What are they?
Fatty acids are the main constituents of the triglycerides which are food lipids that we commonly call fat. Fats, together with carbohydrates and proteins are the main ingredients of what we eat. The main source of energy comes from fats, so that they are considered to be the central energy resource in the human being. Normally, eating fats is related with being overweight but in reality the consumption of fats is essential to health. Apart from being a source of energy they have a fundamental role in the composition and operation of the cell membranes in our bodies.
Types of fatty acids
There are four families of fatty acids
• Monounsaturated (oleic acid)
• Polyunsaturated (acids ω6 and ω3)
• Trans: which come from industrially-produced products and are considered to be damaging to health.
It is important to consume a balance of the different types of fatty acid. In general, it is recommended that you should only eat a small amount of saturated fatty acids and trans fatty acids and a larger amount of monounsaturated and polyunsaturated fatty acids.
Part of the family of the polyunsaturates, linoleic and alpha-linoleic fatty acids, the so-called ESSENTIAL FATTY ACIDS (EFAs), should be especially mentioned. They are the precursors of the ω6 and ω3 series respectively and are called «essential» due to the fact that our organism cannot synthesise them, with the result that they must be consumed. These EFAs have primordial functions in the body, such as, for example, the formation of hormones (prostaglandins, leukotrienes and thromboxanes, among others) and they are also essential components of the cell membranes .
Fatty acid sources in your food
In general, it can be considered that saturated fatty acids are plentiful in terrestrial animal products (meat, eggs, fats for spreading and milk and derivatives) as well as in such foods as coconut and palm oil. Monounsaturated fatty acids, mainly oleic acid, are to be found in olive oil. Among the fatty acids in the ω6 series, the most abundant is linoleic acid, which is to be found mainly in seed oils although they are also, in lesser quantity, in green vegetables, fruit, dried fruits and cereals. Finally, among the fatty acids of the ω3 series, alpha-linolenic acid can be found in small but sufficient quantities in foods which are generally present in the diet. The other two important fatty acids in the series (docosahexaenoic and eicosapentaenoic) are to be found almost exclusively in aquatic animals, mainly in those from cold waters (oily fish). Linseed oil also contains ω3 fatty acids in substantial quantities. It should be emphasised that although in general milk and derivatives are rich in saturated fats, human milk is an exception for two reasons:
• It contains a small proportion of saturated fats.
• It contains a larger quantity of ω3 acids and not only in the form of alpha-linolenic acid but eicosapentaenoic acid and docosahexaenoic acid are also present, which fulfil significant functions in the development of the newborn child, mainly in the development of the nervous system and of the retina.
In general, for the adult population, it is recommended that the consumption of fats should represent 30%-35% of the total energy intake. If we break this figure down into the different classes of fatty acids:
• Saturated fats should not be more than 10% of the total energy.
• The principal fatty acid should be oleic acid (olive oil) which should amount to between 15% and 20% of the total energy.
• The remaining 5% should come from polyunsaturated fatty acids ( 4% from ω6 and 1% from ω3).
CURRENTLY IN THE DIET AN EXCESS OF SATURATED FATS AND OF Ω6 IS CONSUMED SO THAT A REDUCTION IN THE FORMER AND AN INCREASE IN THE CONSUMPTION OF Ω3 IS RECOMMENDED, WHICH IS TO BE FOUND MAINLY IN FISH AND ALSO IN SOME ENRICHED FOODSTUFFS.
Benefits of ω3
It has been proven that ω3 has numerous benefits: Benefits in inflammatory processes: they improve the condition of smokers and asthmatics and those with bronchitis since in these people the state of the lung inflammation is chronic. It has likewise been shown that it improves the condition of persons with inflammatory illnesss such as Crohn’s disease, rheumatoid arthritis and bacterial and viral pneumonia. It also improves the condition of those suffering from eczema. This is thanks to the fact that ω3 fatty acids tend to suppress or limit the production of inflammatory substances. Anti-carcinogenic effects of ω3 fatty acids: it is believed that 80% of malignant tumours are caused by environmental factors and life habits, so that it is considered that they can be avoided by means of changes in the diet. The consumption of ω3 fatty acids contributes to preventing breast, prostate and colon cancer among others as well as reducing the risk of metastasis in cancer sufferers as it has been shown that the ω3 fatty acids tend to reduce the growth of carcinogenic cells as well as reducing the mobility of such cells. Reduction of cardio-vascular risk; the consumption of ω3 reduces vascular risk for a number of reasons:
• It prevents the appearance of arrhythmia as ω3 has the capacity to stabilise the heart electrically.
• It increases life expectancy of heart attack victims as it has an anti-thrombotic, anti-inflammatory and vaso-dilatory effect.
