After eating a portion of food, molecules in the digestive system called enzymes break down proteins into amino acids, fats into fatty acids, and carbohydrates into simple sugars (such as glucose). Apart from sugar, the body can use both amino acids and fatty acids as energy sources when it needs them. These compounds are absorbed by the blood, which is responsible for transporting them to the cells. Once inside the cells, other enzymes accelerate or regulate the chemical reactions necessary to “metabolize” these compounds. During this process, the energy from the compounds can be released for use by the body or stored in body tissues, especially the liver, muscles, and body fat.
In this way, metabolism is a kind of juggling in which two types of activities intervene simultaneously: the manufacture of body tissues and the creation of energy reserves, on the one hand, and the decomposition of body tissues and energy reserves to generate the fuel necessary for bodily functions, on the other:
Anabolism, or constructive metabolism, is about manufacturing and storing: it is the basis for the growth of new cells, maintaining body tissues, and creating energy reserves for future use. Small and straightforward molecules are modified during anabolism to build more extensive and more complex carbohydrate, protein and fat molecules. Catabolism, or destructive metabolism, is the process by which the energy necessary for all activities is produced. In this process, cells break down large molecules (mostly carbohydrates and fats) to obtain energy. Apart from being the fuel necessary for anabolic processes, the energy produced allows the body to warm up, move it, and contract the muscles. When they break down chemical compounds into simpler substances, the waste products released in the process are flushed out through the skin, kidneys, lungs, and intestines.
Several hormones manufactured by the endocrine system are responsible for controlling the speed and direction (“ana” or “tasting”) of metabolism. Thyroxine, a hormone produced and secreted by the thyroid gland, plays a critical role in determining the rate at which chemical reactions of metabolism occur in a person’s body.
Another gland, the pancreas, secretes or secretes hormones that help determine whether the body’s main metabolic activity at any given time will be anabolic or catabolic. For example, after the main meal, anabolism generally predominates over catabolism because eating increases the concentration of glucose – the body’s primary fuel – in the blood. The pancreas captures the highest glucose concentration and releases the hormone insulin, which signals the cells to increase their anabolic activities.
Metabolism is a complex chemical process, so it is not surprising that many people tend to simplify it, conceiving it merely as something that determines how easily our body gains or loses weight. This is where calories come into play. A calorie is a unit that measures how much energy a particular food provides to the body. A chocolate bar has more calories than an apple, which means it provides the body with more energy – and sometimes more than it needs. In the same way that a car stores gasoline in the tank until it needs it to feed the engine, the body stores calories – mainly in the form of fat. If you overfill a car’s gas tank, it will overflow the tank and spill onto the road. Similarly, if a person eats too many calories, they will “spillover” as excess body fat.
The number of calories a person burns in a day is influenced by the amount of physical exercise, the amount of fat and muscle their body contains, and their basal metabolic rate. Basal metabolism measures the rate at which a person “burns” energy, in the form of calories, in a state of rest, that is, while resting. Basal metabolic rate can play a role in a person’s tendency to gain weight. For example, a person with a slow basal metabolism (that is, burns few calories while sleeping) will tend to gain more weight than a person of the same size with an average basal metabolism who eats the same amount of food and does the same amount of exercise.
What are metabolic disorders?
Here are some examples of metabolism disorders, which you may already know:
Galactosemia: is a congenital metabolic disorder. The babies born with this problem have difficulty metabolizing (assimilating) the simple sugar enzyme or galactose. The sugar enzyme is also found in dairy products. Phenylketonuria: Another congenital disorder caused by a defect in the enzyme responsible for breaking down the amino acid phenylalanine, necessary for average growth and the manufacture of proteins. Hyperthyroidism: occurs when the thyroid gland secretes (produces) an excessive amount of thyroxine, which accelerates the basal metabolism. It causes weight loss, rapid heart rate, high blood pressure, prominent or bulging eyes (exophthalmos), and a bulging in the neck due to an enlarged thyroid gland (goitre). Hypothyroidism: occurs when the thyroid gland is absent or produces little thyroid hormone (thyroxine). Sometimes due to the production of antibodies that partially destroy this gland, which therefore secretes an insufficient amount of the hormone thyroxine. Which slows down the basal metabolism. In infants and children, it can cause growth and mental retardation. In adults, it causes fatigue, decreased heart rate, weight gain, and constipation. Diabetes, type 1 or type 2 diabetes: the first (type 1 diabetes) occurs when the pancreas does not produce or secrete enough insulin (insulin is required for treatment), the second (type 2 diabetes) occurs when the body does not responds to insulin appropriately, has insulin resistance that occurs. In advanced cases, there may not be enough insulin. Possible symptoms
Typical symptoms include frequent urination, being very thirsty, and being very hungry. You can also lose weight, although people with type 2 diabetes tend to be overweight or obese.
In the long term, if left unchecked, it can cause serious complications. These include kidney problems (diabetic nephropathy), nerve damage (diabetic neuropathy), retinopathy and blindness, and cardiovascular disease.
In all cases, metabolic disorders must be treated and generally controlled, and people with metabolic problems can maintain a good quality of life. Consult your doctor if you have questions about your health or think you may have a metabolism disorder.