Science and human health

Introduction

In science, health is often defined as an organism's ability to respond to challenges and maintain a state of balance. Good nutrition and physical exercise are very important for human health. New scientific discoveries have improved the diagnostics (identification) and treatment of different human diseases. Today, the science of genetic engineering is an important part of the food industry. This chapter looks at some recent scientific discoveries that have changed the way we produce our food and treat diseases.

Genetic engineering and cloning

The science of changing an organism's genetic information is called genetic engineering. Today, genetic engineering techniques are used in many areas. In medicine, for example, it is sometimes possible, by reading DNA molecules, to find out how some diseases occur. It might be possible to fight some diseases by changing the DNA structural units that cause them. Powerful antibiotics can be created by changing the genetic code of organisms which produce antibiotics. Changing the genetic code of plants and animals in agricultural practices can lead to improved food products.

Dolly the sheep was the first mammal to be successfully cloned. To clone an organism means to duplicate it without the help of sexual reproduction. Sexual reproduction involves the union of male and female cells.

Genetically engineered (GE) food is a type of food that has been produced using genetic engineering processes. The genetic code is altered to modify the size, taste and weather resistance of some fruits and vegetables. Livestock are also being genetically modified to enhance the amount and quality of the meat they produce.

Genetically engineered food has not been around for long. It is hard to predict the outcome of using GE food over a long period of time. Many scientists are concerned that engineered organisms might harm people's health and the environment. For example, engineered crops might infect the food supply with drugs, kill beneficial insects and damage valuable natural resources.

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X-rays and cancer treatment

An X-ray is a type of high-energy radiation. In low doses, X-rays are used to diagnose diseases by taking pictures of the inside of the body. X-radiation can penetrate human skin tissue but is stopped by dense bones. This property makes X-rays valuable in medicine. In high doses, X-rays are used to treat cancer. Cancer is a disease that involves uncontrolled growth of the body's cells.

The use of high-energy radiation from X-rays to kill cancer cells is called X-ray therapy. X-ray radiation may come from a special machine or from radioisotopes (chemicals that produce radiation).

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Antibiotics

Antibiotics are chemicals produced by bacteria or fungi (small microscopic organisms) that can destroy harmful bacteria. The first antibiotic penicillin (extracted from the mould Penicillium notatum) was discovered by Alexander Fleming in 1929. Antibiotics used to be extracted only from natural sources like moulds. Today, many antibiotics are made by scientists in laboratories.

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