of CHD.3 Consumption of fruits and vegetables of three or more servings per day versus less than once per day was associated with a 27% reduction in cardiovascular disease. Intake of green leafy vegetables and foods rich in carotenoids and vitamin C contribute particularly in reduction of cardiovascular risk factors.
Whole grains and fiber
Consumption of whole grains reduces cardiovascular disease.4 This effect may be related to fiber intake, but all studies have not indicated that the relationship with fiber intake is independent of other variables.5 Consumption of sugar and starches may have adverse effect on cardiovascular risk factors. The blood glucose elevation following consumption of a dietary carbohydrate can lead to undesirable metabolic consequences like increase in postprandial insulin level and increase in plasma triglyceride.6 Glycemic index can be assigned to food on the basis of the magnitude of blood glucose elevation following consumption of food. The reliability of glycemic index as the relation glycemic load to disease risk has been challenged. A meta-analysis indicated an average 27 % reduction in coronary heart disease independently associated with whole grain consumption.7
Legumes
Some analyses have shown reduced CVD risk with increased intake of legumes like peas, beans and soybeans.8 The beneficial effect of soy protein in lowering cholesterol has been challenged. 9
Nuts
Nuts are good sources of MUFA, fiber, minerals and flavonoids. Walnuts are particularly rich in PUFA such as linoleic acid and alpha-linolenic acid.10 Almond intake has been found to have beneficial effects on plasma lipoprotein.11
Fish and Omega-3 fatty acids

[LA- linoleic acid, AA- arachidonic acid, LNA- linolenic acid, EPA- Eicosapentaenoic acid, DHA- docosahexaenoic acid]

Alcohol
Moderate alcohol consumption is strongly and consistently associated with lower risk for CHD than either abstention or higher intakes. Wine gives particular benefit possibly due to its content of polyphenols such as resveratrol, which may have direct benefits on vascular reactivity, thrombosis and oxidative stress. The major benefit of alcohol consumption is related to an increase in HDL cholesterol and perhaps to other effects such as reduced fibrinogen, platelet aggregation and inflammation.18 Current recommendations from the AHA and the U.S. Dietary Guidelines Advisory Committee are that men who drink alcohol may consume up to two alcoholic beverages per day and women no more than one per day.19 

Effect of specific dietary components on risk factors for CVD

The major diet related risk factors are plasma lipids, lipoproteins and blood pressure. Other than omega-3 fatty acids, there is little indication of dietary effects on thrombosis.

Modifying Plasma Lipids by nutrition
Total and LDL Cholesterol
Dietary management of LDL cholesterol remains a major goal of CAD risk management. Although, total fat intake tends to correlate with that of saturated fat, there is no evidence that LDL levels rise due to increased total fat intake.  When substituted for carbohydrate, the greatest increase in LDL cholesterol result from lauric, myristic and palmitic fatty acids found in dairy fat, meat and tropical oils, with equivalent changes in induced by trans monounsaturated fatty acids found in baked foods, stick margarine, and fried fast foods such as French fries. In contrast, stearic acid, which is found in many of the same foods, generally does not raise LDL cholesterol level.

HDL Cholesterol
Although HDL cholesterol correlates inversely and independently with risk for coronary artery disease, it remains uncertain whether changes in HDL cholesterol, and in particular those induced by diet, predict changes in risk. A review of 60 dietary trials has indicated that the plasma cholesterol-to-HDL cholesterol ratio did not change if saturated fatty acids replaced an isocaloric amount of dietary carbohydrates.  However, this ratio decreased if unsaturated fatty acids replaced saturated fatty acids.21

Triglyceride and Atherogenic Dyslipidemia
Elevated plasma triglyceride independently but rather weakly predicts coronary heart disease. Simple sugars and rapidly hydrolyzed starches have a greater glyceridemic effect than more complex carbohydrates and those in conjunction with higher intake of fiber. The glycemic effect of carbohydrates tends to correlate with their glycemic effects.6 Dietary carbohydrate induced increase in plasma triglyceride is often accompanied by decrease in HDL cholesterol and increases in levels of small, dense LDL particles.23 Dietary glycemic load, a measure of the quantity of high glycemic foods related to high plasma triglyceride and low HDL cholesterol, strongly and independently predicts CHD risk.5

