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August 2, 2018

Ask the Doctors – Which spikes blood glucose more? Sugar in fruit or food?

By Ask the Doctors

Dear Doctors: I’m trying to lower my blood glucose level but I have a sweet tooth. What raises blood glucose more -- the sugar from fruit, or foods with refined sugar?  Is diet the only way to keep blood glucose steady?

Dr. Elizabeth Ko and Dr. Eve Glazier

Dr. Elizabeth Ko and Dr. Eve Glazier

Managing your level of blood glucose, which is the measurement of how much of a certain sugar is dissolved in the blood, is important to good health. Glucose, which comes from the foods we eat, is a major source of energy to cells throughout the body. However, blood glucose levels that remain consistently high can lead to a variety of health problems, including prediabetes, a condition that frequently leads to type 2 diabetes.

Blood glucose starts its journey in the form of carbohydrates, which are the main nutrients in foods like bread, pasta, rice, fruits, vegetables, legumes, grains and some dairy products. When we eat these foods, the digestive process frees the sugars within the food and makes them easily available to the body.

Glucose, the smallest sugar molecule, moves from your small intestine and into your blood. There, it is distributed throughout the body to provide energy to the cells. To get from the blood and into the cells, glucose needs the help of insulin, a hormone produced by the pancreas, a long, flattened gland that sits behind the stomach.

As your question notes, not all foods release glucose in the same amounts or at the same rate. Foods like sugary breakfast cereals, pastries and candy are basically glucose bombs. But naturally sweet foods like apples, strawberries or yams, which contain carbohydrates but are also high in fiber, release glucose more slowly. However if you turn that apple into juice, you’ve just accelerated the rate at which your blood glucose level will rise. And if the candy bar you’re eating contains a handful of nuts, the fiber they contain will slow the rate of glucose absorption.

A little confusing, we know. Fortunately, a handy tool known as the glycemic index has taken much of the guesswork out of maintaining a healthy blood glucose level. The glycemic index, or GI, ranks each food relative to how it will affect your blood glucose level.

Foods high on the GI release their sugars more rapidly, which can cause blood sugar levels to spike. Foods lower on the scale release their energy more gradually, and blood glucose levels remain steady.

Interestingly, research has shown that exercise has an effect on blood glucose levels. When you increase your level of activity, your body works harder and your muscles’ demand for glucose increases. The insulin your body produces becomes more effective as well. The key here, as with diet, is moderation.

A brisk walk, a dance class, an aerobic bout of house cleaning or yard work, any of these can add balance to the blood glucose equation. The good news is that even a little bit of regular exercise, say 30 minutes three times a week, will also help your heart, lungs and even your mood.


Eve Glazier, MD., MBA, and Elizabeth Ko, MD., are internists at UCLA Health. Dr. Glazier is an associate professor of medicine; Dr. Ko is an assistant professor of medicine.

Ask the Doctors is a syndicated column first published by UExpress syndicate.

Tags: Ask the Doctors, Ask the Doctors, blood glucose, Dr. Eve Glazier, Dr.Elizabeth Ko, fruit, glycemic index, Healthy Living, prediabetes, processed food, sugar in food, type 2 diabetes, Wellness

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