Generality
What is Alpha Linolenic Acid?
Alpha linolenic acid is an essential fatty acid, which is also identified with the letters ALA, AaL, LNA or 18: 3 (ω3).
In nutrition, the adjective "essential" defines the total inability of the organism to synthesize an element, or to do it in quantities adequate to its own needs; this implies the relative need to introduce it with the diet.
Among the essential omega-3s, ALA is considered the least metabolically active one. Nevertheless, alpha-linolenic acid is the only truly indispensable, because from it the organism is also able to extract EPA and DHA. The enzymatic reactions that drive this conversion are not always fully functional and can be compromised by increasing the food requirements of EPA and DHA.
Although ALA is less effective than its two derivatives, it also has advantages that mainly affect the profile and the undesired effects.
Alpha linolenic acid is contained in various dietary foods used as a condiment and in certain dietary supplements of health interest.
ALA in food
Food sources of omega 3 are mainly represented by some vegetables, rich in ALA, and by fishery products, together with algae, which are rich above all in EPA and DHA.
Of the three, alpha linolenic acid is generally the most abundant in the diet. At one time no distinction was made between the molecules and a minimum level of indiscriminate recruitment was suggested. Today, however, there is a tendency to give importance also to the specific presence of EPA and DHA.
Alpha linolenic acid is significantly contained in the fat portion of the seeds; this is more abundant in oily ones, but it also abounds in the embryo of cereals, legumes, pseudo-cereals and other lesser-known ones.
Obviously, the oils produced by squeezing these foods are a very concentrated source of alpha linolenic acid.
The alpha linolenic acid content in foods of animal origin is generally less than 1%, while its EPA and DHA derivatives predominate.
The table below summarizes the content of ALA in the richest foods.
| Amount of Alpha Linolenic Acid Contained in the Oil Extracted from the Seeds of Certain Plants | |||
| Common name | Alternative Name | Binomial nomenclature | % ALA † |
| Chia | Salvia chia | Salvia hispanica | 64% |
| Kiwi | Chinese gooseberry | Actinidia chinensis | 62% |
| Perilla | Shiso | Perilla frutescens | 58% |
| Linen | / | Linum usitatissimum | 55% |
| Cranberry | / | Vaccinium vitis-idaea | 49% |
| Camellia | Camelina | Camelina sativa | 35-45% |
| Porcelain | Portulaca | Portulaca oleracea | 35% |
| Sea buckthorn | Sea berries | Hippophae rhamnoides | 32% |
| Hemp | Cannabis | Cannabis sativa | 20% |
| wot | English or Persian nuts | Juglans regia | 10.4% |
| Canola | Turnip from seed | Brassica napus | 10% |
| Soy | / | Glycine max | 8% |
| † average value | |||
Despite being excellent sources of alpha linolenic acid, these foods are poor in its EPA and DHA derivatives.
Soybean oil: not always a good choice
To reduce the "susceptibility" to the rancidity of alpha linolenic acid, commercial soybean oil is almost always subjected to an incomplete hydrogenation process, to transform a part of the fatty acids into "cis" to "trans" conformation.
This soybean oil cannot be considered a good source of alpha linolenic acid, nor a completely healthy choice.
Indications
When to use alpha linolenic acid?
Foods rich in alpha linolenic acid and the supplements that contain it must be used especially when the diet is not able to cover individual needs.
It is not easy to identify the omega 3 deficiency and statistically this deficit affects mainly EPA and DHA.
To guarantee the contribution of ALA is sufficient:
- Consume the right portions of cereals, legumes, fruit and vegetables.
- Prefer integral forms, not processed.
- Eat at least 50% of raw fruit and vegetables.
- To be careful, partially replace the extra virgin olive oil with another oil rich in omega-three (such as chia, flax, kiwi, etc.) to be used raw.
The demand for omega 3 increases in proportion to energy expenditure and total metabolic effort; it is usually not essential to take supplements based on alpha linolenic acid, while it seems more important to take EPA and DHA.
These products have a specific utility in case of:
- Vegetarian or vegan diet, which requires the exclusion of foods of animal origin.
- Reduced tolerance to taste and gastrointestinal reactions of animal-based omega three supplements.
Property and Effectiveness
What benefits has ALA shown during the studies?
The main functions performed by alpha linolenic acid are also linked to the role of its derivatives EPA and DHA.
In particular, omega-3s play a role: structural, anti-inflammatory, anti-aggregating, fluidifying, anti-thrombotic, vasodilating, positive on metabolic pathologies, protective on cardio-cerebro-vascular events and improvement on some brain functions.
STRUCTURAL FUNCTION
These fatty acids are incorporated into the plasma membranes of the cells.
They are of great importance in the formation and maintenance of nervous and ocular tissue (especially in the initial development of the fetus, of the child and in maintenance in the third age).
ANTI-AGGREGATE, FLUIDIFYING AND VASODILATORY FUNCTION
Following trauma, infection and inflammation, omega three are used to produce anti-inflammatory cytokines. This function is at the basis of their beneficial effect also for the pathogenesis of atherosclerosis.
Omega three decrease plasma viscosity and platelet aggregation; this causes a decrease in the probability of thrombotic occlusion.
Furthermore, they have a vasodilatory effect that promotes venous, arterial and capillary circulation.
