About the benefits of fats

Fat mythology

ABC MagazineRecently, nutritionists have removed the taboo from the use of fat, but at the same time prescribed a number of recommendations and clarifications, in which it is difficult for an ordinary consumer to understand without basic knowledge in organic chemistry.

At the same time, a number of myths and prejudices appeared, so it's time to consider the main ones in detail.

Let me remind you that until recently, dietary fats were conditionally divided into "good" (unsaturated, vegetable), "bad" (saturated, animal) and "very bad" (artificially saturated, margarine containing trans fats). Since then, the situation has changed radically, because animal fats can be useful, and modern margarine has completely rehabilitated itself. What remains relevant is that excess fat in the diet, as an excess of something, can be harmful; in addition, in order for fats to bring health benefits, you need to know what fats are and how to use them correctly.

Truth number one: despite the neutral taste of fats, even when it comes to refined and deodorized oils, our tongue still has receptors for their perception. Therefore, no matter how we persuade ourselves and convince ourselves, fatty foods still taste better to us.About the smoking point

Our regional cuisine is characterized by frying products.

Modern cuisine offers a variety of means to reduce the amount of fat for frying, such as special dishes that allow frying without fat. But – see "Truth number one". In addition, there are vitamins that dissolve in fats and are optimally absorbed by the body only in this form. However, during frying, some rules should be followed. All fats have a so-called smoking point, which signals the release of acrolein. It smells unpleasant when oil is smoking in a frying pan, and, much worse, it is a highly irritating substance to the mucous membranes of the eyes and respiratory tract and belongs to hazard class I (extremely dangerous substances). Of course, in order to bring its concentration in the air to the maximum permissible, it is necessary to leave the frying pan on the fire and leave the kitchen for a long time, but it is advisable to avoid small portions of poison.

The temperature of the beginning of smoking depends on the content of free fatty acids in the oil: the more fatty acids, the lower the temperature of the beginning of smoking, respectively (see table).

Table 1. Smoke point, °C

What are fatty acids?Reference from organic chemistry: fatty or carboxylic acids are organic molecules in the form of a carbon chain of various lengths with a carboxyl group at the end.

Let me remind you that the carbon atom (C) is quadrivalent: imagine for simplicity that it has four hands that can grab something. With two hands, carbon holds adjacent carbon atoms, forming a chain. Thus, there are still two free "hands" – valences that can be occupied by hydrogen (H) atoms, i.e. be saturated with hydrogen. Sometimes it happens that carbon atoms, instead of grabbing hydrogen, grab their neighbor twice. Then it is said that double covalent bonds are formed, and fatty acids in this case are called unsaturated (i.e. unsaturated with hydrogen). If there is one double bond for the entire fatty acid chain, then this is called monounsaturated fatty acids. If there are two or more such bonds, then we are talking about polyunsaturated fatty acids.

If I haven't completely confused you yet, I'll confuse you now:
– Are fatty acids fat? – No, but it's lipids.

– Oh! And lipids are not fat? – Lipids are a large group of chemicals, which includes both fats and fatty acids.

– And what is fat, then? – Fat is a compound of three molecules of fatty acids with one molecule of glycerin, which itself is an alcohol.


Of interesting things, you can also add that the potassium or sodium salt of fatty acids is soap. Fatty acids are also used as raw materials for emulsifiers. They often treat the surface of apples (who remembers, they are sometimes so greasy to the touch); in the food industry, fatty acids pass under the sign E570, and quantum satis (Lat. "how much is needed", without any restrictions in quantity).

Saturated or unsaturated?From the point of view of chemistry, we have already figured out a little about saturated and unsaturated fatty acids.

They can be recognized by their consistency: saturated fats are solid at room temperature, so from our own experience we can intuitively approximately distinguish that at least animal fats and butter contain saturated fatty acids. And vegetable fats, which are thinner, obviously contain unsaturated fatty acids.

However, there are exceptions to this simple rule in the form of solid vegetable saturated fats – such as coconut or palm oil, for example. Or fish oil, which, although liquid, is animal and contains unsaturated fatty acids.

The question arises, which ones are more useful? The advice of nutritionists, as a rule, begins with a demonstration of a table in which the percentage ratio of certain types of fatty acids is described in detail. It is believed that unsaturated fats are healthier, and there are several explanations for this.

