Wednesday, October 12, 2011

Chocolate 'cuts stroke risk'

The usual story about chocolate is that it is only dark chocolate that is beneficial, and, as the study rightly notes, only about 10% of the population eat dark chocolate. But in this study total chocolate only was measured. So the results are a little surprising

It is notable that only BIG chocolate eaters gained a benefit and one should also note that the effect is small in absolute terms. That does rather suggest some third underlying variable producing the effect.

Could that be the usual social class effect? Sweden has aggressively enforced income equality so could it be that the wives of the smarties who manage to evade those pressures to some extent and gain a higher than usual disposable income show their status via a high chocolate intake? There is of course a general tendency towards assortative mating: Husbands and wives will generally have fairly similar IQs. And people with high IQs are healthier

It's all very speculative and the data is poor anyway (weakly validated self-report) but all interpretations of epidemiological correlations are speculative. With 350 items in the questionnaire the results could also be nothing more than a product of data dredging

Women who eat a bar of chocolate a week could reduce their chances of having a stroke by 20 per cent, according to a new study.

A study of more than 33,000 Swedish women found that those who ate the most chocolate had the lowest chance of stroke. People who ate 66g per week – about a bar and a half – were 20 per cent less likely to suffer a stroke, while those who consumed 8g a week or less were at the highest risk.

The findings, published in the Journal of the American College of Cardiology, add further weight to previous studies which highlight the health benefits of eating chocolate and cocoa.

Earlier this year Cambridge University experts found that regular doses of chocolate can reduce the risk of heart disease by a third, while a separate study suggested it can be as good for the health as exercise.

Scientists from the Karolinska Institute in Stockholm questioned 33,372 women about their eating habits in 1997 and over the next decade about 1,600 suffered strokes.

Susanna Larsson, one of three researchers, said: "We followed 33,000 women over the course of 10 years, and we found that those who ate most chocolate had a much lower risk – 20 per cent lower – of suffering a stroke."

Chocolate was expected to help protect against stroke because it lowers blood pressure, thereby reducing a key risk factor, she added.

The women who took part were not asked whether the chocolate they ate was dark or light, a distinction which would have helped establish a firmer connection between cocoa – the protective agent in chocolate – and stroke risk.

The researchers will now carry out a similar study in men, and expect to find similar results.

Dr Sharlin Ahmed, of The Stroke Association, said: “Previous research has suggested that dark chocolate can increase levels of good cholesterol and decrease blood pressure, both of which can reduce your risk of stroke.

"However, it’s very hard to say whether this is true of all types of chocolate and it’s difficult to determine whether the reduced stroke incidence found in this study is directly linked to the amount of chocolate consumed. A lot more research is needed.”


High doses of vitamin E 'can significantly INCREASE risk of prostate cancer'

Vitamin E is favoured by the anti-oxidant cultists so this may be one reason why they die younger. The effect is small, however

High doses of vitamin E can significantly increase the risk of men developing prostate cancer, says a major study.

The chances of developing the disease rose by 17 per cent, even years after men stopped taking the vitamin, claim researchers.

The latest warning over potential harm caused by vitamin supplements follows a study which found women taking multivitamins and other supplements have an increased risk of dying.

The new findings come from a U.S. trial which was attempting to confirm earlier reports that extra vitamin E and the mineral selenium could help prevent prostate cancer.

Instead the researchers discovered the opposite - more cases of prostate cancer among men taking 400 international units (IU) of vitamin E a day than placebo, or dummy capsules.

This is the equivalent of 363mg a day – the measurement used in Britain – which is 30 times more than the recommended daily amount.

Lead researcher Dr Eric Klein, of the Cleveland Clinic in Chicago, said millions of older Americans take supplements containing vitamin E, many of them at the megadose levels of the study.

Writing in the Journal of the American Medical Association (must credit), he said ‘The observed 17 per cent increase in prostate cancer incidence demonstrates the potential for seemingly innocuous yet biologically active substances such as vitamins to do harm.

‘The lack of benefit from dietary supplementation with vitamin E or other agents with respect to preventing common health conditions and cancers or improving overall survival, and their potential harm, underscore the need for consumers to be sceptical of health claims of unregulated over-the-counter products in the absence of strong evidence of benefit demonstrated in clinical trials.’

More than 35,000 healthy men in their 50s and older took part in the Selenium and Vitamin E Cancer Prevention Trial (Select) at 427 centres in the US, Canada and Puerto Rico. They were given either a daily placebo or various combinations of vitamin E and selenium supplements between August 2001 and June 2004.

In 2008, volunteers were told to stop taking the supplements because the trial was not going to achieve an expected 25 per cent reduction in prostate cancer risk.

The researchers continued monitoring the health of some men, which is when more cases of prostate cancer emerged in the group assigned to take vitamin E.

A total of 529 men given placebo pills developed prostate cancer compared with 620 taking vitamin E alone, 575 taking selenium alone, and 555 taking both supplements.

Although selenium alone, and selenium plus vitamin E, were associated with slightly raised prostate cancer rates, they were not statistically significant.

But the researchers said the extra risk associated with vitamin E became apparent during the third year of the trial and could not have occurred by chance.

But co-author Dr Lori Minasian, acting director of the US National Cancer Institute, said it was a biological ‘mystery’ why taking vitamin E should result in an extra risk of prostate cancer.

Dr Helen Rippon, head of research management at The Prostate Cancer Charity, said ‘This new large-scale research radically challenges the hope that vitamin E and selenium supplements might be an effective way for men to reduce their risk of developing prostate cancer.

‘Rather, the researchers have shown that, far from being protective, selenium has no effect upon prostate cancer rates in men, whilst excessive levels of vitamin E actually increases a man’s risk of getting the disease considerably. 'For men, a simple dietary supplement to protect against prostate cancer remains elusive'

‘Dietary supplements are often taken without the advice of medical professionals as they are often seen as risk free – but as this important new study shows, the true effects of these supplements are not always clear.

‘Unfortunately for men, this means that a simple dietary supplement to protect against prostate cancer remains elusive. Therefore, any man wishing to reduce their risk of the disease should stick to a healthy, balanced diet which will ensure they get the right level of vitamins and minerals they need, without supplements.’

In the UK, the recommended daily amount of vitamin E is 12mg and most multivitamin pills contain between 15mg and 30mg. However, the UK Expert Group on Vitamins and Minerals says the upper ‘safe’ limit is between 700 and 800mg a day – twice as much as taken in the study.

Dr Carrie Ruxton from the industry-backed Health Supplements Information Service, said the study volunteers were taking extremely high doses that would be regularly taken by few Britons.

She said ‘This is yet another trial, of which there have been many during recent years, in which very high dose dietary supplements are used in an attempt to prevent disease.

‘Yet, vitamins and minerals are not intended for this purpose; they are essential nutrients which should be consumed in recommended amounts to maintain health and prevent nutrient deficiency.’


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