Essential Fatty Acids
What is there to know?
Definition
Essential fatty acids (also known as AGE or EFAs) are lipids.
Types
Essential fatty acids belong to two families: omega 3 (ω3 or n-3) and omega 6 (ω6 or n-6).
- Omega 3: Alpha Linoleic Acid, Docosahexaenoic Acid or DHA (22: 6 ω3) and Eicosapentaenoic Acid or EPA (20: 5 ω3).
- Omega 6: Linoleic acid, gamma linolenic acid or GLA (18: 3 ω6), diomo-gamma-linolenic acid or DGLA (20: 3 ω6) and arachidonic acid or AA (20: 4 ω6).
Functions
Essential fatty acids perform functions that are, to say the least, fundamental to health; consequently their lack, the excess or the altered balance between them can cause undesirable effects.
The most relevant functions are:
- They build cell membranes
- Balance the production of eicosanoids (super-hormones mediating inflammation, promoting or suppressing action, based on the specific eicosanoid)
- Promote metabolic balance (blood pressure, cholesterolemia, triglyceridemia, blood sugar, etc.)
- They protect (even if sometimes indirectly) the heart and the brain from vascular pathologies (atherosclerosis, thrombi, emboli)
- They support neurological development
- They protect the nervous system from aging
- They support the visual function
- Optimize the child's embryonic development and growth
- They seem to be involved in reducing major depression, etc.
Sources
The foods that contain more than essential fatty acids are: the fishery products (especially of the cold seas), the algae, the krill, many oil seeds, fat fleshy fruits and the starchy seed germ.
Ratio: Excess and Enzymes
Relationship
The ratio of essential fatty acids is a very important factor.
Although it is often underestimated, this ratio represents a criterion of nutritional balance which is, to say the least, fundamental.
We must not forget that all nutrients have a metabolic impact on the body; even lipids are no exception, on the contrary, fatty acids are among the most active molecules in this sense.
The researchers found important correlations between the pathogenesis of various disorders and the alteration of the relationship between the two essential fatty acids in the diet.
Excess
With this premise, we would be led to believe that the more essential fatty acids are eaten the better; this is only partially true!
First of all, polyunsaturated fatty acids are very sensitive to oxidation and peroxidation. By eating too many, in addition to increasing the portion of energy fats, one runs the risk of favoring the oxidative stress of the body (which many try to compensate by increasing the intake of vitamin E). On the other hand, this occurrence is mainly related to the unreasonable abuse of specific food supplements, lacking adequate antioxidant protection or poor quality (rancidity).
Furthermore, certain omega 6 are involved in the synthesis of eicosanoids that promote inflammation; this means that if taken in excess they could promote systemic inflammation.
Enzymatic competition
The omega 6 and omega 3 fatty acids have common enzymatic processes.
Since omega 6 is naturally more abundant in the contemporary western diet, omega 3 is "metabolically penalized".
These are the fundamental reasons for which an optimal relationship between omega 6 and omega 3 has been established.
Effective Consumption and Suggested Values
In 1996
According to the 1996 LARN (Recommended Levels of Nutrient Intake for the Italian population, published by the Italian Society of Human Nutrition - SINU), the average effective ratio between omega 6 and omega 3 in the diet was 13: 1, which corresponded to a overall energy percentage of 6% on daily caloric consumption.
This means that the Italian population introduced about 5.54% of daily calories in the form of omega 6 and 0.46% in the form of omega 3 (values referring to the total energy share).
Furthermore, in the same edition it was advised to hire:
- In infants (6 months - 1 year): approximately 4.5% of total daily calories in the form of omega 6 and 0.2-0.5% in the form of omega 3, with a recommended ratio of 22.5 / 9: 1 (total 0.5 g / day)
- In children (1-3 years): about 3% of total daily calories in the form of omega 6 and 0.2-0.5% in the form of omega 3, with a recommended ratio of 15 to 6: 1 (total 0.7 g / day)
- For all the others: about 1-2% of the total daily calories in the form of omega 6 and 0.2-0.5% in the form of omega 3, with a recommended ratio of 4: 1 (total 1 or 1, 5 g / day).
Analyzing these data it seems clear that the total contribution of essential fatty acids is well within the recommendations; however the relationship is clearly unbalanced.
Today
The most recent version of LARN focuses more on the distribution of omega 3s, suggesting specific values based on the type of molecule:
- In infants (6 months - 1 year): the proportion of omega 3 has increased up to 0.5-2.0%, of which at least 250 mg / day in the form of EPA and DHA + other 100 mg / day of DHA . The omega 6 are contained in the measure of 4-8%. In all, essential fatty acids make up 5-10% of total calories.
