Function of Fat
Flavor and Texture - fat gives a soft and smooth texture to food and certain drinks
Healthy Hair and Skin - fat helps to keep hair and skin, soft and supple
Body Temperature - fat helps with thermoregulation. It preserves body heat and maintains body temperature.
Insulation and Protection - structural fat helps to insulate, protect and hold organs in place. We also have fat pads on the palms of our hands, soles of our feet, and our buttocks. This offers cushioning and support.
Absorption and Transport of Fat Soluble Nutrients - vitamins A, D, E, and K are fat soluble and need fat for proper absorption and transport around our body. Without adequate dietary fat these nutrients can not be absorbed and used by our body.
Energy - fat is a concentrated source of energy and also used for energy storage in our body.
Essential Fatty Acids - our diet needs to provide the essential fatty acids, linoleic acid and linolenic acid.
The Structure of Fat
Fat is the largest nutrient of all. It has a solid backbone made of glycerol, with three fatty acids extending from it. There are many different fatty acids, and these determine the nature of the fat.
Fatty acids are long chains of the element carbon and each has a hydrogen element attached to it. These chains differ in their length and structure. Some are long, others are short, and the number of hydrogens attached can vary. Some carbons are totally ‘saturated’ with hydrogens, and others have less hydrogens attached, and are ‘unsaturated’. The structure of the fatty acid determines the nature of the fat.
Saturated fats are strong in nature, but this makes them harder for our body to break down. If we consume too many of these fats, then they can accumulate in our body in the form of bad cholesterol in our blood, plaque in our blood vessels, or other detrimental fatty deposits in our body. This can increase our chance of cardiovascular disease. A high intake of saturated fats may also increase our chance of certain types of cancer. Saturated fats are also solid at room temperature and have a higher melting point. This can be seen in butter, lard, coconut oil and the fatty deposits in and around red meat and poultry.
Unsaturated fats are a liquid at room temperature, and this can be seen in olive oil and other vegetable oils. They are not as strong and stable in nature as saturated fats, and this makes them easier for our body to break down. This also means they don't accumulate in our body the same way that saturated fats can. They can instead, contribute to and better our health.
To understand this, let's take a look at our blood stream. It's a constant circulation of hormones, enzymes and nutrients, and fat is one of them. Blood fats are transported in our blood as lipoproteins. They vary in size and composition and can be measured in two groups; high-density lipoproteins (HDL's) and low-density lipoproteins (LDL's). LDL's are also called the 'bad fats'. They carry a high amount of cholesterol and move slowly through our blood stream, can clog it up, leave fatty deposits, and increase our chance of cardiovascular disease. The HDL's carry less cholesterol, more protein and move faster through our blood stream. They transport cholesterol to the liver, where it is converted into bile salts. They will even collect and transport LDL's from our blood to our liver. By transporting cholesterol to our liver and removing LDL's from our blood, HDL's can help to reduce our chance of cardiovascular disease. For this reason, HDL's and LDL's need to be kept in the right amounts, and unsaturated fats can help us to do this.
Unsaturated fats help to maintain and increase HDL's in our blood, and there are two types. Monounsaturated fats and Polyunsaturated fats.
Monounsaturated fats help to lower the undesirable LDL's in our blood, and may also increase the beneficial HDL's. This helps to keep our cholesterol levels in check, ward off cardiovascular disease, and promote our general well being.
Polyunsaturated fats supply us with essential fatty acids (EFA). Our body is capable of synthesizing fatty acids, but there are two primary fatty acids that it cannot. These need to be supplied by our diet and they are the EFA's. The two primary EFA's are Omega-3 alpha-linolenic acid (ALA), and omega-6 linolenic acid (LA).
Omega-3 Fatty Acids
Omega-3 fatty acids are highly praised in our body. They support our cardiovascular health, as well as our joints, eyes and brain. Omega 3 fatty acids are concentrated in certain foods, like fish, nuts and seeds. Processed foods do not favor the use of these healthy oils, as they are not a cheap oil to use in the food industry. If our diets rely too much on processed and refined foods, then we may be missing out on our omega-3 fatty acids and their health benefits.
