Skepticism, Science & Pseudoscience

Cardiovascular Disease & Diabetes

Updated:Mar 23,2016

The following statistics speak loud and clear that there is a strong correlation between cardiovascular disease (CVD) and diabetes.

At least 68 percent of people age 65 or older with diabetes die from some form of heart disease; and 16% die of stroke.
Adults with diabetes are two to four times more likely to have heart disease or a stroke than adults without diabetes.
The American Heart Association considers diabetes to be one of the seven major controllable risk factors for cardiovascular disease.

Why are people with diabetes at increased risk for CVD?

Diabetes is treatable, but even when glucose levels are under control it greatly increases the risk of heart disease and stroke. That's because people with diabetes, particularly type 2 diabetes, may have the following conditions that contribute to their risk for developing cardiovascular disease.

High blood pressure (hypertension)
High blood pressure has long been recognized as a major risk factor for cardiovascular disease. Studies report a positive association between hypertension and insulin resistance. When patients have both hypertension and diabetes, which is a common combination, their risk for cardiovascular disease doubles.

Abnormal cholesterol and high triglycerides
Patients with diabetes often have unhealthy cholesterol levels including high LDL ("bad&quot cholesterol, low HDL ("good&quot cholesterol, and high triglycerides. This triad of poor lipid counts often occurs in patients with premature coronary heart disease. It is also characteristic of a lipid disorder associated with insulin resistance called atherogenic dyslipidemia, or diabetic dyslipidemia in those patients with diabetes. Learn more about cholesterol abnormalities as they relate to diabetes.

more at: http://www.heart.org/HEARTORG/Conditions/Diabetes/WhyDiabetesMatters/Cardiovascular-Disease-Diabetes_UCM_313865_Article.jsp/#.WBD0R3dh2Rs

The glycemic index (GI) is a measure of the power of foods (or specifically the carbohydrate in a food) to raise blood sugar (glucose) levels after being eaten. The GI values of foods must be measured using valid scientific methods. It cannot be guessed by looking at the composition of the food. Currently, only a few nutrition research groups around the world provide a legitimate testing service. Professor Jennie Brand-Miller at the Human Nutrition Unit, Sydney University has been at the forefront of glycemic index research for over a decade, and her research group has determined the GI values of more than 2500 foods.

The GI value of a food is determined by feeding 10 or more healthy people a portion of the food containing 50 grams of digestible (available) carbohydrate and then measuring the effect on their blood glucose levels over the next two hours. For each person, the incremental area under their two-hour blood glucose response (glucose iAUC) for this food is then measured. On another occasion, the same 10 people consume an equal-carbohydrate portion of glucose sugar (the reference food) and their two-hour blood glucose response is also measured. A GI value for the test food is then calculated for each person by dividing their glucose iAUC for the test food by their glucose iAUC for the reference food. The final GI value for the test food is the average GI value for the 10 people.

Measuring carbohydrate effects can help glucose management

glycemix load

The glycemic index is a value assigned to foods based on how slowly or how quickly those foods cause increases in blood glucose levels. Also known as "blood sugar," blood glucose levels above normal are toxic and can cause blindness, kidney failure, or increase cardiovascular risk. Foods low on the glycemic index (GI) scale tend to release glucose slowly and steadily. Foods high on the glycemic index release glucose rapidly. Low GI foods tend to foster weight loss, while foods high on the GI scale help with energy recovery after exercise, or to offset hypo- (or insufficient) glycemia. Long-distance runners would tend to favor foods high on the glycemic index, while people with pre- or full-blown diabetes would need to concentrate on low GI foods. Why? People with diabetes can't produce sufficient quantities of insulin—which helps process blood sugar—which means they are likely to have an excess of blood glucose. The slow and steady release of glucose in low-glycemic foods is helpful in keeping blood glucose under control.