Modifying Blood pressure by Nutrition

Current recommendations for nonpharmacological management of elevated blood pressure include weight reduction, moderate alcohol consumption, limitation of sodium intake and increased intake of certain other minerals.19 The DASH study found that a diet rich in fruits and vegetables and low fat dairy products along with reduced saturated and total fat content, reduced systolic and diastolic pressure by 5.5 and 3 mm Hg.24 In the CARDIA study, diets rich in whole grains, refined grains, fruits, vegetables and nuts or legumes were found to be inversely related blood pressure.25

Dietary sodium
A high intake of sodium can result in an increase in blood pressure.26 Meta-analyses have shown that on average, reducing sodium intake by about 1.8 gm/day yields systolic and diastolic blood pressure reductions of about 4 and 2 mm Hg in hypertensive patients and smaller reductions in normotensive subjects.27 The AHA guideline recommends 6 gm/day of salt intake to manage hypertension.19 Careful selection of foods and limitation of added salt can substantially lower sodium intake and these measures can have particular benefit in hypertensive patients.

Potassium, magnesium and calcium intake
Incorporation of minerals like potassium, magnesium, and calcium help to reduce cardiovascular risk factors.28 A meta-analysis of randomized trials of the effects potassium found that, on average, supplementation of diets with 60-120 mmol/day reduced systolic and diastolic blood pressure by 4.4 and 2.5 mm Hg in hypertensive patients and 1.8 and 1 mm Hg in normotensive subjects.29 The preferred strategy for increasing intake of these minerals is through foods rather than supplements.

Other cardiovascular risk factors related to diet

Other cardiovascular risk factors related to diet include homocysteine level, C- reactive protein and oxidative stress.  Elevated plasma homocysteine levels increase the risk for ischemic heart disease.30 Recent study using combination of folic acid, vitaminB6 and vitamin B12 to lower homocysteine levels found no differences in cardiovascular in cardiovascular endpoints.31 The use of folic acid and multivitamin supplements in the prevention of cardiovascular disease are unwarranted.32 A study has showed a number of nutritional factors influence C-reactive protein.33 Despite evidence supporting the role of oxidative stress in atherogenesis, studies have shown no benefit of antioxidant on risk of cardiovascular disease.32

Dietary requirements for Indian Population
Daily dietary requirement and diet chart for Indian population is shown in table- 3 and 4.34

Cardiac rehabilitation and cardiovascular disease
In 2007, American Heart Association and American Association of Cardiovascular and Pulmonary Rehabilitation recommended cardiac rehabilitation programs for patient assessment, nutritional counseling, risk factor management, psychosocial management, physical activity counseling, and exercise training.35

Cardiovascular response to exercise

Increased myocardial contractility and stroke volume
Exercise increases myocardial contractility and contributes (table 5) to the increase in cardiac stroke volume.36 The increase of myocardial contractility enhances the oxygen consumption (VO2) of the myocardium. On the other hand, it reduces average ventricular dimensions and wall tension, and thereby facilitates perfusion of the critical endocardial zone by perforating branches of the coronary artery.
Exercise may increase cardiac stroke volume by 20% or more, both at rest and during vigorous exercise (table 6).36,37 Mechanisms include an increase of preload due to increased peripheral venous tone and plasma volume expansion, and a reduction of afterload due to strengthening of the skeletal muscles and a reduction of systolic pressures.

Reduction of blood pressure

Exercise leads to a progressive increase in systolic blood pressure and slight decrease in diastolic pressure with net reduction in total peripheral resistance. Resting blood pressure and blood pressure at any given rate of exercise are lower after training, this trend being augmented by a strengthening of the skeletal musculature; however, pressures remain unchanged at a fixed fraction of maximal oxygen intake.36 Reduced afterload of the left ventricle allows an increase of ejection fraction and stroke volume.37 Thus the peak cardiac output is augmented, with an associated gain in functional capacity. Further, at any given rate of submaximal exercise, the lower systolic pressure yields a corresponding reduction in double-product and thus reduces the risk of myocardial ischemia.

