Nutrition, nourishment, or aliment, is the supply of materials - food - required by organisms and cells to stay alive. In science and human medicine, nutrition is the science or practice of consuming and utilizing foods.
Fast facts on nutrition
- The human body requires seven major types of nutrients.
- Not all nutrients provide energy but are still important, such as water and fiber.
- Micronutrients are important but required in smaller amounts.
- Vitamins are essential organic compounds that the human body cannot synthesize.
What is nutrition?
As molecular biology, biochemistry, and genetics advance, nutrition has become more focused on metabolism and metabolic pathways - biochemical steps through which substances inside us are transformed from one form to another.
Nutrition also focuses on how diseases, conditions, and problems can be prevented or reduced with a healthy diet.
Similarly, nutrition involves identifying how certain diseases and conditions may be caused by dietary factors, such as poor diet (malnutrition), food allergies, and food intolerances.
What is the difference between a dietitian and a nutritionist?
A registered dietitian nutritionist (RD or RDN) studies food, nutrition, and dietetics through an accredited university and approved curriculum, then completes a rigorous internship and passes a licensure exam to become a registered dietitian.
A nutritionist (without the title of an RD or RDN) studies nutrition via self-study or through formal education but does not meet the requirements to use the titles RD or RDN. The two terms are often interchangeable, but they are not identical.
Dietetics
Dietetics is the interpretation and communication of the science of nutrition; it helps people make informed and practical choices about food and lifestyle in both health and disease.
Part of a dietician's course includes both hospital and community settings. Dietitians work in a variety of areas, from private practice to healthcare, education, corporate wellness, and research, while a much smaller proportion work in the food industry.
A dietitian must have a recognized degree or postgraduate degree in nutrition and dietetics and meet continuing education requirements to work as a dietitian.
Nutrition
Nutrition is the study of nutrients in food, how the body uses nutrients, and the relationship between diet, health, and disease.
Major food manufacturers employ nutritionists and food scientists.
Nutritionists may also work in journalism, education, and research. Many nutritionists work in the field of food science and technology.
There is a lot of overlap between what nutritionists and dietitians do and study. Some nutritionists work in a healthcare setting, some dietitians work in the food industry, but a higher percentage of nutritionists work in the food industry and in food science and technology, and a higher percentage of dietitians work in healthcare, corporate wellness, research, and education.
The human body requires seven major types of nutrients
A nutrient is a source of nourishment, a component of food, for instance, protein, carbohydrate, fat, vitamin, mineral, fiber, and water.
- Macronutrients are nutrients we need in relatively large quantities.
- Micronutrients are nutrients we need in relatively small quantities.
Macronutrients can be further split into energy macronutrients (that provide energy), and macronutrients that do not provide energy.
Energy macronutrients
Energy
macronutrients provide energy, which is measured either in kilocalories
(kcal or calories) or Joules. 1 kilocalorie (calorie) = 4185.8 joules.
Energy macronutrients include:
Carbohydrates - 4 kcal per gram
Carbohydrate molecules include monosaccharides (glucose, fructose, galactose), disaccharides, and polysaccharides (starch).
Nutritionally,
polysaccharides are favored over monosaccharides because they are more
complex and therefore take longer to break down and be absorbed into the
bloodstream; this means that they do not cause major spikes in blood
sugar levels, which are linked to heart and vascular diseases.
Proteins - 4 kcal per gram
There
are 20 amino acids - organic compounds found in nature that combine to
form proteins. Some amino acids are essential, meaning they need to be
consumed. Other amino acids are non-essential because the body can make
them.
Fats - 9 kcal per gram
Fats are
triglycerides - three molecules of fatty acid combined with a molecule
of the alcohol glycerol. Fatty acids are simple compounds (monomers)
while triglycerides are complex molecules (polymers).
Fats are
required in the diet for health as they serve many functions, including
lubricating joints, helping organs produce hormones, assisting in
absorption of certain vitamins, reducing inflammation, and preserving brain health.