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Eating more fruit is associated with a reduced risk of developing type 2 diabetes. PamelaJoeMcFarlane/Getty Images
  • Type 2 diabetes is a leading form of disability globally.
  • Scientists have shown that eating a balanced diet, along with staying physically active, protects against type 2 diabetes.
  • The present observational study found that regularly consuming whole fruits, but not fruit juice, is likely to reduce the risk of developing the condition.

In a new study, researchers have found an association between eating moderate to high amounts of fruit on a regular basis and a lower risk of type 2 diabetes.

The researchers behind the study, which appears in the Journal of Clinical Endocrinology & Metabolism, also found that eating more fruit was associated with beneficial levels of glucose tolerance and insulin sensitivity, which are both linked to type 2 diabetes.

According to the Centers for Disease Control and Prevention (CDC), around 1 in 10 people in the United States have diabetes, and of those, 90–95% have type 2 diabetes.

If a person has type 2 diabetes, the cells in their body are struggling to take up glucose from the blood. Experts also call this insulin resistance, as it is insulin — a hormone produced in the pancreas — that facilitates the transfer of blood sugar to cells.

The pancreas will continue to create insulin, and as long as it produces enough of it, the person’s blood sugar will remain stable.

However, once the pancreas stops producing sufficient amounts of insulin to help the cells overcome their inability to take up glucose, the person’s blood sugar will rise to dangerous levels. High blood sugar over a prolonged period of time can cause health issues, including vision loss, heart disease, and kidney disease.

According to the National Institute of Diabetes and Digestive and Kidney Diseases, individuals can prevent or delay diabetes by reaching a moderate weight, being more physically active, and eating a more balanced diet.

In an article in The Lancet, Dr. Frank B. Hu from the Department of Epidemiology at Harvard School of Public Health in Boston, MA, and his co-authors summarize current research on nutrition and diet, as it relates to preventing diabetes.

Dr. Hu and his co-authors highlight that “healthful dietary patterns for diabetes prevention and management were typically rich in whole grains, fruits and vegetables, nuts, [and] legumes, moderate in alcohol consumption, and lower in refined grains, red/processed meats, and sugar-sweetened beverages.”

In the present study, the researchers wanted to specifically examine the role that fruit may play in preventing type 2 diabetes.

To do so, they drew on data from the Australian Diabetes, Obesity, and Lifestyle Study. The study recruited 11,247 people between 1999–2000, with follow-up surveys occurring in 2004–2005 and 2011–2012.

For the present study, the researchers excluded people who did not complete an initial food frequency questionnaire, had energy intakes that were unlikely, had diabetes, or were pregnant. This left data from 7,675 participants.

The researchers tracked how much fruit people consumed, which particular fruits they ate, and how much fruit juice they drank.

The researchers then looked to see how many of the participants developed type 2 diabetes between the first and final follow-ups. They also looked at biological markers associated with type 2 diabetes risk.

The researchers found an association between high levels of fruit intake and lower risk of developing type 2 diabetes at the 5-year follow-up survey.

They also found a link between higher fruit consumption and better measures of insulin sensitivity and glucose intolerance.

According to corresponding author Dr. Nicola Bondonno of Edith Cowan University’s Institute for Nutrition Research in Perth, Australia, “we found [that] people who consumed around 2 servings of fruit per day had a 36% lower risk of developing type 2 diabetes over the next 5 years than those who consumed less than half a serving of fruit per day.” She went on to say:

“We did not see the same patterns for fruit juice. These findings indicate that a healthy diet and lifestyle, which includes the consumption of whole fruits, is a great strategy to lower your diabetes risk.”

The researchers point out that their results only demonstrate an association between whole fruit consumption and reduced diabetes risk. More research will be necessary to see whether they can identify a causal relationship.

Nonetheless, the researchers offer a number of reasons that may account for this association. They note that “most fruits typically have a low glycemic load, whilst being rich in fiber, vitamins, minerals, and phytochemicals, all of which may play a contributory role.”

Dr. Bondonno and her colleagues emphasize the fact that researchers have linked low fiber levels in particular with type 2 diabetes.

This may also account for why they found no association between fruit juice intake and reduced risk of type 2 diabetes: almost all the fiber from fruit is removed during fruit juice processing.