Obesity Increases the Risk of Glucose Intolerance
Glucose intolerance, otherwise known as impaired glucose tolerance (IGT), is a condition that is often found to be in patients who eventually develop type 2 diabetes mellitus. (1) A patient with glucose intolerance is often also at high risk of cardiovascular disease as well as being resistant to insulin. The most significant characteristic of glucose intolerance is that it is often referred to as a “gateway to developing type 2 diabetes.” (2) Additionally, obesity has been shown to play a significant role in the development of both glucose intolerance and diabetes. (3) Furthermore, another study specifically found that ‘upper-body obesity’, that is an abundance of adipose body fat around the abdominal area as well as hypertension are all related to glucose intolerance as well. This is often referred to as the ‘deadly quartet’ of upper-body obesity, glucose intolerance, hypertriglyceridemia, and hypertension. (4)
Even though all these conditions are related, the important news is that your weight and body-fat are both factors that you can control. What seems to be confusing for many people is that it is often unknown whether someone being overweight is related to other conditions or directly to glucose intolerance. (5)
The causes of glucose intolerance
Glucose intolerance is a serious health condition that’s caused by there being too much blood sugar in your veins instead of in your cells. Higher than normal levels of blood sugar circulate throughout your body, but they may not be high enough yet for a patient to be classified as having diabetes. Doctors can test whether a person is glucose intolerant by using a test which measures glucose levels in the bloodstream after an 8- to 12-hour fast and then a glucose tablet of 75mg (6) is used while the patient is monitored. If the patient has a blood sugar level between 140 and 199 mg/dL, then glucose intolerance is definitely not normal, and this suggests that diabetes can also develop. According to the National Diabetes Fact Sheet, 2011, 35% of American adults, roughly 79 million people, suffer from this condition. (7)
The link to obesity
According to the Centers for Disease Control and Prevention, the United States is referred to as an obesogenic society, which simply means that our lifestyles promote eating too much and getting too little exercise. (8) More than one-third of American adults are obese according to statistics and the epidemic of obesity is often extremely high, up to 50%, in older African American and Hispanic women. Obesity is determined by a patient’s body mass index (BMI), which is calculated using your weight and your height. If your BMI is between 18 and 24 then you are considered in the “normal” category. If it’s between 25 and 29 you are overweight and anything higher than 30 is considered obese and at high risk for glucose intolerance as well as type 2 diabetes, as well as a host of cardiovascular illnesses, deep vein thrombosis and some cancers. Body-fat, especially excessive body-fat around the abdominal area, is also known to be much more “metabolically active” than other kinds of fat. One of the main purposes of fat in the body is to release a hormone into the bloodstream known as leptin, whose function is to regulate and suppress appetite. Through an interesting mechanism, the more body-fat you have accumulated in excess of normal levels results in an overdose of leptin in the body, which causes desensitization to the appetite-suppressant effects of leptin, resulting in an appetite that is far too large. (9)
The pancreas and insulin
Extremely high glucose levels are known to be poisonous to your pancreas. (10) The function of the pancreas is to remove glucose from the bloodstream and deposit it into your cells. (11) The pancreas cannot work hard enough if you are glucose intolerant and thus too much glucose is left in your bloodstream. Progressive, untreated, glucose intolerance can also affect other metabolic functions, such as high blood pressure and fluctuating cholesterol levels.
Childhood conditions also a factor
A third factor, that coupled with childhood obesity and glucose intolerance, is hypertension. (12) The relationship, as clarified by Dr Paul Franks of Umeå University Hospital, Sweden, is that “obesity is probably the primary metabolic derangement that causes hyperglycemia and high blood pressure.” (13) In other words, it’s obesity that causes the blood disorders and is directly responsible for the glucose intolerance and the type 2 diabetes to follow. At first this may seem chilling. It’s rare in medical science that one can find a direct causal link between an unhealthy lifestyle and a life-threatening condition, but here it is.
Specifically, undisciplined gains in body mass index from childhood were the direct cause of death of 166 patients from a cohort of 4857 American Indian children aged 5-19 years without diabetes who were followed for a period of 24 years or until the end of 2003. (14) The majority of the endogenous causes of death were directly related to BMI, in that the higher the rate of obesity of the patients in the cohort, the more likely were they to die from endogenous causes. Additionally, trends gleaned from this study were also shown to mirror trends in the larger United States population over the past few decades. (15)
Treatment of obesity and glucose intolerance
In recent tests on mice in laboratories, DHA derivates were shown to reduce obesity levels and glucose intolerance. (16) This could be manufactured eventually into a drug that can reverse glucose intolerance and combat obesity. It could possibly even lead to a cure for type 2 diabetes. For the moment though, the best way to combat type 2 diabetes, glucose intolerance, hypertension resulting from hypoglycemia and obesity is recognition of the direct causal relationship between the ‘deadly quartet’ and taking steps to assure that you or your children maintain a body mass index appropriately between the 18 and 24 range. Healthy eating habits, regular activity and efforts to move away from a sedentary lifestyle all play important factors in this quest.