CHICAGO - For the first time, an experimental drug shows promise for halting the progression of Alzheimer's disease by taking a new approach: breaking up the protein tangles that clog victims' brains.
The encouraging results from the drug called Rember, reported Tuesday at a medical conference in Chicago, electrified a field battered by recent setbacks. The drug was developed by Singapore-based TauRx Therapeutics.
Even if bigger, more rigorous studies show it works, Rember is still several years away from being available, and experts warned against overexuberance. But they were excited.
"These are the first very positive results I've seen" for stopping mental decline, said Marcelle Morrison-Bogorad, director of Alzheimer's research at the National Institute on Aging. "It's just fantastic."
The federal agency funded early research into the tangles, which are made of a protein called tau and develop inside nerve cells.
For decades, scientists have focused on a different protein — beta-amyloid, which forms sticky clumps outside of the cells — but have yet to get a workable treatment.
The drug is in the second of three stages of development, and scientists are paying special attention to potential treatments because of the enormity of the illness, which afflicts more than 26 million people worldwide and is mushrooming as the population ages.
The four Alzheimer's drugs currently available just ease symptoms of the mind-robbing disease.
TauRx's chief is Claude Wischik, a biologist at the University of Aberdeen in Scotland who long has done key research on tau tangles and studies suggesting that Rember can dissolve them.
He is an "esteemed biologist," and the research "comes with his credibility attached to it," said Dr. Sam Gandy of Mount Sinai School of Medicine in New York. He heads the scientific advisory panel of the Alzheimer's Association.
In the study, 321 patients were given one of three doses of Rember or dummy capsules three times a day. The capsules containing the highest dose had a flaw in formulation that kept them from working, and the lowest dose was too weak to keep the disease from worsening, Wischik said.
However, the middle dose helped, as measured by a widely used score of mental performance.
"The people on placebo lost an average of 7 percent of their brain function over six months whereas those on treatment didn't decline at all," he said.
After about a year, the placebo group had continued to decline but those on the mid-level dose of Rember had not. At 19 months, the treated group still had not declined as Alzheimer's patients have been known to do.
Two types of brain scans were available on about a third of participants, and they show the drug was active in brain areas most affected by tau tangles, Wischik said.
"This is suggestive data," not proof, Wischik warned. The company is raising money now for another test of the drug to start next year.
The main chemical in Rember is available now in a different formulation in a prescription drug sometimes used since the 1930s for chronic bladder infections — methylene blue. However, it predates the federal Food and Drug Administration and was never fully studied for safety and effectiveness, and not in the form used in the Alzheimer's study, Wischik and other doctors cautioned.
On Monday at the International Conference on Alzheimer's Disease, other researchers reported encouraging results from a test of a different experimental drug that also targets tau tangles. That drug, by British Columbia-based Allon Therapeutics Inc., was tested in people with an Alzheimer's precursor, mild cognitive impairment.
The tau-drug results are in stark contrast to the flop of Flurizan, which was aimed at blocking enzymes that form the beta-amyloid clumps. Myriad Genetics announced in June that it would abandon development of Flurizan after the failure. Full results were presented at the conference Tuesday.
Also, fuller results were given from a closely watched test of bapineuzumab, an experimental drug that aims to enlist the immune system to clear out the sticky brain clumps.
Its developers — New Jersey-based Wyeth and the Irish company Elan Corp. PLC — previously announced that the 240-patient study missed its main goal of improving patients' mental performance at 18 months.
But the company found a silver lining — the drug appeared to help the roughly 60 percent of people in the study who did not have a gene that scientists think makes Alzheimer's disease more severe.
The results back up the company's claims of potential effectiveness in some patients, but now there are concerns about possible side effects. Twelve cases of a type of brain swelling occurred in those on bapineuzumab and none in the placebo group. The swelling caused few if any symptoms, company scientists said, but outside experts said it may have contributed to other side effects.
Those were two or more times more common in patients on bapineuzumab than people given the dummy drug. For example, cases of anxiety occurred in 11 percent versus 4 percent on placebo; paranoia, 7 versus 1 percent. Other complaints were vomiting, high blood pressure, weight loss, and back pain.
Three deaths occurred among the 124 patients given bapineuzumab, but they were not related to the drug, said Dr. Sid Gilman of the University of Michigan, who headed the study's data safety monitoring board. One death was due to pneumonia and two others to worsening Alzheimer's disease.
Investors reacted to the news by driving down Wyeth's shares $5.01, or 11.1 percent, in after-hours trading.
