Function of lipids in our body
In human nutrition, fatty acids of vegetable and animal origin also play a structural and metabolic role of primary importance.
Among their many functions we mention:
ENERGY PRODUCTION: thanks to the high number of hydrogen atoms each molecule develops large quantities of energy per unit of weight. The oxidation of a gram of fat in fact develops 9 Kcal, more than double the same amount of carbohydrates and proteins. For this reason, lipids are used as the main energy substrate at rest and during medium-low intensity activities (they provide about 80-90% of the energy needed at rest). As physical effort increases, the use of fats remains constant but there is a progressive increase in the consumption of glucose and muscle glycogen.
ENERGY RESERVE: unlike carbohydrates, whose stocks cannot exceed 400/500 grams, fat reserves are practically unlimited and ensure a constant supply of energy even in conditions of prolonged fasting. Suffice it to say that the oxidation of one kilogram of adipose tissue develops approximately 7800 calories which would allow a 75 kg man to travel over 100 kilometers of continuous running.
Compared to glycogen, adipose tissue is more concentrated for the same mass, because it is poorer in water. However, it has a lower density than the muscle, therefore, for the same weight, it occupies a higher volume.
CELLULAR METABOLISM: fats and in particular phospholipids and cholesterol are fundamental components of cell membranes. They take part in the formation of the phospholipid bilayer by regulating membrane fluidity and permeability.
ANTIOXIDANT FUNCTION: phospholipids and other lipid molecules protect our body from the aggression of free radicals, agents responsible for most degenerative diseases, aging and, it is hypothesized, some forms of cancer.
HEART AND VASES: they are precursors of regulatory substances of the cardiovascular system, blood coagulation, renal function and the immune system such as prostaglandins, thromboxanes, prostacyclin and leukotrienes (actions carried out mainly by polyunsaturated fatty acids).
HORMONAL REGULATION: despite its bad reputation, cholesterol is the precursor of both male and female steroid hormones (testosterone, progesterone, estradiol, cortisol). It is no coincidence that in women an excessive reduction in body fat (below 10-12%) is generally related to alterations in the menstrual cycle such as dysmennorrhea, amenorrhea, delayed menarche, and bone problems (premature osteoporosis).
LIPOSOLUBLE VITAMINS: fats act as transporters for fat-soluble vitamins; cholesterol promotes its absorption by participating in the formation of bile salts; cholesterol, thanks to the action of ultraviolet rays, regulates the synthesis of vitamin D. Our body needs at least 20 g of fat daily to transport fat-soluble vitamins . This aspect is very important as it testifies how fats indirectly regulate numerous metabolic functions mediated by vitamins.
NERVOUS SYSTEM: they participate in the formation of myelin, a substance that protects the nerves and allows the conduction of the nerve impulse. A deficiency of essential fatty acids can alter the normal development of the visual and nervous system in newborns. In adults, their presence it guarantees the optimal functionality of the central nervous system by intervening in the regulation of reflexes and mood.
SKIN: lipids together with proteins and water, give the skin its natural characteristics of softness, flexibility and elasticity. A reduction of lipids, which occurs spontaneously in the winter months, favors the loss of water through the superficial horny layer with consequent dehydration and decreased skin elasticity.
TRAUMA PROTECTION: they protect joints and vital organs (heart, liver, spinal cord, kidneys, spleen, brain, etc.) from possible trauma by keeping them, among other things, in their physiological position.
MODELING OF THE BODY SHAPES: lipids regulate the storage of fat in specific areas of the body, which differ according to sex. In women, the fat mass is generally concentrated in the hips, buttocks, thighs and abdomen below the navel (gynoid obesity).
In men, an android-type distribution prevails (fat mass concentrated in the face, neck, shoulders and especially in the abdomen above the navel) which is associated with higher levels of glycaemia, triglycerides and blood pressure.
THERMAL INSULATION: the fat intervenes in the body thermoregulation processes acting as a real insulator able to protect the body from low temperatures.
SENSE OF SATIETY: fats have a high satiating power in the long run and delay the onset of hunger. In fact, they require a digestive time varying from 3 to 4 hours. However, due to the long stay of the food in the stomach, they accelerate the fermentation phenomena of sugars and putrefactive proteins, reducing the absorption of nutrients and indirectly stimulating food intake.
FOOD APETABILITY: they improve the flavor of foods by encouraging their consumption.
The deficiency, rare in men, is characterized by: dry and scaly skin, rebellious impetigo, eczematous lesions, peri-anal irritation, generalized erythema, frequent bowel movements, bristly and sparse hair and thrombocytopenia
The fats or lipids
Function of fats
Fat requirement
NON hydrogenated vegetable fats
