Dr Lydia Bazzano and colleagues from Tulane University School of Public Health and Tropical Medicine in Louisiana and other medical and academic centres across the USA carried out this study. The research was supported by the National Institutes of Health. One of the researchers received a grant from the Office of Research on Women’s Health and Office of Dietary Supplements. It was published in the peer-reviewed medical journal: Diabetes Care.
This was a cohort study of over 70,000 female nurses followed for 18 years to determine the links between diet and risk of various outcomes. The study has published many parts of its results over time, and in this particular paper the researchers report on the association between all fruit and vegetables, particular types of fruit or vegetable, and fruit juice with the onset of type 2 diabetes during the 18 years of follow-up.
This confirms advice by qualified nutritionists, good dietitians and the Food Standards agency that warn it's whole fruit and vegetables you need for optimum health not fruit juice.
No matter how much juice you drink it only counts as 1 portion towards your 5 (better 8 or 9) portions of fruit and veg per day.
Juice is quite often not juice at all and this study doesn't seem to differentiate. Many juices on the market are 'fruit drinks' with added sugar or worse still added sweeteners. Juice is very rarely fresh more likely pasteurised that would kill the beneficial enzymes that you would get from live fresh fruit. Even smoothies are pasteurised so although you benefit from the fibre and are thus better than juice or no fruit at all they are still not as good as a home made berry smoothie or the fresh fruit itself.
Intake of total fruit and green leafy vegetables appeared to reduce the risk of type 2 diabetes which confirms nutritionist and Raw Foodists claims that green is the most important colour in your rainbow menu.
Same old same old - 3 portions of fresh fruit and 5 portions of vegetables per day with a rainbow of colours - emphasis on the green. Fresher and the least processed (raw?) the better.
Fresh smoothies are getting easier to buy with smoothie bars opening up in shopping malls - they usually use frozen berries which some would argue is better than limp fresh ones. For convenience you could add a heaped teaspoon of green hemp protein or seaweed and algae to your fruit smoothie to lessen the strain of the sugar on your insulin levels or eat a handful of seeds with your smoothie.
The one juice exception may be wheat grass but I suspect we'll have to wait quite some time before we see a research study of 121,700 nurses on their wheat grass juice consumption and the effects on insulin levels over 18 years even in the USA