Wyeth and Elan have already said they will move on to late-stage testing of bapineuzumab in more than 4,000 patients.
___
On the Net:
National Institute on Aging: http://www.nia.nih.gov
Alzheimer's Association: http://www.alz.org
Tuesday, July 29, 2008
Sunday, July 27, 2008
Study: Exercise slows Alzheimer's brain atrophy
NEW YORK - Patients with early Alzheimer's disease who exercised regularly saw less deterioration in the areas of the brain which control memory, according to a study released Sunday at the 2008 International Conference on Alzheimer's Disease in Chicago.
Magnetic resonance imaging (MRI) studies showed that exercise positively affected the hippocampus region of patients' brains, an area which is important for both memory and balance. In Alzheimer's, the hippocampus is one of the first parts of the brain to suffer damage.
Exercise and physical fitness have been shown to slow down age-related brain cell death in healthy older adults, and earlier this month a preliminary study was published showing that exercise may help slow brain shrinkage in people with early Alzheimer's disease.
Now, researchers at the University of Kansas Medical Center in Kansas City, Kan., have used MRI and other neuroimaging tools to analyze how exercise affects the brains of those with early Alzheimer's.
The researchers found that patients with early Alzheimer's had a "significant relationship" between the size of key brain areas associated with memory and fitness, unlike healthy older adults. Those patients with better fitness ratings had less brain tissue atrophy and those with worse fitness had more brain damage.
"This is the first study to get an inside look into specifically where these changes occur in the brain — we're able to locate the changes associated with fitness to the actual memory region, the hippocampus, which is a key area for Alzheimer's-related atrophy," said Robyn A. Honea, PhD, a lead investigator on the study. "This suggests that maintaining cardiorespiratory fitness may positively modify Alzheimer's-related brain atrophy."
The study was funded by the National Institute on Aging and National Institute on Neurological Disorders and Stroke.
Another report from ICAD 2008 showed that a 12-month home-based exercise program reduced falls and improved balance in patients with dementia. According to researchers from Western Medicine, a consultant physician service provider for Hollywood Hospital in Nedlands, Western Australia, people suffering from dementia fall up to three times more than those who have no cognitive impairment.
"Falls have a negative impact on a person's quality of life, often resulting in nursing home placement, increased mortality and significant costs to the community," said Megan J. Wraith, a speech pathologist at Western Medicine and a researcher on the study. "Targeting this high risk group may be a relatively cost effective way of having a significant impact on the overall rate of falling in the elderly."
The study was funded by the Sir Charles Gairdner Research Foundation and Hollywood Private Hospital Research Foundation.
Currently, the prognosis for patients with Alzheimer's is bleak. The Alzheimer's treatment market is small, led by Pfizer Inc.'s Aricept, Forest Laboratories Inc.'s Namenda, Razadyne from Johnson & Johnson and Shire Ltd., Novartis AG's Exelon and Sciele Pharma Inc.'s Cognex. But while those drugs fight Alzheimer's symptoms, they can't stop its ultimate progress.
Wyeth and Elan Corp. are currently developing a new kind of Alzheimer's treatment, bapineuzumab, which is designed to actually slow progress of the disease. In June, study data showed that drug was shown to benefit Alzheimer's patients who lacked a certain gene.
Magnetic resonance imaging (MRI) studies showed that exercise positively affected the hippocampus region of patients' brains, an area which is important for both memory and balance. In Alzheimer's, the hippocampus is one of the first parts of the brain to suffer damage.
Exercise and physical fitness have been shown to slow down age-related brain cell death in healthy older adults, and earlier this month a preliminary study was published showing that exercise may help slow brain shrinkage in people with early Alzheimer's disease.
Now, researchers at the University of Kansas Medical Center in Kansas City, Kan., have used MRI and other neuroimaging tools to analyze how exercise affects the brains of those with early Alzheimer's.
The researchers found that patients with early Alzheimer's had a "significant relationship" between the size of key brain areas associated with memory and fitness, unlike healthy older adults. Those patients with better fitness ratings had less brain tissue atrophy and those with worse fitness had more brain damage.
"This is the first study to get an inside look into specifically where these changes occur in the brain — we're able to locate the changes associated with fitness to the actual memory region, the hippocampus, which is a key area for Alzheimer's-related atrophy," said Robyn A. Honea, PhD, a lead investigator on the study. "This suggests that maintaining cardiorespiratory fitness may positively modify Alzheimer's-related brain atrophy."
