Recently I have been taking an in-depth look at dietary fats. So far I have covered saturated fats and monounsaturated fats. Today I am going to be looking at polyunsaturated fats in greater detail.
WHAT IS POLYUNSATURATED FAT?
Fats are all made from a chain of carbon and hydrogen atoms. With saturated fats all the carbon atoms are bonded to hydrogen atoms. With unsaturated fats there are one or more double bonds between the carbon atoms which prevent them from being fully bonded to hydrogen atoms. So in other words saturated fats are ‘saturated’ with hydrogen atoms whilst unsaturated fats are not fully saturated with hydrogen atoms so they are ‘unsaturated’.
There are two main types of unsaturated fat; monounsaturated and polyunsaturated. Monounsaturated fats have just one double carbon bond hence the name ‘mono’ which means one. Polyunsaturated fats have two or more double carbon bonds hence the name ‘poly’ which means many.
Polyunsaturated fats have a very low melting point and stay liquid at room temperature. There are two main types which each have a double carbon bond in different positions:
Omega 3 Essential Fatty Acids:- Omega 3s have a double carbon bond 3 carbons away from the methyl group at the end.
Omega 6 Essential Fatty Acids:- Omega 6s have a double carbon bond 6 carbons away from the methyl group at the end.
WHICH FOODS CONTAIN POLYUNSATURATED FATS?
Polyunsaturated fats can be sourced from various foods. Unlike other fats, polyunsaturated fats are essential fatty acids (EFAs). This means they cannot be produced by your body and must be sourced from food. Below are some examples of the best dietary sources of omega 3 and omega 6 essential fatty acids.
1) OMEGA 3 ESSENTIAL FATTY ACIDS:
– Cold water fish such as anchovies, herring and salmon.
– Dairy products such as cheese and milk from grass fed cows.
– Eggs.
– Flaxseed oil.
– Meats such as grass fed beef and lamb.
2) OMEGA 6 ESSENTIAL FATTY ACIDS:
– Nuts.
– Oils such as corn oil, soybean oil and sunflower seed oil.
– whole grain products such as bread and cereal.
ARE POLYUNSATURATED FATS HEALTHY?
Until recently dietary fat was seen as the least healthy of the macronutrients. Carbohydrates were seen as the body’s preferred energy source whilst protein was seen as the body’s building blocks. However, dietary fat was negatively associated with increased body fat levels.
More recently research has suggested that dietary fat actually has a number of health benefits. Polyunsaturated fats are no exception to this. The omega 3 essential fatty acids found in this type of fat have been linked with improved brain health, reduced risk of cancer, reduced risk of heart disease and more. The omega 6 essential fatty acids found in this type of fat also have multiple health benefits such as strong bones and healthy skin.
However, the research on polyunsaturated fats is not all good. Other studies suggest that excess consumption of omega 3 and omega 6 essential fatty acids can lead to a number of complications. Below I will be outlining both the benefits and risks associated with polyunsaturated fat consumption.
WHAT ARE THE BENEFITS OF POLYUNSATURATED FATS?
OMEGA 3 ESSENTIAL FATTY ACID BENEFITS:
1) IMPROVED BRAIN HEALTH:- Omega 3 essential fatty acids can improve brain health in a number of ways. Research suggests that they can protect you from Alzheimer’s disease (a disease that destroys your brain cells). They are also used by your brain to produce cell membranes, signal pathways and other neurological systems.
2) HEALTHY VISION:- Omega 3 essential fatty acids are used to build retinal tissue and therefore support healthy vision. Failure to consume adequate levels can lead to vision problems.
3) ABSORPTION OF FAT SOLUBLE VITAMINS:- Omega 3 essential fatty acids are required for the proper absorption of vitamins A, D, E and K. These fat soluble vitamins have a number of health benefits which include assisting in the absorption of essential minerals, helping your blood clot, providing protection from damaging free radicals and supporting healthy vision.
4) REDUCED RISK OF HEART DISEASE:- Omega 3 essential fatty acids can reduce blood triglyceride (a type of fat linked with heart disease) levels. They can also prevent blood clots and reduce the growth rate of fatty plaques on the arteries which both help lower your risk of heart disease.
5) REDUCED INFLAMMATION:- Omega 3 essential fatty acids are linked with reduced inflammation and can minimise the pain associated with conditions such as arthritis, asthma and eczema.
6) REDUCED CANCER RISK:- A number of studies have linked consumption of omega 3 essential fatty acids with a reduced risk of contracting cancer. In particular they have been linked with a lower risk of breast cancer, colon cancer, prostate cancer.
