Omega-3 fatty acids
Omega-3s are used in the development of highly unsaturated fatty acids and series 3 eicosanoids. These substances have favorable effects on the composition of cell membranes as well as on numerous biochemical processes in the body: regulation blood pressure, elasticity of the vessels, immune and anti-inflammatory responses, aggregation of blood platelets.
Among the omega-3s, only alpha-linolenic acid (AAL) is described as “essential”. In fact, the other omega-3 fatty acids can be synthesized by the body from ALA. It is particularly present in flax and hemp oil and seeds, as well as canola (rapeseed) and soybean oil.
Omega 3: understand everything in 2 min
Eicosapentaenoic acid (EPA). The human body can synthesize it from alpha-linolenic acid, although the conversion rate is very low. It is therefore important to consume foods rich in EPA, especially certain fatty fish. Populations that consume large quantities of fish (the Greenland Inuit and the Japanese, for example) are significantly less affected by cardiovascular disease. In addition, EPA is transformed into eicosanoids of series 3, substances which contribute to the protection of the arteries and the heart and which have recognized anti-inflammatory and anti-allergic effects.
Docosahexaenoic acid (DHA). DHA is also present in marine products, especially in some fatty fish. It plays a fundamental role in the development of the brain and the retina as well as in the formation and motility of sperm.
See our fact sheet on fish oil for a complete overview of the numerous scientific researches that have been carried out on EPA and DHA.
Our Omega-3 Needs
The Omega 3 and their properties are the subject of much research each year, which leads to a rapid evolution and frequent updates in the nutritional recommendations on their subject. Here is a brief update.
Several countries, as well as the World Health Organization, have issued recommendations for omega-3 intake, which can be summarized as follows :
- AAL: 0.8 g to 1.1 g / day
- EPA + DHA: 0.3 g to 0.5 g / day
In 2004, a committee of international experts set the ideal contribution in AAL 0.7% of daily kilocalories, or 1.5 g per day for a diet providing 2,000 kilocalories. These experts also recommend a minimum intake of 500 mg per day of EPA / DHA for the maintenance of good cardiovascular health.2.
In North America, sufficient intake of AAL is currently fixed at 1.1 g per day for women and 1.6 g for men, or around 0.5% of energy intake3. No intake is set forAEP/ ADH. These recommendations are criticized by some experts, who consider them insufficient to allow a reduction of coronary heart diseases in North America.
|To obtain 1.3 g of omega-3 of plant origin (ALA)||To obtain 1.3 g of omega-3 of marine origin (EPA + DHA)|
Sources: USDA National Nutrient Database for Standard Reference.
Note. In recent years, omega-3 eggs have been found commercially. They are laid by hens whose feed is enriched with flax seeds, which, compared to ordinary eggs, multiplies their omega-3 content by ten: an enriched egg fills 25% to 35% of daily omega-3 needs. 3.
As a food supplement, the benefits of omega-3
Essential fatty acids are so named because the body cannot synthesize them itself. They have to be found in food, supplements or dietary supplements. Typically omega-3 and omega-6 allow the proper functioning of the cardiovascular, cerebral, inflammatory, hormonal, etc. systems. Also, each of its families of fatty acids have properties, for example omega-3 are good allies for reducing the level of triglycerides in the blood. The omega-3 requirements (more precisely alpha-linolenic acid) are between 0.8 and 1.1 g / day. Regarding omega-6, their intake should be equivalent to 2% of the amount of kilocalories ingested per day.
Omega 3 Benefits
Albuminuria and hypertension. Consumption of cod liver oil may reduce albuminuria in diabetic patients with neuropathy, as well as blood pressure in patients with mild hypertension.
Arrhythmia and depression. Some preliminary data suggests that cod liver oil decreases symptoms related to ventricular arrhythmia as well as depressive symptoms, compared to those who don’t.
Arthritis, premenstrual syndrome. According to preliminary clinical studies, an extract of krill oil with a high content of omega-3 (300 mg / day for one month; Neptune Technologies & Bioresources, Inc) reduces certain symptoms linked to arthritis (pain, stiffness) and premenstrual syndrome. More studies are needed to validate these results on krill oil. Krill oil also contains omega-9 but small amounts of omega-6.
Omega-6 fatty acids
The body uses the omega-6 to develop highly unsaturated fatty acids and eicosanoids of series 1 and 2. These substances play an important role in the proper functioning of the nervous, cardiovascular, immune systems, as well as in allergic and inflammatory reactions and healing of wounds. When consumed in excess, omega-6 fatty acids can counteract the beneficial effects (especially cardiovascular). Too much omega-6 can also cause pain and inflammatory conditions like asthma or arthritis.
Among the omega-6s, only linoleic acid (LA) is qualified as “essential”. Indeed, the other fats omega-6 can be made by the body from LA. Unlike alpha-linolenic acid, linoleic acid is abundantly present in modern food: corn, sunflower, soy, safflower, grapeseed oils, etc.
