According to the World Health Organization, cardiovascular diseases remain the leading cause of morbidity and mortality worldwide. It accounts for 31% of global deaths every year. Epidemiologic studies have established a link between regular eating of fish and lowering heart attack-related deaths. In this article I have tried to address the common questions about Omega 3 fatty acids and how they potentially can improve human health.
What are the different types of fatty acids?
The most common fat in the human diet is a triglyceride. This is a glycerol molecule combined with 3 fatty acids. The body breaks down fats during digestion, and this generates fatty acids. There are three (3) types of fatty acids, and they are classified according to their molecular structure. Basically they are classified by the double bonds in their structure.
- Saturated. Saturated fats have a linear structure and no double-bond.
- Monounsaturated. Monounsaturated fats are bent structures that have a double bond.
- Polyunsaturated. Polyunsaturated fats have a more bent configuration and have multiple double bonds.
The structural configuration of the fatty acids affects the lipid structures. Saturated fats produce solid fats at room temperature. Butter and coconut oil are examples of saturated fats. On the other hand, monounsaturated and polyunsaturated fats are referred to as oils, since they remain in liquid form at room temperature. There is a good table of common fats and oils and what they are made up of here.
What is the difference between Omega 6 and Omega 3?
The omega number determines the position of the double bond in the molecule. Polyunsaturated fats can be Omega 6 or Omega 3. Both of the fatty acids improve heart health and cholesterol levels. However, they differ in chemical configuration. From the tail of the carbon chain, Omega 3 has the final double bond at the third carbon atom (N-3 position), while Omega 6 has the final double bond at the six-carbon atom (N-6 position).
Further classifications of Omega 3 fatty acids are Eicosapentaenoic Acid (EPA) , Docosahexaenoic Acid (DHA), and Alpha Linolenic Acid (ALA). They are limited diet sources of Omega 3. However, they are abundant in flaxseed, green leafy vegetables, and canola oils. They are also richly found in cold-water fishes and fish oils. On the other hand, Omega 6 fatty acids can be Linoleic Acid (LA), Gamma Linolenic Acid (GLA), and Arachidonic Acid (AA). They are common in the Western diet which tends to have less fish and more highly processed food products. Vegetable oils and seeds also hold Omega 6 fatty acids.
What is the story about the Greenland Eskimos and heart attacks?
The Greenland Eskimos survive on a largely carnivorous diet. Their diet comprises food with fewer carbohydrates and more proteins. Yet, despite a high-meat diet and very few plant foods, indigenous Eskimos rarely contract chronic health conditions like heart disease and cancer.
Researchers from the American Journal of Clinical Nutrition described the Eskimo diet as predominantly seal and fish – and rich in marine oils. They suggest that the rarity of the heart disease in Eskimos is attributed to the anti-thrombotic property of polyunsaturated fatty acids. Though, in the current time, their nutrition has gone downhill since the introduction of the contemporary diet and the steady decline of marine mammals.
What are the uses of fatty acids in the body?
Nutritionists say that 30% of our daily caloric intake should come from fats. Keto fanatics would probably dispute that though!! Fats are a component of a healthy diet. Fatty acids are lipid components that have simple and complex biological functions. They have essential roles in the body – just like the other macronutrients.
Not all fatty acids are produced by the body. Thus, they need to be sourced from the food we eat. The following summarizes the functions of fats:
- Fats are a fundamental source of energy.
- Fats are needed to absorb vitamins. Vitamin A, D, and E are fat-soluble vitamins.
- Fats play a role in developing the nervous system, especially in the first 18 months of life.
- Fats are essential for performing bodily processes such as hormone production, blood clotting, and adrenal activity.
What are EPA and DHA?
EPA stands for eicosapentaenoic acid.
DHA stands for docosahexaenoic acid
They are both long-chain polyunsaturated Omega-3 fatty acids. The body cannot produce EPA and DHA in significant amounts. Thus, they are commonly acquired from seafood and fish oil.
From the structural point of view, EPA has a shorter chain than DHA. The longer chain of DHA makes it more susceptible to damage as a result of oxidation. This explains why fish oils and other related products have a shorter shelf life. Both EPA and DHA play a role in maintaining and developing brain health. Pregnant women who are deficient in DHA can have infants with brain and eye complications. On the other hand, lack of EPA is associated with mental health problems and mood disorders such as depression.
