Cardiovascular Diseases

Overview

Cardiovascular disease is a class of diseases that affect the heart and blood vessels (arteries and veins). In the majority of cases, this is due to the progressive effects of atherosclerosis in the arteries. (Hardening of the and thickening of arterial walls with loss of elasticity)

General risk factors for cardiovascular diseases

Non modifiable factors are age, gender, genetic factors and race. A family history of high blood pressure (HBP) and a "pre-hypertension" 120-139/80-89mmHg may be a risk of HBP, diabetes and kidney diseases.

High salt (sodium chloride) intake: when sodium is taken in excess more water is drawn into the circulation, increasing the volume of blood to be pumped. In addition, excess salt makes the arterial walls to be more rigid leading to arteriosclerosis. Much of the salt we eat is added to the table during eating (20%), fifteen percent comes from salt naturally found in foods and 60% comes from salt added to processed foods (hidden salt).

High blood cholesterol: There are two types of cholesterol that is dietary cholesterol contained in food and blood or plasma cholesterol that is essential from body metabolism. Excess cholesterol causes arteriosclerosis (narrowing and hardening of arteries due to deposits of cholesterol) and increased risk of heart attack (myocardial infraction) and stroke (thrombosis). The amount of cholesterol in the diet is not reflected by the amount in the blood; this is mostly determined by the amount of saturated fatty acids in the diet. Animal based foods and products (milk and its derivatives, eggs, fish, shellfish and all types of meat), variety of meats especially offal (particularly liver and brain), shrimps and eggs have the highest cholesterol content. Plant based foods do not contain cholesterol. However, there are minute amounts of cholesterol in vegetable oils that are considered incidental.

Too much fat, saturated fatty acid, Trans -unsaturated fatty acids: These increases harmful cholesterol (LDL) levels in the blood and reduces the good cholesterol. The major dietary sources of saturated fatty acids include animal based foods and products such as butter, cured cheeses, margarine, bacon, sausages and pork, fresh eggs, cream, hydrogenated vegetable fats, lard, palm oil and whole cow's milk. Plant based foods are low in saturated fatty acids with some exception such as coconut and palm oil.

High levels of low density lipoprotein (LDL) cholesterol: Cholesterol is transported around the body attached to specific proteins called lipoproteins. There are two types of lipoproteins; low density lipoproteins (LDL) and high density lipoproteins (HDL). LDL carry about three-quarters of the cholesterol in the blood and high LDL level usually reflect high cholesterol level and imply a high risk of heart disease. HDL, which carry much less fat signals a lower than average risk of heart disease.

Smoking cigarettes: produces nicotine which stimulates the production of certain body chemicals. These chemicals raise pulse rate, BP and the force of heart contraction. Smoking also makes the heart need more oxygen at the same time reduce the amount of oxygen available. In addition, it helps to increase the substance that clogs the arteries.

Alcohol: has got a higher caloric density than protein or carbohydrates and is a source of additional empty calories.

Obesity: although obesity is a disease on its own right, it is also one of the key risk factors for CVD.

Reduced physical activity: makes the energy from food not to be expended thus leading to increased body fats.

Stress: While stress can affect all the body organs and functions of the body, its effect tends to be concentrated on the heart and the cardiovascular system which is obliged to work hard.

Prevention and nutrition management of CVD

Reduced sodium intake can prevent CVD in persons at risk and can facilitate CVD control in older age persons on medication. Sodium should be limited to 6g per day, an equivalent of 100mmols of sodium (2400mg) per day. To achieve this, choose food low in sodium and limit the amount of salt added to food.

Consumption of diets that include a wide variety of fruits and vegetables: These are high in nutrients and fibre and relatively low in calories and hence are nutrient dense. In addition, consuming a variety of fruits and vegetables (especially those that are dark green, deep orange or yellow) helps ensure adequate intake of micronutrients normally present in these foods. Micronutrients that play a role in controlling HBP include, potassium, magnesium, calcium and vitamin especially vitamin C.

Dietary patterns high in grain products especially whole grains: Grain products provide complex carbohydrates, vitamins, minerals and fibre. Foods high in starches (polysaccharides e.g. bread, pasta, cereals and potatoes) are recommended over sugars. Sugars supply only energy without the other nutritive benefits. A high complex carbohydrate diet is rich in fiber, minerals, vitamins, saponin (a phytochemical) and essential fatty acids. It is rich in antioxidants E, ascorbic acids and carotenoid especially lutein and zeaxanthin, which are important in preventing heart disease and delaying aging. A high carbohydrate diet especially complex carbohydrate is also rich in folic acid that helps to control an abnormal homocysteine level, an emerging cardiovascular disease risk.

