Saturday Quack - Fruit Juice Has Hidden Drawbacks

It’s easy to think that a glass of fruit juice will count as one of “5-a-day”, i.e. one of the 5 servings of fruit and vegetables you should eat every day. True – fruit juice may contain enough fiber and vitamins to qualify, but they often usually contain far more sugar than you need. This is shown in a study done at Tulane University, New Orleans, and published in the journal Diabetes Care.

Food intake data from the Nurses’ Health Study were analyzed for the possible effect of diet on the frequency of development of diabetes. Food questionnaires were administered to over 70,000 women aged 38-63 for 18 years. The women were free off cardiovascular disease, cancer, and diabetes at the start of the study in 1984.

Over the 18 years’ follow-up, over 4,500 cases of diabetes were reported by the participants, giving a cumulative incidence of 7.4%. The women were classified into 5 groups according to their fruit and vegetable intake, and they were also grouped using fruit juice consumption. It was found that an increase of 3 servings a day in whole fruit-and-vegetable intake was not linked to any change in diabetes risk, whereas an increase of 3 servings a day of whole fruit intake was linked with a lower risk of diabetes - 18% less risk, in fact. An increase of one serving of a leafy green vegetable cut the risk by 9%. (An increased or decreased risk of diabetes means the difference in diabetes frequency between one or more of the five groups classified above).

The big surprise came when fruit juice intake was analyzed. An additional daily serving of fruit juice increased the likelihood of developing diabetes by 18%. The investigators blamer the sugar content of the fruit juice, pointing out that this represents a big sugar load presented in a liquid form, allowing rapid absorption. The moral of this story: don’t count fruit juice as “one of 5-a-day”, eat some spinach or kale (ugh!) instead.