When it comes to foods as basic and healthy as fruit, it seems to be a no-brainer to recommend them for health. Perhaps the simplest and best all-around nutritional advice you could receive is to eat a diet high in lean protein sources, fruits, and vegetables. Fruit is right in there as one of the major healthy food categories. But, while there is no doubt that fruit is generally healthy, the types of fruits you eat might actually make a difference.
Fruit is an interesting food from a health perspective. Most fruits tend to be rich in antioxidants, nutrients, and fiber, but the amounts of each of these vary considerably depending on the type of fruit. Another aspect that needs to be considered is total sugar, and perhaps more importantly, glycemic value (the speed in which the sugar enters the blood.) The rich nutritional content of fruit could be seen to help diseases such as diabetes, but the sugar content could be a hindrance. In a recent study in the BMJ, researchers examined the types of fruits eaten and compared them to the incidence of type 2 diabetes over time.
Because diabetes takes time to develop, a study like this takes a lot of people and a lot of time to be done well. And that’s exactly what the researchers did. In fact, if you multiply the participants of this study by the number of years of follow-up for each, the result is nearly 3.5 million years of follow-up combined. That’s no typo, this study is pretty large and thorough.
The researchers found several interesting trends that may not be surprising, but are certainly good to know:
First, there didn’t seem to be much association with either a fruit’s glycemic load or glycemic value and the risk of type 2 diabetes, at least where whole fruits were concerned. However, fruit juices were associated with a higher risk of diabetes. The juice of a fruit tends to be lower in fiber, and so tends to also be higher in glycemic value. Juice may be less filling as well, increasing the total sugar taken in. Perhaps less nutritional value and more sugar, put together in juice form, is substantial enough for higher risk of diabetes.
Next, there was a difference in the type of fruit and the risk of diabetes. Blueberries, grapes, and apples were associated with a reduced risk of diabetes. With less conservative measurements, bananas and grapefruit were also consistently associated with reduced risk. Cantaloupe was associated with a higher risk of diabetes.
Finally, total whole fruit consumption was associated with a weak reduction in diabetes risk. Replacing juice with whole fruit reduced the risk associated with the juice as well. Because there is a significant difference between individual fruits, this further suggests that the variations in different fruits do make a difference. So if you are what you eat, you’re better off being a blueberry, a grape, or an apple – at least as far as diabetes is concerned.
1. Isao Muraki, et. al., “Fruit consumption and risk of type 2 diabetes: results from three prospective longitudinal cohort studies,” BMJ, 347:f5001, 2013
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