Cellular Nutrition: Fueling Life, Energy, and Health

1. Nutrients, Material, and Energy Source

Nutrients are the raw materials from which cells produce their own components. They replace lost components, facilitate growth, and produce new cells. Nutrients are the fuel for cells.

Other nutrients that reach the cells are used as fuel for cellular respiration. Glucose is the nutrient most used by cells as fuel. During cellular respiration, the following events occur:

• Oxygen consumption
• Release of energy usable by cells
• Production of carbon dioxide and water

Lipids and proteins can also be used as fuel to provide nutrients for energy. Cells use this energy to perform their functions.

Our body needs energy-containing nutrients to function; this energy is called chemical energy. Cellular respiration releases chemical energy, which is transformed into three forms of energy:

• Mechanical: for muscle contraction
• Chemical: to produce new molecules
• Thermal or heat: to maintain body temperature

2. Food-Related Disorders

Malnutrition refers to inadequate nutrition, both due to a poor diet and food binges.

Deficiency Diseases

Malnutrition occurs when the amount of food taken is not sufficient to meet the body's energy demands. Monotonous diets can lead to a lack of certain nutrients, which is a form of malnutrition and causes deficiency diseases.

Anorexia and Bulimia

Anorexia nervosa is a disease characterized by an intense fear of gaining weight and a distorted body image. This malnutrition leads to a serious deterioration in physical and physiological health. Patients often suffer from bulimia, which involves eating large amounts of food and then inducing vomiting to prevent weight gain.

Obesity

Obesity is excess body fat caused by excessive ingestion of energy-rich foods associated with a sedentary lifestyle.

3. Hormones: Chemical Messengers

Hormones are chemical messengers of lipid or protein nature that are carried in the blood to regulate certain body functions. They exert their function on cells by controlling and coordinating their activities. Hormones have the following characteristics:

• They are specific: Each hormone acts on certain cells called target cells.
• They are very effective.
• Their production is controlled.

Cells use glucose to obtain energy. The amount of glucose in the blood is controlled by two hormones secreted by the pancreas: insulin and glucagon. The control mechanism is performed as follows:

• When blood glucose levels rise, the blood passes through the pancreas and stimulates the secretion of insulin.
• Insulin acts on certain organs and stimulates glucose storage and the processing of excess glucose into fat.
• When the blood glucose level is low, the pancreas produces glucagon, which stimulates the release of glucose.