The study was funded by the National Institute on Aging and National Institute on Neurological Disorders and Stroke.
Another report from ICAD 2008 showed that a 12-month home-based exercise program reduced falls and improved balance in patients with dementia. According to researchers from Western Medicine, a consultant physician service provider for Hollywood Hospital in Nedlands, Western Australia, people suffering from dementia fall up to three times more than those who have no cognitive impairment.
"Falls have a negative impact on a person's quality of life, often resulting in nursing home placement, increased mortality and significant costs to the community," said Megan J. Wraith, a speech pathologist at Western Medicine and a researcher on the study. "Targeting this high risk group may be a relatively cost effective way of having a significant impact on the overall rate of falling in the elderly."
The study was funded by the Sir Charles Gairdner Research Foundation and Hollywood Private Hospital Research Foundation.
Currently, the prognosis for patients with Alzheimer's is bleak. The Alzheimer's treatment market is small, led by Pfizer Inc.'s Aricept, Forest Laboratories Inc.'s Namenda, Razadyne from Johnson & Johnson and Shire Ltd., Novartis AG's Exelon and Sciele Pharma Inc.'s Cognex. But while those drugs fight Alzheimer's symptoms, they can't stop its ultimate progress.
Wyeth and Elan Corp. are currently developing a new kind of Alzheimer's treatment, bapineuzumab, which is designed to actually slow progress of the disease. In June, study data showed that drug was shown to benefit Alzheimer's patients who lacked a certain gene.
Monday, July 21, 2008
Vytorin fails to meet main goal of heart study
NEW YORK (Reuters) - The cholesterol fighter Vytorin sold by Merck & Co Inc and Schering-Plough Corp failed to meet the main goal of improving outcomes in a closely-watched heart study, according to data presented on Monday.
Slightly higher incidents of cancer deaths were also seen in those taking the drug -- 39 versus 23 on placebo -- although the lead researcher said those could have occurred as a result of chance.
The shares of both companies fell after the data were released, with Schering off more than 15 percent and Merck down by 7 percent.
No significant difference in the study's composite heart goals was seen between the patients who received Vytorin and those who received a placebo, according to data presented in London by its primary researcher, Dr. Terje Pedersen of Ulleval University Hospital in Oslo, Norway.
Researchers played down the cancer data, saying much larger studies of Vytorin have not showed increased cancer risk.
"There is no overall credible evidence of an increase in cancer," said Sir Richard Peto, professor of medical statistics and epidemiology at the University of Oxford, who reviewed the data. "We should not be diverted (from using Vytorin) by fears of cancer."
Merck and Schering-Plough delayed reporting quarterly financial results, which were expected on Monday morning, so investors could first learn about the outcome of the study.
The primary composite goals of the study of patients with irregular thickening of the main valve to the aorta were broken into two sets of secondary goals and Vytorin was superior on one of those sets, researchers said.
Vytorin was significantly better than placebo in reducing atherosclerotic events, defined as nonfatal heart attacks, need for coronary artery bypass surgery or artery-clearing procedures, hospitalization due to chest pain and strokes.
"The study has given a clear-cut answer whether lipid lowering will influence the cause of aortic stenosis and we can conclude it does not," Pedersen said.
But he noted that Vytorin did offer some benefits in reducing risk of coronary artery disease in the study.
The drug was no better than placebo on the other secondary measure of reducing aortic valve disease events -- the need for surgical valve replacement, hospitalization because of heart failure and cardiovascular death.
"Overall it looks positive. They did decrease atherosclerotic events, which is sort of what everyone expected," said Jon LeCroy, an analyst for Natixis Bleichroeder.
He said cancer fears should be allayed by results of larger, previous studies.
"But we've seen with drugs in the past any time cancer gets tagged on them sometimes the prescriptions can come off a little bit," he added.
Vytorin did lower bad LDL cholesterol by 61 percent throughout the study.
"The bottom line is there was a trade-off in this trial -- in a reduction in some cardiovascular events and an excess of cancer deaths. It's obviously not a favorable result," said Dr Steven Nissen, chairman of cardiovascular medicine at Cleveland Clinic, who has been critical of Vytorin use in the past.
The trial was designed to determine whether aggressive cholesterol lowering can lessen the need for surgical replacement of aortic valves, reduce cardiac death and reduce cardiovascular events, including heart attacks.
The 1,873-patient study, meant to follow subjects for a minimum of four years, is the largest formal trial ever conducted in patients with the condition, known as aortic stenosis. An estimated 2 percent of people over age 65 have the condition, which can lead to heart failure.
