Omega 3 fatty acids |Essential fatty acids for Human health

Why Omega 3 is important for human health

1. They are responsible for hormonal regulation that regulates blood clotting, contraction and relaxation of artery walls, and inflammation.
2. Both omega-6 and omega-3 are essential ,However, most of us get too much omega-6 and very little of omega-3 fatty acid. This leads to over-nutrition of omega-6 and under-nutrition of omega-3 fatty acid.
3. The imbalance of omega’s is the root cause of the increase in severity and incidences of several diseases.
4. Imbalance’s leads to heart disease, diabetes, arthritis, cancer, mental disorders, pregnancy complications, infant mortality, and child health.
5.  Role of omega-3 in well-known during pregnancy in particular for infant nerve and eye function. Therefore it is critical to provide adequate supply of omega-3-poly unsaturated fatty acid during last trimester of pregnancy.
6. Omega-3 fatty acid, particularly DHA, has an important role in the development of human brain. If you regard human brain as super computer, it would be appropriate to regard DHA as the hardware of the brain.
7. .DHA is abundantly present in the human brain and is an essential requirement in every step of brain development such as neural cell proliferation, migration, differentiation, and synaptogenesis.
8. The multiple double bonds and unique structure of DHA allows imparting special membrane characteristics for effective cell signaling.
9. Evidences indicate that DHA accumulates in areas of the brain associated with learning and memory.
10. Many development disorders such as dyslexia, autism spectrum disorder, attention deficit hyperactivity disorder, and schizophrenia are causally related to decreased level of DHA.
11. Alpha-linolenic acid (ALA) is the most common omega-3 fatty acid in the vegetarian diet. It comes from plants and is found in vegetable oils—primarily flaxseed, walnut, canola, and soybean oils.
    • ALA is a strictly essential fatty acid and is used in our body to produce EPA and DHA.
    • Flax seed oil, which contains more than 50 % ALA, is the most commonly used in supplements. Other good sources include chia seed oil, perilla oil, lingonberry seed oil, and kiwifruit seed oil.
    • Purslane, a vegetable used in soups and salads along the Mediterranean basin and in the Middle East, is unique because it is the richest source of ALA and one of the few plants known to contain EPA.
12. EPA and DHA are known as the “long-chain” or marine omega-3 fatty acids since they are mainly found in fish and fish oils. Fish oil is the most widely used commercial source of omega-3 due to its high content of EPA/DHA.
13. Further EPA and DHA are claimed to have the most potent health benefits of the omega-3 fatty acids. EPA plays a role in cardiovascular health and is recommended by the American Heart Association for its cardiovascular benefits.
14. DHA is the most abundant in the brain and retina and is an important structural component of the nerve cells in the brain and eyes and a key component of the heart.

What is Omega 3 Fatty acids

1. There are two essential fatty acids (EFAs) in human nutrition: ALA (ALA; 18:3n-3), alpha linoleic acid (an omega-3 fatty acid), and linoleic acid (LA; 18:2n-6), an omega-6 fatty acid.
2. Humans must obtain EFAs from foods because the human body cannot synthesize it. 
3. ALA and LA are precursors of long chain fatty acid i.e. EPA and DHA which in turn get converted to eicosanoids and lipid mediators and control many biological functions such as cell signaling, inflammatory actions and ion transport. They also regulate gene expression .
4. Alpha-linolenic acid (ALA, C18:3) is the representative of omega-3 family, and linoleic acid (LA, C18:2n-6) is the representative of omega-6 family.
5. Longer chain omega-3 fatty acids, include eicosapentaenoic acid (EPA, C20:5n-3),docosahexaenoic acid (DHA, C22:6n-3), and long-chain omega-6 fatty acids include arachidonic acid (C20:4n-6) (AA).
6. PUFA play important role in modulation of many physiological processes .Also blood levels of LC PUFA are considered biomarkers of health status.
7. Fats have a fundamental structural and functional role in the brain and central nervous system (CNS) and are a key factor in the development ADHD. The two fats that are thought to be especially important are EPA and DHA, not only because of their role in the brain and body but because of the relative lack of them in many people’s diets.
8. Omega-3 fatty acid imparts positive effect on diseases such as hypertension, arthritis, atherosclerosis, depression, diabetes mellitus, myocardial infarction, thrombosis, and heart disease.
9. Various attempts have been made to fortify food products with omega-3, which includes juice, breakfast cereals, bread, butter, yoghurt drink, milk and eggs Fortification of food with LA may offer an effective way of increasing omega-3 long-chain polyunsaturated fatty acid intakes.

