The types of fats we eat are of extreme importance. Fats provide a concentrated source of energy in the diet, and they also provide the building blocks for cell membranes and a variety of hormones. Fats eaten in a meal slow down nutrient absorption, making us feel fuller for longer. They are also carriers for important fat-soluble vitamins like A, D, E and K. Dietary fats are needed for the conversion of carotene to Vitamin A, for mineral absorption and for many other important functions.

Most people, especially growing children, could benefit from more fat in the diet rather than less. But the fats we eat must be chosen with care. This article explains the different types of fats, and which fats are most beneficial for health.

The types of fats are:

• Saturated: saturated fats are highly stable, because their chemical structure consists of all atom bonds being complete and are therefore packed tightly together. This means that they do not normally go rancid, even when heated, and they are solid at room temperature. Saturated fats are found in animal fats like butter, in tropical oils like coconut oil, and the body also makes them from carbohydrates.

• Monounsaturated: these fats contain a double-bond in their chemical structure and lack two hydrogen atoms, so they do not pack together as easily as saturated fats, and therefore tend to be liquid at room temperature. Like saturated fats, however, they are relatively stable and do not go rancid easily so can be used in cooking. The body makes monounsaturated fatty acids from saturated fatty acids and uses them in many ways. The main one found in our food is oleic acid, the main component of olive oil.

• Polyunsaturated: these fats have two or more double bonds and therefore lack at least four hydrogen atoms. This makes these oils highly reactive and they turn rancid easily. They remain liquid, even when refrigerated. The two polyunsaturated fatty acids found most frequently in our foods are omega-6 and omega-3. The body cannot make these fatty acids and hence they are called 'essential'. They must be obtained from the food we eat.

All fats and oils are a combination of these three types of fatty acids.

Polyunsaturated fats are the fats to cut down on. Excess consumption of refined polyunsaturated oils has been shown to contribute to a large number of diseases, including heart disease and cancer, digestive and immune system disorders, damage to organs and weight gain.

One reason that polyunsaturates cause so many health problems is that they tend to become oxidized or rancid when heated, as in cooking and processing. When ingested, they cause free radicals to attack cell membranes and red blood cells in the body, causing tissue, blood vessel and skin damage that are the precursor to disease.

Many polyunsaturated oils are in the form of vegetable oils that contain mostly omega-6 and very little omega-3. Also, modern practices have reduces the amount of omega-3 fatty acids in commercially available vegetables, eggs, fish and meat. For example, organic eggs from hens fed on green plants can contain omega-3 and -6 in the beneficial ratio of one-to-one, but supermarket eggs from hens fed mostly on grain can contain as much as nineteen times more omega-6 than omega-3. This excess of omega-6 in ratio to omega-3 can cause imbalances in important processes in the body, leading to increased risk of inflammation, high blood pressure, and a compromised immune system.

To correct this omega-6/omega-3 imbalance, eat foods and oils high in omega-3 like free range farm eggs and fish oil. Flax seed oil is an excellent source of omega-3 - it is composed of over 50 percent of this beneficial fatty acid.

Out of all the substances ingested by the body, it is polyunsaturated oils that become most dangerous by food processing. These processes include hydrogenation, which turns polyunsaturates that are liquid at room temperature into solids, such as margarine. This process causes chemical changes in the fat, making it toxic. The body, instead of eliminating them, stores these trans fats in cell membranes, which wreak havoc on cell metabolism, and research has found a strong correlation between the consumption of hydrogenated fats and cancer and heart disease. Homogenization is another process used on fats, whereby fat particles of cream are strained through tiny pores under great pressure to make them stay in suspension rather than rise to the top of milk. This makes the fat more susceptible to rancidity and research indicates that homogenized fat is linked to heart disease.

Saturated fats, on the other hand are not the cause of modern diseases, in fact they play many important roles in the body.

Saturated fatty acids consist of at least 50 percent of cell membranes, giving them stiffness and integrity so that they can function properly. They play a vital role in bone health and calcium absorption, enhance the immune system, protect the heart, and are needed for the proper utilization of essential fatty acids throughout the body, just to name a few uses. Check out the articles below for more information about saturated fats.

In summary, we all need fat in our diet but not all fats are beneficial for health. Avoid all processed foods containing hydrogenated and polyunsaturated oils. Instead use natural fats and oils like high quality butter and coconut oil for cooking, and unrefined oils like extra virgin olive oil and flax seed oil eaten raw.