The human body requires seven major types of nutrients

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 monosaccharides (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).

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.

· Water


About 70-80% 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.

Дата добавления: 2015-10-29