Importance of Omega 3 Index for health monitor (Omega 3 to Omega 6 ratio)

Omega 3 Index :The omega-3 index is the combined percentage of eicosapentaenoic acid  (EPA) and docosahexaenoic acid (DHA )of total fatty acids in red blood cell membrane .It is inferred that man as hunter–gatherer consumed almost equal amount of omega fatty acid ,the omega-3 index was close to 1:1. But in recent times, his food has very little of omega-3 and is excessively loaded with omega-6 fatty acid , the omega-3 index is 1:10, 1:20, or even 1:50, but ideally the healthy omega-3 index recommended to be 1:5.

Why Omega 3 to Omega ratio of 1:5 is important

1.This ratio 1:5 has been thought to be ideal because omega-3 fatty acid (ALA) and omega-6 fatty acid(LA) are processed by the same set of enzymes i.e. Elongase¹and desaturases ²to highly unsaturated fatty acids (HUFA), EPA and DHA (both omega-3), and AA (omega-6).

2.Five times higher levels of omega-6 do not affect the conversion of omega-3 PUFA to omega-3 HUFA. This is because the elongases and desaturases have higher affinity to omega-3 than omega-6 fatty acids. Therefore, even at five times less level of omega-3 fatty PUFA’s can be equally converted.  In order to cut down omega-6 fatty acid consumption, omega-9 (MUFA olive oil) oleic acid is being promoted all over the world .

4.Humans can convert short-chain omega−3 fatty acids to long-chain forms (EPA, DHA) with an efficiency below 5%. The omega−3 conversion efficiency is greater in women than in men. Higher ALA and DHA values found in plasma phospholipids of women may be due to the higher activity of desaturases.

Note 1 :Elongase is a generic term for an enzyme that catalyses carbon chain extension of an organic molecule, especially a fatty acid. Elongase play a variety of roles in mammalian organisms, accounting for changes in tissue function, lipid regulation, and the overall physiology of an organism.

Note 2 : Desaturases -A desaturase is an enzyme that removes two hydrogen atoms from a fatty acid, creating a carbon/carbon double bond. These desaturases are classified as: Delta – indicating that the double bond is created at a fixed position from the carboxyl end of a fatty acid chain.)

Key benefits of taking Omega 3 fatty acids |Importance of DHA and EPA in human Nutrition

1.The modern diet is deficient in omega-3 fatty acid and excess of omega-6 fatty acid. Therefore, there is a very severe imbalance of omega-3 to omega-6 fatty acid ratio, which is said to be the root cause of our health problems. The relative excess of omega-6 fatty acid not only inhibits the formation of EPA and DHA, but also enhances the synthesis of eicosanoids which are involved in inflammatory, cardiovascular, and immunological disorders .

2.Prevention of Chronic diseases :In addition, LA have been reported to play a key role in prevention and treatment of many other chronic diseases, such as neurological disorders, cancer, inflammatory diseases, obesity, and diabetes mellitus . Lewis et al. noticed that consumption of n-3 PUFA is critical and these vital fatty acids can check cancerous growth, reduce threat of CVD, and decrease/loss of immunity.

3.Several studies have shown positive roles for n-3 PUFA in infant development, and in combating cancer, coronary heart diseases (CHD), hypertension, obesity, type II diabetes, and more recently, various mental illnesses, including depression, attention-deficit hyperactivity disorder (ADHD), and dementia .

4.Lower Cholesterol level : Omega-3 fatty acids are associated with numerous health benefits. One of the biggest proven health benefits is its ability to lower the level of bad cholesterol-LDL cholesterol thereby leading to lower risk of coronary heart diseases and blood pressure.

5.Importance in Pregnancy a) There is evidence that adequate intakes of omega-3 fatty acids are important during pregnancy to safeguard cognitive, retinal, and immune development in the infant . There is also a high requirement for DHA in the last trimester of pregnancy and in the first 3 months of life.

b) DHA is important in the developing nervous system of new borns and influences structural and functional parameters during rapid brain growth . Some clinical trials indicate benefit for infants in terms of immune function, visual acuity, and cognitive function .In view of the importance of DHA for the development of brain, retinal, and neural tissues in fetuses’ and young children, adequate DHA intake in pregnant and nursing woman is very much essential .