Plasma volume expansion
Aerobic exercise induces an expansion of plasma volume and the possible mechanism is adjustment in the renin system. Exercise augmented ventricular preload contribute to the increase of cardiac stroke volume.38 Ventricular preloading is increased, contributing to the increase of cardiac stroke volume in the trained individual. However, there may be an associated decrease in the hemoglobin content of unit volume of blood, so that oxygen transport per liter of cardiac output is unchanged or even diminished.36

Increased peripheral venous tone
Training induces an increased peripheral venous tone.36 This increases central blood volume and thus ventricular preloading; cardiac stroke volume is increased, and the likelihood of hypotension after a bout of exercise is reduced. Ischemic ST-segment depression and ventricular fibrillation can be precipitated by the sudden fall in blood pressure at the end of exercise. The increase venous tone decrease possibility of ischemic ST segment depression and ventricular fibrillation.

Cardiac Rehabilitation in Practice
Despite the knowledge of benefits of cardiac rehabilitation in management of life threatening cardiac conditions, the applicability of cardiac rehabilitation in practice is limited and unsatisfactory in terms of achieving positive cardiac outcomes.39 However, several recent studies have shown the association and application of physiotherapy in cardiovascular diseases like peripheral vascular disease, myocardial infarction, heat failure, hyperlipidemia, etc.

Peripheral Vascular Disease
Peripheral vascular disorders result in inadequate blood supply to the extremities and consequently lead to physical impairment and loss of function of the affected part(s).40 It can be caused by a number of pathologies of blood vessels. Simple walking along with structured stretching activities prior to walking and aerobic exercise program helps patients with intermittent claudication.41 Quell et al. demonstrated that brisk walking on a flat surface with exercise intensity, induces training heart rate more than 70%, and has been proved beneficial.42
Myocardial Infarction
Myocardial infarction refers to insufficient myocardial perfusion resulting in damage and necrosis of heart, and results from narrowing and occlusion of coronary blood vessels secondary to atherosclerosis.43 Optimal treatment prescription is based on the patient’s overall signs and symptoms of coronary insufficiency and hemodynamic instability.44 Junger et al. demonstrated the effect of cardiac rehabilitation in patients with myocardial infarction. Strong association of cardiac rehabilitation with markedly reduced mortality was noticed, during 1-year follow up after ST elevation myocardial infarction (STEMI) or Non ST elevation myocardial infarction (NSTEMI).39 Yu et al. conducted a prospective randomized controlled trial to see the long term effect of cardiac rehabilitation in patients with myocardial infarction or percutaneous coronary intervention (PCI). Increase in quality of life (QOL) of patients was noticed with cardiac rehabilitation.44

Heart Failure
The primary pathology of heart failure results from abnormalities in cardiovascular function, abnormalities in peripheral blood flow, skeletal muscle morphology, metabolism, strength, and endurance all contribute to the heart failure syndrome.45 Davies et al. noticed improved short term exercise capacity in mild to moderate heart failure patients with exercise training compared to usual care.46 In addition to improving exercise capacity, exercise training in heart failure patients has been shown to improve cardiac output at maximal workloads, improve mitochondrial size and density, increase skeletal muscle oxidative enzymes, reduce endothelial dysfunction, and decrease circulating catecholamines.47

Hyperlipidemia and Ischemic Heart Disease
Toufan and Afrasiabi performed a study to know the effect of cardiac rehabilitation on lipid profile. It showed that cardiac rehabilitation has important impacts on improving functional capacity, well being sensation, return to work and decreasing serum lipid profiles in coronary patients.48 Omiya K conducted a study to identify the usefulness of cardiac rehabilitation in patients with ischemic heart disease. It was observed that an exercise based cardiac rehabilitation program was effective for improving exercise tolerance, quality of life, coronary risk factors and many other aspects of life for ischemic heart disease patients.49

Exercise training program

The American College of Sports Medicine (ACSM) guidelines suggests that an individual should do an aerobic exercise to achieve significant improvements in cardiorespiratory fitness and optimum cardiovascular benefits.50 There are three parts of exercise program (Figure 4): 

Aerobic exercise can be started in healthy individual to improve cardiovascular fitness with parameters shown in table-7.
Aerobic exercises for cardiac patients can be categorized into 3 phases.
Phase I (In patient Phase)
Phase I aims at stabilization of the patient’s cardiovascular system after myocardial infarction or bypass surgery during hospitalization period. Initiate activities of daily living like sitting to standing. Monitor vital signs while ambulation.
Parameters for aerobic exercises during Phase II and III rehabilitation are mentioned
Conclusive considerations of nutrition and cardiac rehabilitation in cardiovascular disease