Cholesterol and Heart Disease

In recent times there have been a number of newspaper and other articles about fats in the diet, their effects on the increase in serum cholesterol level and resulting coronary Heart Disease (CHD). the discussion has mainly focussed on the intake of saturated fats and CHD. It is special concern to us the large amount of coconut and coconut oil that are used in Sri Lankan meals.

What is CHOLESTEROL?

Cholesterol is a type of essential fat that is needed by the body and is found i9n small amounts in the human body and in animals. Consequently it is found in small quantities in animal food products such as meat, milk, eggs etc. the major portion of cholesterol is synthesised in our liver and only a little comes from the diet. Cholesterol is not found in any plants. Coconut oil like other vegetable oils, does not have cholesterol. In the blood, cholesterol and fatty acids are carried by proteins. These ‘fat-protein’ molecules are called lipoproteins. These are two types of lipoproteins, the HDL (High Density Lipoprotein) cholesterol and LDL (Low Density Lipoprotein) cholesterol. The normal level of serum cholesterol is 200 mg/100 ml. high levels of cholesterol in blood is a matter for concern. Cholesterol deposition in the blood vessels is facilitated by LDL cholesterol, causing the thinning of arteries and blocking the free flow of blood into the heart muscles, resulting in CHD. HDL cholesterol on the other hand acts as a scavenger of cholesterol.

Synthesis of cholesterol in the liver is influenced by our diet. The type and amount of fatty acids and the content of cholesterol in the foods we eat, affects the types and levels of cholesterol in the blood. It has been accepted that high contents of cholesterol and saturated fatty acids in the food cause elevated cholesterol levels in the blood. Foods such as butter, cheese and pork increase the synthesis of cholesterol because of the high content of long chain saturated fatty acids that are found in these foods.

Where do we stand with regard to coconut oil?

The predominant fatty acids in coconut oil are saturated;

This has for a long time let to the belief that coconut oil is an unhealthy fat that can result in CHD. The reason for this belief is mainly the result of that experiment carried out using hydrogenated coconut oil, which showed elevation of serum cholesterol in the subjects used for the experiment.

Recently however there has been reassessment of previous experiment data and the present thinking is that coconut oil, is after all, not so bad. Nutritionist believes that even tough coconut oil has a large proportion of saturated fatty acids (91.6%) that these are mostly of the medium chain (carbon atoms 6 to 12 in the chain) fatty acid types. Lauric, Myristic and other medium chain fatty acid account for 60 to 70% of the saturated fatty acids. The medium chain fatty acids are easily broken down to give energy and do not remain available in the blood to result in an increase of LDL cholesterol, This however is not the casa with long chain fatty acids as found in animal fats.

Hydrogenated coconut oil however is not so good because not only is the oil further saturated but the nature of the essential fatty acids is also changed from ‘Cis’ to ‘Trans’ fatty acids. The body cannot use Trans-linoleic acids as essential fatty acids. There is also evidence to show that ‘Trans’ fatty acids are injurious to health.

The polyunsaturated also should be eaten for the essential fatty acids.

It must be remembered that where CHD is concerned, cholesterol is only one factor, others being obesity, high blood pressure, smoking and diabetes mellitus.