Nutrition

What Is Nutrition? Why Is Nutrition Important?

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. In hospitals, nutrition may refer to the food requirements of patients, including nutritional solutions delivered via an IV (intravenous) or IG (intragastric) tube.

Nutritional science studies how the body breaks food down (catabolism) and repairs and creates cells and tissue (anabolism) – catabolism and anabolism = metabolism. Nutritional science also examines how the body responds to food. In other words, “nutritional science investigates the metabolic and physiological responses of the body to diet”.

As molecular biology, biochemistry and genetics advance, nutrition has become more focused on the steps of biochemical sequences through which substances inside us and other living organisms are transformed from one form to another – metabolism and metabolic pathways.

Nutrition also focuses on how diseases, conditions and problems can be prevented or lessened with a healthy diet.

Nutrition also involves identifying how certain diseases, conditions or problems may be caused by dietary factors, such as poor diet (malnutrition), food allergies, metabolic diseases, etc.
What is the difference between a dietician and a nutritionist?
A dietician studied dietetics, while a nutritionist studied nutrition. The two terms are often interchangeable, however they are not 100% identical.

• Dietetics: the interpretation and communication of the science of nutrition so that people can 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. The majority of dieticians work in health care, education and research, while a much smaller proportion also work in the food industry. A dietician must have a recognized degree (B.Sc. or M.Sc), or postgraduate degree in nutrition and dietetics to work as a dietician.

• Nutrition: 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 dieticians do and studied. Some nutritionists work in health care, some dieticians work in the food industry, but a higher percentage of nutritionists work in the food industry and food science and technology, and a higher percentage of dieticians work in health care.

One could very loosely generalize and say that a nutritionist focuses firstly on a food, and then looks at its effects on people, while a dietician looks at the human, and then how that human’s health is influenced by food.

If I discovered a new fruit and wanted to find out what it consisted of I would go to a nutritionist. If I found out I had a long-term disease and wanted to know whether I needed to adjust my food intake because of the disease, I would go to a dietician. Please bear in mind that this very loose comparison is both subjective and possibly too geographically bound on my part (British, National Health Service), and is simply aimed at exaggerating the differences so that lay people may see some gap between the two – differences and disagreements in my interpretation will exist in different countries, within regions of a countries, and also from college to college – and many in those areas will disagree with each other.

From what I can glean from hundreds of studies and texts that I read as an editor of a medical journal, in the USA, Australia, and to a lesser extent in the UK and the Republic of Ireland, people who call themselves dieticians are more likely to have full university bachelor’s or postgraduate qualifications, while nutritionists mostly do as well, but a higher proportion may not.

In the US, dietitians are registered or licensed with the Commission for Dietetic Registration and the American Dietetic Association, and are only able to use the title dietitian as described by the business and professions codes of each respective state, when they have met specific educational and work experience requirements and passed a national registration or licensure examination, respectively.

Everyone in medicine is involved in nutrition

If you ask any health care professional, be it a doctor, nurse, psychologist, or dentist to identify a part of medicine that is not at all related to nutrition, there will be a long silence as they scratch their heads.

Nutrition is present in all processes of life. Right from the very moment the sperm fertilizes an egg, through fetal development in the uterus, to the birth, human growth, maturity, old age, and eventual death. Even after death the human body serves as nutrition for other organisms. Anything that involves life and chemical or biochemical movement has nutrition at its core.

Anything that lives is dependent on energy, which results from the combustion of food.

The human body requires seven major types of nutrients
A nutrient is a source of nourishment, an ingredient in a food, e.g. 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.

Energy macronutrients – these provide energy, which is measured either in kilocalories (kcal) or Joules. 1 kcal = 4185.8 joules.

• Carbohydrates – 4 kcal per gram

Molecules consist of carbon, hydrogen and oxygen atoms. Carbohydrates include monosaccharide (glucose, fructose, glactose), sisaccharides, and polysaccharides (starch).

Nutritionally, polysaccharides are more favored for humans because they are more complex molecular sugar chains and take longer to break down – the more complex a sugar molecule is the longer it takes to break down and absorb into the bloodstream, and the less it spikes blood sugar levels. Spikes in blood sugar levels are linked to heart and vascular diseases.

• Proteins – 4 kcal per gram

Molecules contain nitrogen, carbon, hydrogen and oxygen. Simple proteins, called monomers, are used to create complicated proteins, called polymers, which build and repair tissue. When used as a fuel the protein needs to break down, as it breaks down it gets rid of nitrogen, which has to be eliminated by the kidneys.

• Fats – 9 kcal per gram

Molecules consist of carbon, hydrogen, and oxygen atoms. 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). For more details on dietary fat, go to What is fat? How much fat should I eat?
Other macronutrients. These do not provide energy

• Fiber

Fiber consists mostly of carbohydrates. However because of its limited absorption by the body, not much of the sugars and starches get into the blood stream. Fiber is a crucial part of essential human nutrition. For more details go to What is fiber? What is dietary fiber?

• Water

About 70% of the non-fat mass of the human body is water. Nobody is completely sure how much water the human body needs – claims vary from between one to seven liters per day to avoid dehydration. We do know that water requirements are very closely linked to body size, age, environmental temperatures, physical activity, different states of health, and dietary habits. Somebody who consumes a lot of salt will require more water than another person of the same height, age and weight, exposed to the same levels of outside temperatures, and similar levels of physical exertion who consumes less salt. Most blanket claims that ‘the more water you drink the healthier your are’ are not backed with scientific evidence. The variables that influence water requirements are so vast that accurate advice on water intake would only be valid after evaluating each person individually. 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. In hospitals, nutrition may refer to the food requirements of patients, including nutritional solutions delivered via an IV (intravenous) or IG (intragastric) tube.
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. In hospitals, nutrition may refer to the food requirements of patients, including nutritional solutions delivered via an IV (intravenous) or IG (intragastric) tube.