There are mainly two types of FAT, unsaturated and saturated.
Unsaturated FATAn unsaturated fat is a
fat or
fatty acid in which there are one or more
double bonds in the fatty acid chain. Where double bonds are formed,
hydrogen atoms are eliminated. The greater the degree of unsaturation in a fatty acid (ie, the more double bonds in the fatty acid), the more vulnerable it is to
lipid peroxidation (
rancidity).
Antioxidants can protect unsaturated fat from lipid peroxidation. Unsaturated fats also have a more enlarged shape than saturated fats.
Examples of unsaturated fats are
palmitoleic acid,
oleic acid,
linoleic acid, and
arachidonic acid. Foods containing unsaturated fats include
avocado, nuts, and
soybean,
canola, and
olive oils. Meat products contain both saturated and unsaturated fats.
Unsaturated FATs are
1. Monounsaturated fat
2. Polyunsaturated fat
3. Trans fat
4. Omega: 3, 6, 9
Monounsaturated FAT
Monounsaturated fats are fatty acids with one double-bonded carbon in the molecule, with all of the others single-bonded carbons, in contrast to polyunsaturated fatty acids which have more than one double bond.
The most common monounsaturated fatty acids are palmitoleic acid (16:1 n−7) and oleic acid (18:1 n−9).
Monounsaturated fats are found in natural foods like
nuts and
avocados, and are the main component of
olive oil (
oleic acid). They can also be found in
grapeseed oil, ground nut oil,
peanut oil,
flaxseed oil,
sesame oil and
corn oil.
Canola oil is 57%−60% monounsaturated fat and olive oil is about 75% monounsaturated fat.
Polyunsaturated FAT
Polyunsaturated fat is an abbreviation of polyunsaturated fatty acid. That is a fatty acid in which more than one double bond exists within the representative molecule.
Polyunsaturated fat can be found mostly in grain products, fish and sea food (herring, salmon, mackerel, halibut), soybeans, and fish oil. Foods like mayonnaise and soft margarine may also be good sources, but you should always check the nutritional label first. Polyunsaturated fat is necessary for the body and protects against illness.
Although polyunsaturated fats protect against cardiovascular disease by providing more membrane fluidity than monounsaturated fats, polyunsaturated fats are more vulnerable to lipid peroxidation (rancidity) than monounsaturated fats. Some studies have shown that consuming high amounts of polyunsaturated fat may increase the risk of an individual developing cancer.On the other hand, monounsaturated fatty acids (like unsaturated fats) promote insulin resistance, whereas polyunsaturated fatty acids are protective against insulin resistance.
Polyunsaturated fat, along with monounsaturated fat are "healthy fats," the amount of which in one's daily diet should be near 45 g (in a 2000 calorie-per-day diet).
Trans FAT
Unlike other fats, trans fats are neither required nor beneficial for health.[1] Eating trans fat increases the risk of coronary heart disease.[2] For these reasons, health authorities worldwide recommend that consumption of trans fat be reduced to trace amounts. Trans fats from partially hydrogenated oils are generally considered to be more of a health risk than those occurring naturally.
Trans fats occur naturally in the milk and body fat of ruminants (such as cows and sheep) at a level of 2-5% of total fat.[4] Natural trans fats, which include conjugated linoleic acid and vaccenic acid, originate in the rumens of these animals.
It is found in the fast food, snack food, fried food etc. It has been established that trans fats in human milk fluctuate with maternal consumption of trans fat, and that the amount of trans fats in the bloodstream of breastfed infants fluctuates with the amounts found in their milk.
Omega-3
Omega-3 fatty acids are a family of polyunsaturated fatty acids which have in common a carbon-carbon double bond in the ω-3 position.
