saturated fa

Saturated fatty acids are more resistant to thermal treatment as they have a higher smoke point. At room temperature, the acids remain in a solid form. Higher consumption of such FA represents one of the causes of many chronic diseases. They can be the cause of incorrect blood and tissue oxidation, accelerate the ageing process, increase the cholesterol level and thus the risk of occurrence of cardio-vascular diseases.

Saturated FA are found mainly in animal products. Most of them are in red meat, fat dairy products, lard and butter. The latest nutritional recommendations call for reducing the consumption of saturated FA down to 7-10 % of the total daily energy intake.

Virgin coconut oil belongs to the same group of saturated fatty acids as animal fats; it has, however, a different impact on human body. Fatty acids are used as an immediate source of energy, do not deposit in the body and do not block the vessels.

With the level of unsaturation (mono, polyunsaturated) of the fatty acids decreases the smoke point of fats and increases their dissolvability (in water, blood plasma). At the same time, however, increases disposition to oxidative rancidification in case of improper storage (taste, aroma and colour of the fat changes in an undesired way). Oils with high ratio of polyunsaturated acids are, on principle, not used for frying or deep frying.

Unsaturated fatty acids are divided into the following categories:

Fatty acids in edible oils 

Each type of vegetable oils has a specific composition, significant differences are especially in ratio of individual substances. Common feature for most oils is high content of unsaturated fatty acids and, on the contrary, low content of saturated fatty acids and absence of cholesterol.

Vegetable oils have, unlike animal fats, much higher ratio of unsaturated fatty acids, with the exception of palm, kernel and coconut oils, in which saturated fatty acids predominate.

In nature, and consequently then in foodstuff, lipids contain the following groups of fatty acids:

· Saturated fatty acids

· Monounsaturated fatty acids – with one double bond 

· Polyunsaturated fatty acids – with two or more double bonds

· Trans-unsaturated fatty acids

Procentage content of fatty acids in 100 g

OIL TYPEsaturated FAmonounsaturated FApolyunsaturated FA
Flax Seed8.619.171.7
Hemp Seed11.012.077.0
Pumpkin20.025.055.0
Evening Primrose8.36.084.7
Rice15.044.036.0
Avocado (organic, with lemon/ garlic)2073.36.7

Human body cannot synthetize (produce) certain polyunsaturated fatty acids although they are essential for life. They are fatty acids of the omega-3 line (α-linolenic acid) and omega-6 line (linoleic acid). These acids have to be then supplied in food. Most quantity of these acids are consumed in production of cellular and intra-cellular membranes, including cellular membranes of the skin. Long-term shortage of these acids in the body may cause pathological changes in livers, kidneys, skin and hair and retarded growth in children.

MONOunsaturated FA

These oils are regarded as ideal as their regular application reduces the level of the bad LDL cholesterol and slightly increases the level of the good HDL cholesterol. Apart from that, these oils are less prone to oxidative changes. 

Among monounsaturated fatty acids count omega-9 acids.

Omega-9 fatty acids

The most significant fatty acid of this type is oleic acid which can be partially produced by human body from stearic acid and which is utilized, above all, in metabolic reactions where energy is released from molecules. It also has the ability to influence positively the composition of blood fats and thus reduce the risk of atherosclerosis development. As oleic acid shows smaller tendency to deposit in fat reserves in comparison with saturated FA, it does not support development of obesity.

OIL TYPEPumpkin OilFlax OilAvocado oils (organic, with lemon/ garlic)
Oleic acid24.0 g19.1 g64.0 g

Tyto oleje jsou považovány za ideální, protože jejich pravidelné užívání snižuje hladinu škodlivého LDL cholesterolu a mírně zvyšuje hladinu ochranného HDL cholesterolu. Kromě toho jsou oleje méně náchylné k oxidačním změnách.

Mezi mononenasycené MK řadíme kyseliny omega-9.

Omega-9 mastné kyseliny

Nejvýznamnější MK této řady je kyselina olejová, kterou si tělo z části dovede samo vytvořit z kyseliny stearové, a která je využívána hlavně v metabolických reakcích, při kterých se z molekuly uvolňuje energie. Má také schopnost příznivě ovlivnit skladbu krevních tuků a tak snižovat riziko rozvoje aterosklerózy. Protože kyselina olejová vykazuje menší tendenci ukládat se do tukových zásob než nasycené MK, nepodporuje vývoj obezity.