Sales of the pill have suffered this year and Merck and Schering-Plough stock has fallen sharply, following Vytorin's failure to cut plaque in neck arteries in a separate trial called Enhance.
Widespread unfavorable publicity followed release of the Enhance results in mid-January and subsequent recommendations by researchers that patients first try other cholesterol fighters before opting for Vytorin.
Linda Bannister, an analyst for Edward Jones, said it would have been a positive surprise had Vytorin met the main goal of the latest study, called SEAS.
"The concern is how this is going to be portrayed and perceived and is it just going to be another issue where there is a lot of negative publicity surrounding the drug," Bannister said.
Merck shares were down $2.80, or 7.4 percent, at $34.28, while Schering-Plough shares were down $3.36, or 15.6 percent, at $18.08 in afternoon trading.
Slightly higher incidents of cancer deaths were also seen in those taking the drug -- 39 versus 23 on placebo -- although the lead researcher said those could have occurred as a result of chance.
The shares of both companies fell after the data were released, with Schering off more than 15 percent and Merck down by 7 percent.
No significant difference in the study's composite heart goals was seen between the patients who received Vytorin and those who received a placebo, according to data presented in London by its primary researcher, Dr. Terje Pedersen of Ulleval University Hospital in Oslo, Norway.
Researchers played down the cancer data, saying much larger studies of Vytorin have not showed increased cancer risk.
"There is no overall credible evidence of an increase in cancer," said Sir Richard Peto, professor of medical statistics and epidemiology at the University of Oxford, who reviewed the data. "We should not be diverted (from using Vytorin) by fears of cancer."
Merck and Schering-Plough delayed reporting quarterly financial results, which were expected on Monday morning, so investors could first learn about the outcome of the study.
The primary composite goals of the study of patients with irregular thickening of the main valve to the aorta were broken into two sets of secondary goals and Vytorin was superior on one of those sets, researchers said.
Vytorin was significantly better than placebo in reducing atherosclerotic events, defined as nonfatal heart attacks, need for coronary artery bypass surgery or artery-clearing procedures, hospitalization due to chest pain and strokes.
"The study has given a clear-cut answer whether lipid lowering will influence the cause of aortic stenosis and we can conclude it does not," Pedersen said.
But he noted that Vytorin did offer some benefits in reducing risk of coronary artery disease in the study.
The drug was no better than placebo on the other secondary measure of reducing aortic valve disease events -- the need for surgical valve replacement, hospitalization because of heart failure and cardiovascular death.
"Overall it looks positive. They did decrease atherosclerotic events, which is sort of what everyone expected," said Jon LeCroy, an analyst for Natixis Bleichroeder.
He said cancer fears should be allayed by results of larger, previous studies.
"But we've seen with drugs in the past any time cancer gets tagged on them sometimes the prescriptions can come off a little bit," he added.
Vytorin did lower bad LDL cholesterol by 61 percent throughout the study.
"The bottom line is there was a trade-off in this trial -- in a reduction in some cardiovascular events and an excess of cancer deaths. It's obviously not a favorable result," said Dr Steven Nissen, chairman of cardiovascular medicine at Cleveland Clinic, who has been critical of Vytorin use in the past.
The trial was designed to determine whether aggressive cholesterol lowering can lessen the need for surgical replacement of aortic valves, reduce cardiac death and reduce cardiovascular events, including heart attacks.
The 1,873-patient study, meant to follow subjects for a minimum of four years, is the largest formal trial ever conducted in patients with the condition, known as aortic stenosis. An estimated 2 percent of people over age 65 have the condition, which can lead to heart failure.
Sales of the pill have suffered this year and Merck and Schering-Plough stock has fallen sharply, following Vytorin's failure to cut plaque in neck arteries in a separate trial called Enhance.
Widespread unfavorable publicity followed release of the Enhance results in mid-January and subsequent recommendations by researchers that patients first try other cholesterol fighters before opting for Vytorin.
Linda Bannister, an analyst for Edward Jones, said it would have been a positive surprise had Vytorin met the main goal of the latest study, called SEAS.
"The concern is how this is going to be portrayed and perceived and is it just going to be another issue where there is a lot of negative publicity surrounding the drug," Bannister said.
Merck shares were down $2.80, or 7.4 percent, at $34.28, while Schering-Plough shares were down $3.36, or 15.6 percent, at $18.08 in afternoon trading.
Saturday, July 5, 2008
Green tea can protect the heart's arteries, new study shows
The next time you're offered a choice between Earl Grey and green tea, you might want to go green.