Diet high in fiber (Fibre)

Fiber is found exclusively in plant based foods. Animal foods such as milk, eggs, fish, meat and their derivatives contain no fiber. Insoluble fibres are found in higher concentration in vegetables such as carrots, green leafy vegetables, wheat and cereals. The insoluble fiber is found primarily in grain bran. Other sources of insoluble fiber include brown rice, rice bran, wheat bran, corn bran, whole grain bread and cereals, cabbage family, cauliflower, green beans, green peas, legumes, mature vegetables, root vegetables, tomatoes, nuts, fruits such as pears, peaches, plums, seeds, strawberries, apples and bananas. High concentration of soluble fiber occurs in fruits, oats, barley and legumes such as peas, beans and lentils. High carbohydrates based on whole plant foods prevent obesity.

Consumption of diet that lower LDL (harmful) cholesterol: polyunsaturated fatty acids which include fish and fish oils, soybeans, wheat germ, canola oil, sunflower oil, corn oil, cotton seed oil, walnut, some vegetables for example spinach, lettuce and broccoli, monounsaturated fatty acids such as avocado, cashews, canola oil, peanuts and poultry. The polyunsaturated and monounsaturated fatty acids lower BP, the level of triglycerides and LDL cholesterol and consequently lead to increase in HDL cholesterol that carries cholesterol in the blood back to the liver for recycling or disposal.

Fish and fish oils help prevent the development of atherosclerosis and heart disease. It is believed that fish oil exert their protective effect by lowering BP levels, blood triglycerides and LDL. Fish oils are also believed to reduce platelets and suppress the growth of smooth muscle cells in the arterial walls.

Soy protein is well known to produce less hypercholesterolemia and less atherosclerosis than animal proteins.

Micronutrients and cardiovascular

Magnesium: High consumption of magnesium reduces the production of prostacyclin which is vasodilating and increases the release of thromboxane which is vasoconstricting (Prostacyclins and thromboxanes are hormone like the one compounds referred to as eicosanoids that regulate BP, clotting and other body functions). Magnesium also stabilizes calcium channels. Low blood magnesium lowers potassium level and leads to hypokalemia.

The food sources of magnesium ranked by milligram of magnesium per standard amount include bran, pumpkin and squash seeds kernel roasted, sesame, nuts, wheat germ, whole wheat flour, soybeans, molasses, spinach, white bean, green leafy vegetables, potatoes and oranges.

Potassium: Potassium causes increased excretion of sodium by the kidney. It may also result in a decrease in BP via its response in neither circulating nor epinephrine (a hormone produced by the adrenal gland and is a vasoconstrictor). In addition, it modifies the excitability of vascular tissue and relaxes arteriolar muscle. Potassium also reduces secretion of rennin which operates to conserve sodium and blood fluids.

Dietary sources of potassium include foods such as blackstrap molasses, soybeans, wheat germ, pumpkins, bananas, almond, avocado, spinach, potatoes, sweat potatoes, carrot juice, tomatoes, whole grain bread, melon, cucumber, prune juice, beans, oranges, mangoes. Others from animal sources include salmon, cod, beef steak, cheese, cow's milk and fresh eggs.

Vitamin C: Vitamin C is an electronic donor and this property accounts for its known functions. It acts as a potent water soluble antioxidant in humans thus preventing oxidative damage to tissues and the genesis of atherosclerosis. Vitamin C is found majorly in plant sources such as sweet red pepper, guava, black currant, broccoli, orange, lemon, cassava, peas, tangerine, tomatoes, potatoes and water melon. It may also be found in small amounts in animal sources such as beef, liver, oyster, trout and chicken. Human beings can neither synthesize this vitamin nor store it in significant amounts; therefore it must be taken in daily.

Calcium: It increases sodium excretion. It also alters the vascular smooth muscle reactivity. Milk and dairy products are well known as the best sources of calcium. However, there are a variety of plant based foods providing as much or more calcium as milk: sesame, blackstrap molasses, almonds, beans, corn, cabbage, broccoli and oranges are also good sources of calcium.

Physical activity: Physical activity has measurable biological effects affecting cholesterol levels, insulin sensitivity and vascular reactivity. Moreover these effects are dose dependant such that the more the exercise, the greater the health benefits. The WHO (2002) describes the opportunities for people to be physically active in terms of 4 domains: at work; for transport; in domestic duties and leisure time.

Engaging in moderate level of physical activities such as intermittent walking for 30 to 45 minutes is recommended for prevention of CVD. Moderate exercise such as walking may both lower LDL and raise HDL levels if the activity is constantly pursued for a long time. Moderate means 30 minutes brisk walking (3-4 miles) per hour, walking upstairs, dancing, bicycling and any exercise that will expend 200 calories per day.