Important omega-3 fatty acids in nutrition are: α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). The human body cannot synthesize omega-3 fatty acids de novo, but can synthesize all the other necessary omega-3 fatty acids from the simpler omega-3 fatty acid α-linolenic acid. Therefore, α-linolenic acid is an essential nutrient which must be obtained from food, and the other omega-3 fatty acids which can be either synthesized from it within the body or obtained from food are sometimes also referred to as essential nutrients.
The most widely available source of EPA and DHA is cold water oily fish such as wild salmon, herring, mackerel, anchovies and sardines. The oil from these fish have a profile of around seven times as much omega-3 as omega-6. Farmed salmon, being grain fed, have a higher proportion of omega-6 than wild salmon. Other oily fish such as tuna also contain omega-3 in somewhat lesser amounts.
Flax (aka linseed) (Linum usitatissimum) and its oil are perhaps the most widely available botanical source of omega-3. Flax like chia, contains approximately three times as much omega-3 as omega-6.
Other sources are eggs and meat. Meat from grass-fed animals is often higher in omega-3 than meat from the corresponding grain-fed animal. Commercially available lamb is almost always grass-fed, and subsequently higher in omega-3 than other common meat sources. Milk and cheese from grass-fed cows may also be good sources of omega-3.
palm fruit also contains omega-3 fatty acids.
Walnuts are also a good source, as they are one of few nuts that contain a meaningful amount of omega-3s.
Omega-3 fatty acids in fish oil, fish and seafood lower the total amount of fat in the blood, which can lower blood pressure and decrease the risk of getting cardiovascular diseases.
Omega-6
Omega-6 fatty acids are fatty acids where the term "omega-6" signifies that the first double bond in the carbon backbone of the fatty acid, occurs in the omega minus 6 position; that is, the sixth carbon from the end of the fatty acid.
Linoleic acid (18:2), the shortest chain omega-6 fatty acid is an essential fatty acid. Arachidonic acid (20:4) is a physiologically significant n-6 fatty acid and is the precursor for prostaglandins and other physiologically active molecules.
Dietary sources of omega-6 fatty acids include:
cereals
whole-grain breads
most vegetable oils
eggs and poultry
baked goods.[2]
Omega-6 fatty acids in sunflower oil and safflower oil also reduce the risk of cardiovascular disease, but can contribute to allergies and inflammation.
Omega-9
Omega-9 fatty acids are a class of unsaturated fatty acids which have a C=C double bond in the ω-9 position.
Two commercially important ω-9 fatty acids are:
Oleic acid (18:1 ω-9) which is a main component of olive oil and other monounsaturated fats.
Erucic acid (22:1 ω-9) which is found in rapeseed, wallflower seed, and mustard seed.
Others are
eicosenoic acid
mead acid
nervonic acid
Saturated FAT
Saturated fat is fat that consists of triglycerides containing only saturated fatty acids. Saturated fatty acids have no double bonds between the carbon atoms of the fatty acid chain; hence, they are fully saturated with hydrogen atoms. There are several kinds of naturally occurring saturated fatty acids, their only difference being the number of carbon atoms - from 1 to 24. Some common examples of saturated fatty acids are butyric acid with 4 carbon atoms (contained in butter), lauric acid with 12 carbon atoms (contained in breast milk, coconut oil, palm oil), myristic acid with 14 carbon atoms (contained in cow milk and dairy products), palmitic acid with 16 carbon atoms (contained in meat) and stearic acid with 18 carbon atoms (also contained in meat and cocoa butter).
Foods that contain a high proportion of saturated fat are butter, ghee, suet, tallow, lard, coconut oil, cottonseed oil and palm kernel oil, dairy products (especially cream and cheese), meat, and some prepared foods.
Interesterified FAT
Interesterified fats are oils (such as soybean oil) that have been chemically modified. This is done in order to make them more solid, less liable to go rancid and more stable for applications such as deep frying. The interesterification process is used as an alternative to partial hydrogenation, which results in trans fats. However, research indicates that interesterified fats may pose health risks, some greater in magnitude than trans fats.
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