• It reduces blood pressure and triglycemia
ω3 during pregnancy and lactation: The consumption of ω3 during pregnancy and lactation is fundamental for the development and growth of the newborn. It is for this reason that the expectant mother and the foetus as well as breastfed children have a very high need for these fatty acids especially during the third trimester of pregnancy where the foetal requirements are very high due to the growth of the nervous system and the development of the neurones. (there are structures in the nervous system which contain a great many omega 3 fatty acids such as the retina which contains 60 % of DHA). It is recommended that at least 100 mg a day of omega 3 should be consumed by pregnant women, double the amount required by women normally. Other benefits: a balance in the consumption of ω3 will also help to ensure correct functioning of the nervous system, correct gastro-intestinal function, balance of the immunological system and the health of the skin, hair and nails.
Cocoa and its derivatives: The fats which come from cocoa butter contain a large proportion of stearic acid, a saturated fatty acid which, unlike other fatty acids, does not increase the level of cholesterol in the blood. Cocoa is also a source of minerals such as potassium, phosphorous, magnesium, calcium and vitamins. If it is milk chocolate or cocoa is dissolved in milk, the amount of calcium is significantly increased. Cocoa as a raw material contains vitamins such as thiamine (B1) and folic acid. Other beneficial components .of cocoa are the phyto-chemical elements (non-nutritive), of which the most important are: teobromina, which although it is of the same family as caffeine has a much lower stimulatory effect and the poly-phenols (anti-oxidants), compounds which contribute to avoiding the oxidation of the so-called bad cholesterol (LDL-c) and which have been related with the prevention of cardio-vascular disturbances and the stimulation of the body’s defences. The liver converts stearic acid rapidly into oleic acid and therefore despite being saturated it only raises cholesterol a little. The supply of saturated fatty acids should not exceed 10% of the total calorie supply, that is to say 15-29g a day.
Elaidic Acid: Trans marker
This isomer of oleic acid is not natural. it is a product which is made industrially for the manufacture of margarines from oleic acid and linoleic acid. Margarines generally have 18%-20% of trans fatty acids.
It raises LDL cholesterol and reduces HDL cholesterol and also raises LPA. It increases the risk of thrombosis as it increases the aggregation of platelets as it blocks delta-6-desaturase, which puts a brake on the production of DGLA (dihomo-gamma-linolenic acid) from the ω6 series and the metabolism of ω3. Its presence in industrial pastries is of the order of 5-7% of the product.
Trans fats are to be found mainly in industrially produced foods with vegetable oils, and a daily dose of 5 grams is considered to be dangerous. Here, you have a list of ten foods with a high content of this type of fat:
• Chips (150 g): .7 gr. of trans fats.
• Industrial apple cake (1 piece): 6 gr. of trans fats .
• Industrial pastry (1 unit): 5-6 gr. of trans fats .
• Hamburger (200 gr.): 3 gr. of trans fats .
• Fresh cheese (1 unit): 2.2-5.2 gr. of trans fats .
• Fairy cake (1 unit): 1-2.1 gr. of trans fats .
• Biscuits (2 units): 1.3 gr. of trans fats .
• Margarine (1 spoonful): 0.9 gr. of trans fats
• Commercial bread (1 unit): 0.85 gr. of trans fats
However, it raises cholesterol less than butter. In order to raise cholesterol 9% 200 grams of margarine are necessary or 50 grams of butter.
Some swelled cereals have trans fatty acids.
This does not raise cholesterol if there is no lack of linoleic acid. It is to be found mainly in milk, milk products, palm oil and coconut oil, pork fat, tallow butter and cocoa butter. It increases cholesterol and LDL when it replaces carbohydrates or another kind of fat in the diet.
It is to be found mainly in olive oil, although it is also in dairy fats and cheese.
Monounsaturated fatty acids reduce LDL-cholesterol.
They have a beneficial effect on arterial blood pressure and aggregation of platelets.
In olive oil, rape-seed oil and peanut oil, oleic acid is in the second position of glycerol and this involves an increase in the HDL/LDL ratio, an increase in ApoA1 and a decrease in triglycerides.
However, the oleic acid in animal fats (pork and beef) and in certain fish (herring and mackerel) is not in position 2 in the triglyceride molecule and as a consequence is not absorbed very much.
Their presence as a supply of unsaturates in the circulating lipo-proteins prevents there being a surplus of polyunsaturates, which would make them very vulnerable to oxidation by free radicals.
The poly-phenols from extra virgin olive oil (hydroxytyrosol and oleuropein) stimulate the formation of Nitric Oxide (NO) which is liberated from the macrophages and has an «anti-atheromatous» action.
The monounsaturates must represent 15-20% of the total calorie supply, that is to say 35-40 grams per day with food which is moderately hypoglycemic and normolipid.
If oleic acid is low and the levels of stearic acid are high, it is necessary to increase the consumption of olive oil and supplement with co-factors of the . desaturase enzyme such as niacin or vitamin B3, vitamin B6, vitamin C, zinc and magnesium.
It is present in borage and evening primrose oils. The organism can synthesise it from linoleic acid by the action of delta 6 desaturase.
