No Proven Benefits for Diet and Exercise in Lowering Risk of Diabetes
In a surprising outcome, a major US study of more than 5,000 overweight and obese people over 11 years was terminated because it show a negative outcome.
The study was initiated because following preliminary results the researchers had assumed exercise and calorie controlled diets would help to lower blood sugar levels, blood pressure and cholesterol levels. and so help lower the risk of developing Type 2 diabetes and heart disease and strokes. The level of prediabetes in children is of special concern.
The researchers hoped to conclusively show that dieting and exercise could help over-weight people from crossing the threshold into diabetes and thereby help to protect people from heart disease.
However, the researcher were quick to stress that dieting and exercise had been shown to have many other benefits if they did not reduce the risk of cardiovascular disease and stoke in people with diabetes.
Other recent research has highlighted the link between Alzheimer's disease and diabetes, with many people calling Alzheimer's - Type 3 Diabetes.
This article discusses the study results, which have yet to be published and the implications of the negative outcome.
The Diabetes Epidemic linked to Excessive Weight and Obesity
It is estimated that more than 25 million people in America have Type 2 diabetes. Most of these people are obese or clearly overweight. Studies have shown that people with diabetes have twice to three greater risk of developing heart disease and other diseases such as:
Skin-Related Diseases - affect about 33% of people with diabetes (1 and 2)
High Blood Pressure - About 65% of adults with diabetes have hypertension which increases the risk of heart attack.
Stroke - The risk of stroke is increased four fold, with elevated cholesterol levels a contributing factor.
Peripheral Arterial Disease or PAD - This disease occurs when the arteries in the legs become restricted due to narrowing or blocked by fat. Symptoms of PAD may include tingling or numbness or in the calves and feet, sores that only heal very slowly, sores or infections on the feet, as well as pain in the leg muscles during walking, jogging or other exercises.
Coronary Artery Disease - This is likely to develop among diabetics with high levels of fat and/ or cholesterol in the blood stream, which build up and block the flow to blood vessels supplying the heart muscles with oxygen.
Eye Damage - Diabetes can damage the eyes and cause damage to the retina due to restrictions in the blood vessels supplying the retina at the back of the eyes. Diabetics have a 40% higher risk of developing glaucoma, and 60% higher risk of developing cataracts.
Other Diseases are Ketoacidosis which causes a lack of insulin or an inability to use insulin, kidney failure and damage to the nerves.
For more details see information provided by the American Diabetes Association.
Why Doesn't Dieting and Exercise in Overweight and Obese People Reduce the Rates of Heart Disease
The study randomly assigned 5,145 obese or overweight people suffering from Type 2 diabetes to two groups:
- One group undertook a strict diet and exercise regimen. The diet involved calorie restrictions to about 1,200 -1,500 calories a day depending on the subjects initial weight. The exercise program was moderate exercise for about 3 hours.
- The other group were given session of general health information about Diabetes.
After eleven years the average weight loss for the group on the exercise and diet program lost about 5 % of their body weight and keep it off for the duration of the study. However this was not enough to reduce cardiovascular risk factors. The data showed that the two groups had virtually identical rates of strokes, heart attacks and cardiovascular related deaths. The benefits of the small but significant weight loss and the benefits of regular exercise could not be proven.
The reason for the negative outcome may be because the amount of weight loss was insufficient. The other general finding was that the dieters used fewer medications on average, than the control group. It appears that drug treatments including, blood pressure medications and statins to reduce blood cholesterol are so powerful that they masked the modest effects of exercising, dieting and weight loss on cardiovascular risk.
One positive aspect to the study was that people with diabetes may have a choice. Either to use diet and exercise to reduce the risks or to take drugs over long periods of time and to suffer the side effects of these drugs.
It remains to be seen whether higher rates of weight loss are more effective in controlling Type 2 Diabetes of reducing the risks of heart disease and stroke.
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© 2012 Dr. John Anderson