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People stubbornly thought for many years that fats are bad for our bodies and that was the reason why they tried to completely avoid them. However, it did not make us healthier. Perhaps because we avoided not only bad, but also good healthy fats.
Our body needs fats from food. It is the main source of energy and it also helps us to absorb some vitamins and minerals. Fat is needed for the cell membranes formation as it is the exterior of each cell and the protective nerve sheath. It is definitely essential for blood clotting and muscles movement.
Why are fats important?
Fats have several important functions:
- supply energy (1 gram of fat contains 9 calories, while 1 gram of carbohydrate contains only 4 calories)
- provide absorption of vitamins A, D, E, and K, that are soluble in fat (fat must be present in order to absorb these vitamins)
- protect organs, nerves and tissues, help regulate body temperature
- Each cell membrane in the body needs fat for protection and the growth of new healthy cells as well
- are part of the production of essential body hormones process
- maintain healthy hair, skin and nails
Some fats are healthier than others, when talking about fats in a long-term perspective. “Good” fats are unsaturated – monosaturated and polysaturated. “Bad” fats are industrially produced trans fatty acids, and they also sometimes include saturated fats.
All fats have a similar structure : a chain of carbon atoms bonded to hydrogen atoms. The length and shape of the carbon chain and the number of hydrogen atoms attached to the carbon are attributes that make differences between different types of fats. However, the seemingly small differences in their structure significantly affect form and functions of fats.
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Bad fats = trans fats
Trans fats are definitely the worst type of fats. It is a secondary product of a process called hydrogenation which is used in the production of hardened fats from healthy oils and prevents the later “frowstiness”. When you heat a vegetable oil in the presence of hydrogen atoms and a catalyst, such as palladium, the hydrogen atoms attach to the carbon chain. This converts oil into the solid component and changes healthy vegetable oils into hardened fats, that are not that healthy. This ingredient is called as a “hydrogenated vegetable oil” in nutrition facts. At the beginning of twentieth century, these hardened fats could be mainly found in margarines and vegetable fats. But later, a lot of big production companies learned how to use them and started adding them to almost every other product – from cakes, desserts, doughs to fries.
Consuming these fats increases the amount of unhealthy LDL cholesterol in the blood and reduce the amount of good “HDL” cholesterol. Trans fats cause inflammations, that are also associated with heart diseases, stroke, diabetes and other chronic diseases. They trigger insulin resistance that increases the risk of developing diabetes type 2. Recent study from the Harvard School of Public Health and other institutions indicates that trans fats are harmful to our health even in small quantities : every 2% of calories from trans fats consumed daily increases the risk of heart disease by 23%.
Studies have also proved that intake of trans fats can lead to diabetes. Researchers from Harvard School of Public Health in Boston suggest replacing these trans fats with polyunsaturated fats that are found in vegetable oils and fishes. This can prevent diabetes up to 40%.
Recent studies also say that these fats have no beneficial effects on our health and there is no safe level of their consumption. Since 2006, the american FDA (Food and Drug Administration) has required to write trans fats in nutrition facts as a specific item. As a result, large food production companies have reduces the amount of these trans fats in the majority of foods. Moreover, many governments have banned the use of these trans fats in restaurants. This is also the reason why we notice slowing down of the use of these trans fats.
Saturated fats – are they healthy or unhealthy?
Saturated fats are basically used worldwide. They are solid at the room temperature. The best known sources are red meat, whole milk and its products, cheeses, coconut oil, commercially produced bakery products and others. The word “saturated” demonstrates the number of hydrogen atoms that are surrounding the carbon atom. A chain of carbon atoms, that keeps as many hydrogen atoms as possible, is saturated with hydrogen.
Coconut oil led to the lowering of triglycerides when it was compared with butter and beef, in two different studies. However, the overall proofs are unequivocal for coconut oil, as it does not improve triglycerides more than unsaturated sunflower oil. And while some saturated fatty acids are associated with higher LDL cholesterol levels, coconut oil in a mixture of fatty acids, that were beneficial in this study (myristic acid and palmitic acid that makes about a quarter of the fats in coconut oil). Therefore, coconut oil is not good, but also not bad for our body.
As the study shows,palmitic acid, that is the main saturated fat in palm oil, has the same effects on cholesterol lipids as the polyunsaturated fat – oleic acid, which is recommended by researchers. In addition, palm oil contains linoleic acid, oleic acid and vitamin E tocotrienols, that are strong antioxidants and also inhibit cholesterol synthesis. So it has been proved that also palm oil does not have good, but also not bad effects on our body. One of the biggest reason why many people condemn palm oil is its negative impact on the environment. The cultivation of palm oil is associated with deforestation, what leads to climate changes. Moreover, palm plantations and their burning affect some endangered animal species that are situated in tropical areas.
