Dietary fats - a guide to the types of fat in our diet.
Contrary to what many people believe, a certain amount of fat in our diet is vital and essential for good health and the correct functioning of our body.
It is important however, that we eat the right kinds of fat rather than those that are detrimental and put our health at serious risk.
Therefore, we must learn about each type of fat and what effect they have on our body, in particular on our blood cholesterol levels.
What do we need fat for?
Our body would not be able to survive without any fat. Fat is crucial to a number of processes that take place within the body and every single cell contains essential fatty substances in their membranes.
Fat is for one, an excellent source of energy. It also protects our organs and the layer of fat underneath our skin keeps the body warm and generates heat.
Fat is also needed to produce and protect hormones and it aids in the absorption and transportation around the body of vital fat-soluble nutrients and vitamins.
How many types of fat are there?
There are four types of fat, of which two are actually beneficial to the body, whilst the other two are seriously bad for the body if consumed in excess.
Saturated fats and Trans fats are known as the "bad" fats. A large intake of these fats, which are often hidden in some foods, can make us gain weight and become obese but more importantly, they can lead to cardiovascular disease, heart disease and stroke.
Polyunsaturated fats and monounsaturated fats, on the other hand, are good for us and they can reduce the risk of these diseases.
What does this have to do with cholesterol?
Cholesterol is a fatty wax-like substance that is produced by the body itself, in the liver.
There are two types of cholesterol, good cholesterol, (HDL - High density lipoprotein) and bad cholesterol (LDL - Low density lipoprotein). They are both made up of lipoproteins that transport the cholesterol around the body.
The LDL transport the cholesterol from the liver to the rest of the body, however, when there is too much cholesterol in the bloodstream, some of it is deposited on the walls of the arteries.
If more and more cholesterol is produced and not cleared away, the cholesterol accumulates on the walls of the arteries and eventually narrows them so that it is very difficult for the blood to flow through them.
At this point several things can happen. Firstly, as the blood is trying to push through, in order to reach the heart and the brain, pressure builds up and the artery walls are put under a terrible strain. This results in high blood pressure.
Secondly, due to the pressure from the blood trying to push through, the artery walls can weaken. When this happens, bulges in the walls may form, which if they burst or rupture, can cause a stroke or heart attack.
If there is such a build up of cholesterol deposits that a blockage forms in one of the main arteries, the brain and heart can become starved of oxygen and blood, which will eventually lead to a heart attack or stroke.
So, the underlying factor is that if there is too much cholesterol in the bloodstream, there is a higher risk of cardiovascular disease and stroke.
How is this linked to the fats that we eat?
Basically the different types of fat that we consume work differently in our body.
The main problem here is that cholesterol is produced when saturated fats and trans fats are consumed. If we eat too many foods that contain these bad fats, too much cholesterol will be produced and we put our health at risk.
It is vital to know that if you eat foods containing saturated or trans fats, your body will produce cholesterol. If you consume a lot of these fats, your body will produce a lot of cholesterol.
What about the good fats?
Polyunsaturated and monounsaturated fats increase the levels of HDL, which is the good cholesterol and can reverse the process of the accumulation of fatty deposits in the arteries. They also lower the levels of LDL in the bloodstream.
HDL actually carries the cholesterol in the blood back to the liver, from where it is eliminated from the body. Therefore, it cleans out the arteries and reduces the risk of heart disease occurring.
In which foods can we find these fats?
Saturated fats are mainly found in animal products and they are solid at room temperature. Animal fats raise the levels of bad cholesterol but also raise the levels of good cholesterol too. However, they need to be limited in the diet.
Sources of saturated fats are whole milk, butter, cream, ice cream, red meat with fat, the skin on chicken, chocolate, crisps, cheese, beef, lamb, pork, lard, beef fat, most commercially produced cakes, biscuits, pastries, fast foods, coconut oil and palm oil.
Trans fats are the most damaging and harmful type of fats, yet they are found in smaller amounts in the diet. They raise the levels of LDL and also lower the levels of HDL. They are solid or semi-solid at room temperature and are produced by heating vegetables oil with hydrogen in order to make them solid. Trans fats are also known as hydrogenated fats and are found in most margarines, butter, whole milk, shortening, cooking oils, processed foods, snack foods and commercially fried foods. They should be totally eliminated from the diet, as they pose a great risk to our health.
Monounsaturated fats are good for the health, as they lower LDL levels and raise HDL levels.
They are primarily found in plant oils and should be consumed instead of saturated and trans fats.
Sources of monounsaturated fats include olives, olive oil, canola oil, avocados, peanut oil, peanuts and most other nuts.
Polyunsaturated fats are beneficial to our health. They can lower blood cholesterol levels, protect the heart and prevent heart disease.
They are divided into two types: omega-3 fatty acids and omega-6 fatty acids.
Omega-3 fatty acids can be found in oily fish such as mackerel, herring, sardines, salmon, tuna, swordfish, as well as in oils such as soy oil and canola oil and spreads made from these oils.
Omega-6 fatty acids are found in nuts such as walnuts, brazil nuts and seeds such as sunflower and sesame seeds. They are also present in corn oil, sunflower oil and safflower oil.
How much fat do we need?
Nutritionists advise us that a maximum of 35% of our calorie intake should come from fats, with only 10% derived from saturated fats.
Most people consume too much fat and need to reduce their fat intake.
1g of fat is the equivalent of 9 calories and therefore on the basis that the average daily calorie intake for a male is 2500 and 2000 for a female, we should be consuming around 800 calories or 600 calories from fats respectively.
People who try to cut fat out completely from their diet are also putting their health at risk and the minimum amount of fat that should be consumed is 30g a day for optimum health.
What can we do to reduce our fat intake and only eat fats that are good for us?
It is important to reduce the intake of saturated and trans fats and when possible try to replace the bad fats with the good fats. Try the following in order to raise HDL cholesterol and lower LDL cholesterol:
- Eat less red meat and trim off any visible fat.
- Use healthier cooking methods such as boiling, grilling and steaming.
- Cut out commercially produced cakes, pastries and biscuits.
- Do not eat fast food or limit to once a month.
- Replace meat with fish.
- Choose leaner cuts of meat.
- Consume oily fish twice a week.
- Snack on fruit, nuts and seeds.
- Eat bigger portions of fruit, vegetables and carbohydrates such as cereals and grains.
- Swap full-fat milk and cheese for semi-skimmed or skimmed milk and soft cheeses such as cottage cheese.
- Eat low-fat yoghurts.
- Use healthier oils for cooking such as olive oil or canola oil.
- Spread butter or margarine thinly and substitute mayonnaise for a healthier option.
- Prepare tomato-based sauces for pasta instead of cream-based sauces.
- Add pulses to stews and casseroles as a substitute for meat.
- Use olive oil instead of butter for frying and for a spread on bread.
- Make your own cakes and biscuits but not too often.