Thursday, April 08, 2010

The made-up "five a day" rule bites the dust

No effect on cancer found but vege-eaters get less heart disease. Or do they? The effect on heart disease is just speculation, as the last sentence below acknowledges

Official guidelines recommend at least five portions of fruit and vegetables a day in order to be healthy but new research has found that this may not have a substantial effect on cancer.

For every extra two portions consumed the risk of cancer reduced by just three per cent, the research conducted by a team at Mount Sinai School of Medicine, in New York suggested.

It comes after other experts said thousands of cases of cancer could be avoided if Britons drank less alcohol and maintained a healthy weight.

More than 400,000 people were involved in the respected EPIC trial from across Europe, including Britain and the results are published in the Journal of the National Cancer Institute.

Average, across the whole group, was around 335 grams of fruit and vegetables a day, or around four portions. This varied greatly between the countries with people in Sweden eating the least and those in Spain eating the most.

Experts said that although the link between fruit and vegetables and cancer incidence was weak there was strong evidence that the diet reduced the risk of heart disease and should still be recommended.

Dr Walter Willett, of the Harvard School of Public Health, in Boston, America, said: "In summary, the findings from the EPIC cohort add further evidence that a broad effort to increase consumption of fruits and vegetables will not have a major effect on cancer incidence.

"Such efforts are still worthwhile because they will reduce risks of cardiovascular disease, and a small benefit for cancer remains possible. Research should focus more sharply on specific fruits and vegetables and their constituents and on earlier periods of life."

He said those eating five portions a day had a 30 per cent lower risk of cardiovascular disease than those eating an average of 1.5 portions a day.

Meanwhile other experts said even a modest link between fruit and vegetable consumption on cancer risk, if applied to the whole population still meant thousands of cancers could be avoided with a healthier diet.

Dr Rachel Thompson, Science Programme Manager for World Cancer Research Fund, said: “This study suggests that if we all ate an extra two portions of fruits and vegetables a day, about 2.5 per cent of cancers could be prevented.

“Given the fact that there are many types of cancer where there is no evidence eating fruits and vegetables affects risk, it is not surprising that the overall percentage is quite low. But for the UK, this works out as about 7,000 cases a year, which is a significant number.

“If you look at specific types of cancer, including mouth, pharynx and larynx, stomach and oesophagus, the evidence shows that eating plenty of fruits and vegetables probably reduces risk.

“Even if fruits and vegetables did not directly reduce risk, it would still be a good idea to eat them because people who eat plenty of fruits and vegetables are less likely to become overweight. Scientists now say that, after not smoking, maintaining a healthy weight is the most important thing you can do for cancer prevention.”

Yinka Ebo, health information officer at Cancer Research UK, said: “This study, the largest on diet and cancer to date, shows that eating lots of fruits and vegetables can slightly reduce your cancer risk.

“It’s still a good idea to eat your five-a-day but remember that fruits and vegetables are pieces in a much larger lifestyle jigsaw. There are many things we can do to lower our chances of developing cancer such as not smoking, keeping a healthy weight, cutting down on alcohol, eating a healthy balanced diet, being physically active and staying safe in the sun.”

The researchers found that high fruit and vegetable consumption was more beneficial for those who drank heavily.

The authors added that the results may be skewed because people who ate lots of fruit and vegetables were also likely to be healthier overall, with fewer smokers, lower alcohol consumption and greater physical activity levels.


Study explains near-death experiences

People who have "near-death experiences," such as flashing lights, feelings of peace and joy and divine encounters before they pull back from the brink may simply have raised levels of carbon dioxide (CO2) in the blood, a study suggests.

Near-death experiences (NDEs) are reported by between 11 and 23 per cent of survivors of heart attacks, according to previous research. But what causes NDEs is strongly debated. Some pin the mechanisms on physical or psychological reasons, while others see a transcendental force.

Researchers in Slovenia, reporting on Thursday in a peer-reviewed journal, Critical Care, investigated 52 consecutive cases of heart attacks in three large hospitals. The patients' average age was 53 years. Forty-two of them were men.

Eleven patients had NDEs, but there was no common link between these cases in terms of age, sex, level of education, religious belief, fear of death, time to recovery or the drugs that were administered to resuscitate them.

Instead, a common association was high levels of CO2 in the blood and, to a lesser degree, of potassium.

Further work is needed to confirm the findings among a larger sample of patients, say the authors, led by Zalika Klemenc-Ketis of the University of Maribor.

Having an NDE can be a life-changing experience, so understanding its causes is important for heart-attack survivors, they say.


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