A diet rich in saturated fats may cause an increase in absolute cholesterol levels and move its balance to the harmful LDL cholesterol, that causes clogged blood vessels. This is the reason why experts recommend limiting the consumption of these fats to less than 10% of the daily consumed calories.
Several recent reports refer to a connection between saturated fats and heart diseases. One meta-analysis of 21 studies reported that there was insufficient evidence to make a conclusion that saturated fats increase the risk of heart diseases, but that substitution of saturated fats with polyunsaturated fats may reduce the risk of heart diseases.
Two other studies made a conclusion, that replacing saturated fats with polyunsaturated fats, such as vegetable oils and high-fibre carbohydrates, is the best option to reduce the risk of heart disease. On the other side, replacing saturated fats with highly processed carbohydrates may have the opposite effect. However, there are very interesting recent analyzes of red meat and saturated fats that do not prove any direct connection with heart disease. Even though saturated fats have an important metabolic function and are apparently not explicitly negative or positive for out body, so there is no need to overtake them.
Good fats = unsaturated fats
Good fats are mainly included in vegetables, but also in nuts, seeds and fishes. The difference between unsaturated and saturated fats is that they have a smaller amount of hydrogen atoms attached to the carbon chain. Healthy fats are liquid at room temperature, not solid. There are two types of the best known categories of healthy fats : monounsaturated and polyunsaturated fats.
When you soak bread in olive oil in an Italian restaurant, you apparently consume monounsaturated fats. Monounsaturated fats have one double bond of carbon atoms. It means, that the chain has two hydrogen atoms less than saturated fats. This structure is the reason why these fats are still in the liquid state at room temperature.
Seven Countries Study of 1960 stated, that monounsaturated fats can be healthy. It has been shown that residents of Greece and other Mediterranean countries are less susceptible to cardiovascular diseases, despite consuming larger amounts of fat. The reason is that the fats in their diet were not of animal origin, as in the countries where cardiovascular diseases were more common. It is mainly olive oil which contains a larger amount of monounsaturated fats. This finding has extremely increased interest in this type of oil and in the Mediterranean lifestyle.
Although there are no recommended amounts of these fats, it is recommended to consume them as much as possible together with polyunsaturated fats as a complete substitute for saturated and trans fats.
Polyunsaturated fats are essential, which means that they are needed for our body, but it cannot make them by itself, so we need to consume them in food. Polyunsaturated fats form cell membranes and nerve shells in our bodies. They are also required for blood coagulation, muscle movement and inflammation.
There are two types of polyunsaturated fats: omega-3 and omega-6 fatty acids. The number refers to the distance between the beginning of the carbon chain and the first double bond. Both of them are beneficial to our health. Consumption of these fats reduces the level of harmful LDL cholesterol and overall improve cholesterol levels. It also reduces triglycerides.
Walnuts, other nuts and seeds and “fatty” fish, such as salmon, mackerel and sardines are good sources of omega-3 fatty acids.
Omega-3 fatty acids
Omega-3 fatty acids can prevent and even treat heart diseases and stroke. They also lower blood pressure and increase HDL cholesterol levels. There are also some proofs about how they can reduce the need for corticosteroid therapy of people with rheumatoid arthritis. In addition, studies also connects omega-3 with wide range of other health improvements, including reducing the risk of dementia. But unfortunately, they are not convincing and were criticized due to many significant and noticeable deficiencies.
Recent study, with the purpose to find the effects of omega-3 fatty acids on eyesight, confirmed that the DHA acid, found in omega-3 is one of the major components of the brain and retina of the eye. Regular use of omega-3 fatty acids was associated with a reduction in the risk of macular degradation, which is one of the most common eye disease that leads to eye damage and loss.
Omega-6 fatty acids
Omega-6 fatty acids are also used to prevent heart diseases. Foods, that are rich in linoleic acid and other omega-6 fatty acids, are vegetable oils, such as corn, sunflower, soy and others. Another study made on nearly 40 000 participants in 20 different experiments found that people, who have increased linoleic acid level in their blood (one of the main component of omega-6), have less probability to have diabetes type II., that those with lower fatty acids level.
Although omega-6 appears to be beneficial, scientists at the American Heart Organization (AHA) have stated that daily intake should not exceed 5-10 % of total daily energy intake, as the increased amount was associated with inflammations and heart diseases.
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