In particular, EPA decreases fibrinogenemia, enhances fibrinolysis and inhibits the production of platelet-derived growth factor C (PDGFC), a protein that stimulates the production and migration of smooth muscle cells within the vascular wall.
POSITIVE FUNCTION ON METABOLIC DISEASES
Omega 3 has a positive effect on lipemia, reducing excess triglycerides (EPA is a very effective hypotiglyceridemic, thanks to its ability to reduce VLDL protein synthesis). Some studies, but not all, suggest a positive effect also on cholesterolemia by increasing the fraction of HDL (good cholesterol).
They reduce blood pressure and appear to have a beneficial effect on the effects of chronic hyperglycemia and on the complications of type 2 diabetes mellitus.
PROTECTIVE FUNCTION ON CARDIO-CEREBRO-VASCULAR EVENTS
Omega three exert a direct preventive effect on blood vessels, protecting them from endothelial lesions typical of atherosclerosis.
As anticipated, they reduce systemic inflammation and decrease plasma viscosity, as well as platelet aggregation.
All this contributes to the reduction of overall cardio-cerebrovascular risk, especially in patients with metabolic pathologies.
Is alpha linolenic acid less effective than EPA and DHA?
Due to the reduced ability to synthesize EPA and (even more) DHA starting from alpha linolenic acid, the health benefits deriving from the integration of vegetable oils rich in alpha linolenic acid are much lower than those obtainable through consumption of fish oil or other supplements rich in EPA and DHA.
This function is compromised above all in the following cases: old age, alcoholism, hypoproteic diet, hyperglycemia, diet rich in linoleic acid (omega 6 abundant in vegetable oils) and prolonged treatments with glucocorticoids (cortisone).
Doses and Mode of Use
How to treat foods and especially oils rich in alpha linolenic acid?
Alpha linolenic acid is very delicate.
It is adversely affected by:
- Oxygen
- Free radicals
- Heat
- Light.
Products containing alpha linolenic acid must be stored in airtight containers, for the shortest possible time, in dark containers, in the dark and in the cold (preferably in the freezer).
Oils extracted from seeds rich in alpha linolenic acid must necessarily be produced by cold pressing.
They are best preserved if added with vitamin E (a powerful antioxidant).
Oils rich in alpha linolenic acid must be used strictly raw (for example to dress salads).
How much alpha linolenic acid do you consume?
The recommended intake level for alpha linolenic acid is not well defined.
It falls within that of the entire omega 3 group which, according to recent LARN, must include about 0.5-2.0% of the total kilocalories in the diet.
However, recommendations for a more generous contribution are not lacking. Considering that for an adult 250 mg must be supplied by EPA and DHA, in a 2000 kcal diet the α-linolenic acid should be present on average for 2.5-2.6 g.
Making use of a dietary supplement in capsules or capsules, it is necessary to estimate the daily quantity based on the specific format, remembering not to exceed (except for special needs) the 3 g / day.
On the contrary, wanting to exploit the beneficial power of the EPA and DHA derivatives (produced in the body), in agreement with the doctor it is possible to significantly increase the dose.
Side effects
Alpha linolenic acid is almost totally odorless and tasteless.
The side effects of supplementation with alpha linolenic acid are very low or almost zero.
Some gastrointestinal discomforts may occur, however more frequent in the supplement with EPA and DHA; for example: belching, nausea, abdominal cramps, dyspepsia and diarrhea.
Complications of the blood coagulation system are rare.
They appear to be very rare and linked exclusively to overdoses, metabolic peroxidosis and other serious disorders.
Contraindications
When should alpha linolenic acid not be used?
Alpha linolenic acid supplements should not be used in case of allergy or hypersensitivity linked to the components of the product.
It is advisable to pay close attention to the association of alpha linolenic acid (and omega three in general) with some drugs (see below).
Pharmacological Interactions
What drugs or foods can change the effect of alpha linolenic acid?
The drugs with which it is not advisable to take considerable doses of alpha linolenic acid are:
- Anticoagulants (coumadin, sintrom, warfain, acenocumarol), aspirin, non-steroidal anti-inflammatory drugs, garlic and ginkgo biloba: they would increase the risk of bleeding due to the double anti-aggregating effect.
- Oral hypoglycemic agents: it is advisable to consult your doctor before starting the alpha linolenic acid supplement, even if the hypoglycemic power, mainly linked to the function of EPA and DHA, is not well defined and sometimes seems of little relevance.
Precautions for Use
What do you need to know before taking alpha linolenic acid?
Before starting the integration with alpha linolenic acid it is important:
- Evaluate if it is really necessary
- Consider what is mentioned in the side effects, contraindications and drug interactions
- Consult your doctor, especially in the case of pregnancy, breastfeeding, pediatric age (despite the clear advantages offered by omega 3 in developing the fetus and younger children), pathologies and pharmacological treatments.
It is advisable to stop taking alpha linolenic acid before surgery to avoid the risk of excessive bleeding.
Bibliography:
- Reasoned medical therapy - Aldo Zangara - Piccin - pag 20
- The aging. Aging in good health with the strategies of functional medicine - Massimo Pandiani - New techniques - pag 68-69.
- Levels of recommended nutrient intake for the Italian population (LARN) - Italian Society of Human Nutrition (SINU)
- Commission of the European Communities - 1993.
