Dr. Toshi Is In! "Does eating too much sugar cause Diabetes?"

Dear Dr. Toshi,

Does eating too much sugar cause diabetes?

We talked about diabetes last week and I'd like to continue a little bit more on that topic today. Many people think that if you eat too much sugar, you'll get diabetes, but does eating sugar really cause diabetes?

Before getting into details, I'd like to introduce a very important concept when it comes to talking about risks today, namely the difference between "causality" and "association." You might have heard a sentence like this in the past: "A causes B," or "B is caused by A." For instance, smoking causes lung cancer. You may also have heard "A is associated with B." For instance, when I was in medical school, my professor gave this example: "Driving BMWs in this city is associated with a higher incidence of breast cancer in women." Well, of course it's unlikely that just driving a BMW in that city is what causes breast cancer. They just found that there was an association. It maybe that women who drive BMWs tend to do something else more than other women that leads to their higher incidence of breast cancer, e.g., maybe they go to tanning salons more, or eating more rich, high-fat food, or smoke more, or sunbathe on beaches more than other women. The researchers have to do more research and sort out many factors to find out more about this association.

The relationship between sugar intake (particularly sugar-sweetened beverages) and risks of diabetes (Type 2 diabetes in this case) has been studies quite extensively, but we don't know that sugar-sweetened beverages cause diabetes. However, many studies show that sugary beverages are associated with an increased risk of developing diabetes. The important point is that it shows increased risk. Studies show that higher consumption of sugar-sweetened beverages is strongly associated with both greater weight gain and type 2 diabetes, and obesity is also associated with diabetes. So, to be scientifically accurate, we have to say that high consumption of sugary beverages is strongly associated with diabetes, but we can't say for sure—at least yet—that drinking sugary beverages causes diabetes.

There are many other factors that are associated with developing Type 2 diabetes, too. Pre-diabetes is very strongly associated. Other factors include family members who have diabetes, your ethnicity (there's more diabetes among Asians, Latinos, and Black Americans than among White Americans), obesity, "abdominal obesity" (having a large waist size), high childhood weight, lifestyle (poor exercise and diet), smoking, and inadequate sleep. A lower risk of developing Type 2 diabetes is associated with a Mediterranean diet, eating nuts every day, and a high fiber diet, for example.

Dr. Toshiko ("Toshi") Luckow, MD, is a Family Physician at the West River Health Services Hospital and Clinics.