A new study published in the British Medical Journal suggests that eating more fruit, particularly blueberries, apples and grapes, is linked to a reduced risk of developing type-2 diabetes.
Blueberries cut the risk by 26% compared with 2% for three servings of any whole fruit – but fruit juice did not appear to have the same effect.
The research looked at the diets of more than 187,000 people in the US.
Researchers from the UK, US and Singapore used data from three large studies of nurses and health professionals in the US to examine the link between fruit consumption and the risk of contracting type-2 diabetes.
In these studies, 6.5% of participants (12,198 out of 187,382) developed type-2 diabetes.
The studies used food frequency questionnaires to follow up the participants every four years, asking how often, on average, they ate a standard portion of each fruit.
The fruits used in the study were grapes or raisins, peaches, plums or apricots, prunes, bananas, cantaloupe, apples or pears, oranges, grapefruit, strawberries and blueberries.
The researchers’ analysis of the data showed that three servings per week of blueberries, grapes and raisins, and apples and pears significantly reduced the risk of type-2 diabetes.
Eating more fruit, particularly blueberries, apples and grapes, is linked to a reduced risk of developing type-2 diabetes
While all fruit was shown to reduce the risk, these fruits appeared to be particularly effective.
The researchers said this could be due to the fact these fruits contain high levels of anthocyanins, which have been shown to enhance glucose uptake in mice. The same fruits contain naturally-occurring polyphenols which are known to have beneficial effects.
In the study paper, they wrote: “Fruits have highly variable contents of fibre, antioxidants, other nutrients, and phytochemicals that jointly may influence the risk.”
But the glycaemic load of different types of fruit – the quality and quantity of carbohydrate they contain – did not fully explain the results, the study said.
When they looked at the effects of fruit juice consumption, the researchers found a slightly increased risk of type-2 diabetes.
The study calculated that replacing weekly fruit juice consumption with whole fruits could bring health benefits.
For example, replacing fruit juice with blueberries could reduce the risk of contracting type-2 diabetes by 33%, with grapes and raisins by 19%, apples and pears by 13% – and with any combination of whole fruit by 7%.
Replacing fruit juice with oranges, peaches, plums and apricots had a similar effect.
Qi Sun, study author and assistant professor at Harvard School of Public Health, said, in general, fruit juices contained less of the beneficial compounds found in whole fruits.
“The juicing process gets rid of the fruit, just leaving fluids which are absorbed more quickly, causing blood sugars and insulin levels to rise if they contain sugars.
“To try to minimize the risk of type-2 diabetes as much as possible it is reasonable to reduce fruit juice consumption and increase consumption of whole fruits.”
Experts say the best way to reduce your risk of developing type-2 diabetes is to eat a balanced, healthy diet that includes a variety of fruits and vegetables and to be as physically active as possible.
Fabulous frozen yoghurt and gorgeous granita make deliciously refreshing desserts.
Ingredients (Serves 8):
100 g (3½oz) caster sugar
100 ml (3½fl oz) water
200 g (7oz) blueberries
500 g (1lb 2oz) vanilla yoghurt
2 tsp vanilla extract
8 ice-pop moulds and sticks
Blueberry and yoghurt ice lollies
In a saucepan, bring the sugar and water to a boil, then simmer for 6-7 minutes or until syrupy. When totally cool, process in a blender with the blueberries until smooth.
Press the mixture through a fine sieve to remove the seeds. Pour the yoghurt and vanilla extract into a large bowl.
Drizzle over the blueberry and sugar mixture and gently fold it through with a skewer to create a soft swirl (don’t over-mix it). Spoon the mixture into ice-pop moulds, insert the sticks and freeze for 3-4 hours or until set.
To remove the pops, dip the moulds in warm water for 10-12 seconds and gently release the pops.
Antioxidants enhance the immune system’s defense against the diseases caused by free radicals. They include Vitamins A, C and E and selenium, and we have been told they may help prevent cancer, heart disease and even such neurological conditions as Alzheimer’s.