Borage seed oil
This is the most abundant source of gamma-linolenic acid (AGL) which is the essential fatty acid., Omega-6. AGL is an important component of cell membranes and is metabolised in dihomo y linolenic acid (DAGL), a substrate for the enzymes which produce the prostaglandins of series 1, which have vaso-dilatory properties. These properties facilitate good perfusion of nutrients in the tissues. Research has shown that very often hyperactive children have a lack of ADH and DAGL 12,13. Evening primrose oil is unusual in that it contains preformed gamma-linolenic acid, with the result that your organism saves one step in the transformation to obtaining another end substance of interest, which is prosta-glandin E1 (or PGE 1).
If the levels of DGLA are low and those of Arachidonic Acid (AA) are high, it is recommended that you should consume only olive oil for cooking, reduce your consumption of vegetable oils, supplement with EPA, which will reduce the activity of delta-5-desaturase. Eat a diet that is poor in sugar, relatively high in proteins and complex carbohydrates (beans, complete vegetables and fruit).
Also test in parallel for a profile of dysglicemia (insulin and glycosylated haemoglobin).
Linoleic acid (LA)
If your LA is high and also your AA, we recommend that you use only olive oil for cooking, avoid all other vegetable oils, avoid margarine and products with added margarine. If your LA is high and your DGLA is low, we recommend that you consume primrose oil, borage oil, blackcurrant seed oil. If you are also low in AA, the problem is more severe and we recommend that you eat egg yolks, lean meat and beef that is free of steroids.
Arachidonic Acid (AA)
It can be synthesised from linoleic, gamma-linoleic and dihomo-y-linolenic acids.
It is the metabolite that is the origin of the synthesis of the «inflammatory» eicosanoides (thromboxanes, leukotrienes and prostaglandins) with platelet-aggregating and vaso-constricting effects).
It is to be found mainly in animal meats. Also in fish oils, but in them EPA is dominant.
The main metabolite, PGE2, has the following actions:
Relaxation of the cervix, constriction of the coronary arteries, fever in the hypothalamus, stimulation of pain receivers, relaxation of the stomach muscle, reduction in the absorption of sodium by the kidney, increase in the secretion of chlorides in the intestine, swelling-oedema in damaged tissues.
Docosahexaenoic acid (DHA)
Important to vision. It is synthesised from EPA with low performance. It is not involved in the synthesis of eicosanoids. It is found, with high values, in the membranes of the retina. A deficit can give rise to lesions in the retina. It has an important role in the regeneration of Rhodopsin, a crucial pigment in the system which converts light into vision. Important for cerebral function: In comparison with the rest of the body, the content is very high in the brain. In cell cultures, it has been shown to protect the neurones from apoptosis, which may lead one to think that it has a significant role in the survival of the neurones. This may be linked to the fact that a high content increases the fluidity of the neuronal membranes. This membrane fluidity facilitates the availability of neuro-transmitters and their exchange at the synapse. Regulation of the genetic expression «in vitro» in a tissue culture, and «in vivo» with animals, has been observed with omega-3 (especially DHA) and it is involved in the regulation of genetic expression, through the activity of certain transcription factors (proteins which alter the genetic transcription by joining to the elements of the specific response of the target genes). Among the transmission factors modulated by omega-3, is NF-Kappa B and members of the PPAR family (peroxisome proliferator- activated receptor). It is recommended in those cases where there is a deficit of this fatty acid, that you should consume cold water fish, salmon, sardines or anchovies, tuna, wild trout…
It can be synthesised by the body from linolenic acid but with a very low performance which almost makes it essential in the human species. Furthermore, this capacity for synthesis is reduced in the elderly, diabetics and in cases of hypercholesterolemia.
This is the origin of the synthesis of non-inflammatory eicosanoides (thromboxanes, leukotrienes, prostaglandins).
The presumed benefit attributed to fish oil is a result of its content of omega 3 particularly eicosapentanoic acid (EPA) and docosahexanoic acid (DHA). Both are incorporated into the cell membrane where they exercise an influence on the fluidity, the reception function, enzyme activity and production of icosanoids. The latter perform a significant role in the control of inflammatory and immunological responses.
However, the incorporation of EPA and DHA into the cell membrane also strengthens its peroxidation, which requires an increase in anti-oxidants, particularly Vitamin E.
A linoleic acid becomes eicosapentanoic acid (EPA) which is important in the correct functioning of the nerves. EPA is present in fish oils and it is believed to be beneficial in the reduction of the symptoms of arthritis and the risk of cardiac illnesses. For this reason, fish oils are sometimes used therapeutically.
It is recommended in cases where there is a deficit of this fatty acid that you should eat cold water fish, salmon, sardines or anchovies, tuna, wild trout…
Vegetable oils which contain large quantities of that acid may be used as an alternative by vegetarians. Linseed and linseed oil are especially rich sources of linoleic acid.
Alpha linolenic acid
If it is low, you should eat: flax-seed oil, walnuts and walnut oil, dried fruits and seeds, and green-leafed vegetables.