Nutrients are the substances required to sustain all life. For human beings there are six categories of essential nutrients: proteins, carbohydrates, fats, minerals, vitamins and water. In this article, I will cover the basics by listing the main functions of each category (with more details about minerals and vitamins as they contain many varieties) and the foods or other elements which contain them.
Proteins are made of tiny modules called amino acids. They are very important in the growth and development of body tissues and are the main component in muscles, blood, skin and all internal organs (e.g. heart and brain). Proteins are also needed for the formation of enzymes (i.e. hormones) which control chemical processes such as sexual development and metabolism. Some proteins are manufactured in the body and others must be obtained from the diet in protein-rich foods such as meat, fish, eggs, dairy products, soy beans and nuts.
Carbohydrates are starches and sugars. They are the main source of energy utilized by the body in all its functions and are specifically required for: digestion, regulating protein and fat metabolism and assisting in the break down of fats in the liver. Starches are found in rice, wheat, corn and potatoes. Sugars are the refined variety which are contained in sweets and should be eaten in moderation as they do not contain any nutrients (i.e. they do not serve any purpose other than to tickle your taste buds).
Fats are a rich source of energy and are absolutely necessary for optimum health. Fats protect vital organs, are a component in all body cells and regulate body temperature. The main source of dietary fat is from animals – this is also known as saturated fats. These fats can increase cholesterol which can cause cardiovascular problems. However, cholesterol also plays an important role in digestion and the formation of many of the body’s hormones. It is always present in the body regardless of the foods consumed and it will only cause problems when excessive levels, unable to be absorbed by the body’s cells, start to accumulate in the walls of blood vessels. Unsaturated fats are healthier and are found in vegetable oil, olive oil and fish, such as salmon.
Minerals are chemical elements which are obtained via the diet only (i.e. they cannot be manufactured in the body). There are many but for the purposes of this article I will focus on the main ones – calcium, phosphorus, iodine, magnesium, potassium, sodium, iron and zinc.
Calcium is the major component of bones and teeth – it is also vital for blood clotting and regulating nerve signals. The best dietary sources are dairy products as well as green leafy vegetables, nuts and sardines.
Phosphorus works with calcium to strengthen bones and teeth. Foods high in calcium and protein will also provide enough phosphorus.
Iodine is required for proper thyroid gland functioning (this gland is responsible for cellular metabolism). Seafood and sea plants (i.e. seaweed) are good sources of iodine. Iodized table salt is also available from supermarkets for those who cannot or do not eat seafood.
Magnesium works with calcium in the formation of bones and plays a vital role in the electrical movements of muscles and nerves. Even though magnesium is found in many foods (e.g. unrefined grains, spinach, beans, nuts and peas) it is destroyed during cooking so dietary supplementation is recommended.
Potassium is important in enabling the balance of water in the body which in turn stimulates nerve signals for the heart and other muscle movements. It is abundantly found in bananas, avocados, potatoes, apricots, fish and green leafy vegetables.
Sodium has a similar function to potassium in that it regulates water levels in the body. It is a component of salt and so is readily available in the diet.
Iron assists in the building of red blood cells and carrying oxygen from the lungs to the rest of the body. Rich sources of iron are red meat, egg yolks and green leafy vegetables.
Zinc is a component of several different enzymes which are involved in digestion and metabolism. It is important in the development of reproductive organs and in strengthening the immune system. Zinc is found in peanuts, lamb, cocoa or dark chocolate, sesame seeds, wheat germ and oysters.
Vitamins are substances that the body either cannot manufacture at all or it cannot create enough to sustain health so, once again, they must be present in your diet. The main vitamins (or groups of vitamins) are: Vitamin A, B-group vitamins, Vitamins C, D, E and K.
Vitamin A is needed for healthy bones, vision and skin. Most Vitamin A is stored in the liver which needs a sufficient quantity of zinc in order to be released into the bloodstream. Foods high in this nutrient are dark green, red, yellow and orange fruits and vegetables.
B-group vitamins are important in maintaining a healthy nervous system as well as converting carbohydrates into energy. They also maintain the muscle tone of the heart and the digestive tract. B vitamins are found in whole grains, meat (especially liver), fish, eggs, milk, bananas, lentils and soybeans.
Vitamin C is necessary for the creation of collagen which is the connective tissue in skin, ligaments and bones. It is required for healthy teeth, gums, blood vessels and immunity. It also assists the body to absorb iron. Most fruits and vegetables contain high amounts of this nutrient.
Vitamin D is required for the absorption of calcium and phosphorus to form strong bones and teeth. It strengthens the immune system, is involved in the creation of blood cells and cell reproduction. Sunlight exposure on the skin allows the body to create Vitamin D but it is also obtained via foods such as, egg yolks, butter, fish livers and oil.
Vitamin E assists in the prevention of blood clotting (i.e. reducing the risk of stroke and heart attacks) and increasing muscle stamina. Whole grains and seeds contain Vitamin E.
Vitamin K is needed for blood clotting and bone formation. It is made in the body by bacteria in the intestinal tract and is also found in spinach leaves, cabbage, cauliflower and pork liver.
Water is absolutely vital for every cell in the body. It is important in many chemical processes as well as regulating body temperature and assisting in the elimination of waste. Drinking water is the main way to ingest this nutrient, however, fruit is also a good source as it contains more than ninety percent of this life-sustaining liquid.
Dunne L.J., 2002, Nutrition Almanac (Fifth Edition), New York, McGraw-Hill.
© New Age Power (Helen Papadopoulos)
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