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.

Must Know: Facts about fat in Your Diet

Although the effect of the total amount of fat in the diet on blood cholesterol levels has been well documented, the most important effectrelates to the type of fat.

Saturated fats have a profound hypercholesterolemic effect (in other words, they increase blood cholesterol levels significantly) and simultaneously increase concentrations of LDL or 'bad' cholesterol. Sources: Saturated fatty acids are found in both animal and plant products, but animal products (such as butter, cheese, full-cream milk, cream, ice-cream, beef, pork and lamb) are the major source of saturated fat in the average South African diet. Similarly, hard or brick margarine (the product packaged in a wrapper) is high in saturated fat; soft of 'tub' margarine is the healthier alternative, since it is low in this type of fat and higher in polyunsaturated fats. Using a polyunsaturated fat will also help to improve your P:S ratio (see below). Coconut oil, cocoa butter, palm oil and palm kernel oil are common 'saturated' vegetable fats which are generally found in many commercially baked goods such as biscuits, also in non-dairy creamers, cake mixes and chocolates. Read labels carefully if youwant to avoid these products.

Mono-unsaturated fats were previously thought to be 'neutral' intheir action on blood cholesterol levels, but recent studies suggest that these fatty acids may play a useful role in the dietary prevention of CHD, since they appear to have most of the benefits of polyunsaturated fatty acids.

Sources: Olive oil, avocado pears and nuts are rich sources of monounsaturated fat.

Polyunsaturated fats lower blood cholesterol levels as well as the concentraton of LDL cholesterol.

Sources: Sunflower oil, tub margarine.

There are two classes of polyunsaturated fatty acids, namely omega-3 and omega-6, which have a variety of functions in the body. Omega-3 fatty acids are found in some vegetable oils and, in particular, in fatty fish. Eicosapentanoic acid (EPA) - a fatty acid which falls into thissub-class - is derived from fish and is highly concentrated in fish oils. Research suggests that this fatty acid may play a beneficial role in a diversity of biological processes including arthritis, eczema and even cancer. However, the role of omega-3 fatty acids - and specifically EPA - in the treatment of hypertension and raised serum cholesterollevels remains controversial.

It seems from studies done so far that fish and fish oil supplements may lower triglyceride levels, reduce clot formation, decrease blood viscosity (or thickness) and lower blood pressure levels. However, the optimal doses of these fatty acids have not been established and until answers to these questions are known, the widespreadsupplementation of omega-3 fatty acids is not recommended. It is a better idea to substitute fish, especially fatty fish (such as salmon, galjoen, snoek, pilchards and tuna) as a source of protein in two or three meals a week, thus consuming a whole spectrum of nutrients and not just a single fatty acid fraction.

The P:S ratio

The ratio of polyunsaturated to saturated fatty acids in a diet is known as the P:S ratio. The typical South African diet has a P:S ratio of 0.5:1.0 (in other words, twice as much saturated as polyunsaturated fat). However, the eating plan recommended for the prevention of CHD suggests a ratio of at least 1:1 (or an equal quantity of both), which for most of us means restricting our saturated fat intake and replacing it, where practical, with polyunsaturated fat such as fish or sunflower oil. Most of the comparisons between the effects of saturated and polyunsaturated fat have indicated that gram for gram, the blood cholesterol-raising effect of saturated fat is up to two times greater than the cholesterol-lowering effect of polyunsaturated fat.

Many studies have shown that so-called 'intervention trials' aimed at lowering raised blood cholesterol levels, reduce the CHD risk and slow the progress of arterial damage. These studies provide strong support for recommendations for a considerable overall decrease in dietary fat by the general public, from the present 35-38°/o to 30% of total kilojoule intake, and a decrease in saturated fat to 10% of total kilojoule intake.