Nutrition

The role and qualities of fat in the diet

What role does fat play and what are its qualities?

This is a good question…

As we already know, what we eat has great influence on our both intellectual and physical development. In order to fully take advantage of our developmental potential, our diet has to be rich in various food products that will contain appropriate portions of: proteins, carbohydrates, vitamins, minerals and fats. And in this topic we will focus on fats.

Many people exclude fats from their diets thinking that they are the main cause of their obesity or other problems related to excess weight. They think that the role of fats is minor and that they are unnecessary. This is the biggest mistake made by people. Fats are lipids, i.e. complex molecules, also called fatty acids. They play a very important role in our organism and we could not properly function without them, e.g. excluding fats or their improper intake causes serious cardiovascular diseases that pose a risk to many people nowadays, especially in developed countries, where people “watch their weight” without basic nutrition knowledge.  Fats provide much more energy than carbohydrates, but our organism uses them unwillingly and treats them as a supply that may be burnt later. It means that the presence of fat in food is essential, especially during hard physical work. High amounts of energy are needed then and only proteins and carbohydrates cannot fully satisfy these needs. It then seems reasonable to introduce to our diet products rich in fats, both vegetable and animal. However, if the work does not require such energy input, it may happen that the meals containing high amounts of fat will provide their excess. This leads to energy imbalance and its surplus will be changed in fat stored in adipose tissue. Therefore, we cannot exaggerate with fats.

It is not a mystery that high amounts of fat in foods increase their energy value. Eating high-fat products with low physical activity is a simple way to obesity and other related diseases. Fat from food also negatively influences the composition of blood, especially triglycerides, total cholesterol and LDL cholesterol. Increased concentration of these atherogenic indicators in blood serum is a sign of improper lipid processes and predisposes one to atherosclerotic changes in blood vessels. Such a dependency does not concern all people, but rather the elderly, the people with genetic predisposition to atherosclerosis and when lipid processes are already disturbed due to other diseases, e.g. diabetes, obesity or certain hormonal problems. High amounts of fat in foods, which in our food culture is often animal, pose also other risks. In such a diet usually there is too much cholesterol and improper composition of fatty acids. Cholesterol contained in food causes the increase of cholesterol level and other atherogenic blood indicators.  A similar influence is shown by saturated fatty acids contained in foods, in which the main source of fat are fat meats, grease, lard, butter and fat milk. In these products there are not much monounsaturated and polyunsaturated fatty acids, which provide the organism with essential fatty acids (EFAs). In order to maintain good health, at least 1-2% of daily energy should be derived from burning EFAs. Fatty acids that are dangerous to our health are saturated.

Let us start with the divisions. We may divide fats into various categories. The first one may be, for example, the fat origin: we divide them into vegetable fats – most of these contained in seeds, fruit flesh and animal fats contained in all living organisms, e.g. in subcutaneous adipose tissue or in cells and organs of various organisms. It could be said much more about fat structure, but I will try to make it short, reasonable and clear. As mentioned above, fats, also called lipids, are present in all organisms. They are found in tissues and store the substances responsible for controlling solubility of important vitamins K, E, A and D. Another division of lipids (fats) is on the basis of their chemical structure: there are simple and composite fats. The first ones are a composition of carbon, hydrogen and oxygen and these are for example glycerol and fatty acids esters. Composite lipids, on the other hand, are composed of carbon, hydrogen and oxygen, but contain also other compounds, such as nitrogenous bases, sulphuric acids etc. One of the basic component of all lipids both simple and composite are fatty acids. 

We may distinguish a couple kinds of fatty acids: saturated fatty acids (lack of double bonds, characterized by a single bond between carbon atoms), unsaturated fatty acids (there appear a few couples of double bonds), monounsaturated fatty acids (one double bond between carbon atoms) and polyunsaturated fatty acids (two or more double bonds). Let us move on to the occurrence of fatty acids. Saturated fatty acids are usually present in fats of animal origin, e.g. grease, but they are also found in vegetable fats, such as coconut oil or palm oil. These fats are acknowledged to be harmful to people’s health and it is said that we should rather avoid them, as they cause the increase of “bad” cholesterol, especially in case of elderly and middle-aged people, they also cause atherosclerosis and in their burning process free radicals are produced. The main representative of monounsaturated fatty acids is oleic acid present in olive oil and peanut oil (about which more below). Lots of monounsaturated fatty acids, as already mentioned, are contained in olive oil, which has a good influence on our cardiovascular system and against the common belief that monounsaturated fatty acids are not good for frying – they are. Why? Because having only one double bond they are not susceptible to oxidation and high temperature to such an extent as sunflower oil or corn oil. I, personally, take it with a pinch of salt, as there is no ideal oil and each has some faults.

