Abstract
According to researches conducted by clinicians, there exist numerous medical problems impacting the most countries in the recent times. These clinicians postulated that obesity is the most common problem that is affecting children in greater part of the world. It is estimated that about 20% of the children and half of the adults are overweight and significant increment was realized in the late 1960s and early 1970s. Most federal governments and other medical agencies have stepped forward with various strategies that can combat this problem. They have advocated that people should reduce the level of sugar and fat intake to curb this prevalence. These agencies have further postulated that people should consume more of complex carbohydrate. It is noteworthy that there has been general increase in the number of obese persons in America despite the reduction in the level of fat and sugar intake suggesting that there are some dietary factors that are critical to human body regulation. Glycemic index has been considered to be one of the factors that play a critical role in regulating the body weight (Brouns, 2005)
Introduction
Early studies show that different foods have different complexities in their nature due to the fact that foods are not created equal. The diverse foods that we take have different effects to our body as they have different characteristic. The glycemic index or GI is defined as a measure of the diverse effects of the carbohydrate on the level of glucose in our body. It best describes the difference by ranking the different effects of carbohydrates on the blood glucose. The breaking down of carbohydrates during digestion process leads to release of glucose into the bloodstream. The rate at which these carbohydrates are broken down in our body systems determines the rate at which glucose is supplied into bloodstream. The more rapid the breakdown of this glucose the more rapid the glucose are released into our body system. Carbohydrates that break down slowly leads to slow release of glucose into the body system. In research to find the best food that people should take to avoid obesity, Dr. David J. Jenkins developed a concept of Glycemic Index and he stated that the more the breakdown of glucose the rapid the glucose level in our body system hence high GI and vice versa is true.
Studies conducted by Jenkins defined the glycemic index of a food as the area under two hour blood glucose response (AUC) that accompanies the ingestion of certain quantity of carbohydrate which is usually 50 g. (Brouns, 2005). The secret of long term illness that results from the level of glucose in our body system is choosing low GI carbs which produce minimum fluctuations in the level of insulin and glucose. This in turn has the effect of reducing the risks of heart diseases and diabetes that are associated with the high glucose and insulin level in our body system. Some clinicians have suggested that a lower glycemic index involves the reduction in the rate of digestion and food absorption (carbohydrates). It also clearly indicates greater removal of these foods from the liver and the periphery of the products of carbohydrates absorption. The lower glycemic is postulated to be equal to the low insulin demand which leads to reduction in the level of blood lipids.
In this measure, insulin index is of paramount importance because it measures directly the reaction of insulin to food (Roche, 2003)
Benefits of the Glycemic Index
Consumption of high GI foods is very harmful to the human health since it pushes the body to extremes. It is quite imperative to change the diet at any time to curb the issue of high level of glucose in the body. The consumption of high GI foods is detrimental especially if the subject is inactive and he or she is overweight. Having lower GI in our body systems is very advantageous as because it enhances body sensitivity to insulin when there is low GI in the body. It also reduces risks that are related to heart diseases which are very dangerous to the human life. According to Voster, lower GI aids in the reduction in the level of blood cholesterol in the body. Another important thing to note about lower GI is that individuals will be able to endure problems that affect the physical fitness of the body. In addition, lower GI helps people reduce and control weight.
Ways of switching to low GI
Clinicians suggested the best approach for switching to low GI is swapping high GI carbs for Low GI carbs. This simply done by eating low GI diet such as Increasing fruits and vegetables consumption, constant consumption of oats, barley and bran as breakfast, reducing consumption of potatoes and eating plenty of salad vegetables with a vinaigrette. The GI of a particular food is determined mainly by carbohydrate type, fiber, protein, food form and method of preparation. The belief that digestion of carbohydrate is linked to the length of the saccharide chain is very controversial as there is close relationship.
People use the glycemic index to choose the type of diet to take especially food rich in carbohydrates that will increase the level of blood sugar in the body minimally. This is mainly intended to reduce health problems that are caused by high blood sugar. These health problems may include diabetes, the insulin resistance syndrome, hypoglycemia and heart diseases. It is imperative to note that dietary glycemic index can also be utilized by athletes who are undergoing training exercise. They can choose to use high glycemic food-index food after e tedious exercise to refill exhausted carbohydrates (Roche, 2003)
Low fats versus low GI
It is imperative to understand the fact that protein intake for most individuals remains within a fairly narrow range hence reduced consumption of dietary fat leads to compensatory rise in carbohydrate consumption. The rise in carbohydrate consumption is a replacement of fat in low fat diet which is a typical high GI. About data that agricultural departments have been collecting and analyzing, about 81% of the carbohydrates that are consumed by human beings would give rise to increase in of GI as compared to table sugar. The rate at which carbohydrates are consumed increases after the ingestion of low fat meal due to the fact that fat acts to delay the process of gastric emptying. This in turn has the effect of increasing the GI hence prevalence to obesity (Roche, 2003)
Effects of GI on metabolism
Clinical studies suggest a role dietary glycemic index on body weight regulation and other risks that are associated with heart attack. High GI has been indicated to enhance adiposity in certain class of animals such as rodents. According to relevant studies conducted it has been observed there are long term metabolic effects of high and low GI. When animals take food that can be rapidly absorbed into the body system, there are high chances that the respiratory quotient of these animals is going to be high. If examination is done on two different groups of people who have taken different types of carbohydrates i.e. slowly absorbed carbohydrates and rapidly absorbed carbohydrates, with same respiratory quotient, physical activity and energy expenditure, it will be found that there are differences in metabolic process in the body system of these people. Those people who take rapidly absorbed carbohydrates grow fat as compared to those who take the slowly absorbed carbohydrates. The respiratory quotient of those who have taken rapidly absorbed carbohydrates is high which indicates clearly that the process of fat oxidation is less in comparison with those who have taken the slowly absorbed carbohydrates. If animal models are used to study these processes, the outcomes will be that GI affects body composition which is interceded by changes in substrate oxidation. Another outcome would be high GI diet leads to insulin resistance and dietary composition can impact physical activity level.
