Frequently we hear people say that they don’t want to eat food that contains chemicals. From a nutritional standpoint this always confuses us, since each food is actually an amazing natural mixture of chemicals.

The body requires some of these food chemicals for essential physiological processes; other food chemicals are relatively unimportant for the body. And last, some naturally occurring food chemicals are potentially toxic to the body. When we select a reasonable combination of various types of food, we consume enough of the required chemicals and not too much of the toxic components.

Question: How many chemicals occur naturally in food?

Answer: Foods are composed of literally thousands of chemical compounds and elements. Between 40 and 50 of these chemicals are considered essential nutrients. In other words, the body needs to obtain these essential nutrients in adequate amounts from the diet for growth, reproduction and the maintenance of health and life.

Q: What chemicals are typically contained in any single food?

A: Virtually all foods have at least a small amount of water. Even crackers are about 5 percent water. Breads are about 35 percent and cooked rice is about 70 percent water. Most fruits and vegetables are 80 to 90 percent water. Living in a humid tropical climate, even our salt, sugar and oils take on trace amounts of water.

The combination of water, proteins, lipids (fats and oils) and carbohydrates (sugars, starch and fiber) make up about 98 percent or more of the chemicals in foods. Consequently, these chemicals are called macronutrients. Depending upon the food, the proportion of these macronutrients will vary.

Q: What chemicals are in the remaining food content?

A: Vitamins and minerals make up the remaining nutrient chemicals in food. Since these are needed in very small amounts, they are classified as micronutrients. In addition to nutrients, foods contain a variety of other naturally occurring chemicals, generally in small amounts. Some of these are beneficial but not essential, others are rather neutral and some are toxic when consumed in excessive amounts.

Q: With all of these chemicals in food, how can people make sure they consume adequate amounts of all the essential nutrients?

A: Consuming a wide variety of food from the various food groups helps to ensure adequate consumption of essential nutrients. The meat and meat alternative group, plus the milk group, provide the majority of protein in the typical American diet. The meat group consists of meat, fish, poultry, eggs, beans, nuts and seeds. Vitamin B-12 is found in the animal foods in this group and in B-12-fortified vegetarian foods. Red meat also provides most of the zinc and the most absorbable form of iron, called heme iron.

Typically, the grain, fruit and vegetable groups provide the majority of carbohydrate and calories in the diet. These food groups, as well as beans, nuts and seeds, also provide dietary fiber for gastrointestinal health.

The milk group also supplies carbohydrate and is the key food group supplying calcium, but there are also a few vegetables such as choy sum and kai choy that contain a fair amount of calcium that is also absorbable by the body.

As you can see, good nutrition is all about variety.

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Joannie Dobbs, Ph.D., C.N.S., and Alan Titchenal, Ph.D., C.N.S., are nutritionists in the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii-Manoa. Dobbs also works with University Health Services.