It is important to balance time of stress with moments of relaxation. Do something that takes the mind off problems such as gardening, walking, playing as sport, meditating or listening to soothing music.

Prevent and control obesity: Limitation of dietary fats and alcohol (7kcal/g) is effective means to reduce both energy density and total energy. The diet should be within ≤30% of total kilocalories as fat to predict a weight loss of ½ kg per week (minus 500 to 1000kcal/day).

Types of CVDs

Coronary heart disease

Congestive heart failure

Hypertension

Stroke

CORONARY HEART DISEASE (CHD

It is the most common of the CVD and is as a result of lack of blood flow to the network of blood vessels surrounding the heart and those serving the myocardium. Coronary heart disease (CHD) occurs when plaques containing lipoproteins, cholesterol, tissues debris, and calcium form on the intima, or interior surface of blood vessels. The plaques roughen the intima, and platelets are attracted to the roughened areas, forming clots. When the plaques enlarge sufficiently to occlude the blood flow, tissues are deprived of oxygen and nutrients, creating an area of infarct. This means that the arteries can not expand with each heart beat as they would normally. This puts strain to the heart and damages the arteries further.

The underlying cause of CHD is atherosclerosis which is the most common type of coronary disease. This is characterized by accumulation of accumulation of lipids and other cellular materials in the intima layer. It is a term describing a hard and thickening of the arterial wall with loss of elasticity.

Some of the risk factors include;

Diet high in cholesterol especially lDL
Advanced in age,
Diabetes
Obesity
Smoking
Genetically predisposed (heredity)

Physical inactivity.

NB/ dietary management

Dietary Management

Reduce total fat intake(15-20%) -LDL-(saturated fat to 7% and dietary cholesterol 200mg/day)
Reduce body weight for the overweight clients to the ideal body weight
Avoid smoking and alcohol
Increase fiber intake
Physical activity is recommended

ATHEROSCLEROSIS

This is a generative process that begins with the accumulation of soft fatty streaks along the inner arterial walls especially at the branch points. These streaks gradually enlarge and become hardened with minerals forming plaques. The artery walls lose elasticity and narrows the passage. This means that the arteries cannot expand with each heart beat as they would normally thus the blood pressure rises. This puts strain to the heart and damages the artery walls futher.

Consequences of atherosclerosis

Obstruction of the blood flow

High blood pressure

Tissue damage

Risk factors

High calorie intake; high saturated fat and cholesterol intake; increased serum LDL (harmful cholesterol) levels above 5mmol/liter; sedentary lifestyles; stress; hypertension; obesity and diabetes.

Aims of management

To normalize blood lipids,
control the modifiable risk factors
Prevent complications.

Management

Reduce total fat intake(15-20%) -LDL-(saturated fat to 7% and dietary cholesterol 200mg/day)
Reduce body weight for the overweight clients to the ideal body weight
Avoid smoking and alcohol
Physical activity is recommended

Other complications of atherosclerosis

MYOCARDIAL ISCHEMIA

This is a heart disability resulting from inadequate supply of oxygen and nutrients to the heart muscle due to obstruction or construction of the blood vessels

It can be manifested by

Myocardial infarction (heart attack)- This is sudden tissue death caused by prolonged blockages of vessels or arteries that feed the heart muscle, also called heart attack/cardiac arrest. This will lead to death of some heart muscle. There is usually severe pain.

Infarction- an area of necrosis or death due to inadequate supply of the blood to the area for cellular survival

Angina pectoris-this is a tight pressing severe pain or discomfort across the chest that follows exertion stress. It may last for about 15 minutes and may radiate to the back and lead to sudden death.

Risk factors include hypertension and arteriosclerosis. Other contributors include abnormal blood clotting, spasms of the coronary artery, rheumatic heart disease, infections of the membranes covering the heart and electrical disturbances that alter the hearty rate.

Implications

Strained cardiac function

Aims of nutritional management

To reduce the work load of the heart
To relieve pain and stabilize the heart rhythm
To treat infections and the underlying causes
To regulate electrolyte balance

Nutritional Management

When the patient is in shock, withhold food intake-nil per oral until shock resolves
When shock resolves provide between 1000-1200 kcal that progresses from low sodium soft foods of moderate temperature in frequent and small feeding.
After recovery adjust the diet to meet the individual needs and to deal with the underlying conditions such as hyper lipidemia, hypertension, and obesity
Avoid caffeine as it stimulates metabolic rate and increase the workload of the heart

A healthy heart requires minimal consumption of saturated fats and cholesterol, reduced use of salt and sugar, avoiding use of tobacco and too much coffee and regular exercise.

