The three macronutrients that we need in our diets are protein, carbohydrates, and fat. During digestion, enzymes in the gut break down the most plentiful fat in our diet, triglycerides, into fatty acids and a molecule called glycerol. Once absorbed these molecules reassemble into triglycerides, and as they cannot move freely through the watery bloodstream, they combine with protein and cholesterol to form lipoproteins. Extra calories, sugar, and alcohol also gets converted into triglycerides in the liver; transported in lipoproteins and stored in fat cells in the body.
Two of these fatty acids, omega-3 and omega-6, are essential to survive – we need to obtain both of them from breast milk initially and after that from our diet, as the body is unable to make its own. These two essential fatty acids have different functions and effects in the body. Omega-3 has been widely studied for its attributes in aid of good health.
Fats in food:
Fat is an essential nutrient that is used to build hormones, cell membranes, and is a major component of brain tissue. Fat is also used as fuel to provide energy for body cells, and excess fat gets stored in the fat cells as a reserve source of energy. Certain vitamins are fat soluble, such as vitamins A, D, E, and K, and only gets absorbed if there is fat in your diet. Fat is high in calories and excess amounts of unhealthy fats can cause a range of health problems.
The three major types of dietary fats in food can affect one’s health differently. In particular, they have different effects on the fluidity, and thus functioning, of individual cell membranes in the body.
- Unsaturated fats – these are the healthier kind of fat and consist of monounsaturated fat (found in avocados, nuts and oils such as olive oil and canola oil), polyunsaturated fat (found in most vegetable oils), and omega-3 fatty acids (found in oily fish such as anchovies, sardines, and pilchards). Healthier fats have a lower melting point than the unhealthy fats, which are solid at room temperature – healthy fats are a liquid at room temperature.
- Saturated fats – this type of fat is found in meat and animal products (butter, cream and cheese) and a high consumption can raise blood LDL levels and increase the risk of heart disease.
- Trans fats – This type of fat is created when vegetable oils are hydrogenated (hydrogen atoms are added to the fat molecule) to become more solid and spreadable at room temperature, and are found in margarine, baked goods, and commercially prepared fried foods and snack foods. Trans fats are known to raise LDL levels and increase the risk of heart disease.
Fatty acids:
Fatty acids are the building blocks of triglycerides in our bodies and play an important biological role as an essential component of the membrane of cells. Fat also provides energy when energy from carbohydrates is running low. The human cell consists of the membrane, the cytoplasm, and the nucleus. The membrane, consisting of a bilayer of fats and proteins, forms the barrier that protects the cell and plays a role in transporting nutrients in and out of the cell.
The type of fatty acid affects the fluidity of cell membranes. Saturated fatty acids have a straight rigid chain and form a more rigid and viscous membrane, while unsaturated fatty acids form more a more flexible and fluid membrane. This explains why polyunsaturated fatty acids such as omega-3 have, for example, a beneficial effect on arterial and venous walls by increasing their flexibility, with positive effects in cardiovascular diseases. This fluidity also has a positive effect on nerve cells by increasing their permeability and aiding signal transmission, which is relevant for proper functioning of brain activity.
Omega-6 is the second essential fatty acid, also needed for maintaining fluidity of cell membranes, but unfortunately highly concentrated in popular foods in the modern diet, leading to a ratio of omega-6 to omega-3 as high as 15:1, instead of the healthy 1:1 ratio. Too much omega-6 can increase inflammation in the body, a risk factor for various medical conditions.
Sources of omega-3 fatty acids
Fish, especially oily fish, are the best food sources of omega-3 fatty acids, and it is also found in some plants. Two members of omega-3 fatty acid family found in fish are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), while the parent omega-3, called alpha-linolenic (ALA), is found in chia seeds, seaweed and algae, hemp seeds, flax seeds, walnuts, edamame and soyabean oil, and leafy green vegetables, such as spinach, avocado and broccoli. ALA does not provide the same health benefits as EPA and DHA, as the body is not always able to convert ALA to EPA and DHA efficiently, with only about 10% of intake being converted.