Types and Sources of Omega-3 Fatty Acids

1.Omega-3s belong to a broader group of fats called polyunsaturated fats, found in a wide variety of foods, . They are classified as essential fatty acids because our body cannot synthesize them but they are necessary for the regular metabolic activities.

2.Common available source of omega-3 fatty acids include algae, flax, and fish. When it comes to sources of EPA and DHA, fish and seafood are the best sources with oily fish , such as salmon, trout, mackerel, sardines, herring and anchovies, being especially rich.

3.There are 3 major types of omega-3 fatty acids:1. Alpha-linolenic acid (ALA) C18:3 ,2. Eicosapentaenoic acid (EPA) C20:5 3. Docosahexaenoic acid (DHA) C22:6.

4.The richest dietary sources of LA are certain vegetable and seed oils, including sunflower, safflower, soya, palm, peanut and sesame, all of which should be eaten in good amounts along with oils that are rich in ALA such as rapeseed (canola), flaxseed (linseed) and walnut oil.

5.Olive oil is also recommended, despite having quite a low ALA content, as it is rich in beneficial monounsaturated fats.

6.Other sources of ALA include green, leafy vegetables such as rocket, watercress and spinach as well as fresh green herbs, such as basil, coriander, mint and parsley. Consequently, the food products of animals allowed to graze on open pasture will also be rich in ALA and so organic, free-range and outdoor reared meat, milk and eggs are the best choice

6.DHA can also be found in liver and egg yolks and so these foods should be incorporated into the diet regularly, unless you are taking a nutritional supplement that contains vitamin A in which case you should not eat liver or foods containing liver.

7.Algae used for Omega 3 Production These include Crypthecodinium cohnii, which is used industrially to produce DHA by fermentation, and Phaeophyceae brown algae, which contains EPA.

8. As EPA and DHA are naturally contained in algae, the focus on obtaining EPA and DHA from algae was prompted to seek “vegetarian,” and sustainable sources of EPA and DHA which are more acceptable than fish.

9. Algae cultivation for Omega 3 for sourcing A large part of the population do not consume fish. The presence of pollutants such as heavy metals and polychlorinated biphenols (PCBs) in fish , raises the safety concern in fish consumption. Therefore, other dietary sources for EPA and DHA are being sought.

Three methods are employed in Omega 3 Production from Plant sources

General Recommendation for Combined daily doses of EPA & DHA (Omega 3 Fatty acids)

1.A general recommendation of a combined daily dose of 500 mg EPA and DHA is needed to avoid functional deficiency of these important fats, although individuals with ADHD may have an even higher requirement.

2.Pure fish oil supplements that provide a daily standard dose of EPA and DHA are useful in addition to a diet containing fish and seafood.

3.Increasing evidence from well-designed clinical trials have indeed shown that supplementation with EPA and DHA alleviate ADHD-related symptoms in some children. These supplements also have the advantage of being relatively safe and offering general health benefits, specifically in terms of cardiovascular protection.

Omega 3 from different sources (85gms ) per serving
Common Name	Omega in grams
Barramundi	0.1
Blue eye cod	0.31
Broccoli	0.10–0.20
Cod	0.15–0.24
Eggs, large regular	0.109
Flax	11.4
Flounder	0.48
Gemfish	0.4
Green shell/lipped mussels	0.95
Grouper	0.23
Halibut	0.60–1.12
Hemp	11
Herring, sardines	1.3–2
Hoki (blue grenadier)	0.41
King mackerel	0.36
Lean red meat	0.031
Milk, regular	0.001
Strawberry or Kiwifruit	0.10–0.20
Swordfish	0.97
Sydney rock oysters	0.3
Tuna	0.21–1.1
Tuna (canned, light)	0.17–0.24
Tuna, canned	0.23
Turkey	0.03

Important abbreviations

ALA	Alpha-linolenic acid
n-3-FA	Omega-3 fatty acid
n-3 LC-PUFA	Omega-3 long-chain polyunsaturated fatty acid
LA	Linoleic acid
EFAs	Essential fatty acids
DHA	Docosahexaenoic acid
EPA	Eicosapentaenoic acid
AA	Arachidonic acid

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