Clinicians have proved beyond doubt that consumption of higher GI diet some minutes before exercise results in the decrease of blood glucose when the body is exposed to some exercise. There is also reliance of carbohydrate as fuel during the exercise process. From this, it has been concluded that lower GI foods promotes metabolic response before exercise is initiated. When one is undergoing an exercise, it is recommendable that carbohydrates-rich items are provided to him. This is aimed at reducing the rate at which depletion of body carbohydrate which in turn delays the inception of fatigue. Consumption of high GI foods has the effect of increasing insulin and thus depressing fatty acids which are obviated upon the consumption of carbohydrate when the body is on exercise. This occurs due to the fact that exposing body to exercise induces epinephrine elevation which depresses the release of insulin from the pancreas. This was proved by clinicians such as Brouns (2005)
Effects of Dietary Glycemic Index on health and diseases
There are minimal effects experienced if a healthy young man low glycemic index diets in the short term. The dietary glycemic index suggests that ingestion of fiber leads to a decrease in the rate of nutrients from the gut. This idea is also present in the fiber hypothesis. Early clinicians have shown that some of the chronic diseases that are attributed to central obesity and insulin resistance are related to glycemic index. Dietary glycemic index has the effect of giving rise to insulin resistance. It is important to note that starchy foods affect postprandial blood glucose in different ways. The starchy carbohydrates also affect the way insulin response to subjects that are related to health and diabetes which depends entirely on the rate of digestion in the body system. Consumption of carbohydrates with high GI has the effect of altering the rate at which glucose is absorbed which might result in related diseases such as glycemia and insulinemia. It is from these effects of different starchy food that indicates there are differences in the effects of carbohydrates due to the differences in the GI level. Early studies indicate that the classification of carbohydrates is relevant in treatments and prevention of diseases such as diabetes (Vorster, 2002)
Low-glycemic-index diets are very useful because it improve the glycemic control in patients suffering from diabetes. It also reduces serum lipids among individuals who have hyperlipidemic problems. Consumption of high glycemic index diets can lead to cardiovascular diseases hence people should consume low glycemic index food to curb these problems.
Low glycemic index food is been advocated by many doctors than high glycemic index food because high glycemic index food can lead to increase in the sugar level in blood. To counterattack this phenomenon, the body produces insulin in large amount. It is with this respect that the human body cannot tolerate the high level of blood sugar and insulin that are produced rapidly by the body due to high glycemic index foods in the diet. The trend of food consumption is changing in the modern days, where people are consuming high glycemic index food such as low fiber flours and whole grains. This is due to human civilization where primitive Stone Age diets are being replaced by high glycemic index. These changes in the consumption trend where higher glycemic-index foods in the diet are mostly consumed, is very dangerous and hazardous to the normal functioning of the body. Too much production of insulin when high glycemic index food can lead to insulin resistance hence the cells that are responsible for responding to insulin become less active and cannot respond to its effects as suggested by Vorster (2002)
Dietary Glycemic index can be utilized to prevent and treat cancer. Insulin resistance is suggested to be associated with diet related cancers such as breast and prostate. There is direct link between colon and breast cancer and dietary glycemic index (Brouns, 2005). These attributes of excessive high glycemic index, insulin resistance, high levels of insulin are very daring to the human health. These have led to body disorders and health problems such as obesity, type 2 diabetes heart diseases and sometimes cancers. It is important to note that studies conducted have shown that human beings should change to low glycemic –index food. This reduces insulin resistance; it lowers blood levels and enhances blood sugar control. Advocates have constantly criticized high glycemic index food to result in serious health problems. Suggestions have been made by other advocates that diet can be more healthful if glycemic index is integrated with other health concepts (Jenkins, 1998)
Criticism of Dietary Glycemic Index
Glycemic has had a lot of criticism from various clinicians due number of reasons. Clinicians and other doctors have postulated that glycemic index does not consider variety of factors apart from glycemic response. These other factors include insulin response which is measured by the insulin index which is considered to be more appropriate in ascertaining the effects of certain carbohydrates rich items. The glycemic response is never constant as it varies depending on the kind of food, the ripeness of food and the length of time it was stored. Mode of cooking also matters. Blood glucose levels are the main determinant of GI hence this varies from person to person difficult to ascertain the efficient GI level that is necessary for human beings. Again, there is difficult in predicting the GI of meals which contains variety of food items e.g. when a meal has both protein and fats the more it stay longer in the stomach hence reduction in food GI (Vorster, 2002)
Conclusion
The various research and studies conducted concluded that concept of dietary glycemic index indicates that it has a role in the digestion process of carbohydrate. This concept is also very useful in prevention and treatment of diseases that are associated with insulin resistance. Glycoside hydrolase inhibitors is been used in management of diabetes and it is a pharmacologic approach that is accepted universally (Jenkins, 1998)
References
Brouns, G., 2005. Dietary Glycemic Index..” Nutrition Research Reviews 18; 140-174
Gibney, M. 2004. Glycemic Index and Metabolism. The Definitive Science-based Weight Loss, 20; 150-169.
Jenkins, J., 1998. Glycemic index of foods. 350-370.
Roche, H., 2003, Metabolism and Nutrition. 120-127.
Vorster, M., 2002. A Health Promotion Approach. 360-378. Nutrition Research Reviews 18; 145-17.