Examples of popular oily fish that are rich in omega-3 fat, in gram per 100 gram portion, are mackerel (2,5 g); lake trout (2 g); salmon (1,8 g); anchovy (1,4 g); longfin tuna (1,5 g); bluefin tuna (1,2 g); and white meat canned tuna (0,5 g).
However, the way the fish is prepared makes a huge difference. Broiled, grilled or baked fish is the healthy option, while fried fish cancels out the benefits of fish oil, due to the unhealthy fats that are normally used for deep frying.
Health benefits associated with omega-3:
Essential fatty acids, such as omega-3, are key components in the fluidity of cell membranes and in anti-inflammatory processes. Omega-3 has been widely studied for its effects on inflammation and immune function as a potential therapy for a variety of medical conditions.
Cardiovascular health – earlier studies (2010) on diets rich in seafood have shown moderate evidence that people who eat seafood more than once a week have a lower risk to die of heart disease than people who rarely eat seafood. While seafood should be included in a heart-healthy diet, research did not find strong evidence that omega-3 supplements will protect against heart disease.
Recent studies (2018) by Harvard Medical School found that while omega-3 supplements did not seem to protect most healthy people against future heart problems, it did benefit people who eat less than 1,5 servings of fish per week or rarely eat fish. However, people who have already experienced heart problems or had other significant risk factors for heart disease, may have a 25% reduction in the risk of dying from heart disease, or having a heart attack or stroke, when taking a daily high dose (4-gram) of omega-3 supplements.
Harvard concluded that healthy people with low risk of heart disease, who eat at least two servings a week of fatty fish, probably do not need to take omega-3 supplements as protection against heart disease. You will not only get omega-3 fatty acids from the fish, but the fish would probably replace less healthy food such as red meat, processed foods, or refined grains. Omega-3 supplements may benefit people who consume little or no fish.
Inflammation – the body’s natural inflammatory response is a normal reaction to fight infections and injuries. Long term chronic inflammation, however, contributes to a wide range of chronic illnesses, such as metabolic- and heart diseases. Omega-3 fatty acids can reduce the production of molecules and substances that results from chronic inflammation and the anti-inflammatory properties of omega-3 is well documented.
A 2017 study by the Norwegian University of Science and Technology indicated that macrophages (immune cells living in all tissues and organs) play an important role in coordinating the inflammatory reactions in the body. Sensors on their surface convert the signals they receive from their environment into the secretion of hormone-like signaling substances that control the inflammatory reactions in the body. The study found that omega-3 fatty acids can dampen many inflammatory mechanisms within the macrophages.
Infant development – getting ample omega-3’s during pregnancy and for the growing infant is important for brain growth and development, as well as development of the eyes. Around 40% of the polyunsaturated fatty acids in the brain and about 60% in the retina of the eye consists of DHA, a member of the omega-3 family.
Autoimmune diseases – autoimmune disease results from the immune system mistaking healthy cells for foreign ones and attacking them, for example when the immune system attacks the insulin producing cells in the pancreas, resulting in type 1 diabetes. Amongst the fatty acids, omega-3 have the most potent immunomodulatory activities and can help the body to fight type 1 diabetes as well as other autoimmune diseases.
Mental decline – omega-3 fatty acids are abundant in the membranes of brain cells, where it preserves cell membrane health and facilitate communication between brain cells. Lower levels of DHA in the blood of older adults have been associated with smaller brain size, which indicates accelerated brain aging. Age related decline in brain function is unavoidable, but studies have indicated that omega-3 supplements are beneficial when taken in the early stages of age-related mental decline. However, no benefits were found in advanced stages of mental decline, such as in Alzheimer’s disease.
Depression – studies have indicated that regular omega-3 intake, and in particular, EPA, of the omega-3 family, may well be a promising natural treatment for mood disorders and help to treat or prevent depression and anxiety. It is deemed possible by the ability of omega-3 fatty acids to easily travel through the brain cell membrane and interact with mood-related molecules inside the brain, as well as the known anti-inflammatory properties of omega-3.