Naturally occurring chemicals, antioxidants are found in fruits and juices, made into supplements, and even added to make-up.
But adding extra antioxidants to our diet gives no benefit. You can eat as many blueberries – or whatever the antioxidant-containing food du jour is – as you like and it won’t stop you getting these illnesses. And loading up with supplements may be bad for your health.
Some antioxidants are produced by the body and some by plants, and so they can be derived from the diet. Their job is to combat free radicals – highly reactive molecules formed as a natural by-product of cellular activity. Free radicals are also created by exposure to cigarette smoke, strong sunlight, and breathing in pollution.
These aggressive chemicals present a constant threat to cells and DNA. We know they can lead to cell damage, cancer, diabetes and cardiovascular problems. Free radicals have also been implicated in everything from strokes to Parkinson’s and Alzheimer’s.
Antioxidants stop the chain reactions triggered by free radicals that can damage and destroy cells. So it may seem entirely reasonable that it would be a good thing to eat and drink more antioxidants to boost the supply – or even rub them into your skin. But this is by no means the case.
You might have seen some antioxidant- containing products labeled with a number, usually in the thousands. This is the oxygen radical absorbance capacity (ORAC) number.
It compares the antioxidant with a standard substance called trolox – itself an antioxidant. Cranberries, for example, have an ORAC level of 8,983, which is related to the number of molecules of trolox that would have the same antioxidant strength. Taken in isolation, the number is pretty meaningless, but it makes it possible to compare different foods. So theoretically, the higher the ORAC number, the better the food.
Although there is evidence that antioxidants may have an effect on cancers, much of it is based on experiments on free radicals in cells cultured outside the body, in labs
In reality, beyond a certain point, there is no benefit. In 2008, a study of nearly 15,000 men showed no benefits from Vitamin C and E supplements. There is no recommended daily amount of antioxidant consumption. And although there is evidence that antioxidants may have an effect on cancers, much of it is based on experiments on free radicals in cells cultured outside the body, in labs.
So if antioxidants are good for us, why doesn’t eating more of them have an even more beneficial effect? We know that people with poor diets are more prone to a host of diseases, and that those who eat a balanced diet with at least five fruits and vegetables a day, take exercise, and other very mundane things such as that, have the best chance of not becoming ill. But trials where people have consumed higher than usual levels of antioxidants by taking supplements have found that, if anything, they have a negative impact on health.
A Cochrane Review published last month, which looked at the results of hundreds of individual studies, found that current evidence does not support the use of antioxidant supplements in the general population or in patients with various diseases.
And when the review looked at the mortality rate over 78 randomized clinical trialsfor a range of conditions and using various antioxidants, those consuming antioxidants were 1.03 times more likely to die early.
Another clinical trial last month showed that antioxidant supplements don’t slow down the progression of Alzheimer’s. Two 1994 clinical studies showed a possible increase in lung cancer when taking antioxidants.
Almost all things are poisonous in large enough quantities – even water, though you would have to drink an awful lot to kill you. Similarly, the amounts of antioxidants found in foods are relatively small, so it would be difficult to overdose. Fruit has plenty of other benefits – vitamins that are crucial for healthy functioning and fibre for good digestion, but, like everything, you can consume too much. Excessive consumption may cause damage to the enamel of the teeth or stomach problems.
It is only the excessive consumption of antioxidants through unnecessary diet supplements that could cause any concern.
Using antioxidants on the skin, rather than eating them, may have benefits. Clinical trials have shown that they provide considerable protection against the formation of free radicals in the outer layers of skin when added to sunscreens.
How can we avoid cancer, heart disease, diabetes and the like? Don’t smoke, don’t drink to excess, eat a sensible, balanced diet, including a good mix of fruit and vegetables, and don’t get fat. It’s boring, but true. We know for a fact that the big killer diseases are caused by unhealthy lifestyles.
It would be lovely if eating blueberries or popcorn would somehow counteract a lifetime of abuse, but it’s just not going to happen. And no matter what you do, you can get ill anyway.