OMEGA 6 ESSENTIAL FATTY ACID BENEFITS:
1) STRONG BONES:- Consumption of omega 6 essential fatty acids enhances your body’s ability to absorb calcium (a mineral that strengthens your bones and teeth). Not consuming enough has been linked with bone loss and osteoporosis (a condition where your bone density is reduced).
2) HEALTHY SKIN:- Omega 6 essential fatty acids play a key role in the formation of healthy skin cell membranes. It has also been linked with relieving certain skin conditions such as eczema and dermatitis.
3) REDUCED PREMENSTRUAL SYNDROME (PMS) SYMPTOMS:- Omega 6 essential fatty acids are linked with reducing a number of symptoms associated with PMS. Research has shown they can relieve bloating and breast tenderness.
WHAT ARE THE HEALTH RISKS OF POLYUNSATURATED FAT?
OMEGA 3 ESSENTIAL FATTY ACID HEALTH RISKS:
1) BLOOD THINNING:- Consuming high levels of omega 3 essential fatty acids can make your blood thin. This can lead to a number of problems including abnormal bleeding and excessive bruising.
2) ELEVATED BLOOD GLUCOSE LEVELS:- Some research suggests that omega 3 essential fatty acids can raise blood glucose levels which can cause problems for people who suffer from diabetes.
OMEGA 6 ESSENTIAL FATTY ACID HEALTH RISKS:
1) INTERFERENCE WITH OMEGA 3 ESSENTIAL FATTY ACIDS:- Consuming too much omega 6 essential fatty acid prevents your body from breaking down omega 3 essential fatty acids properly. This means that excess consumption negates all the benefits associated with consuming omega 3 essential fatty acids.
2) INCREASED CANCER RISK:- Whilst consumption of omega 3 essential fatty acids is linked with a lower cancer risk, eating too much omega 6 essential fatty acid can contrastingly increase your cancer risk. Research suggests that omega 6 essential fatty acids stimulate the growth of both breast cancer and prostate cancer cells.
3) DEPRESSION:- Research has linked high levels of omega 6 essential fatty acids in the brain with depression.
4) INCREASED HEART DISEASE RISK:- Whilst omega 3 essential fatty acids can help prevent internal blood clots, excess consumption of omega 6 essential fatty acids does the opposite. These blood clots prevent blood from getting to the heart and can ultimately lead to heart attacks.
5) EXCESSIVE INFLAMMATION:- As discussed above omega 3 essential fatty acids help lower inflammation in the body. However, eating too many omega 6 essential fatty acids undoes this good work and causes excessive inflammation. High levels of inflammation can lead to much more serious health conditions such as cancer, diabetes and heart disease.
HOW CAN I ENJOY THE BENEFITS AND AVOID THE RISKS?
Polyunsaturated fats are essential for good health. However, you can get too much of a good thing. The health risks associated with polyunsaturated fats are caused by excessive consumption. In particular, the health risks linked to omega 6 essential fatty acids are caused by consuming too much of this fat type in comparison to omega 3 essential fatty acids.
Fortunately, these health risks can be avoided by simply making the right dietary choices. Our modern diets generally contain extremely high levels of omega 6 essential fatty acids and relatively low levels of omega 3 essential fatty acids. By choosing foods that address this balance you can avoid all the health risks whilst enjoying the benefits.
Therefore, where possible avoid processed foods as these contain high levels of omega 6 essential fatty acids and low levels of omega 3 essential fatty acids. Also make sure that fish is a regular part of your diet as this is one of the richest natural sources of omega 3 essential fatty acids. Finally, stop using vegetable oils and products that contain vegetable oils. Not only do these add high levels of omega 6 essential fatty acids to your diet but they are not shelf stable and quickly go rancid when exposed to light or oxygen.
POLYUNSATURATED FATS SUMMARY
Like so many things in life the key to polyunsaturated fats is balance. If you make sure that you consume relatively equal amounts of omega 3 and omega 6 essential fatty acids you can ensure that your body is operating optimally.
Now I want to hear from you guys. Is your polyunsaturated fat intake relatively balanced? Are there any benefits I have missed? Let me know by leaving a comment.
Sources:
Benefits of Omega 3
Omega 6 Benefits
Polyunsaturated Fats (Wikipedia)
Polyunsaturated Fat and Dieting (AnneCollins.com)
The Potential Health Risks of Polyunsaturated Fatty Acids (Omega3FattyAcids.co.uk)