But the glycemic index tells only part of the story. What it doesn't tell you is how high your blood sugar could go when you actually eat the food, which is partly determined by how much carbohydrate is in an individual serving. To understand a food's complete effect on blood sugar, you need to know both how quickly the food makes glucose enter the bloodstream, and how much glucose it will deliver. A separate value called glycemic load does that. It gives a more accurate picture of a food's real-life impact on blood sugar. The glycemic load is determined by multiplying the grams of a carbohydrate in a serving by the glycemic index, then dividing by 100. A glycemic load of 10 or below is considered low; 20 or above is considered high. Watermelon, for example, has a high glycemic index (80). But a serving of watermelon has so little carbohydrate (6 grams) that its glycemic load is only 5.

To help you understand how the foods you are eating might impact your blood glucose level, here is a listing of the glycemic index and glycemic load, per serving, for more than 100 common foods...

FOOD Glycemic index (glucose = 100) Serving size (grams) Glycemic load per serving

Banana cake, made with sugar Glycemic index 47 60g load 14

Banana cake, made without sugar Glycemic index 55 60g load 12

...

Waffles, Aunt Jemima® Glycemic index 76 35g load 10

Bagel, white, frozen Glycemic index 72 70g load 25

...

Fruit Roll-Ups® 99 30 24

M & M's®, peanut 33 30 6

Microwave popcorn, plain, average 65 20 7

Baked russet potato 111 150 33

Boiled white potato, average 82 150 21

Hummus (chickpea salad dip) 6 30 0

Chicken nuggets, frozen, reheated in microwave oven 5 min 46 100 7

Pizza, plain baked dough, served with parmesan cheese and tomato sauce 80 100 22

Pizza, Super Supreme (Pizza Hut®) 36 100 9

Honey, average 61 25 12

The lowdown on glycemic index and glycemic load

If you have diabetes, you probably know you need to monitor your carbohydrate intake. But different carbohydrate-containing foods affect blood sugar differently, and these effects can be quantified by measures known as the glycemic index and glycemic load. You might even have been advised to use these numbers to help plan your diet. But what do these numbers really mean — and just how useful are they?

What these numbers measure

The glycemic index (GI) assigns a numeric score to a food based on how drastically it makes your blood sugar rise. Foods are ranked on a scale of 0 to 100, with pure glucose (sugar) given a value of 100. The lower a food's glycemic index, the slower blood sugar rises after eating that food. In general, the more cooked or processed a food is, the higher its GI, and the more fiber or fat in a food, the lower its GI.

But the glycemic index tells just part of the story. What it doesn't tell you is how high your blood sugar could go when you actually eat the food. To understand a food's complete effect on blood sugar, you need to know both how quickly it makes glucose enter the bloodstream and how much glucose it can deliver. A separate measure called the glycemic load does both — which gives you a more accurate picture of a food's real-life impact on your blood sugar. Watermelon, for example, has a high glycemic index (80). But a serving of watermelon has so little carbohydrate that its glycemic load is only 5.

Should you eat a low-GI diet?

Some nutrition experts believe that people with diabetes should pay attention to both the glycemic index and glycemic load to avoid sudden spikes in blood sugar. The American Diabetes Association, on the other hand, says that the total amount of carbohydrate in a food, rather than its glycemic index or load, is a stronger predictor of what will happen to blood sugar. And some dietitians also feel that focusing on the glycemic index and load adds an unneeded layer of complexity to choosing what to eat.

The bottom line? Following the principles of low-glycemic-index eating is likely to be beneficial for people with diabetes. But reaching and staying at a healthy weight is more important for your blood sugar and your overall health.

If you'd like to give low-glycemic-index eating a try, click here to see our table of the glycemic index and load for over 100 common foods.

And for more information on how to live well — and eat well — with type 2 diabetes, buy Healthy Eating for Type 2 Diabetes, a Special Health Report from Harvard Medical School.

Updated: September 26, 2016
Originally published: May 2016