Thursday, September 20, 2012

More Honey, More Problems



It is common knowledge nowadays that Americans are getting larger. The convenience of a McDonald's or a Taco Bell can be seen in every state. With all the skinny celebrities out there, people often try to lose weight by taking a certain type of food out of their diet. In truth, Americans need to eat less overall and have a balance of all types of food. More than anything, they need to exercise. The excess fat in a human body may just appear to be a social issue, but it's an extreme health issue. It causes obesity, metabolic syndrome, and type 2 diabetes, which can cause more complications in your eyes, skin, heart, brain, ears, feet, bone and kidneys. In fact, type 2 diabetes is the “leading cause of kidney failure, non-traumatic lower-limb amputations, and new cases of blindness.” (Center for Disease Control and Prevention). But how does it make the transition from just excess body fat to a life-threatening disorder?

Obesity is a buildup of fat, specifically visceral fat or abdominal fat. The typical test for obesity is a Body Mass Index (BMI) test, calculated using a person’s weight (in kilograms) over height (in meters) squared. By definition, a person is obese if their BMI is over 30 kg/m2. The BMI test does not reflect fat distribution, however, so often times just measuring the waist circumference of a person can show the level of obesity. MRIs can also show a dispersion of fat.

Obesity is one of the core components of Metabolic Syndrome, originally called “Syndrome X.”  Metabolic Syndrome is the combination of any of a lot of core pathologies that together create an increased risk of cardiovascular disease. The main pathologies include insulin resistance, hyperinsulinemia, glucose intolerance, visceral obesity, dyslipidemia, and essential hypertension.  The International Diabetes Foundation (IDF), The National Cholesterol Education Program, and The World Health Organization all have slightly different definitions as to how to diagnosis metabolic syndrome, but overall they agree that hyperinsulinemia and obesity are they top signs.

There are multiple ways for these pathologies to arise. When fat and glucose are not being broken down at proper rates, due to lack of exercise or overeating, they build up in the bloodstream. The hormone insulin will tell the muscle cells to start taking in the glucose. The cell has to constantly be breaking them down to lower the blood glucose levels. But if the cell is working on overdrive to break down the metabolites, eventually it gets tired and starts breaking down less despite the same stimulus from insulin. This is insulin resistance. The pancreas can not tell that the muscle cells are resistant. All it can tell is that the blood glucose levels are too high, so it dumps more insulin in the blood to tell cells to take more out. This is how hyperinsulinemia occurs. Glucose intolerance is the next step. The easy test for this is an oral glucose tolerance test (OGTT). After overnight fasting, the patient is given a sugary drink to see how the body will handle the increase of glucose consumption. After a two hour period, the blood will drawn and blood glucose levels measured. Anything under 140 mg/dl is healthy. Above 140 mg/dl shows glucose intolerance. A result above 200 mg/dl means the patient has type 2 diabetes.

Type 2 diabetes is often confused with type 1 diabetes. Type 1 diabetes is generally genetic, and it is when the body does not produce enough insulin. This results in cells not getting enough glucose and therefore can cause fatigue, increased hunger, and increased thirst. These people need insulin injections daily to cope with their disease. Type 2 diabetes does not require any injections. Their bodies have produced more insulin than they have needed in the past due to overeating fatty or sugary foods. Now the excessive insulin in the blood triggers less of a stimulus. While there may have been a genetic predisposition for type 2 diabetes, it was ultimately their life choices that brought them to this disorder. According to the Center for Disease Control, as of 2011, 25.8 million people worldwide have diabetes.

The three main causes of diabetic complications are hypertension, high blood glucose levels, and dyslipidemia. Dyslipidemia is an abnormally high amount of cholesterols and fats in the blood. It is caused from hyperinsulinemia of insulin-resistant individuals. The insulin in the blood is a stimulant for adipocytes to release free fatty acids into the blood stream to be broken down in muscle cells. The muscle cells are not taking any fat or glucose in though, due to the resistance to insulin. Hypertension is also caused by hyperinsulinemia. The high glucose levels causes renal water retention, which leads to increased cardiac output due to either higher stroke volume or faster heart rate. Overall, the increased cardiac output leads to higher blood pressure, hypertension.

The combination of these three symptoms leads to many complications, however diabetes is not a death sentence. Every year more studies are coming out linking diabetes to more and more diseases, but if the disease is managed properly there is no need for such complications. With a proper diet and daily exercise, insulin-resistance can be reversed. There are also medications out to decrease each of the symptoms of metabolic syndrome to prevent type 2 diabetes in the first place. The important thing is to maintain a healthy, active lifestyle.

References:

Centers for Disease Control and Prevention. “National diabetes fact sheet: national estimates and general information on diabetes and prediabetes in the United States, 2011.” Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, 2011.

 “Diabetes.” Medline Plus, National Institute of Health, 2 July 2012. http://www.nlm.nih.gov/medlineplus/diabetes.html

“Healthy Weight – it’s not a diet, it’s a lifestyle!” Centers for Disease Control and Prevention, 13 September 2011. http://www.cdc.gov/healthyweight/index.html

Mayo Clinic. “Glucose Tolerance Test.” Mayo Foundation for Medical  Education and Research, 2010. http://www.mayoclinic.com/health/glucose-tolerance-test/MY00145

“What is Type 1 Diabetes (T1D)?” Juvenile Diabetes Research Foundation. http://info.jdrfdsw.org/what-is-type1diabetes.php

Also (not sure how to reference)

Dr. Henriksen’s PSIO303A class at the University of Arizona

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