A new study shows that the beverage, which is more popular in Eastern cultures, can protect heart arteries by keeping them flexible and relaxed, and therefore better able to withstand the ups and downs of constant changes in blood pressure. Led by Dr. Nikolaos Alexopoulos of Athens Medical School in Greece, the researchers found that among 14 subjects, those who drank green tea showed greater dilation of their heart arteries on ultrasound 30 min. later than those drinking either diluted caffeine or hot water. That's because, the scientists speculate, green tea works on the lining of blood vessels, helping cells there to secrete the substances needed to relax the vessels and allow blood to flow more freely. It's the flavonoids in the tea, which work as antioxidants and help prevent inflammation in body tissue, that keep the vessels pliable. These substances may also protect against the formation of clots, which are the primary cause of heart attacks. "We found very promptly [that] after drinking green tea, there was a protective effect on the endothelium," says Dr. Charalambos Vlachopoulos, a cardiologist and one of the authors of the study.
All it took, says Vlachopoulos, was 6 g of green tea, which amounts to 3 to 4 cups. To make sure the dilation effect was not due to the small amounts of caffeine found in green tea, the group compared the arterial sizes in the green-tea drinkers with those consuming a diluted caffeine beverage and found no change in arterial size in the caffeine drinkers. Even more intriguing, the beneficial effect seems to be long-lasting and cumulative. When the doctors measured the green-tea drinkers' arteries two weeks after daily consumption of the beverage, they found that their vessels were more dilated than they had been at the beginning of the study. "It's something that needs to be investigated, but we think that if someone takes green tea for one or two months, the beneficial effect will be even greater," says Vlachopoulos.
But experts caution that one study isn't enough to catapult green tea to wonder-drink status. Dr. Robert Eckel, a professor at the University of Colorado, Denver, and past president of the American Heart Association, notes that endothelial function is affected by a number of factors, including large doses of vitamins E and C. "Green-tea consumption may have beneficial effects on the arteries, but we should stop short of translating that into a recommendation that everybody should be drinking green tea because it's been proven to reduce heart attacks and strokes," he says. He acknowledges, however, that early studies hint that green tea may be a good addition to a heart-healthy diet. The American Heart Association does not yet include the beverage in its dietary recommendations, but more studies like this one may change that. In the meantime, if you're drinking tea, it might not be such a bad idea to go green.
A new study shows that the beverage, which is more popular in Eastern cultures, can protect heart arteries by keeping them flexible and relaxed, and therefore better able to withstand the ups and downs of constant changes in blood pressure. Led by Dr. Nikolaos Alexopoulos of Athens Medical School in Greece, the researchers found that among 14 subjects, those who drank green tea showed greater dilation of their heart arteries on ultrasound 30 min. later than those drinking either diluted caffeine or hot water. That's because, the scientists speculate, green tea works on the lining of blood vessels, helping cells there to secrete the substances needed to relax the vessels and allow blood to flow more freely. It's the flavonoids in the tea, which work as antioxidants and help prevent inflammation in body tissue, that keep the vessels pliable. These substances may also protect against the formation of clots, which are the primary cause of heart attacks. "We found very promptly [that] after drinking green tea, there was a protective effect on the endothelium," says Dr. Charalambos Vlachopoulos, a cardiologist and one of the authors of the study.
All it took, says Vlachopoulos, was 6 g of green tea, which amounts to 3 to 4 cups. To make sure the dilation effect was not due to the small amounts of caffeine found in green tea, the group compared the arterial sizes in the green-tea drinkers with those consuming a diluted caffeine beverage and found no change in arterial size in the caffeine drinkers. Even more intriguing, the beneficial effect seems to be long-lasting and cumulative. When the doctors measured the green-tea drinkers' arteries two weeks after daily consumption of the beverage, they found that their vessels were more dilated than they had been at the beginning of the study. "It's something that needs to be investigated, but we think that if someone takes green tea for one or two months, the beneficial effect will be even greater," says Vlachopoulos.
But experts caution that one study isn't enough to catapult green tea to wonder-drink status. Dr. Robert Eckel, a professor at the University of Colorado, Denver, and past president of the American Heart Association, notes that endothelial function is affected by a number of factors, including large doses of vitamins E and C. "Green-tea consumption may have beneficial effects on the arteries, but we should stop short of translating that into a recommendation that everybody should be drinking green tea because it's been proven to reduce heart attacks and strokes," he says. He acknowledges, however, that early studies hint that green tea may be a good addition to a heart-healthy diet. The American Heart Association does not yet include the beverage in its dietary recommendations, but more studies like this one may change that. In the meantime, if you're drinking tea, it might not be such a bad idea to go green.
