Fruits are a rich source of antioxidants, natural cell-protectors that may reduce the risk of some diseases. But fruit is also naturally high in fructose. Some fruit juice contains large amounts of this natural sugar even when no additional sugar is added. For this reason, some doctors recommend that people with diabetes or who have risk factors for the disease limit the amount of fruit juice they drink. What is the relationship between fruit juice and diabetes risk?
Fruit Juice and Diabetes Risk: What Does Research Show?
A large prospective study involving over 71,346 nurses, as part of the Nurse’s Health Study, looked at the issue of fruit and vegetable intake and how it affects the risk of type 2 diabetes. It found that eating whole fruits and vegetables lowered the risk of type 2 diabetes, while drinking fruit juice had the opposite effect – it elevated the risk. This was true even after researchers controlled for other factors that could affect type 2 diabetes risk. Munching on three additional servings of whole fruit a day lowered the risk of type 2 diabetes by 18%, but drinking just one added serving of fruit juice daily raised the risk by the same amount. Not good news for fruit juice lovers.
Why This Discrepancy Between Fruit Juice and Whole Fruit?
Fruit juice is a concentrated source of natural sugar. Plus, some canned and bottled fruit juice has sugar added in the form of high fructose corn syrup, which contains two times as much fructose by weight as table sugar. According to some research, high fructose corn syrup increases the risk of obesity and raises triglyceride levels, which isn’t a good thing for people at risk for type 2 diabetes.
Even if you buy fruit juice without high fructose corn syrup, or squeeze your own, a one cup serving of orange juice has around 26 grams of carbohydrates – and if you happen to have a passion for grape juice, you're getting 38 grams of carbs in a single cup. The rapidly absorbed carbs in fruit juice raise blood sugar levels quickly and cause an insulin surge. This surge in insulin can, over time, can lead to insulin resistance, a precursor to type 2 diabetes. Fruit juice is also higher in calories than whole fruit, which can contribute to obesity, another risk factor for type 2 diabetes.
When it comes to fruit juice and diabetes risk, there’s another problem. Fruit juice is not as filling as eating a piece of fruit. The whole fruit contains fiber which not only slows down absorption and reduces the blood sugar response; it also makes it more filling and satisfying than drinking a glass of fruit juice. The fiber in fruit is also good for heart health.
Fruit Juice and Diabetes Risk: The Bottom Line?
Fruit juice is a good source of antioxidants, but it’s high in sugar and low in fiber. If you’re worried about your risk of type 2 diabetes, choose the whole fruit – and limit the amount of fruit juice you drink.
Princeton.edu website. “A sweet problem: Princeton researchers find that high-fructose corn syrup prompts considerably more weight gain”
Diabetes Care. 2008 Jul;31(7):1311-7. Epub 2008 Apr 4.
Merck Manual. Eighteenth edition. 2006.