Language researchers have traced the origin of the old saying “An apple a day keeps the doctor away” to 1866, when it appeared in different phrasing as a Welsh proverb: “Eat an apple on going to bed and you’ll keep the doctor from earning his bread.” In other words, it’s a pretty old maxim.
But that doesn’t mean it doesn’t have any validity. In fact, according to a study by Australian researchers recently published in the Journal of Clinical Endocrinology & Metabolism, eating whole fruits can lower the risk of type 2 diabetes.
For a long time, nutritionists and diabetes researchers have believed that good dietary practices most likely play a role in diabetes prevention. The American Diabetes Association (ADA), for example, while cautioning that not everyone’s body responds the same way to different foods, recommends at least two servings of fruit per day, along with whole grains, vegetables, and legumes. According to the ADA, most fruits contain useful fiber while also having a low glycemic index (GI), which is a ranking system that measures how quickly a certain food causes blood sugar levels to rise. Still, published studies on fruit consumption and diabetes have had mixed results, although some have concluded that low-glycemic-index (LGI) fruits might not only help prevent diabetes, but also other chronic conditions, such as heart disease and hypertension (high blood pressure). LGI fruits include apples, oranges, grapes, pears, peaches, bananas, kiwis, and berries.
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This latest research report, however, reinforces the theory that fruit consumption does have a beneficial effect when it comes to preventing or delaying the onset of type 2 diabetes. For their analysis, the scientists utilized data from a national survey called the Australian Diabetes, Obesity and Lifestyle Study, or AusDiab. This was a review of diabetes prevalence and risk factors in people aged 25 and up in the six states and the Northern Territory of Australia. There were 7,674 Australians enrolled. Slightly more than half (55%) were female and the average age was 54. The subjects had a median daily fruit intake of about 6 ounces (162 grams). The survey was conducted between May 1999 and December 2000 with follow-up periods from 2004-2005 and 2011-2014.
Fruit consumption linked to lower risk of developing type 2 diabetes
The researchers determined that people who ate two or more servings of fruit every day had a 36% lower risk of developing type 2 diabetes over a five-year period. This conclusion applied mostly to apples, but also to bananas and oranges to a lesser degree. Interestingly, this finding did not apply to fruit juice, which led the researchers to consider that “we should focus on consuming whole fruits.” As the researchers put it, “Higher total fruit intake was associated with better measures of glucose tolerance and insulin sensitivity. Furthermore, moderate to high fruit intake was associated with lower odds of diabetes after 5 years of follow-up.” These findings were considered significant because of the large size of the study population, although the researchers warned that the subjects tended to be of a higher social and economic status and generally healthier than the rest of the Australian population. As might be expected, people who eat more fruit tend to have better health habits.
In an interview with the medical news service Medpage Today, lead author Nicola Bondonno, PhD, explained, “We found a correlation between fruit intake and markers of insulin sensitivity, meaning that people who consumed more fruit had to produce less insulin to lower their blood glucose levels. We also observed that those who consumed around two servings of fruit per day had a 36% lower risk of developing T2D [type 2 diabetes] over the next five years than those who consumed less than half a serving of fruit per day.”
And what about the fact that fruits contain sugar? Dr. Bondonno said, “Many people know that sugar is bad and think that this must apply to all sugar. However, evidence shows that many of the health risks from sugars — from tooth decay to unhealthy weight gain — are related to consuming added sugar, not the natural sugars found in fruit.”