The Effects of Fatty Foods and Fats - Saturated, Unsaturated, Polyunsaturated and Trans Fats - on the Human Body
Energy is available to us through what we eat and the foods that we eat are essentially rich in carbohydrates, protein or fats. Protein and carbohydrates provide about 4 calories per gram while fats provide 9 calories per gram.
Besides being a rich source of energy, some other functions that fats carry out in the body are:
- They help in the absorption and transportation of the fat-soluble vitamins - Vitamins A, D, E and K.
- They also protect our vital organs from harmful chemicals as fats store these chemicals if they reach harmful levels in the blood. But only till the time they are removed from the body.
- Fats also have a role to play in the cell membrane and hormone formation.
- They are necessary for milk production and the healthy growth of a child.
- They are needed to develop the brain and a healthy nervous system.
- They protect the body from the vagaries of weather.
Fats can be solid or liquid at room temperatures. All fats are insoluble in water but soluble in organic solvents. Fats are composed of fatty acids and glycerol.
Types Of Fats
Broadly, fats can be classified into 2 types :
- Saturated Fats
- Unsaturated Fats
Unsaturated fats are further subdivided into 3 types :
- Monounsaturated Fats
- Polyunsaturated Fats
- Trans Fats
Trans fats, however, are a product of the hydrogenation of oils and are man-made. For example, margarine contains trans fats.
Classification Of Fats
Fats are classified on the basis of :
- The length of the fatty acids.
- Their saturation levels (Carbon atoms with hydrogen atoms).
Classification On The Basis Of The Length Of The Fatty Acids
Fats have been classified into 4 types on this basis :
- Short Chain Fatty Acids - With a chain length of 4 to 6 carbon atoms.
- Medium Chain Fatty Acids - With a chain length of 8 to 12 carbon atoms.
- Long-Chain Fatty Acids - With a chain length of 14 to 18 carbon atoms.
- Very Long-Chain Fatty Acids - With a chain length of 20 to 24 carbon atoms.
Short Chain Fatty Acids
These fats are saturated and antimicrobial. They do not need bile salts for digestion and are directly absorbed to provide energy fast. Thus these fats are not stored and hence do not increase weight. They also benefit the immune system.
Medium Chain Fatty Acids
These are also microbial in action, absorbed directly to give energy fast and thus not stored as fat. They increase the metabolism rate and hence contribute to weight loss. They too benefit the immune system.
They are found in tropical oils like coconut oil and butterfat.
Long Chain Fatty Acids
These can be saturated, monounsaturated and polyunsaturated. They are difficult to digest and thus are more strenuous on the liver and the digestive system. They need specific digestive enzymes for easier digestion. They are stored as fat and deposit on the arteries as cholesterol.
Most common seed oils and vegetable oils are long-chain fatty acids.
For example :
- Stearic acid is a saturated fatty acid found in beef and mutton tallow.
- Oleic acid is a monounsaturated fatty acid found in olive oil.
- Palmitoleic acid is a monounsaturated fatty acid found in animal fats.
- Gamma linoleic acid is a polyunsaturated fatty acid found mostly in plant oils like black currant oil, primrose oil etc.
Very Long Chain Fatty Acids
These fats are highly unstable as they are highly unsaturated. Some people can make these fatty acids from the essential fatty acids they consume but some cannot. Those whose body cannot have to obtain it from animal organs, egg yolks, butter and fish oils.
Some of these fatty acids are needed for the production of prostaglandins(hormones) and some play a role in maintaining healthy nerves and a healthy nervous system.
Classification Of Fats On The Basis Of Saturation
On the basis of their degree of saturation with hydrogen atoms, fats are classified as:
- Saturated fats
- Monounsaturated fats
- Polyunsaturated fats
These are explained below.
1. Saturated Fats
These fats have all the carbon atoms attached to the hydrogen atoms. For this reason, saturated fats remain very stable on heating and do not go rancid easily. They are mostly solid at normal temperatures. Animal fats are saturated and so are some tropical oils like coconut and palm oil. These oils can be used to cook at high temperatures due to their stability.
All oils and fats from animal or vegetable sources are a combination of saturated fatty acids, monounsaturated fatty acids and polyunsaturated acids.
2. Monounsaturated Fats
The monounsaturated fats are short of just 2 hydrogen atoms and have 1 double bond. Monounsaturated fatty acids are made by the body from saturated fatty acids as they are needed by the body.
They are liquid at normal temperature and are stable so they do not oxidise or turn rancid easily. Therefore they can be used in cooking but not at high temperatures or for frying. Olive oil is best eaten as cold salad oil.
Our main consumption of monounsaturated fatty acids is in the form of oleic acid and this is found in olive oil, canola oil, sesame oil, almond oil, peanut oil, cashews, almonds, pistachios, peanuts, peanut butter, avocado.
Interestingly, almost 50% of fat in beef is monounsaturated.
3. Polyunsaturated Fatty Acids
The polyunsaturated fatty acids are short of 4 or more hydrogen atoms. Thus there are 2 or more pairs of double bonds.