Eye health – the DHA omega-3 fatty acids are a major structural component of the retina of the eye. An ample intake of omega-3 has been linked to a reduced risk of macular degeneration.
Metabolic syndrome – this is a cluster of conditions that occur together and increase the risk of heart disease, stroke, and type 2 diabetes. These conditions include high blood sugar levels, increased blood pressure, abnormally high cholesterol levels, pro-inflammatory markers, insulin resistance, and excess body fat around the waist. Omega-3 fatty acids can help to reduce inflammation and insulin resistance and have been shown to reduce levels of triglycerides and LDL cholesterol.
ADHD – studies have found that children with attention deficit hyperactivity disorder (ADHD) have lower levels of omega-3 fatty acids in their blood stream and supplementation with omega-3 can reduce the symptoms of ADHD, such as improving attention and reducing hyperactivity, aggression, and impulsiveness.
Asthma – omega-3 intake has been associated with a lower risk of asthma in children and young adults. Asthma is caused by inflammation and swelling in the airways of the lungs and is a chronic lung disease with symptoms such as wheezing, shortness of breath and coughing. Studies found that omega-3 supplements can reduce the production of the antibodies (IgE) that cause allergic reactions in people with milder cases of asthma, but was less effective for people with more severe cases of asthma, who used steroid drugs to reduce the symptoms.
Arthritis – Studies have shown that people with rheumatoid arthritis who took omega-3 supplements experienced a reduction in joint pain, although not in joint damage. One of the studies revealed that omega-3 converts into compounds that are much more powerful than normal fatty acids, including compounds called resolvins, which helps to bring the body’s inflammatory response to an end. Resolvins are lipid (fat) mediators with anti-inflammatory properties.
Sleep – low levels of omega-3 are linked to lower levels of the sleep related hormone melatonin, while omega-3 supplements may improve the length and quality of sleep.
Skin – cell membranes make up a large part of your skin and the EPA fatty acids in omega-3 can play a role in keeping the skin healthy, prevent premature aging, and helping to prevent sun damage.
Omega-3 fatty acids are important.
Omega-3 polyunsaturated fatty acids have proven health benefits, due to their positive effect on the mechanism of action at cellular level, and anti-inflammatory qualities. Omega-3 fatty acids are vital for optimal health and eating fatty fish at least twice a week ensures sufficient intake, otherwise a good quality supplement is recommended daily.
Sources:
Should you be taking an omega-3 supplement? Published April 2019. Harvard Women’s Health Watch. Harvard Medical School. (www.health.harvard.edu)
17 Science-based benefits of omega-3 fatty acids. Published 15 October 2018. Healthline. (www.healthline.com)
Omega-3 fatty acids. Published online. Cleveland Clinic. (www.my.clevelandclinic.org)
7 Things to know about omega-3 fatty acids. Published online. National Center for Complimentary and Integrative Health. National Institutes of Health. USA. (www.nccih.nih.gov)
Omega-3 fatty acids. EPA and DHA: health benefits throughout life. Published 5 January 2012. Advances in Nutrition. (An international review journal.) Oxford University Press. (www.academic.oup.com)
Definition: fatty acids. Published online. KidsHealth. (www.kidshealth.org)
Importance of fatty acids in physiopathology of human body. Published 21 June 2017. IntechOpen. (Academia and industry created content.) (www.intechopen.com)
Evidence points to fish oil to fight asthma. Published 8 February 2017. University of Rochester Medical Center. New York. (www.urmc.rochester.edu)
The benefits of omega-3 fatty acids for arthritis. Published 29 July 2015. Arthritis Foundation. USA. (www.arthritis.org)
Understanding how omega-3 dampens inflammatory reactions. Published 23 August 2017 by the Norwegian University of Science and Technology, in ScienceDaily. (www.sciencedaily.com)
HEALTH INSIGHT