There's the essential omega-3 fatty acid, ALA, and there's also eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). DHA is found in the retina of the eye, and also in high concentrations in the brain. Therefore, DHA can contribute to eye and brain health. It may also help in the prevention of depression and mood disorders, as well as cognitive decline and the development of Alzheimer's disease.
EPA is also found in our brain, but in smaller amounts than DHA, and may also help with cognitive function. EPA may also have anti-inflammatory properties, which may help in the prevention and treatment of inflammatory conditions, like arthritis.
Omega-6 Fatty Acids
Omega-6 fatty acids are just as important as the omega-3's, but many of our diets already supply more than enough. Where omega-3 is lacking, omega-6 is thriving. This relates to the source of omega-6 fatty acids, their extensive use in the food industry, and farming practices that favor their development.
Omega-6 fatty acids are found in many vegetable oils that are used extensively in the food industry. If we consume a diet high in processed foods, or foods prepared outside the home, then it's likely we are consuming a large amount of these omega-6 fatty acids. Intensive farming practices where the livestock are fed on grain, as opposed to pastures, can also produce meat that is higher in omega-6 fatty acids.
While omega-6 fatty acids are required for our health, too many of them can come with drawbacks. When omega-6 levels are too high, they can interfere with the metabolism of omega-3, and they can also increase our chance of developing cardiovascular disease, certain cancers, arthritis and even depression. To rectify and avoid the imbalance, we need to identify the sources of omega-3 and omega-6 fatty acids and make dietary changes where necessary. We will get what we need and reap the benefits of both.
There's one more type of fat and it's the most notorious fat of all. Trans fat. It's an unsaturated fat, that behaves like a saturated fat, but worse. Trans fats are the quickest route to cardiovascular disease. Monounsaturated, polyunsaturated and even saturated fats, are all essential to our health and needed in the right amounts. Trans fats are not at all essential. They do not contribute to the function of our body, instead they only create problems. Trans fats increase the undesirable LDL's in our blood, at the same time as decreasing the favorable HDL's. Trans fats are trouble makers that are best avoided.
Trans fats can be found naturally in animal products like meat and dairy, but only in very small amounts. But they can also be manufactured and used in processed foods and here's how. Unsaturated oils, or vegetable oils, are used extensively in the food industry. They have a reasonable price tag and a reasonable shelf life, but what if these 'reasonable' qualities were made exceptional? What if they had an even cheaper price tag and a longer used by date? They can. When unsaturated vegetable oils are tampered with, through a process called hydrogenation, this produces a product that is less perishable in nature and one that is more economical for the food industry. It produces hydrogenated or partially hydrogenated vegetable oils; a once unsaturated fat that behaves more like a saturated fat. It's the partially hydrogenated vegetable oils that we need to be cautious of. They contain the notorious trans fats. If we regularly consume processed foods containing partially hydrogenated vegetable oils, then we are potentially consuming dangerous amounts of these trans fats.
Our body can handle small amounts of trans fats from animal products, but if we add to this load with artificial trans fats from processed foods, then we are giving our body more than it can handle. The best way to avoid these trans fats, is to avoid foods containing partially hydrogenated oils, and favor a diet based in natural and unprocessed foods.
Sources of Fat
Coconut oil - comes from the pulp of the coconut. Also in coconut cream, coconut milk, and dried coconut products
Palm oil - comes from the fruit, or pulp, of the oil palm. Used in processed foods like baked goods, biscuits, crackers. It has a longer shelf life and is also quite economical.
Palm kernel oil - comes from the kernel, or seed, of the oil palm. This oil is also used in the commercial food industry.
Cocoa beans and chocoalte products
Plant sources of unsaturated fats contain both monounsaturated and polyunsaturated fats, but different foods are often higher in one or the other.