The body’s benefit from food’s energy and nutrients occurs on the cellular level. To comprehend how this occurs, it is necessary to know some biochemistry. While this may be a daunting term, it is simply the study of the chemistry that occurs within living organisms. Knowing something about biochemistry helps in understanding how nutrients from foods and beverages are assimilated in living systems.
A basic principle of biochemistry is that all living things contain six key elements (or atoms): carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. These are the building blocks of organic material, carbon-containing compounds that are often living material. All the elements have the capacity to join together with similar or different elements to produce molecules or compounds, which then combine to create all the substances on earth.
Some organic compounds can be broken down by the body chemistry to create the energy, in the form of calories, needed to sustain life. Carbohydrates, fat, protein, and vitamins are organic molecules, but only the first three provide calories. A gram of carbohydrate or protein yields 4 calories while the same amount of fact provides 9 calories. Alcohol, though not strictly a nutrient, yields 7 calories per gram. Carbohydrates, fats, proteins, and alcohol are the only sources of calories form the diet. No calories are obtained from vitamins, minerals or water. Both water and minerals are inorganic compounds, substances that do not contain carbon and cannot provide calories.
This topic focuses on both organic and inorganic compounds by covering the six nutrient groups found in food and people : water, carbohydrates, fats, proteins, vitamins and minerals. These nutrients serve as the foundation underlying all the principles in food and nutrition.
Key Terms:
Nutrients
Food components that nourish the body to provide growth, maintenance and repair.
Molecule
A unit composed of one or more types of atoms held together by chemical bonds.
Compound
A substance whose molecules consist of unlike atoms.