Objectives:
3.2.3 |
List three examples each of monosaccharides, disaccharides and polysaccharides.
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1 |
3.2.4 |
State one function of glucose, lactose and glycogen in animals, and of fructose, sucrose and cellulose in plants. |
1 |
You've probably seen ads for low-carb foods and diets, but kids and adults need carbohydrates (say: kar-bo-hi-draytz). Most foods contain carbohydrates, which the body breaks down into simple sugars - the major source of energy for the body.
Two Types of Carbohydrates
There are two major types of carbohydrates in foods: simple and complex.
Simple carbohydrates: These are also called simple sugars. Simple sugars are found in refined sugars, like the white sugar you'd find in a sugar bowl. If you have a lollipop, you're eating simple carbohydrates. But you'll also find simple sugars in more nutritious foods, such as fruit and milk. It's better to get your simple sugars from food like fruit and milk. Why? Because they contain vitamins, fiber, and important nutrients like calcium. A lollipop does not.
Complex carbohydrates: These are also called starches. Starches include grain products, such as bread, crackers, pasta, and rice. As with simple sugars, some complex carbohydrate foods are better choices than others. Refined (say: ree-find) grains, such as white flour and white rice, have been processed, which removes nutrients and fiber. But unrefined grains still contain these vitamins and minerals. Unrefined grains also are rich in fiber, which helps your digestive system work well. Fiber helps you feel full, so you are less likely to overeat these foods. That explains why a bowl of oatmeal fills you up better than sugary candy that has the same amount of calories as the oatmeal.
So which type of carbs should you eat? Both can be part of a healthy diet.
ScienceDaily (Jun. 28, 2007) — Foods of the kind that were consumed during human evolution may be the best choice to control diabetes type 2. A study from Lund University, Sweden, found markedly improved capacity to handle carbohydrate after eating such foods for three months.
During 2.5 million years of human evolution, before the advent of agriculture, our ancestors were consuming fruit, vegetables, nuts, lean meat and fish. In contrast, cereals, dairy products, refined fat and sugar, which now provide most of the calories for modern humans, have been staple foods for a relatively short time.
Staffan Lindeberg at the Department of Medicine, Lund University, has been studying health effects of the original human diet for many years. In earlier studies his research team have noted a remarkable absence of cardiovascular disease and diabetes among the traditional population of Kitava, Trobriand Islands, Papua New Guinea, where modern agrarian-based food is unavailable.
In a clinical study in Sweden, the research group has now compared 14 patients who were advised to consume an ‘ancient’ (Paleolithic, ‘Old stone Age’) diet for three months with 15 patients who were recommended to follow a Mediterranean-like prudent diet with whole-grain cereals, low-fat dairy products, fruit, vegetables and refined fats generally considered healthy. All patients had increased blood sugar after carbohydrate intake (glucose intolerance), and most of them had overt diabetes type 2. In addition, all had been diagnosed with coronary heart disease. Patients in the Paleolithic group were recommended to eat lean meat, fish, fruit, vegetables, root vegetables and nuts, and to avoid grains, dairy foods and salt.
The main result was that the blood sugar rise in response to carbohydrate intake was markedly lower after 12 weeks in the Paleolithic group (–26%), while it barely changed in the Mediterranean group (–7%). At the end of the study, all patients in the Paleolithic group had normal blood glucose.
The improved glucose tolerance in the Paleolithic group was unrelated to changes in weight or waist circumference, although waist decreased slightly more in that group. Hence, the research group concludes that something more than caloric intake and weight loss was responsible for the improved handling of dietary carbohydrate. The main difference between the groups was a much lower intake of grains and dairy products and a higher fruit intake in the Paleolithic group. Substances in grains and dairy products have been shown to interfere with the metabolism of carbohydrates and fat in various studies.
"If you want to prevent or treat diabetes type 2, it may be more efficient to avoid some of our modern foods than to count calories or carbohydrate," says Staffan Lindeberg.
This is the first controlled study of a Paleolithic diet in humans.
Adapted from materials provided by Lund University.
Need to cite this story in your essay, paper, or report?
Lund University (2007, June 28). Original Human 'Stone Age' Diet Is Good For People With Diabetes, Study Finds. ScienceDaily. Retrieved November 27, 2007, from http://www.sciencedaily.com/releases/2007/06/070627225459.htm