In my opinion, we may for example fry eggs for a short time on olive oil, since, as mentioned above, it is quite resilient to heat. The characteristic feature of unsaturated fatty acids is the fact that they easily connect both hydrogen and oxygen, which is the feature of all double compounds. It is used for example in the processes of hardening (hydrolyzing) in the production of e.g. margarines. Most of unsaturated fatty acids can be found in vegetable oils, but in animal oils they also appear. If you have ever wondered why oils are liquid, I will answer this question now – this is because the high content of unsaturated fatty acids. The exceptions are such oils as coconut or palm oil, as they contain a lot of saturated fatty acids and in normal temperatures (room temperature) they have solid consistency. Unsaturated animal fats are cod-liver oil and fish, which are liquid like vegetable oils. In these fats, there is a lot of unsaturated fatty acids, which are important to humans. Out of polyunsaturated acids, the main representative of Omega-6 family is linoleic acid which is found in oilseeds. Oils rich in this acid are: corn, soya, sunflower oils, but also soft margarines. The representative of Omega-3 family is linolenic acid (ALA), which can be found in some vegetable oils (linseed, rapeseed oils) and the most of this acid is contained in plankton and fish that is fed by this plankton. As we know, Omega-3 and Omega-6 fatty acids belong to the group of polyunsaturated acids, therefore the ones that contain at least two double bonds between carbon atoms. The difference between them, represented by the so called omega numbering, relates to the place in which in a carbon chain the first double bond appears. In the case of O-3, the first double bond appears after the third carbon atom and in the case of O-6 it appears on the sixth carbon atom. We therefore know, where the numbers 3 and 6 come from. 

Let us take a closer look at Omega-3 acids. One of the most widely known representatives of O-3 are: ALA, alpha-Linolenic acid contained in linseed, linseed oil, walnuts, rapeseed and soya oils. Equally important acids are DHA, i.e. docosahexaenoic acid and EPA, i.e. eicosapentaenoic acid. They can be found in oily sea fish and seaweeds. They are extremely important to human organism. DHA is especially relevant to the proper functioning of the brain (e.g. cerebral cortex is built in around 60% of this fatty acid). Equally important role of DHA is using it to build neurotransmitters. Summing up, DHA influences our mental abilities in the broadest sense. Research show that people suffering from depression have very low levels of DHA in blood. Other interesting quality is the fact, that DHA constitutes a building block for serotonin and dopamine production. The above information is extremely important, but we, the people who train, always want a certain “thing” to positively influence our body. According to the research on rats, taking higher amounts of O-3 affected better development of neuronal synapses, which entailed managing the training better than the rats with low amount of O-3. Therefore, adding DHA to our daily diet has a positive influence on our self-being and health. Another important acid next to DHA is EPA, which conditions proper eicosapentaenoic synthesis – these are chemically active molecules, called tissue hormones. They are freed from cell membranes, which in turn are built of phospholipids. Eicosanoids are responsible for antithrombotic and anti-inflammatory activity, they stop the development of cancer and limit contractility of blood vessels. Let us move on to Omega-6 acids, which are the most commonly encountered in all people’s diets. They are found in fast-foods, margarines etc. In spite of this, they fell into EFAs category, i.e. essential fatty acids, because our organism cannot function without them. Deficits of EFAs cause a range of changes in the human organism, among others, enlargement of heart, kidney hypertension, enlargement of all organs. There are many more side-effects of EFAs deficits, but in today’s world it is hard not to provide these acids.  However, their common excess poses a serious problem. A rich source of Omega-6 acids are vegetable oils: sunflower, soya. Their excessive intake contributes to the increase of inflammations in the organism. According to various research, higher O-6 intake indicates cancerous activity, while Omega-3 work analogously. Certainly, Omega-6 also have many advantages, therefore its name – EFAs. There are essential to proper development of a young organism and maintaining health through the lifetime. They are important ingredients of tissues and are necessary to proper lipid transport. EFAs are precursors of prostaglandins and their derivatives, thanks to which they have the abilities to prevent blood clots, lower lipid indicators in blood serum and prevents arteriosclerosis. Improper proportion of Omega-6 intake in relation to Omega-3 is a basic factor that decreases O-3 in the organism. Why? Because both O-3 and O-6 are operated by the same enzyme, enabling acid conversion to the proper form. Summing up, each person’s diet should be rich in Omega-3 proportionally to the amount of Omega-6. We should also remember that a substantial overuse of alcohol lowers out O-3 supplies, therefore alcohol should be drunk with caution.
What also decreases O-3 levels is lack of vitamins and minerals improving metabolism, such as vitamins from the B group, which are responsible for biochemical changes of fats or vitamin E, which secures all unsaturated acids from oxidizing right after the intake. The third factor that contributes to decreasing O-3 in the organism is equally important – the age. Our organism is getting older and older, which entails decreasing of the activities necessary to proper enzymatic reactions of fats, including D4 (desaturases), which is essential to proper DHA and EPA synthesis. In general, lack of fat in a diet causes many diseases. Modern nutrition knowledge assumes that both undernutrition and excess of food influence life expectancy, increased disease sensitivity, impairment of psychological and physical efficiency.
Taking main causes of diseases and death in various countries we may claim that improper nutrition, especially deficits of energy, proteins and such basic components like vitamins and minerals as well as excess food intake, when surplus of energy is delivered, contribute to higher death level than any other environmental factor. Remember that by reasonable choices we create better conditions for our organism, which also relates to fat reduction or muscle mass building

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Jack Howard

Jack Howard

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