What is fat how to useful for us ? Types of fats & benefits
Fat supplies essential fatty acids (EFAs). Your body is incapable of producing the EFAs, known as linoleic acid and alpha-linolenic acid, so it must derive them from food.
• Vitamins A, D, E, and K are the fat-soluble vitamins which transports fat into and around the body
• Fat is necessary for maintaining healthy skin, and it plays a central role in promoting proper eyesight and brain development in babies and children.
• For all the good it does, fat is often accused of the culprit in the battle of the bulge. It is easy to understand why. At 9 calories per gram, any type of fat — good or bad — packs more than twice the calories of carbohydrate and protein. Yet, it’s a mistake to equate dietary fat with body fat. You can get fat eating carbs and protein, even if you eat little dietary fat.
Saturated fat (SFA)
It is a type of fat in the oils which makes it thicker (more solid) and when consumed can elevate the levels of total cholesterol (TC) and LDL cholesterol.
Overall, it can 1 contribute to development of heart diseases. Rich sources: Ghee, butter and coconut oil
Polyunsaturated fat (PUFA)
It is another type of fat which when consumed lowers the level of LDLcholesterol but at the same time can also lower HDLcholesterol. Rich sources: Safflower oil, sunflower oil and soya bean oil
Monounsaturated fat (MUFA)
Metabolically, it is the best type of fat because when consumed lowers LDL cholesterol and elevates the HDL 2-4 cholesterol levels.
Rich sources: Olive oil, mustard oil and groundnut oil
However, currently, the focus of research has shifted from saturated fats to individual fats and percentage of fatty acids (SFA, PUFA, and MUFA) in the diet. An adequate intake of both polyunsaturated and saturated fats is needed for the ideal LDL/HDL ratio in blood, as both contribute to 5 the regulatory balance in lipoprotein metabolism
Trans fatty acids (TFAs)
This is an artificial fat produced as a side effect of hydrogenation of animal fat (margarine) or vegetable fat (vanaspati ghee). If hydrogenation is incomplete (partial hardening), the relatively high temperatures used in the hydrogenation process tend to flip some of the carboncarbon double bonds into the “trans” form.
If these particular bonds aren’t hydrogenated during the process, they will still be present in the final product as trans-fatty acid. From the health stand-point, it is the worst type of fat and has been linked with development of Coronary heart disease (CHD
A comprehensive review of studies on trans fats was published in 2006 in the NEJM reports a strong and consistent relation between trans fat consumption and CAD, concluding that “On a per-calorie basis, trans fats appear to increase the risk of CHD more than any other macronutrient, conferring a substantially increased risk at low levels of consumption (1 to 3 % of total energy 6 intake)”.
The New England Journal of Medicine (NEJM) study estimated that consumption of TFAs
constituted for between 30,000 and 100,000 cardiac deaths per year in the United States alone. Another damaging evidence of illeffects of TFAs on CAD were forth-coming from the Nurses’ Health Study, enrolling 120,000 female nurses.
In this landmark study, Hu and colleagues determined that a nurse’s CAD risk roughly doubled for only 2% increase in trans fat calories consumed. Interestingly, it takes more than a 15% increase in saturated fat calories to produce a similar increase in risk.
Furthermore, it was found that replacing 2% of food energy from TFAs with non-trans unsaturated fats more than halved the risk of CHD (53%). By comparison, replacing a larger (5%) of food energy from SFAs with non-trans unsaturated fats reduces the risk of CHD by 43%.The reason for this exaggerated negative response is probably that while both SFAand TFAincrease LDL but unlike SFA, TFA also lowers HDL. The net increase in LDL/HDL ratio with TFAs is approximately 7 double than that due to SFAs.
Furthermore, the negative consequences of TFA consumption may go beyond the CVrisk. There is evidence that eating such diets may increase the risk of other chronic health problems like Alzheimer’s disease, cancer, diabetes, obesity, liver dysfunction, infertility and depression to name a few. Rich sources: Processed fried foods like bhujiya, samosas, biscuits, confectionary items, etc.
Omega-3 fatty acids
Omega-3(N-3)fatty acids are a family of PUFA, which are 8 considered especially good for health. They are one of the two essential fatty acids, so called because humans cannot manufacture it and must get it from food.
N-3fatty acids are precursors to anti-inflammatory compounds in the body. Oily fish caught near polar regions are a good source of it. All seeds of the Brassica family, including mustard (6- 11%), canola / rapeseed (7%) and turnip, have high levels of omega-3 fatty acid. Flax (linseed) oil is the richest source of plant based omega-3 fatty acid (55%) and also hemp oil (20%) is a rich source, but these oils are uncommon as a table or cooking oil .
Soybean oil has 6% omega-3 but contains over 50% omega-6, the fatty acid that competes with the function of omega-3. Other than rapeseed and mustard oils, there are few other common sources of plant based omega-3 in Western and Indian diets. However, when omega-6 intake is kept low, humans can convert the plant-based omega-3
into one found in fish oils (eicosapentaenoic acid), in limited amounts, a useful source for vegetarians.
Omega-6 fatty acids
Omega-6 fatty acids (N-6) are also important for health. They include the essential fatty acid linoleic acid (LA), which is abundant in vegetable oils like corn (60%), cottonseed (50%) and sunflower (50%) oil. Margarine is very high in omega-6 fatty acids. N-6 fatty acids are precursors to pro-inflammatory compounds in the body. Further, large amounts of omega-6 decrease the effect of omega-3.