DRUH OLEJEdýňový olejlněný olejavokádové oleje (BIO, s citronem, česnekem)
Kyselina olejová24,0 g19,1 g64,0 g

POLYUNSATURATED FATTY ACIDS

Polyunsaturated fatty acids are, from the point of view of nutrition, the most essential FA as they participate in many functions in human body. They play an important role in prevention of cardio-vascular diseases and are fundamental also for correct development of brain and eye retinae.

The ratio of polyunsaturated omega-6 FA and omega-3 FA in diet should be maximum 5:1. In fact, the ratio of omega-6 and omega-3 is usually 20:1. That is why it is recommended to reduce the intake of omega-6 to 7% of the total daily energy intake.

Omega-3 fatty acids

In general, intake of these acids is insufficient in our population. The reason is that these acids are found in several foodstuffs only. 

They positively influence the course of cardio-vascular diseases and, with their impact on human body, reduce the risk of their occurrence. They do not, in any significant way, influence the levels of cholesterol but they, rather remarkably, reduce the level of triacylglycerols in blood plasma.

OIL TYPEFlax Seed Oil Hemp Seed Oil
Alpha-linolenic55.8 g16.7 g
Stearidonic acid0 g0.7 g

Omega-6 fatty acids

The most important representative of omega-6 acids is linoleic acid which is formed by prolonging the chemical chain of arachidonic acid (starting compound for production of tissue hormones). Diet enriched with linoleic acid has a positive impact on the intensity of utilizing fat reserves, independently of the fact how much fat there is in the fatty tissue. In case of plentitude of linoleic acid in diet, the risk of fat deposit is not so high. Linoleic acid also assists in reducing the total cholesterol.

Gamma-linolenic acid provably reduces the high level of triacylglycerols and, on the contrary, increases the level of the good HDL cholesterol. It stimulates production of beneficial prostaglandins of the type 1, which, together with antioxidants such as selenium and zinc, effectively suppress inflammatory processes, reduce blood pressure and blood coagulation. A significant vegetable source of this acid are seeds of evening primrose. The natural production of prostaglandins of the type 1 is suppressed by smoking, alcohol drinking, low intake of the B-line vitamins, etc..

OIL TYPE Primrose Oil Hemp Seed Oil Pumpkin Oil Flax Seed Oil Avocado Oils (organic, with lemon/garlic)
Linoleic acid74.9 g51.3 g55.0 g15.9 g6.0 g
Gamma-linolenic acid 9.8 g3.3 g0 g0 g0 g

TRANS UNSATURATED FATTY ACIDS

Trans-unsaturated fatty acids occur at heating-up of oils (above 220°C), e.g. during excessively intense frying of food. The most common one is elaidic acid, which increases the level of the bad LDL cholesterol and reduces the level of the good HDL cholesterol.

They can increase the risk of cardio-vascular diseases and diabetes of the 2nd type. It is indicated that trans-isomers of fatty acids aggravate the ability of tissues to react to insulin and thus increase the risk of diabetes of the 2nd type. Trans-isomers of fatty acids are commonly found in milk fat (approx. 5 %) or in refined oils (approx. 1 %).

Trans-unsaturated fatty acids negatively influence the level of LDL cholesterol, more than saturated fatty acids. The most common source are, nowadays, various types of durable and soft pastry, margarines, fat toppings on food products or fast-food products where partially hardened fats are frequently used.

Application of suitable fats for thermal food preparation can limit their production.

Intake of trans-acids should not exceed 2 % of the total daily energy intake. These acids can be very harmful for human body in case of long-term consumption.

DEFINITIONS:

  • HDL cholesterol – transport of fat, especially cholesterol from vessels to liver.
  • LDL cholesterol – transport of fat from liver to vessels, fat is deposited in vessels – narrowing of vessels.
  • Triacylglycerols - fats deposited in fatty tissue, they represent energy storehouse, increased level of triacylglycerols in blood is one of the risk factors for development of atherosclerosis and relating complications due to insufficient perfusion of individual organs – especially diseases of the heart, brain, lower limbs.
  • Ateroskleróza – disease of vessel walls, consequently, fat is deposited in the artery walls with the result of narrowing the wall and thus restricting the flow of blood.
  • Prostaglandiny – substances similar to hormones, which can occur virtually in all organs. They affect perfusion and blood coagulation and take part in immunity and inflammatory processes.

  

 
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