Hypertension or elevation of blood pressure above normal (120 mm Hg / 80 mm Hg) is a symptom that accompanies many cardiovascular and renal disease.
The causes of Hypertension are
1. Genetic and environmental factors
2. Emotional disturbances
5. Excessive smoking
6. Renal diseases - eg. glomerulonephritis
7. Adrenal tumors
8. High viscosity of blood
9. Narrowing of the blood vessels due to hormone secretions especially cortisone, aldosterone, adrenaline and nor adrenaline.
CLASSIFICATION OF HYPERTENSION
Hypertension is diagnosed when the diastolic pressure is consistently 90 mm Hg or more or the systolic pressure exceeds 140 mm Hg.
Treatment is based on weight loss and sodium restriction.
Nutritional therapy is supported by drugs such as beta blockers.
Along with dietary treatment and beta blockers, peripheral vasodilators are given.
Classification of Blood Pressure
Classification of Blood Pressure according to WHO (1978) Criteria
Normotension Borderline : SBP < 140 mm Hg and DBP < 90 mm Hg
hypertension : SBP 141-159 mm Hg and DBP 91-94 mmHg;
Hypertension : SBP > 160 mm Hg or DBP > 95 mm Hg
SBP - Systolic Blood Pressure; DBP - Diastolic Blood Pressure
Source : Nutrition, Vol. 34. No. 4.
Principles of diet : Low calorie, low fat, low sodium diet with normal protein intake is given.
Energy : Low calorie diet is given to obese patients to reduce weight to normal body weight. For a sedentary worker 20 Kcal / kg of ideal body weight and 25 Kcal / kg body weight for a moderately active worker is given.
Protein : About 60g protein per day is necessary to maintain proper nutrition.
Fats : About 20g partly as vegetable oil is permitted.
Carbohydrate : Complex carbohydrates are helpful in dietetic management.
Sodium : Increased intake of sodium in diet leads to increase in cardiac output and elevates blood pressure. Sodium restriction with weight reduction can effectively control mild or moderate hypertension. Salt should not be used in cooking or at the table. Preserved foods like pickles, canned foods and chips should be avoided.
SODIUM RESTRICTED DIETS
The normal diet contains about 3 to 6 g of sodium daily. The normal diet is modified for its sodium content.
1. Extreme sodium restriction (200 to 300 mg). No salt is used in cooking. Low sodium foods are selected. This diet is used in cirrhosis of the liver with ascites and congestive heart failure.
2. Severe sodium restriction (500 to 700 mg). No salt is used in cooking. Careful selection of foods is necessary. This level is used for severe congestive heart failure.
3. Moderate restriction (1000 to 1500 mg). No salt is used in cooking. Low sodium foods are selected. Measured amount of salt is used. This level is suggested for those with a strong family history of hypertension and patients with borderline hypertension.
4. Mild sodium restriction (2000 to 3000 mg). Some salt is used in cooking but no salty foods are permitted. No salt is used at the table. This level is used as a maintenance diet in cardiac and renal disease.
Sodium in Foods
Sodium content of animal foods is relatively high. Meat, fish, poultry, milk and cheese must be used in measured amounts.
A person suffering from hypertension should not use
1. Salt in cooking or at the table
2. Salt preserved foods - pickles - canned foods
3. Potato chips
4. Spices and condiments, sauces
5. Cheese, butter, salted butter
6. Frozen peas
7. Shell fish, dry fish
8. All processed and baked food