The linoleic acids, Omega-6 and Omega-3 are the two essential polyunsaturated fatty acids that the body does not make and thus these have to come from our food. They remain liquid even under refrigeration. They are extremely unstable and turn rancid very fast. For this very reason, polyunsaturated oils should not be heated or used in cooking.
Examples of high polyunsaturated oils are corn oil, sunflower oil, soy oil, safflower oil, cottonseed oil, seafood and margarine.
Evidence indicates that excess consumption of polyunsaturated fatty acids, increase the risk of cancer. Also, commercial oils containing a high percentage of polyunsaturated fatty acids, have a much higher proportion of Omega-6 to Omega-3 fatty acids as opposed to the ideal 1:1 ratio between the two. This disparity in the ratio can contribute to arthritis, diabetes and heart disease.
Why Polyunsaturated Fats Are Harmful?
We have been led to believe that polyunsaturated fats and oils are good while saturated fats are bad. This is incorrect as can be reasoned below.
It has been found that excess consumption of polyunsaturated oils is the cause of the increase in heart disease and cancer, damage to organs like the liver, lungs etc, digestive problems, issues with the immunity system, lack of proper growth and increased weight gain.
The reason for this is not difficult to see. The polyunsaturated fats are unstable and oxidize readily when heated in the presence of moisture and oxygen as during the process of cooking or processing. Oxidation creates free radicals and they react with the cell membranes, red blood cells, tissues, blood vessels, organs etc, in fact with everything in the body giving rise to various diseases and conditions like plaque development in the blood vessels, tumours in organs, cancer, heart disease, etc.
As most polyunsaturated fats are in the form of Omega 6 linoleic acid with a little Omega 3 linoleic acid this creates an excess of Omega 6 and thus an imbalance in the ratio of Omega 6 to Omega 3. This increases the risk of developing blood clots, high BP, inflammations, deficient immune response, cancer etc.
Most vegetable oils in the market are deficient in Omega-3 fatty acids but are overly concentrated in the Omega-6 fatty acids upsetting the critical Omega-6 to Omega-3 ratio.
Deficiency of Omega-3 leads to conditions like asthma, heart diseases etc. Omega-3 is needed for many cell functions and hormones' production.
Saturated Fats-They Are Good
Benefits Of Saturated Fats
- Saturated fatty acids are needed for the formation of cell membranes as they provide the necessary rigidness.
- They protect the liver from toxins and alcohol. They also lower the levels of Lipoprotein A, a substance whose increased levels in the blood makes on more at risk for heart disease and strokes.
- They are needed to fully absorb calcium for optimum bone health. A minimum of 50% of the dietary fats should be saturated for this.
- They improve the immune system.
- Essential fatty acids can be fully utilized only in the presence of saturated fats.
- The microbial activity of these short and medium-chain fatty acids in the digestive tract protects us.
- Medium-chain fatty acids, those found in saturated fats, like stearic and palmitic acid are beneficial for the body in times of stress.
Research indicates that of the artery-clogging fats, only 26% are saturated. The rest is unsaturated with more than 50% being polyunsaturated.
Coconut oil which is a tropical vegetable oil has a very high percentage of saturated fats - over 90%. Read my hub on Benefits of coconuts at the link provided below.
- Health Benefits Of Coconut, Coconut Oil, Coconut Milk And Coconut Water
Coconut is called a wonder food since it is almost a perfect meal. In the Vedas it has been called 'Kalpa Vriksha' meaning the tree which provides all necessities of life. It is used in many rituals and ceremonies apart from its use as food in a vari
Coconut Oil - The Healthy Saturated Fat
Trans fat is a man-made fat that is produced when vegetable oils are partially hydrogenated by passing hydrogen gas under pressure through the vegetable oil in the presence of a catalyst like nickel or platinum for some hours.
Hydrogenation makes the oils solid, improves the shelf life, the look, feel and texture of a product. However, during this process, the natural components are converted into many different compounds. These are trans fatty acids or trans fat.
Trans fat is found in margarine, shortening, fried foods, bakery stuff etc.
Harmful Effects Of Trans Fat
- They increase LDL or bad cholesterol. and lower HDL or good cholesterol.
- They clog the arteries, cause diabetes and increase the risk of heart disease.
- They affect the immune system negatively.
- They give rise to reproductive problems.
- They cause obesity.
Tip To Find Out How Much Trans Fat Exists In a Food
If the product label has shortening or partially hydrogenated oil as listed as ingredients, you can assume it contains trans fat. The higher up this ingredient is in the list, more is the trans fat.
How To Find Out How Much Trans Fat Is In A Product
Make a sum total of all the different amounts of fat like saturated, monounsaturated, polyunsaturated provided in the list on the product label. Then read the total fat content. The difference between the two is mostly trans fat which is all the more correct if partially hydrogenated oil is listed in the top few ingredients.
Did you have preknowledge about the information provided in this hub?
This researched information is for educational purposes only. You are advised to take the advice and opinion of your health practitioner or medical doctor before you embark on any new health regime.
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This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
© 2012 Rajan Singh Jolly