Firstly, it's about the so-called essential fatty acids (those omega-3s, which will be discussed below), which are not synthesized in the body themselves, but are needed for normal life. And these essential fatty acids are exactly unsaturated. I.e., preferring pork fat, we automatically limit ourselves to essential fatty acids.
Secondly, the content of vitamin E. Vegetable fats contain a large amount of vitamin E, and animals – much less (there is no pork fat at all, there is a little in butter).
Thirdly, until recently, it was assumed that there was a causal relationship between atherosclerosis and cholesterol consumption. But since 90% of cholesterol is produced by the body itself and the causes of atherosclerosis most likely lie in the breakdown of the mechanisms of regulation of its synthesis in the body itself. However, if something has already broken down in the body and the cholesterol level is high, it is probably not worth consuming additional cholesterol. Namely, animal fats have a high cholesterol content, while vegetable fats do not have at all (recall a clever marketing trick – vegetable oil without cholesterol).

Truth number two: 25% of the daily calorie requirement must be covered with fats (for an adult, 60-80 grams per day, most of which should be vegetable fats.About trans

Cis- and trans-isomers are molecules of the same substance, differently "rotated" relative to the double bond line between atoms (Latin cis – on this side, trans - through, through, behind).

If we take a chain of a useful cis isomer of an unsaturated fatty acid and conditionally twist it around its axis at the place of the double bond, then instead we get the so-called trans configuration of this fat. It is this configuration that is under suspicion by nutritionists as a risk factor for cardiovascular diseases.

Where do these trans configurations come from and how to avoid them?

1. Sometimes in nature they form by themselves. For example, they are synthesized by certain bacteria during anaerobic fermentation in the stomach of a cow.

2. Once upon a time, when preparing margarine, unsaturated bonds were artificially saturated with hydrogen on nickel catalysts. And since the melting point of saturated fats is lower than unsaturated fats, the liquid oil became suitable for spreading. Such margarine had a high content of trans fatty acids. Modern margarine production technologies make it possible to reduce the content of trans fatty acids to trace amounts.

3. In addition, some unsaturated fats tend to go into a trans configuration when heated strongly. The less frequently the fat changes during frying, the more both acrolein and trans fatty acids accumulate in it. For example, a 2005 study showed that fats in French fries at McDonalds in Denmark contain 1% trans fat, in Germany - 9-10%, and in the USA – 23% of the total amount of fat. However, the situation has apparently already changed, because since 2008, the use of trans fats in cooking has been completely prohibited by law in New York. How they are going to avoid the formation of a trans-configuration during friting, I do not know.

Truth number three: if oil or fat smokes in a frying pan, then it is better not to eat the dish, and the room is well ventilated. Refined oils are better suited for frying, or if the dish requires unrefined vegetable oil for cooking, then it should be fried at a low temperature.About the mysterious omega-3 unsaturated acids

A few years ago, the advertising of one of the margarine varieties was accompanied by complex scientific graphs that informed the consumer that this margarine was supposedly not only free of cholesterol, but even contributes to its reduction.

However, a little time passed, and it became clear that the manufacturers lied a little – it does not lower, of course, but it does not increase either. Moreover, now virtually all margarines are so cool. Since 1999, the fashionable concept of "omega-3 unsaturated acids" has entered the lexicon of consumers instead of the outdated "vitamin F" (from the English fat - fat), and now manufacturers of oils and margarine boast to each other about the content of this acid. Therefore, it is worth understanding this issue in order not to overpay for myths.

Since we already know what unsaturated fatty acids are, let's figure out what omega-unsaturated ones are. Omega determines the position of the double covalent bond in the molecule. Depending on the number of the carbon atom with a double bond, omega-3, omega-6 and omega-9 unsaturated fatty acids are distinguished.

However, the healing properties are attributed to omega-3 and partially omega-6, and that is still conditional.

A Brief History of Omega-3 Hype1999 – publication of an Italian study in the Lancet journal.

11324 patients with myocardial infarction were observed. Conclusion: daily consumption of 1 g of omega-3 reduces the risk of recurrent heart attack by 45%.

2004 – Food and Drug Administration gives conclusions in the form of advice on omega-3 as a means to reduce the risk of coronary diseases. However, with the careful wording "supportive but not conclusive" ("supportive, but not definitive").

