Drinking fruit juice does not contribute to type-2 diabetes


By John DiTraglia



We have been receiving constantly fluctuating advice about drinking fruit juice for a long time. It’s been even more conflictual than advice about a healthy diet in general. It used to be thought that fruit juice was good. Then fruit juice was associated with obesity and short stature in children. Then since fruits and vegetables are good in general, maybe whole fruit is better than 100% fruit juice. Then in compliance with the sugary beverages (SSB-sugar sweetened beverages) badness is the observation that 100% fruit juice has just as much sugar as Coca-Cola (and milk). So some countries, like the Netherlands, say pure fruit juice is part of the SSB prohibition.

Speaking of the Netherlands, they have recently reported another examination of this fruit juice business by prospectively asking a cohort of 36,147 of their adults, aged 20 to 69, how much fruit juice they drink and how much fruit they eat and then watched by reading their medical records over 15 years to see how many got type 2 diabetes. (1) Type 2 diabetes, you know, is a surrogate for fatness and lots of other bad news.

They found no signal that pure fruit juice, comparing the highest with the lowest drinkers, was associated with type 2 diabetes. This is largely in compliance with many other studies of this issue. Likewise, fruit juice and fruit did not prevent type 2 diabetes. It just doesn’t matter.

This is an observational study and we know how fraught observational studies are because of all the unavoidable sloppiness of confounding by the vicissitudes of free-living humans. So they did the dutiful control of the other usual suspects – socioeconomics, smoking, “goodness” of diet by other measures, family history, alcohol consumption, …. and found that the fruit juice was not a culprit, after all, that was considered and eliminated.

So if we still believe that Coca-Cola causes more type 2 diabetes why doesn’t 100% fruit juice? Well, there must be other stuff in fruit juice or in Coca-Cola that is either protective or detrimental respectively.

This kind of conflict with what we said in a recent Fat Science column called “Fructose and the fat switch,” that fructose, the monosaccharide named after fruit, might be a bad guy. (2)

If you want to hear a report of more conflicting evidence, where fruit juice is not ok after all, then just wait a little while. Maybe we should stop listening to nutrition experts and start eating 3 servings a day of mice or bark or whatever. (3)

1. Scheffers FR, et al. Pure Fruit Juice and Fruit Consumption Are Not Associated with Incidence of Type 2 Diabetes after Adjustment for Overall Dietary Quality in the European Prospective Investigation into Cancer and Nutrition–Netherlands (EPIC-NL) Study. The Journal of Nutrition, January 2020, nxz340, https://doi.org/10.1093/jn/nxz340

2. Portsmouth Times Tuesday, January 21, 2020.

3. https://www.theonion.com/resigned-nutritionists-now-recommend-eating-3-servings-1841645170

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By John DiTraglia

John DiTraglia M.D. is a Pediatrician in Portsmouth. He can be reached by e-mail- jditrag@zoomnet.net or phone-354-6605.

John DiTraglia M.D. is a Pediatrician in Portsmouth. He can be reached by e-mail- jditrag@zoomnet.net or phone-354-6605.