CONGESTIVE HEART FAILURE

This is a condition resulting from a gradual weakening of the heart muscle as it strains to supply adequate blood despite its own reduced supply to the body. This is a syndrome in which the heart can no longer adequately pump blood through the circulatory system. Risk factors include; uncontrolled atherosclerosis and hypertension. In most case the left ventricle of the heart is affected.

The heart tries to compensate for the reduced cardiac output through

Increasing the force of contraction

Increasing the size of the heart

Pumping more often

Stimulating the kidney to conserve sodium and water

Implications

Pooling of the blood in the pulmonary vein leading to Pulmonary oedema
Reduced blood flow to all organs especially the kidney thus leading to fluid retention
Fluid retention hence stagnation of fluids in all organs
Enlarged heart and rapid heart beat
Malnutrition due to high energy needs
Hepatic oedema may occur
Symptoms of chronic heart failure include
Shortness of breath
Anorexia
Nausea
Constipation
Tenderness and enlargement of the liver
Mental confusion, loss of memory, headaches due to decreased supply of blood

Aim of Management

To reduce the workload of the heart
To provide adequate nutrients
To reduce weight for the overweight
Relieve the symptoms
Decrease oedema
Reduce further myocardial damage
Improve prognosis

Nutritional Management

Use foods less likely to produce gas
Restrict sodium, caffeine and fat intake
Encourage gradual weight loss where necessary
Use of liquid formula of high nutrient density as oral supplement or enteral or tube feeding to prevent or reverse malnutrition is recommended. In some cases total parenteral nutrition may be required
Selection of enteral or parenteral formulas should be done carefully to ensure that energy ,fluid, sodium intake will not overload the body
Adjust dietary fiber to avoid constipation but avoid amounts and types that produce gas and abdominal distention
For overweight patient counsel on weight reduction
Restrict cholesterol intake to 300 mg /day
Reduce intake of saturated fats
Encourage intake of unsaturated fats (oils)
Increase intake of dietary fiber to control glucose/fat absorption
Reduce alcohol intake and encourage the patient to avoid smoking to prevent development of atherosclerosis

HYPERTENSION

Hypertension is a cardiovascular disorder characterised by persistently elevated diastolic blood pressure (BP) of above 95mmHg. Uncontrolled hypertension can affect various body organs and can lead to impaired vision, kidney failure, stroke, paralysis, heart attack and brain damage. Risk factors include; diet, race, stress, age, diabetes, obesity, smoking, atherosclerosis and heredity among others.

Implications

Strained cardiac and vascular function
Cellular electrolyte imbalance
Aneurysms (balloon out and busting of the arteries)
Arterial lining injuries which accelerates the plaque formation

Aims of nutritional management

To control blood pressure within the normal ranges
To achieve a gradual weight loss in overweight and obese individuals and maintain their weight slightly below the normal
To reduce sodium intake based on severity
To maintain adequate nutrition
Regulate fat intake

Nutritional management

Provide low calorie diet if the patient is overweight until ideal body weight is achieved
Regulate fat intake. Encourage intake of unsaturated fats (oils). The poly unsaturated and monounsaturated fatty acids lower BP, the level of triglycerides and LDL cholesterol and consequently lead to increase in HDL cholesterol that carries cholesterol in the blood back to the liver for recycling or disposal. Fats should be 20% of total kilo calorie
Restrict alcohol intake
Restrict sodium intake. To achieve this, encourage choice of food low in sodium and limit the amount of salt added to food, restrict processed foods and use of sodium containing spices
Avoid stimulants e.g. caffeine and spirits
Avoid cigarette smoking, which may lead to atherosclerosis
In some cases it may be necessary to restrict fluid intake
Encourage physical activity for those leading a sedentary lifestyle. Physical activity has measurable biological effects affecting cholesterol levels, insulin sensitivity and vascular reactivity. These effects are dose dependant such that the more the exercise, the greater the health benefits

STROKE/TRANSIENT ISCHEMIC ATTACK

This is a temporal reduction in blood flow to the brain that causes temporal symptoms which depend on which part of the brain is affected.

Risk factors

Atherosclerosis
Hypertension or a combination of the two

Implications

Light headedness
Visual disturbances
Paralysis
Staggering
Numbness
Dysphasia ( inability to coordinate swallowing appropriately)

Aim of management

Tube feeding may be indicated initially till the client is safely able to chew and swallow
Some patients To treat the underlying risk factors

Management

Restricted energy intake, total fat and sodium
may need assisted feeding