2006 – reports in the Journal of the American Medical Association, as well as virtually simultaneously in the British Medical Journal with a crushing conclusion: Long chain and shorter chain omega 3 fats do not have a clear effect on total mortality, combined cardiovascular events, or cancer (Long and short chains of omega-3 fats do not have a clear effect for total mortality from cardiovascular diseases or cancer).

2007 was a more gentle year for omega-3. At first, the Japanese reported that these fats are successfully used in the treatment of type 2 diabetes, as well as to lower cholesterol. Then there were a dozen more articles with similar studies, including confirmation of the anti-inflammatory effect.

In fact, the scales "for" and "neutral" have about the same number of arguments. But it is obvious that these omega-3s are at least harmless. It seems that under certain conditions, fats containing these acids can really contribute to health, so while the discussion on whether there is a recommended daily dose for omega-3 acids is still going on, we will see what these omega-3 acids are and in which products they can be found.

There are three types of omega-3 acids:

1. Alpha-linolenic acid (ALA) is found in linseed oil, walnuts, soy and rapeseed oil and in modern margarine. In addition, it is present in all plant photosynthetic green tissues. Please note that olive oil, despite being a favorite among vegetable oils, does not contain linolenic acid.
2. Eicosapentaenoic EPA (found in marine fish)
3. Docosahexaenoic DHA (found in marine fish)

There are separate studies on the supposedly optimal ratio of these acids, but I can hardly imagine how a consumer begins to count how much unsaturated acid he has already eaten in a day.

There is one nuance with sea fish. They, in addition to useful fatty acids, accumulate mercury compounds (sharks, sea bass, mackerel and tuna are most often mentioned about this) and cadmium (which is supposedly not so dangerous). And mackerel, cod, flounder, salmon, sardines and anchovies are considered to contain less mercury. It is quite difficult to overeat fish so that the mercury contained in it harms health, but just in case children, pregnant and lactating women are advised by nutritionists to limit the consumption of fish and eat it preferably boiled.

Truth number four: the healing properties of omega-3 unsaturated acids are clearly exaggerated. As part of a healthy diet, it is enough to eat salads seasoned with oil and delicious sea fish in reasonable quantities.About rapeseed oil

Until now, olive oil has been a favorite among vegetable oils.

It has not only a pleasant smell and taste, optimal fat composition, but also a decent price. However, it turned out that it just didn't work out with the composition of fatty acids: it contains only omega-9 from unsaturated fatty acids. But rapeseed oil in terms of nutritional value, and at the same time in terms of price, olive oil wins, although it has no special taste or smell.

The history of edible rapeseed oil is still quite fresh. Rapeseed is an interspecific hybrid of turnips and cabbage. Although it has been cultivated by mankind for a long time, its oil was used only for technical purposes until 1974. It had a pungent smell and a bitter taste. These properties were given to him by two substances: toxic erucic acid and glucosinolates are compounds that are not harmful and even useful, but bitter (mustard is a typical example). Feeds with a high content of glucosinolates in animals cause problems with the thyroid gland.

In 1974, the first so-called 0-rapeseed with an erucic acid content of less than 2% was bred using classical breeding methods. In 1982, the next version was brought out, 00-rapeseed, which no longer actually had not only erucic acid, but also glucosinolates.

In Canada, this variety was patented under the name "Canola" (Canola, Canadian oil, low acid). Since then, virtually any rapeseed there is now called that. It would be strange if they did not try to improve it further, so already huge areas around the world are sown with transgenic rapeseed, for example, resistant to herbicide. Canola can be either transgenic or not. Technical rapeseed, which is NOT 00-rapeseed and which is inedible, can not be distinguished from canola externally, it is perfectly pollinated with edible canola and poses a much greater threat to health than transgenic blizzard.

Let's summarize the results:
– the composition of fats in rapeseed oil is close to olive oil;
– in addition, it contains omega-3 fatty acids, unlike olive oil;
– the smoking point is optimal for frying.

Final conclusionYou can completely smear either butter or margarine on bread, and put a piece of mackerel on top.

All this is eaten with salad, seasoned with olive or cold-pressed linseed oil. Refined sunflower or rapeseed oil is better suited for frying. It is also possible to take capsules with fish oil or a spoonful of oil on an empty stomach, but at the expense of calories allocated to fat. Although I don't understand why.

The order in fats was brought by Ruslana Radchuk, a molecular geneticist,
Institute of Genetics of Cultivated Plants, Gatersleben, Germany.

Portal "Eternal youth" http://vechnayamolodost.ru22.02.2011