& Joannie Dobbs Saturday
February 10, 2007
Protein plays a strong role in the body
Protein plays an interesting role in the lore of many popular diets. Some hold it out as a savior while others denigrate it to something of little concern. This makes it difficult to understand this nutrient's true value.
Question: What does protein do in the body?
Answer: Our bodies make thousands of specific proteins that determine our body structures and what we look like.
Proteins also regulate thousands of chemical reactions. Proteins are so important that DNA is essentially a cookbook with thousands of recipes (genes) that instruct cells to make unique proteins. Listed below are some key protein functions.
1. Certain proteins serve a major structural role in tissues such as muscle and skin and even provide the matrix for bones and teeth.
2. Proteins are vital to cell division that is necessary for growth, reproduction and healing.
3. Proteins help to transport other nutrients around the body by binding to them and then releasing them when and where they are needed.
4. Protein helps to regulate and maintain a proper fluid balance. This helps to maintain proper blood pressure and even lubricate eyes.
5. Many proteins keep everything working right by regulating chemical reactions. Examples include enzymes, hormones, blood clotting substances, even receptors in the eyes.
6. Protein is essential for the immune system to defend against foreign invaders such as bacteria and viruses.
Q: How does protein in food become protein in the body?
A: Proteins are composed of 20 different chemical building blocks bound in long strands. These building blocks are called amino acids. When we eat these food protein strands, our digestion breaks them down into their amino acid components that are absorbed into the body. The amino acids then circulate through the blood for delivery to cells throughout the body. The cells then reassemble the amino acids in a specific order to form protein strands as directed by our DNA.
Normally, nine of these amino acids must be obtained from food. The others can be formed by converting one amino acid into another. To stay in balance, the body needs a steady supply of these nine amino acids along with enough total protein.
Next time, we'll explore the consequences of getting too little or too much protein.
Alan Titchenal, Ph.D., C.N.S. and Joannie Dobbs, Ph.D., C.N.S.
are nutritionists in the Department of Human Nutrition, Food and Animal Sciences,
College of Tropical Agriculture and Human Resources, UH-Manoa.
Dr. Dobbs also works with the University Health Service
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