Tuesday, July 1, 2008
Study shows how broccoli fights cancer
LONDON (Reuters) - Just a few more portions of broccoli each week may protect men from prostate cancer, British researchers reported on Wednesday.
The researchers believe a chemical in the food sparks hundreds of genetic changes, activating some genes that fight cancer and switching off others that fuel tumors, said Richard Mithen, a biologist at Britain's Institute of Food Research.
There is plenty of evidence linking a healthy diet rich in fruits and vegetables to reduced cancer risk. But the study published in the Public Library of Science journal PLoS One is the first human trial investigating the potential biological mechanism at work, Mithen added in a telephone interview.
"Everybody says eat your vegetables but nobody can tell us why," said Mithen, who led the study. "Our study shows why vegetables are good."
Prostate is the second-leading cancer killer of men after lung cancer. Each year, some 680,000 men worldwide are diagnosed with the disease and about 220,000 will die from it.
Mithen and colleagues split into two groups 24 men with pre-cancerous lesions that increase prostate cancer risk and had them eat four extra servings of either broccoli or peas each week for a year.
The researchers also took tissue samples over the course of the study and found that men who ate broccoli showed hundreds of changes in genes known to play a role in fighting cancer.
The benefit would likely be the same in other cruciferous vegetables that contain a compound called isothiocyanate, including brussel sprouts, cauliflower, cabbage, rocket or arugula, watercress and horse radish, they added.
Broccoli, however, has a particularly powerful type of the compound called sulforaphane, which the researchers think gives the green vegetable an extra cancer-fighting kick, Mithen said.
"When people get cancer some genes are switched off and some are switched on," he said. "What broccoli seems to be doing is switching on genes which prevent cancer developing and switching off other ones that help it spread."
The broccoli eaters showed about 400 to 500 of the positive genetic changes with men carrying a gene called GSTM1 enjoying the most benefit. About half the population have the gene, Mithen said.
The researchers did not track the men long enough to see who got cancer but said the findings bolster the idea that just a few more vegetable portions each week can make a big difference.
It is also likely that these vegetables work the same way in other parts of the body and probably protect people against a whole range of cancers, Mithen added.
"You don't need a huge change in your diet," he said. "Just a few more portions makes a big difference."
The researchers believe a chemical in the food sparks hundreds of genetic changes, activating some genes that fight cancer and switching off others that fuel tumors, said Richard Mithen, a biologist at Britain's Institute of Food Research.
There is plenty of evidence linking a healthy diet rich in fruits and vegetables to reduced cancer risk. But the study published in the Public Library of Science journal PLoS One is the first human trial investigating the potential biological mechanism at work, Mithen added in a telephone interview.
"Everybody says eat your vegetables but nobody can tell us why," said Mithen, who led the study. "Our study shows why vegetables are good."
Prostate is the second-leading cancer killer of men after lung cancer. Each year, some 680,000 men worldwide are diagnosed with the disease and about 220,000 will die from it.
Mithen and colleagues split into two groups 24 men with pre-cancerous lesions that increase prostate cancer risk and had them eat four extra servings of either broccoli or peas each week for a year.
The researchers also took tissue samples over the course of the study and found that men who ate broccoli showed hundreds of changes in genes known to play a role in fighting cancer.
The benefit would likely be the same in other cruciferous vegetables that contain a compound called isothiocyanate, including brussel sprouts, cauliflower, cabbage, rocket or arugula, watercress and horse radish, they added.
Broccoli, however, has a particularly powerful type of the compound called sulforaphane, which the researchers think gives the green vegetable an extra cancer-fighting kick, Mithen said.
"When people get cancer some genes are switched off and some are switched on," he said. "What broccoli seems to be doing is switching on genes which prevent cancer developing and switching off other ones that help it spread."
The broccoli eaters showed about 400 to 500 of the positive genetic changes with men carrying a gene called GSTM1 enjoying the most benefit. About half the population have the gene, Mithen said.
The researchers did not track the men long enough to see who got cancer but said the findings bolster the idea that just a few more vegetable portions each week can make a big difference.
It is also likely that these vegetables work the same way in other parts of the body and probably protect people against a whole range of cancers, Mithen added.
"You don't need a huge change in your diet," he said. "Just a few more portions makes a big difference."
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