Saturday, September 12, 2009

A bowl of blueberries keeps the brain active in the afternoon

But what if it gives you cancer and shortens your life? Antioxidants have been found to do both those things. It also sounds like this was not a double blind experiment so effects from experimenter expectations cannot be ruled out. Just another rite in the antioxidant religion, I suspect

Munching a bowl of blueberries for breakfast can stop you flagging in the afternoon, a new study shows. Researchers found that a large helping of the fruit - described by some as nature's 'superfood' - boosts concentration and memory up to five hours later. In tests, volunteers who drank a blueberry smoothie in the morning did much better at mental tasks in the mid afternoon than people who had an alternative drink.

British scientists who made the discovery believe the antioxidants in blueberries stimulate the flow of blood and oxygen to the brain - and keep the mind fresh. The finding means people could use blueberries and other fruit rich in anti-oxidants to improve their chances during exams or on long, difficult days at work.

Dr Jeremy Spencer of Reading University, who carried out the study, said: 'After one hour there was little difference in the attention tests. 'But after five hours people who didn't have the blueberry smoothie saw their performance fall by 15 to 20 per cent.'

Blueberries are bursting with vitamins C and E. Nutritionists say they are one of the richest sources of cancer-fighting antioxidant called flavonoids, which are also found in green tea, wine, grapes and cocoa. Past studies have shown that flavonoids can protect against degenerative diseases and even help people lose weight.

In the latest study - presented yesterday (THU) at the British Science Festival in Surrey University, Guildford - Dr Spencer recruited 40 volunteers aged 18 to 30 and 40 volunteers aged over 65. On the first day of the experiment, they were given a standard breakfast of toast and marmalade, followed by a mid morning smoothie made from 200g of blueberries.

An hour after the smoothie they carried out 45 minutes of computer based mental tests. The tests measured their short term working memory and their concentration. The tests were repeated five hours after the smoothie. Two weeks later the volunteers carried out the same experiment - but this time drank a 'control' smoothie containing the same amount of sugars and calories but with no blueberries.

In the tests, carried out an hour after the smoothie, the presence of blueberries in the smoothie made no difference to the volunteers' performance. But as the day wore on, the volunteers who didn't have the blueberries saw their performance and concentration slipping. When they were tested after five hours their performance was significantly worse.

In contrast, the volunteers who had the blueberry drink saw no decline in their mental powers, the scientists said. Dr Spencer said the brain boosting power was not unique to blueberries. 'From our studies, other foods containing flavonoids - such as strawberries, cocoa and raspberries - would be similar,' he said. 'It's not right to single out blueberries.'

The Reading researchers believe that flavonoids in berries activate an enzyme in the body called Enos which increases the flow of blood and oxygen to the brain. Without this boost, brains become tired as the day goes on and find it harder to concentrate.

Blueberries contain a cocktail of anti-oxidants including anthocyanins, proanthocyanidins, resveratrol and tannins. The fruit are thought to protect against cancer and heart disease, and may even prevent dementia.


British 'Worried well' are wasting £600m a year on vitamins

Multivitamins taken by millions of 'worried well' are a waste of money and may be doing more harm than good, an expert has said. Brian Ratcliffe, a former government adviser on nutrition, accused the £600million-a-year vitamin pill industry of preying on the fears and finances of people who are essentially healthy.

The tablets, on sale in every supermarket, chemist and health food shop, do little to boost health in those with no medical problems and in some cases could be dangerous. For instance, those who take fish oils as well as multivitamins could be raising their odds of brittle bones in later years because they are consuming too much vitamin A.

The health-conscious should not take any supplements without first consulting their GP or another medical expert, said Professor Ratcliffe, of Robert Gordon University in Aberdeen. He said: 'A lot of people take supplements because they are the worried well and are concerned with taking a belt-and-braces approach to health. 'So they are not thinking very carefully about why they are taking them, how much they should be taking and whether they should be taking them at all. 'They are simply wasting their money and fuelling an industry that is to some extent exploiting their fears. Then, of course, there is a chance they are dabbling in an area where there is a potential for harm.'

The professor, a former adviser to the Food Standards Agency, is not the first to raise concern about the tablets taken by 40 per cent of women and 30 per cent of men a day. Last year, a U.S. analysis of 67 studies said vitamins A and E [i.e. ANTIOXIDANTS] may shorten life, not extend it. Other studies linked the two vitamins to increased risk of cancer.

Even relatively small doses of vitamin A can be toxic, said the professor. The vitamin is found in many fish oil capsules, so those who take these alongside multivitamin pills may be getting more than they should. Too much vitamin A can cause nausea and headaches in the short term and raise the risk of osteoporosis in later years, the British Science Festival in Guildford heard.

On the other hand, high doses of vitamin C are not harmful - but up to three-quarters pass straight through the body. Even small doses may be of little benefit. A recent study found the vitamin C tablets taken by millions to ward off colds have little effect at preventing the sniffles and only marginally shorten their duration.

Professor Ratcliffe said that on average we get enough vitamin C from our diet - and it is easy to raise the amount by eating healthier food. However, some may benefit from specific supplements, including the elderly, who can be low in vitamin D, and pregnant women, who are advised to take folic acid.

Manufacturers said Government figures show that three-quarters of adults fail to eat five helpings of fruit and vegetables a day and many lack key vitamins and minerals. Dr Carrie Ruxton, of the industrybacked Health Supplements Information Service, said: 'Supplements are a useful means of boosting vitamin and mineral intakes while people are gradually improving their diets - this process takes time.'


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