How much EPA and DHA do we get in our diets?
An average person consumes 150 mg of EPA and DHA combined daily from their food. This is a small fraction compared to what Greenland Eskimos get from their daily diet, which can be up to 7000 mg of EPA/DHA daily!
What do Omega 3 fatty acids do to blood cholesterol?
Increased consumption of Omega 3 fatty acids may have atheroprotective properties. It is a common misconception that Omega 3 fatty acids increase LDL levels. Recent evidence suggests the opposite, in fact the have a small LDL lowering effect. Omega 3 fatty acids, displace the number of saturated fats found in the cellular membrane. The activity influences the low-density lipoproteins (LDL) receptors which are situated in the cellular (liver) membranes. The decreasing presence of saturated fats in the membrane increases the efficiency of LDL receptors by eliminating LDL particles from the blood. As a result, the cholesterol level is lowered. Furthermore, Omega fatty acids cause a slight increase in high-density lipoprotein (HDL) which is the ”good cholesterol” and mitigates the risk of heart disease. In addition they markedly lower triglyceride levels.
What was the REDUCE-IT study?
The REDUCE-IT study was a global, double-blind, randomized clinical research study that investigated the potential cardioprotective benefit of Vascepa (Icosapent Ethyl). Vascepa is a pharmaceutical grade ethyl ester of EPA.
The trial enrolled people with established cardiovascular disease or high CV risk (already on a statin) and who had a fasting triglyceride level of 135 to 499 mg per deciliter (1.52 to 5.63 mmol per liter) and a low-density lipoprotein cholesterol level of 41 to 100 mg per deciliter (1.06 to 2.59 mmol per liter). The participants were randomly allocated to receive treatment either a placebo (mineral oil) or 4g of Vascepa per day.
Vascepa was associated with a reduction in heart attack, stroke and death. However, it also increased the risk of atrial fibrillation. The trial has been criticised due to the choice of placebo – mineral oil. Some critics think that this could have caused events and made Vascepa look more beneficial than it actually is.
Is DHA good for your health?
While EPA is called the ”heart-healthy” fatty acids, DHA is the ”brain booster”. DHA is the essential fatty acid for the nervous system, particularly the brain. Its long-chain polyunsaturated Omega 3 fatty acids play a role in the growth and development of the brain and retina. DHA is the precursosr for neuroprotectin. The fatty acids also benefit the older population by inhibiting brain aging and counteracting brain ischemia that causes neurodegenerative disorders. Furthermore, deficiency of DHA contributes to learning deficiencies, fetal alcohol syndrome, personality disorder, cystic fibrosis, and phenylketonuria.
What are the best fish to eat for EPA and DHA?
Generally, marine life is the best source of EPA and DHA. They are readily available from water plants, fish, and other seafood. Both EPA and DHA are essential in promoting health and preventing health diseases – although food sources have variable levels of EPA and DHA.
Fatty fish such as mackerel, salmon, and tuna hold high quantities of DHA. DHA is low in meat and poultry products. On the other hand, fish oil supplements are the richest source of EPA. People can also get EPA by consuming saltwater fish and freshwater fish. Fish oil supplementation is not suitable for vegetarians. So, there are now algal oils available in the market as an alternative source for fish oils.
How much Omega-3 do I need to take per day?
Omega 3 fatty acids, are important for numerous reasons and we have limited dietary sources; thus, supplementation may be necessary in some people. They may have some cardiovascular benefit, however a recent analysis of the STRENGTH trial has brought this into question.
The minimum daily requirement for Omega 3 fatty acids is thought to be between 1,200 to 1,600 mg, but this can be more depending on the individual’s health condition. If you have high triglycerides then Omega-3 supplementation can help lower it. Also, if your dietary intake is inadequate then a supplement be useful. However, they are associated with an increased risk of atrial fibrillation so they should not be taken by everyone. The ideal scenario is to up your intake of natural sources of Omega 3 in your diet rather than need to take a supplement.
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Related article: What is a CT Calcium Score and How Does It Relate to Heart Attacks?
Dr Michael MacDonald is a heart doctor and cardiologist working in Singapore.