Fats & Oils
Omega 3,6&9, The Essential Fatty Acids
The news is full of articles telling us what to and what not to eat. Fats and oils have been focused on in the media several times recently, but often don’t help answer some of the key questions, for example, what is the difference between a polyunsaturated oil and a hydrogenated oil, and what should I be eating more of or avoiding? Here is a few things that we have found out about the current view on what is healthy, and what’s not.Firstly it is important to note that despite all the bad press that fat gets, it is an essential part of our diet. The problem tends to be not that we eat fat, but that we eat too much of the wrong type of fat. Fats consist of long chains of carbon atoms with hydrogen atoms attached. The longer the chain, and the more hydrogen atoms there are, the more solid the fat is. If a fatty chain does not have enough hydrogen atoms it has double bonds instead. Therefore fats can vary by the number of carbon atoms in the chain, and the number of double bonds in the chain. Fats may be saturated, unsaturated or polyunsaturated. This refers to the number of double bonds in the chain.
The picture above shows a fat with one double bond. This is an unsaturated fat. If it had two or more double bonds it would be polyunsaturated, and if had no double bonds it would be saturated. That is all there is to it!
Saturated fats tend to be solid at room temperature. Most animal fats are saturated, as are some vegetable fats (palm and coconut oil). Saturated animal fats may contribute towards heart disease. Most diets today consist of too much saturated animal fat. Unsaturated fats tend to be liquid at room temperature.You may have heard of ‘essential fatty acids’. This is the name for two special fats which are needed by the human body but cannot be made by the body. They are used as precursors (ingredients) for a wide range of molecules within the body, and therefore need to be included in the diet.
Omega 3 essential fatty acids are polyunsaturated fats, with several double bonds, the first of which is attached to the 3rd carbon atom in the chain. They are required in the body for conversion into a series of molecules called prostaglandins, which act to reduce inflammatory conditions. Omega 3 fatty acids have also been shown to reduce the risk of cardiovascular disease, and to be important in the development of the nervous system. Fish oils contain omega 3 fatty acids, as does linseed (flax) oil. Oily fish include: Salmon, Tuna, Halibut, Sardines, Mackerel, Herring, Trout.
Omega 6 essential fatty acids are polyunsaturates with a double bond attached to the 6th carbon atom. They are also converted into prostaglandins, some of which are anti-inflammatory, but also some of which act to increase inflammation. The omega 6 prostaglandins may also modulate hormones, helping to balance them within the body. Therefore these are often taken to help with PMS. They have also been shown to help with dry skin problems. Evening primrose oil contains omega 6 fatty acids, as does sunflower and hemp seed oil.
Omega 9 fatty acids are not essential fatty acids. They have one double bond (monounsaturate) attached to the 9th carbon atom. They are easily converted into energy, but are also incorporated into nerve fibres. Omega 9 fatty acids have been shown to have a beneficial effect on cholesterol levels. Olive oil is high in omega 9 essential fatty acids.
The Unhealthy Fats
While the unsaturated fats are healthy they can be easily converted into unhealthy fats. Hydrogenated vegetable fats are listed as an ingredient in many of the foods we eat. Manufacturers have needed a solid fat, but have wanted to avoid animal fats as these have been implicated in health scares in the past. Therefore unsaturated vegetable oils have been converted into a solid fat by hydrogenation (adding more hydrogen atoms onto the carbon chain). However hydrogenated fats have recently been banned in the USA due to health problems, therefore try to avoid these in your diet. Cooking can also spoil fats, double bonds break down with the heat so that the more double bonds there are in a fat (or oil), then the more likely it is to spoil when it is heated. Therefore cook with a monounsaturated fat (such as olive oil) rather than polyunsaturated oils (such as sunflower oil). Some health experts now say the healthiest fat to cook with is the saturated vegetable fats such as coconut oil, or even saturated animal fats!
Fats are essential to our health, but it is important to keep to the right proportions in our diet. A good handful of nuts a day and a couple of portions of oily fish a week, or a daily tablespoon of linseed or hemp oil will give your body an adequate amount of healthy fat to keep you healthy.
Omega Acid Content of Various Foods
|Omega 3 (%)||Omega 6 (%)||Omega 9 (%)|
|Seed & Nut Oils|
|Other Fats and Oils|
|Eggs and Meat|
|Omega 3 enriched egg||12|