Consuming certain amounts of key nutrients sounds more difficult than it actually is. Most people living in industrial nations have access to more than enough of all the kinds of foods we need every day. The problem lies in
what people choose to eat from among those foods. Having a little nutrition education comes in handy.
Generally, nutrients are divided into two classes: macronutrients and micronutrients. Macronutrients make up the bulk of a healthy diet. They include proteins, carbohydrates, and fats. They are the source of calories in the diet.
Proteins supply amino acids, the building blocks that build, repair, and maintain body tissue. Foods from animals-lean meats, poultry, fish, eggs are dense with proteins. They are called complete proteins because they contain all nine essential amino acids. Beans, nuts, tofu (a soy bean product), peanut butter, and grains are some of the vegetable sources of protein. People who consume vegetable protein as their only source—usually vegetarians—must be sure to consume a well balanced variety. All vegetable proteins are lacking in one essential amino acid or another.
Carbohydrates are the body’s main source of energy or calories. They are either complex (starches) or simple (sugars). The body converts both kinds of carbohydrates to glucose (a form of sugar) and sends it through the blood stream to every cell in the body. Cereals, vegetables, fruits, and sugars (sweet snacks, sugary drinks, candies, and all kinds of desserts are obvious examples) are the main sources of carbohydrates.
The third macronutrient includes fats and oils, the most dense energy sources in our foods. Fats, also known as lipids, are made up of differing amounts of fatty acids. Some kinds are much more healthful than others. Monounsaturated fats are found in plant foods such as olives, peanuts, and avocados. Polyunsaturated fats are found in seed oils such as corn oil, as well as in walnuts, almonds, sardines, cod, pink salmon, tuna, and sardines. Both kinds of unsaturated fats are healthy fats. Vegetable sources of mono- and polyunsaturated fats are easy to recognize because they are liquid at room temperature.
Saturated fats are animal fats and fats that are solid at room temperature, such as butter. Trans-fatty acids found in some margarines and shortenings—are the least healthy forms of all the fats. They should be kept to less than 10 percent of a person’s total calorie intake.
Fats play an essential role in human health. For example, they carry certain vitamins and hormones into and out of our cells. They also add flavor and texture to food. Fats contribute to making us feel full, too, so they help control
our appetite. Fats that gather around internal organs provide insulation. They offer some protection to the heart, kidneys, and other body parts from hard blows and extreme temperatures.
Fats are the raw materials for building cell membranes (lining of the cell) and maintaining nerve function. Therefore, they are especially important during infancy and the early years of growth. Fat is also a lubricant, helping our joints
work more smoothly and our skin stay smoother and softer
Micronutrients, on the other hand, are needed in small quantities, but they are absolutely essential to life. They consist of two categories—vitamins and minerals. Vitamins help control the chemical processes that take place in
the body. Humans need thirteen different vitamins. For the most part, they must be obtained from food.
Minerals also have important roles in health. More than sixty minerals exist in the body, but only about twenty-two are considered essential. Six of these—calcium, phosphorus, sodium, chloride, potassium, and magnesium—are needed in larger quantities. The rest are referred to as trace minerals, even though they are all equally important.
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