Nutrition

Thought If you are what you eat and you don't know what you're eating, do you know who you are? Claude Fischler (2004)

Imagine a night out with your friends, cruising around town, looking for somewhere to hang out and grab a bite to eat. Your choices include a pizza place, a hamburger hangout, or an organic, fibre rich restaurant. Which would you choose?

If you and your friends are like the millions of people who enjoy the thrill of nutritionally void munchies, the choice is obvious. Unfortunately, you live in a country where 23.1% of Canadians aged 18 or older (an estimated 5.5 million adults) had a body mass index (BMI) of 30 or more, indicating that they are obese (Statistics Canada, 2004). Therefore the choices that you and your friends make at breakfast, lunch and dinner will greatly influence the probability of developing diabetes, heart disease, cancer or any other obesity related illness.

The chart above compares the obesity rate of Canadian men and women in 1978/79 to 2004. An increase in the obesity rates is seen for each age group.

Nutrients Just like a car needs fuel to perform at its best, your cells need the optimum performance nutrients in order to carry out their specific tasks. The three main nutrients required by your body are carbohydrates, fats, and proteins. In addition, your cells also require vitamins and minerals to operate properly.

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Carbohydrates Carbohydrates are the main energy source for your cells. The simplest form of a carbohydrate is the sugar glucose, the same product that is produced by plants through photosynthesis. Glucose is a simple sugar made up of one single unit and is called a monosaccharide (mono = one, saccharide= sugar). Disaccharides contain two simple sugars linked together and polysaccharides consist of long chains of simple sugars linked together. All carbohydrates contain carbon, hydrogen, and oxygen molecules in a ratio of 1:2:1 (CH2O).

Sucrose is table sugar. It is formed from the linkage between glucose and fructose, two monosaccharides. Cellulose is a polysaccharide that is found in the cell wall of plants. Humans are unable to digest or absorb the nutrients from cellulose. Cellulose represents a natural fibre that is an important component of human nutrition. As cellulose passes through the digestive tract it extracts water and facilitates the elimination of wastes. Other animals, like cows and rabbits, contain intestinal bacteria that can break down cellulose into its nutritional components.

Simple Carbohydrates These carbohydrates are digested quickly and can be readily absorbed. Simple carbohydrates do not require the cells of the body to work at breaking them down. As a result, an excess of these carbohydrates in a diet can be converted to glycogen (stored glucose) or fat. Simple carbohydrates include table sugar, cakes, pastry, and cookies.

Complex Carbohydrates Complex carbohydrates include foods that are made from whole grains like bread, rice, oatmeal and cereals. These carbohydrates require the body to work at breaking them down into their simple structures. As a result, the breakdown of complex carbohydrates takes longer and the absorption process occurs at a slower rate. This reduces the amount of sugar that will be converted into fat. Foods rich in complex carbohydrates help to maintain balanced blood sugar levels.

Fats / Lipids Contrary to popular rhetoric, fats are an essential component of a balanced diet. They provide long term energy storage, they cushion and insulate internal organs and they are a component of hormones. In addition, lipids are the main component of cell membranes. Fats are composed of carbon, hydrogen and oxygen molecules. Foods that are rich in fats include oils, butter, cheese, milk and meat.

Fats have the same basic structure of a triglyceride Fats have the same basic structure of a triglyceride. They contain glycerol, a three carbon molecule, and three fatty acid chains. The fatty acid contains long chains of carbon atoms attached to hydrogen atoms. The number of hydrogen atoms determines if the fat is liquid or solid at room temperature. Fatty acids with the maximum amount of hydrogen atoms per carbon atom are called saturated. These fats originate from animals and are solid at room temperature

A liquid fat contains carbon atoms that have some double bonds A liquid fat contains carbon atoms that have some double bonds. These fats are unsaturated and are derived from plants. Polyunsaturated fats are found in fish and in oils like soybean and corn. Unsaturated fats are healthy fats and should make up the majority of fats in a diet.

Homework Continue to work on your genetic disorder assignment You are presenting on either Monday or Tuesday!