Overweight and Cholesterol intake in your diet

The effect of dietary cholesterol on cholesterol levels in the blood is less crucial and more variable among individuals than the effects of saturated fat - nevertheless, it plays an important contributory role and this is why the recommended limit for cholesterol consumption has been set at 300 mg per day. Of course, the average person has no means of measuring the amount of cholesterol in various foods, but what you can do is identify those which are rich sources and ensure that you eat them in moderation only (see below).

Foods high in cholesterol

Beef, butter, chicken, turkey, duck, cream, all full-cream dairy products, fish, lamb , mutton, pork, tongue

Foods very high in cholesterol

Brains, caviar, egg yolks, giblets, kidneys, liver, prawns, shrimps

These foods are also high in saturated fat and should be eaten only occasionally. (Saturated fats raise blood cholesterol levels far more than does dietary cholesterol in animal foods.)

Overweight and heart disease

The role of obesity or overweight as an independent risk factor for CHD has not been clearly established, but what is known is that it is associated with risk factors such as raised LDL (`bad') cholesterol and total blood cholesterol, lower HDL (`good') cholesterol, hypertension(high blood pressure) and diabetes mellitus. Hypertension is much more common in overweight people; moreover, when weight is reduced and then maintained at a lower level, blood pressure tends to drop as well - if the weight goes up again, so does the blood pressure. There is a particularly strong link between obesity and hypertension in children and for this reason, it is important that children and adolescents do not gain excess weight - in fact, maintaining an ideal body weight should be a goal for the population in general.

Obesity also seems to be a significant, independent predictor of coronary heart disease, especially in women. Although women generally have lower blood cholesterol levels than men, these tend to rise after the menopause. Smoking also seems to be on the increase in women and this can be an important contributory factor. It has been shown that if you are overweight, a cigarette smoker and you take oral contraceptives, your risk of having a heart attack increases significantly.

In summary, the maintenance of ideal body weight by means of a combined diet and exercise programme makes good sense because of the relationship between obesity and an increased risk of heart disease. Also, for a large number of people who suffer from hypertension, weight control can be an effective way of treating the problem and may prevent the necessity for drug treatment.

Hypertension - the 'silent' killer

Apart from being one of the three major risk factors for CHD, high blood pressure is also the single most important risk factor for cerebrovascular disease (strokes). Hypertension affects one in five people in South Africa - yet many are unaware that they suffer from it until a routine medical check-up reveals the problem.

The specific causes of 95% of hypertension cases are unknown, although it is clear that certain dietary factors are important contributors. These include obesity, stress and excessive intakes of sodium (salt) and alcohol. The danger of high blood pressure is that it adds to the workload of the heart and arteries and accelerates atherosclerosis (blocking of the arteries), causing structural changes in the arteries - the higher the pressure, the greater the amount of damage done.

The salt/hypertension link

Evidence that there is an important link between a high salt intake and hypertension is sometimes described as 'circumstantial', but it is nevertheless very significant. While it may be impossible to prove that sodium is a direct cause of the condition, the incriminating evidence seems sufficient to recommend a general reduction in the consumption of salt.

Sodium is an unnecessary supplement to our diet - many foods have a natural sodium content which is quite sufficient for our needs - but we acquire the taste for added salt simply because it is given to us from an early age and it becomes a habit to pour it onto our food. The average South African consumes 10-15 g of salt a day, which is well above the recommended amount of 7,5 g. This includes salt which has been added to processed foods, in home cooking and at the table.

Although many people have normal blood pressure levels in spite of a high sodium intake, the recommendation is that since a low intake has no ill effects - while too much salt clearly raises the blood pressure levels of a large number of people - it makes sense to be on the safe side and either throw out the salt cellar or at least restrict its use considerably.