Nutrition is the science that interprets the interaction of nutrients and other substances in food in relation to maintenance, growth, reproduction, health, and disease of an organism. It includes food intake, absorption, assimilation, biosynthesis, catabolism, and excretion.
The diet of an organism is what it eats, which is largely determined by the availability and palatability of foods. For humans, a healthy diet includes preparation of food and storage methods that preserve nutrients from oxidation, heat or leaching, and that reduce risk of foodborne illnesses.
In humans, an unhealthy diet can cause deficiency-related diseases such as blindness, anemia, scurvy, preterm birth, stillbirth and cretinism, or nutrient excess health-threatening conditions such as obesity and metabolic syndrome; and such common chronic systemic diseases as cardiovascular disease, diabetes, and osteoporosis.
Macronutrients are nutrients that provide calories or energy. Nutrients are needed for growth, metabolism, and for other body functions. Since "macro" means large, macronutrients are nutrients needed in large amounts. There are three macronutrients: carbohydrates, proteins, and fats.
Carbohydrates are the body's main source of energy. They are called carbohydrates because, at the chemical level, they contain carbon, hydrogen, and oxygen. There are three types of carbohydrates: starches (also known as complex carbohydrates), sugars, and fiber.
Proteins are large, complex molecules that play many critical roles in the body. They do most of the work in cells and are required for the structure, function, and regulation of the body's tissues and organs. Proteins are made up of hundreds or thousands of smaller units called amino acids, which are attached to one another in long chains.
Fats are a type of nutrient that you get from your diet. It is essential for some of your body's functions, such as moving vitamins around your body and helping to make hormones. However, it is important to eat the right kinds of fats and in the right amounts.
Micronutrients are essential elements required by organisms in small quantities throughout life to orchestrate a range of physiological functions to maintain health. Micronutrient requirements differ between organisms; for example, humans and other animals require numerous vitamins and dietary minerals.
Vitamins are organic compounds that are needed in small quantities to sustain life. Most vitamins need to come from food because the human body either does not produce enough of them or it does not produce any at all. Each organism has different vitamin requirements.
Minerals are the exogenous chemical elements indispensable for life. Although the four elements: carbon, hydrogen, oxygen, and nitrogen, are essential for life, they are so plentiful in food and drink that these are not considered nutrients and there are no recommended intakes for these as minerals.
Dietary guidelines are evidence-based recommendations on food and nutrition for health promotion and disease prevention. These guidelines provide advice on foods, food groups and dietary patterns to provide the required nutrients to the general public to promote overall health and prevent chronic diseases.
The Dietary Guidelines for Americans, for example, provide advice on what to eat and drink to meet nutrient needs, promote health, and prevent disease. It is developed and written for a professional audience, including policymakers, healthcare providers, nutrition educators, and Federal nutrition program operators.
Nutritional assessment is the systematic process of collecting and interpreting information in order to make decisions about the nature and cause of nutrition-related health issues that affect an individual. This assessment is typically performed by a registered dietitian nutritionist (RDN) and involves various methods.
There are four main types of nutritional assessments: anthropometric measurements, biochemical data, clinical examinations, and dietary analysis. Anthropometric measurements include height, weight, body mass index (BMI), and other body measurements. Biochemical data involves laboratory tests such as blood tests to assess nutritional status. Clinical examinations involve physical signs of nutritional deficiencies or excesses. Dietary analysis involves evaluating food intake and dietary patterns.
Therapeutic diets are modified diets designed to meet specific nutritional needs of individuals with medical conditions. These diets are prescribed by healthcare providers and implemented by registered dietitians to manage, treat, or prevent certain health conditions.
Examples of therapeutic diets include low-sodium diets for hypertension, low-fat diets for cardiovascular disease, low-sugar diets for diabetes, gluten-free diets for celiac disease, and renal diets for kidney disease. These diets are tailored to the individual's specific needs and may involve modifications in texture, consistency, nutrient content, or frequency of meals.
Understanding nutrition is essential for maintaining good health and preventing disease. By making informed food choices and following evidence-based dietary guidelines, individuals can optimize their nutritional status and overall well-being.