Doctor’s Tip: Diabetes and prediabetes — what they are and what causes them |

Doctor’s Tip: Diabetes and prediabetes — what they are and what causes them

Greg Feinsinger

Diabetes is a major cause of death and disability in countries on a Western diet — high in animal products, sugar, added oil and processed food. Today’s column will discuss what diabetes and prediabetes are and what causes them; next week’s column will discuss how to prevent and reverse type 2 diabetes.

It’s important first to understand what glucose and insulin are. In his book “How Not to Die,” Dr. Michael Greger notes that glucose is “the primary fuel powering all the cells in your body,” and he defines insulin as “the key that unlocks the doors to your cells to allow glucose to enter.” For optimal health, it’s important that blood glucose stays within certain parameters, and insulin — made by the beta cells in the pancreas — is secreted as needed to regulate blood sugar. Diabetes is the disease that results when blood sugar levels aren’t kept in check.

Chronic blood sugar elevation damages blood vessels throughout the body, leading to several complications including cardiovascular disease (heart attacks and strokes); eye disease that can lead to blindness; kidney failure; erectile dysfunction; neuropathy (nerve damage) in the feet and legs and throughout the body; peripheral vascular disease that can lead to amputation of the toes and feet; poor wound healing; and dementia. It can also contribute to depression; increased risk of blood clots; increased harmful inflammation; and weakened immunity.

There are two types of diabetes. Five percent of diabetic cases in the U.S. are type 1, which is an autoimmune disease where a subject’s immune system goes rogue and attacks the insulin-producing beta cells in the pancreas. Type 1 can have a genetic component, and is not related to lifestyle, although all autoimmune diseases are more prevalent in societies on a Western diet. Type 2 diabetes accounts for 95 percent of diabetes in the U.S., and is clearly a lifestyle disease. This column is primarily about type 2 diabetes.

According to the CDC, approximately 50% of Americans have either prediabetes or diabetes, and the prevalence increases yearly as Americans get heavier. We used to call type 2 adult onset diabetes, but we can’t use that term any longer because so many of our kids are now overweight and have type 2 diabetes. Prediabetes is a misnomer because it is not really “pre-disease” but rather is a mild form of diabetes. Prediabetes causes the same, aforementioned, complications that actual diabetes does.

Prediabetes/type 2 diabetes are caused by insulin resistance (I.R.) — where fat in and around organs and muscles prevents insulin from entering cells and doing its job. The insulin resistance-causing type of fat is called central obesity, or extra weight around the middle. Measure your waist at the level of maximum circumference (approximately at the level of your belly button). If you’re a man and the measurement is 40 inches or greater, or a woman and it is 35 inches or greater, you have insulin resistance — with lower cutoffs for Asians and East Indians. Even if you don’t meet those criteria, but have even a little “belly” when you look at your naked profile in the mirror, you probably have I.R.

Your pancreas tries to compensate for insulin resistance by pumping out more and more insulin, and over the years the beta cells eventually wear out and are destroyed. Unfortunately, diabetes often isn’t diagnosed until the fasting blood sugar becomes 126 or greater, and by then significant damage has already been done in the form of the complications mentioned in the third paragraph. Because some 70 percent of cardiovascular disease is caused by I.R., heart attack prevention doctors look for early signs, such as high triglycerides and low HDL (triglyceride/HDL ratio of 3.5 or greater), and small, dense LDL (bad cholesterol) particles. The gold standard test for early diagnosis is a one- and two-hour glucose tolerance test: fast 12 hours, drink a 75 gram glucose load, and if your blood sugar one hour later is 125 or greater or two hours later 120 or greater, you have insulin resistance/prediabetes. If the two-hour result is 200 or over, you have diabetes.

Another blood test that’s used frequently to diagnose diabetes is the A1C, which reflects the average blood sugar level over the previous three months. A normal A1C is < 5.7; prediabetes is 5.7 to 6.5, and 6.5 or above is diabetes. Although this is a useful test to follow diabetics, many heart attack prevention doctors feel it is not accurate for diagnosing prediabetes or diabetes.

Greg Feinsinger, M.D. is a retired family physician who has a nonprofit: Prevention and Treatment of Disease Through Nutrition. He is available by appointment for free consultations (379-5718).

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