What Is the Chemistry of Nutrition?

We've all been told to eat our carrots for good eyesight, or leafy greens for healthy blood, but how do we know that certain foods are so important for our health? The answer lies in the chemistry of nutrition. The human organism is a complex of interdependent systems, all of which operate using chemicals provided by foods. More than our health depends on our choice of foods---our lives depend on providing the right fuel for the chemical reactions that grow and sustain our bodies.

Identification

Diet is what we eat, and nutrition science studies how our bodies use it. Whether food provides nutrition directly (as in the case of protein that forms tissue) or indirectly (like certain enzymes that trigger metabolic processes), all of it is subject to chemical reaction in the digestion process. Identifying chemicals that are beneficial to the body---and the amounts in which they are needed---can help people feel better and live longer. Nutritionists evaluate body chemistry to identify these nutrients, as well as those that can harm the body or interfere with the effectiveness of others.

History

The science of nutrition dates back to the Greeks, who reasoned that certain foods contained elements that benefited the body, since healthy people tended to eat the same groups of foods. The scientific study of nutrition began with the French chemist Lavoisier, who developed the concept of metabolism---the chemical process that provides the energy that runs the body. Through the 19th century, chemists studied the composition and function of minerals and fats in foods, and established the science of nutrition. American universities like Johns Hopkins helped develop nutrition science into more than just a chemical inquiry in the early 20th century. By mid-century, the major vitamins had been identified and governmental organizations had enough information to begin issuing suggested minimum requirements for specific nutrients. Today's nutrition science continues to refine the role of nutrients, particularly trace elements---compounds that appear to be beneficial, but for which no quantified need has yet been established--and compounds that appear to affect brain chemistry. Food "engineering" and nanotechnology are being developed to improve the nutritive value of crops to improve world agriculture.

Function

All food contains chemicals that compose the compounds we know as vitamins, carbohydrates, fats and proteins. Elements like chromium, copper, iodine, iron, manganese and zinc are called "trace" elements, and provide raw materials for blood, bone and nerve production, or trigger the production of hormones, antibodies or immune-system chemicals. Carbohydrates and fats provide raw material for energy production, insulating layers around vital organs and cushioning skin.

Considerations

Chemists and nutritionists have determined that the value of vitamins, minerals and other nutrients is not simply determined by the chemicals contained in them, but by the combinations and forms of the chemicals that are present in groups of foods. Eating a well-balanced diet is always preferable to taking chemical vitamin supplements. As research into the chemistry of nutrition continues, new nutrients (and new functions for old ones) are identified and new guidelines are published. Periodic revisions are published by the U.S. Department of Agriculture.

Misconceptions

You can indeed have too much of a good thing. Too much calcium without the vitamin D needed to metabolize it into bone is useless. Certain compounds can cause problems in large doses or interact negatively with each other. Vitamins A, B, B12, C, D and E all have possible adverse effects in large doses. Be sure you know the chemical consequences before "mega"-dosing any supplements.