Bella Adams
Edible fats (oils) and high temperatures
We use various fats (most commonly sunflower and olive oil) to cook foods in frying, stewing, and sautéing. However, research shows that not all fats should be exposed to high temperatures.
When heated to high temperatures, the components contained in oils oxidize and release toxic aldehydes (oxygenated α,β unsaturated), which are associated with the development of neurodegenerative diseases, cardiovascular pathologies, and certain types of cancer. It has been shown that in oils heated over 190º, which contain a lot of polyunsaturated omega-6 and omega-3 fatty acids (in particular, linseed and sunflower), the formation of toxic aldehydes occurs faster and in greater quantities than in those containing monounsaturated fatty acids (olive, rapeseed).
There are studies that link high blood pressure, impaired fat metabolism, and negative effects on digestive tract cells and intestinal microflora to the effects of these compounds. At the same time, the saturated fatty acids of animal fats, such as butter and lard, are practically not oxidized when heated, and therefore the formation of toxic aldehydes is practically non-existent.
So, butter or lard, or olive oil is best for frying, but sunflower oil is best used in salads or in cooking dishes that do not require high heat. Of course, our body is protected by powerful filters, such as the liver and immune system, but they also have their own resource.
Nutritional value and function in the body
The dietary fats we consume differ in their composition. For example, butter and lard are valuable for us for their cholesterol, which stabilizes the membranes of body cells and is also a precursor of sex hormones, glucocorticoids (involved in stress reactions), and mineralocorticoids (regulating blood pressure), and bile acids.
Saturated fatty acids of animal fats are used to create reserves of body fat for energy needs and the normal functioning of adipose tissue as an endocrine organ (regulates eating behavior, immune system, and blood condition).
Vegetable oils (sunflower, rapeseed, corn) are an essential component of the diet because they contain omega-6 polyunsaturated fatty acids that are not produced in our body (they are essential). Linoleic and arachidonic acids are components of cell membranes, they are used to form local hormones – eicosanoids, which are involved in the development of inflammation and regulation of vascular tone.
Another group of essential polyunsaturated fatty acids, omega-3, whose key representative is linolenic acid, is poorly represented in oils, with the exception of linseed oil, where it is about 53%. Omega-3 acids, which are especially abundant in fatty varieties of marine fish, are the source of a slightly different set of eicosanoids, which generally have anti-inflammatory and antihypertensive effects. Therefore, it is important to maintain an optimal ratio of omega-6 to omega-3 fatty acids, which, according to the literature, should be 4:1.
Digestion and absorption of dietary fats
A healthy diet implies that fats make up no more than 30% of the total energy received.
This component of food requires specific processing by the digestive system, which is impossible without the normal functioning of the liver, which produces bile to emulsify (grind) fat particles, and the pancreas, which secretes the enzyme lipase, which breaks down the emulsified fat. The cells of the small intestine must form new integral molecules from the digestion products of dietary fat, which, together with proteins, reach adipose tissue via the lymph and blood for storage or involvement in metabolism.
