High GI' carbohydrates increase women's heart risk

Women who eat diets heavy in certain carbohydrates may be at greater risk of coronary heart disease, according to researchers.

A study of over 47,000 Italian adults found that women alone whose diets contained a lot of bread, pizza and rice doubled their heart disease risk.

These foods have a high glycaemic index (GI), meaning they release energy and raise blood sugar quickly.

The findings are published in Archives of Internal Medicine.

The experts say much more research is needed to understand why these high GI foods, rather than carbohydrates per se, appear to pose a risk - and why the risk applies to women and not men.

Low GI carbohydrates, such as pasta, which release energy and raise blood sugar far slower, showed no such link with heart disease.

Glycaemic index

The doctors who produced the report studied 15,171 men and 32,578 women who completed dietary questionnaires over many years.

This allowed the researchers to calculate overall carbohydrate intakes as well as the average glycaemic index of the foods eaten and the glycaemic loads of the diets.

They could try broadening the types of bread and cereals they eat to include granary, rye or oat; including more beans, pulses; and accompanying meals with a good helping of fruit and vegetables  Victoria Taylor of the British Heart Foundation

The glycaemic index (GI) is a measure of how much a food raises blood glucose levels compared with the same amount of glucose or white bread.

The glycaemic load is calculated based on the glycaemic index of a given food and also on the total amount of carbohydrates it contains.

After seven years, 463 participants had developed coronary heart disease.

The researchers found that the women whose diet had the highest glycaemic load had more than double the risk of heart disease compared with those women with the lowest glycaemic load.

The authors concluded: "Thus, a high consumption of carbohydrates from high-glycaemic index foods, rather than the overall quantity of carbohydrates consumed, appears to influence the risk of developing coronary heart disease."

The researchers believe that a high-glycaemic diet may dampen 'good' cholesterol levels in women more than in men.

But further research is needed to verify the absence of a link between high-glucose foods and cardiovascular disease in men, says the study.

Victoria Taylor, senior heart health dietician at the The British Heart Foundation, said that for women, choosing lower GI foods could be useful in helping them to reduce their risk of coronary heart disease.

She said: "They could try broadening the types of bread and cereals they eat to include granary, rye or oat; including more beans, pulses; and accompanying meals with a good helping of fruit and vegetables."

Five-a-day has little impact on cancer, study finds

Eating more fruit and vegetables has only a modest effect on protecting against cancer, a study into the link between diet and disease has found.

The study of 500,000 Europeans joins a growing body of evidence undermining the high hopes that pushing "five-a-day" might slash Western cancer rates.

The international team of researchers estimates only around 2.5% of cancers could be averted by increasing intake.

But experts stress eating fruit and vegetables is still key to good health.

In 1990, the World Health Organization recommended that everyone consume at least five portions of fruit and vegetables a day to prevent cancer and other chronic diseases.

The advice has formed a central plank of public health campaigns in many developed countries. It has been promoted in the UK since 2003 and in the US for nearly two decades.

But research has failed to substantiate the suggestion that as many as 50% of cancers could be prevented by boosting the public's consumption of fruit and vegetables.

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  Yinka Ebo Cancer Research UK

This latest study, which analysed recruits from 10 countries to the highly-regarded European Prospective Investigation into Cancer and Nutrition, confirms that the association between fruit and vegetable intake and reduced cancer risk is indeed weak.

The team, led by researchers from the Mount Sinai School of Medicine, in New York, took into account lifestyle factors such as smoking and exercise when drawing their conclusions.

But writing in the Journal of the National Cancer Institute, they said they could not rule out that even the small reduction in cancer risk seen was down to the fact that the kind of people who ate more fruit and vegetables lived healthier lives in many other respects too.

Broccoli not biscuits

In the best case scenario, an extra two portions of fruit and vegetables each day could prevent 2.6% of cancers in men and 2.3% of cases in women, the study concluded.

Research should focus more sharply on specific fruits and vegetables and their constitutents  Walter Willett Harvard School of Public Health

Vegetables, which tend to be richer in nutrients, appeared to be more beneficial than fruits, while heavy drinkers seemed to gain the most from a higher intake of both when it came to protection from cancers caused by alcohol and smoking.

In an accompanying editorial, Professor Walter Willet of Harvard University said the research strongly confirmed the findings of other studies, showing "that any association of intake and fruits and vegetables with risk of cancer is weak at best".

But he stressed specific substances contained in certain fruit and vegetables, if harnessed, could still have an important, protective effect.

Substantial evidence suggests lycopene from tomatoes, for instance, may reduce the risk of prostate cancer, while chemicals in broccoli are thought to stimulate a gene which protects against bowel cancer.

And data still suggests fruit and vegetables may provide protection against cardiovascular disease, one of the major killers in the developed world - although this too has yet to be proven categorically.

Keeping lean

But while the links between diet and cancer remain unclear, obesity is now seen as an established risk factor.

Eating five-a-day still has health benefits

Fruit and vegetables could therefore be beneficial just by virtue of taking the place of more calorific fare, health experts say.

In any event, a reduced risk of 2.5% should not be dismissed out of hand, the World Cancer Research Fund argues.

"For the UK, this works out as about 7,000 cases a year, which is a significant number," says Dr Rachel Thompson from the charity, which in a major 1997 report said there was "convincing evidence" of the protective effect of fruit and vegetables.

Yinka Ebo of Cancer Research UK said: "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."