Gamma-linolenic acid (AGL). The body synthesizes GLA from LA, but several obstacles can hinder this conversion: excessive consumption of cholesterol and “bad fats” (trans, saturated, etc.), alcohol, aging and diabetes, for example. We can also consume products that are direct sources of GLA: borage oil (24% GLA), evening primrose (8% GLA), blackcurrant (18% GLA) and spirulina.
Dihomo-gamma-linolenic acid (ADGL). It is a derivative of the AGL. The only known food source is breast milk. DGLA turns into series 1 eicosanoids that help protect the arteries and the heart, boost immunity and have anti-inflammatory effects.
Arachidonic acid (AA). It is a derivative of DGLA. Egg yolk and animal fats are direct sources. AA, because it is used in the synthesis of eicosanoids of series 2, ensures healing and healing of wounds and contributes to the mechanisms of allergic reactions. However, an excess of these eicosanoids can lead to diseases like arthritis, eczema, psoriasis and several autoimmune diseases.
Our Omega-6 Fat Needs
In 2004, a committee of international experts determined the adequate contribution in AL 2% of daily kilocalories, i.e. 4 g for a diet providing 2,000 kilocalories per day.
Various studies have also reported that it was necessary to consume between 1.2 and 2 g of LA per day to obtain the best effects in terms of prevention, in particular on the prevention of coronary heart disease. Some researchers recommend a daily consumption of LA up to about 1% of the daily caloric consumption, or about 2 g of LA for a diet equivalent to 2000 kCal per day. Adequate consumption of linolenic acid is therefore 2 and 4 g per day.
An essential balance, but very compromised
Until about 1920, the production of consumer oils was done on a small scale. The oils were cold pressed and obtained in small quantities because they did not keep long. Indeed the fats Omega 3 go rancid quickly when exposed to oxygen and light. The imperatives of mass food production have therefore pushed the industry to favor the most stable oils. These oils are also the least rich in omega-3, and they are refined … with great refinement, further decreasing their omega-3 content a little more. In addition, while consumption of fish has decreased, that of processed products rich in omega-6 has increased. The development of intensive farming and farming techniques has also led to the reduction of the omega-3 content of many foods such as green leafy vegetables, meats, eggs and even fish.
Result: it is generally believed that the omega-6 / omega-3 ratio in the Western diet is from 10/1 to 30/1, while it should ideally be between 1/1 and 4/1. In addition, this excess of omega-6 impairs the optimal use of omega-3 by the body. In fact, in order to be metabolized, omega-3 and omega-6 compete for several enzymes and, to a lesser extent, for several vitamins (vitamins B3, B6, C, E) and minerals (magnesium and zinc).
An excess of omega-6 in the plate therefore prevents the body from exploiting its sources of Omega 3. This imbalance induces, among other things, a physiological state favorable to cardiovascular diseases as well as to allergic and inflammatory disorders. To top it all off, if a disease interferes with fatty acid metabolism, the problem gets worse. Diabetes as well as excess alcohol, tobacco or stress can cause difficulty or inability to convert ALA to EPA.
According to several experts, a return to a diet providing an adequate ratio ofomega-6 and D’Omega 3 would have a positive impact on the cardiovascular health of western populations and also reduce inflammatory diseases.
This table, taken from the book Santé la Gaspésie (p. 16), is reproduced with the gracious permission of the authors.
Omega 6 Benefits
Omega-6s are used to reduce the risk of coronary heart disease and cancer, as well as to fight hyperlipidemia (high LDL cholesterol and total cholesterol).
Deficit and attention disorder with or without hyperactivity (ADHD). Taking a combination of omega-3 and omega-6 could decrease symptoms of ADHD, especially in children who also have neurodevelopmental disorders.
Coordination acquisition disorder. Certain symptoms linked to coordination disorder (eg reading, spelling a word, etc.) can be reduced in the presence of a combination of omega-3 and omega-6, according to a preliminary clinical study.
The dysfunction of the Meibomian glands. A preliminary clinical study reports that a 6-month treatment with a combination of linoleic acid (28.5 mg) and gamma-linolenic acid (15 mg) decreases the opacity of the lens caused by an obstruction of the Meibomian gland, in combination with standard hygiene treatment.
Multiple sclerosis and mental development. Taking omega-6 (as arachidonic acid or linoleic acid) has no effect on the baby’s mental development or slowing the progression of multiple sclerosis.
Omega-3: marine or vegetable source?
Experts disagree on the conversion rate ofAAL from vegetable source in AEP and in ADH. According to some researchers, this rate varies from 5% to 10% in the case of EPA and 2% to 5% in the case of DHA. According to other experts, who question the calculation method of their colleagues, these conversion rates are less than 1%.
Although it is therefore much easier to draw AEP and theADH in fish and fish oils, experts still recommend varying sources by regularly consuming fish, but also oils and seeds rich in AAL.