People who eat whole fruits are less likely to develop diabetes than those whose fruit intake is mainly in the form of juice.
In a paper published in the British Medical Journal, last month, Dr Isao Muraki and a team from the Harvard School of Public Health, the UK and Singapore examined the incidence of type 2 diabetes in over 180,000 participants in three long-term health studies over 3.5 million person-years.
The team considered ten fruits: grapes or raisins; peaches, plums or apricots; prunes; bananas; cantaloupe; apples or pears; oranges; grapefruit; strawberries; blueberries. Fruit juice included apple; orange; grapefruit and other fruit juices.
They sent food frequency questionnaires to participants every four years to assess their usual diet.
Participants responded with how often they consumed a standard portion of fruit. Responses, ranged from “never, or less than once per month” to “six or more times per day”.
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The team also gathered information on participants’ body height and weight, cigarette smoking, physical activity, multivitamin use and family history of diabetes as well as menopausal status, post-menopausal hormone use and oral contraceptive use by women.
Over 12,000 (6.5%) of participants developed diabetes. Those who ate whole fruits were seven percent less likely than the average to develop diabetes while those who consumed fruit juice were more likely.
The researchers said; “greater consumption of specific whole fruits, particularly blueberries, grapes and apples was significantly associated with lower type 2 diabetes risk whereas greater fruit juice consumption was associated with a higher risk”.
The results did not depend on the glycaemic index of the particular fruit. However Apples, grapes and strawberries appeared the most effective in preventing diabetes, while substituting cantaloupe (rock) melons for juice had least effect.
The results support Australian dietary recommendations to increase the consumption of a variety of whole fruits as a measure for diabetes prevention.
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Helen Mitchell – General Manager, Health Services Diabetes WA – said when managing diabetes whole fruits are better than juices because they contain fibre and other nutrients, which are lost during juicing.
“Fruit juice is often sweetened or diluted and does not contain whole fruits. A glass of orange or apple juice may contain the juice of up to five pieces of fruit.
“In managing diabetes it is best to choose low glycaemic index fruits. The body absorbs these more slowly. Fruit such as such as apples and bananas are better than most tropical fruits.
“The take home message for seniors to reduce the chance of becoming diabetic or to manage existing diabetes is to eat lots of fresh fruit and vegetables,” she said.
How do you get your daily intake of fruit? What is your favourite way to eat it?