Priya Chaudhari discusses the different types of fat and their importance in our daily diet.
Why fat is necessary?
Fat is an essential nutrient in our diet. Dietary fats make food more appealing, tasty and improve the texture, the flavour, as well as the smell of the food. Fat is made up of building blocks called fatty acids and these are classified as Saturated, Monounsaturated Fatty Acid (MUFA) or Polyunsaturated Fatty Acid (PUFA), depending on their chemical structure. Fat is a concentrated source of energy – one gram of fat contains nine calories. Foods that contain a lot of fat provide a lot of energy and are called energy-dense foods.
Functions of fat
• Fat provides a cushion to protect our vital organs. Without fat, our organs would be more prone to damage. Fat also acts as an insulator by regulating our body temperature.
• Fat helps in the absorption of fat- soluble vitamins A, D, E and K.
• Fats contain Essential Fatty Acids (EFAs) that help in the functioning of the heart and immune system. The human body cannot synthesize its own EFAs and therefore, has to derive from the consumption of healthy fats.
• Some fatty acids like Omega 3 and Omega 6 possess health benefits such as complimenting the cognitive processes of the brain.
• Our bodies store fat for lean times and can pull on its fat reserves during lean times for energy by converting the fat into glucose.
• Each gram of fat has 9 calories. Too much fat, especially too much of saturated type of fat, can cause serious health complaints including obesity, higher blood pressure and cholesterol levels; which in turn lead to a greater risk of heart disease.
Saturated and unsaturated fat
There are two main types of fat – saturated and unsaturated.
Saturated fat is also called as solid fat as it is solid at room temperature. It is mostly found in animal foods such as full-fat dairy
products like cheese, butter, cream. It is also found in margarine, meat and mayonnaise, etc. Cakes, cookies and other desserts also have a high amount of saturated fat.
Saturated fat molecules form regular shapes that clump together easily.
Saturated fat is, therefore, more likely to stick to the sides of the arteries and allow other saturated fat molecules to build up. This gradually clogs the arteries, leading to high blood pressure and making it more difficult for the heart to pump oxygen-rich blood in the body, thus leading to serious health problems such as coronary disease.
Unsaturated fat is generally considered better for your health than saturated fat. The reason is that unsaturated fats are better because of their molecular structure. Unsaturated fats lack one (mono) or more (poly) hydrogen atoms in their chemical makeup. This is what gives them an irregular shape, so that they cannot bond together easily.
Unsaturated fat is liquid at room temperature. Monounsaturated Fatty Acids (MUFA) and Polyunsaturated Fatty Acids (PUFA) are two types of unsaturated fat. It is mostly found in oils from plants such as
safflower, sunflower, sesame, soybean and corn. There are two types of polyunsaturated fat, namely omega-3 and omega-6 fatty acids. Omega-3 fatty acids are found in foods from plants like soybean oil, canola oil, walnuts and flaxseed. They
are also found in fatty fish and shell fish as Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA). Salmon, Anchovies, Herring and Sardines, Pacific oysters, Trout, Atlantic mackerel and Pacific mackerel are high in EPA and DHA. Omega-6 fatty acids are found mostly in liquid vegetable oils like soybean oil, corn oil and safflower oil.
Eating polyunsaturated fat in place of saturated fat may lower LDL (Low-density Lipoprotein) cholesterol.
Trans or hydrogenated fat
Hydrogenated fat or trans-fat is a vegetable fat that has been treated with extra hydrogen. This process changes the chemical structure of the fat, by making it solid at room temperature. This process increases the shelf life of fat. Hydrogenated fat is mainly used in processed foods. It contains some qualities desirable to food manufacturers but it increases the risk of coronary heart disease by raising the levels of LDL-cholesterol and lowering the levels of ‘good’, HDL-cholesterol in the blood.
Perhaps it’s the worst of all fats when it comes to health, and is the most important type of fat to avoid.
Hydrogenated fat is found in processed foods, snacks such as chips and crackers, mayonnaise, cookies, in some margarine and salad dressings and in foods made with shortening and with partially hydrogenated oils.
How much fat do we need?
We only need small quantities and the right kinds of fat to stay healthy. It is recommended that the total fat intake should not exceed 30 per cent of the total daily energy intake from food and saturated
fat should not exceed 11 per cent of the total energy intake from food. Most of the times, our total fat intake is close to these recommendations, but the amount of saturated fat we consume is too high.
Foods high in saturated fat such as butter, fried foods, certain cakes, biscuits and pastries should only be eaten in small amounts, as this type of fat can increase the blood cholesterol levels.
People who are overweight or obese may also need to think about reducing their total fat, as well as saturated fat.
Cholesterol
Cholesterol is a waxy substance, a type of fat found in the blood which in low levels, flows freely in the body through blood.
Cholesterol is carried in the body through the blood stream combined with proteins called lipoproteins. There are two main types of lipoproteins that are used to check the cholesterol levels in the blood – Low- density Lipoprotein (LDL-C) and High- density Lipoprotein (HDL-C). LDL is termed as ‘bad’ cholesterol, whereas HDL is considers ‘good’ cholesterol.
HDL-C retrieves the bad cholesterol from the body and carries it to the liver so that too much of bad cholesterol doesn’t build up in the bloodstream. People with higher levels of cholesterol are more likely to develop coronary artery disease. The risks are further increased for people who also smoke, have high blood pressure, are physically inactive and are overweight, obese, or suffer from Diabetes.
A common cause of high cholesterol in modern society is the consumption of too much of saturated fat. Nearly all the cholesterol in the body is produced by the liver, which is vital to a healthy body and a
building block for other essential chemicals in the body.
To conclude
- Eat more natural foods such as vegetables, fruits, legumes and whole grains as they are sources of nutrients and fibre which are also naturally low in
- Try to incorporate more fibres in your meals which help to lower blood
- Discuss with your dietician and learn about how to cut down on the amount of fat you eat. Make sure you have your cholesterol levels checked according to the schedule given by your health care
Priya Chaudhari is a Consultant Dietician