- The same for children 1 to 2 years old.
- For adults and the elderly: we recommend a share of omega 3 up to 0.5-2.0%, of which at least 250 mg / day in the form of EPA and DHA. The omega 6 are contained in the measure of 4-8%. In all, essential fatty acids make up 5-10% of total calories.
- In pregnancy and lactation: we recommend a share of omega 3 up to 0.5-2.0%, of which at least 250 mg / day in the form of EPA and DHA + other 100-200 mg / day of DHA. The omega 6 are contained in the measure of 4-8%. In all, essential fatty acids make up 5-10% of total calories.
How to fix it
The dietary interventions necessary for nutritional correction could be summarized as follows:
- Drastic reduction of the intake of omega 6 (in particular linoleic acid) contained in sunflower seeds, wheat germ, sesame, walnuts, soybeans, corn, olives, and the related oils.
- Significant increase in the intake of omega 3 (alpha linolenic, eicosapentaenoic and docosahexaenoic fatty acids), whose food sources are:
- Oils and meat from oily fish (especially rich in eicosapentaenoic and docosahexaenoic)
- Chia, kiwi, perilla, linen, cranberry seeds; walnuts and walnut oil, hemp oil, linseed oil, canola oil, canola oil and soybean oil (especially rich in alpha-linolenic acid).
NB : some foods are excellent sources of both essential fatty acids, therefore, in order to correct the balance of the two lipids it would be advisable to prefer the "purer" food sources of omega 3.
Respecting the recommended rations of essential fatty acids could seem a difficult undertaking to say the least; fortunately, it is possible to optimize the ratio between omega 6 and omega 3 by increasing the consumption of bluefish (up to 2-3 servings per week), algae and food supplements, even without reducing the overall intake of omega 6.
| Ω6 / ω3 ratio in some commonly used oils | |
| Linseed oil | 1: 4 |
| Rapeseed oil | 2: 1 |
| Hemp oil | 3: 1 |
| Soybean oil | 8: 1 |
| Olive oil | 9: 1 |
| Wheat germ oil | 10: 1 |
| Peanut oil | 62: 1 |
| Sunflower oil | 71: 1 |
Right Report: Why?
The answer to this question is complex and very complex. In summary, the right balance between omega 6 and omega 3:
- Promotes homeostasis of lipemia
- Improves blood pressure regulation
- GUARANTEES the balance of endogenous EICOSANOIDS.
Inflammatory and anti-inflammatory eicosanoids
The omega 3 are precursors of the eicosanoids type PG1 and PG3, therefore they play an anti-aggregating, vasoprotective and anti-thrombotic function; on the contrary, certain omega 6 are also precursors of proinflammatory and prothrombotic PG2 eicosanoids.
Put simply, the PG2 eicosanoids (those potentially in excess because they derive from the omega 6) Foster inflammation of the inflammation, while the eicosanoids PG1 and PG3 (those probably due to the omega 3) favor the REGRESSION of the inflammation.
It is imperative to specify that ALL eicosanoids (PG1, PG2 and PG3) are molecules essential for the correct functioning of the organism; however, the tendency to CHRONIC inflammation (potentially aggravated by the excess of some omega 6) represents an important risk factor for autoimmune diseases (rheumatoid arthritis, ulcerative rectal colitis, Crohn's disease, etc.) and can aggravate some diseases dysmetabolic increasing the cardiovascular risk.
Ultimately, maintaining the right ratio between omega 6 and omega 3 guarantees the homeostatic balance of eicosanoids, facilitating the prevention of chronic systemic inflammation and reducing the risk of autoimmune and cardio-vascular diseases.
Did you know that ... recent in vivo studies suggest that the relationship between essential fatty acids does NOT play such a decisive role as was hypothesized by interpreting the results obtained in vitro.
This means that it is first of all necessary to worry about REPLACING saturated fats and trans fats with ANALOGUE quantities of unsaturated acids.
In fact, as part of a low saturated and trans fat diet, an intake of omega 6 equal to 5-10% of total calories (in particular linoleic acid) seems to have a protective effect against coronary risk.
On the other hand, experiments carried out on the impact of various fatty acids can lead to not only different but even opposite results.
A recent study showed an inverse correlation between omega 6 and inflammation, highlighting a prevalence of anti-inflammatory activity in vivo, ie the exact opposite of what was suspected by observing the results in vitro.
The explanation could lie in the type of omega 6 used or in other metabolic variables still little known.
