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Fiber and colorectal cancer: Poor relations?
Gastroenterology News John H. Walsh, Section Editor
Fiber and Colorectal Cancer: Poor Relations?
motility, the question can only be answered with certainty by clinical trials. ‘‘This was a large, well-done epidemiological study, but studies of this he article that appeared in the kind are only part of the scientific New England Journal of Medievidence we should use in judging cine ( January 21) and was reported the value or lack of value of compoin every major news outlet might as nents of the diet or any other lifewell have said the sky isn’t blue, style,’’ says Levin. ‘‘We need clinical although the authors were appropritrials to arrive at a more definite ately circumspect in their concluconclusion, and those are under way. sions. That’s not to say that this isn’t an ‘‘Our data do not support the exisimportant epidemiological finding. It tence of an important protective efshould make us rethink the old asfect of dietary fiber against colorectal sumptions. But it’s too early to throw cancer or adenoma.’’ away the baby with the bath water.’’ So stated, Fuchs et al. from the For Levin, the study also Dana-Farber Cancer Institute points to the fact that diets and Harvard after a prospechigh in vegetables and fruits, tive study in which they folwhich, as a result, would problowed the dietary habits of ably be high in fiber, are likely nearly 88,757 women ages to be healthier than diets that 34–59. During a 16-year folfocus solely on one particular low-up period, after adjusting component. ‘‘To use an exfor age, established risk factreme, eating a box of bran tors, and total energy intake, fiber every day in lieu of a they found no link between balanced diet would obviintake of dietary fiber and risk ously not be sensible,’’ he says. of colorectal cancer. But exAyoob says the majority of perts warn against throwing Americans fail to meet the away your cereal boxes. ADA’s recommendation that ‘‘There’s already a large they consume 25 g of fiber a body of evidence that’s accuday. ‘‘Most people get about mulated showing definite posi- Lack of dose response relationship between previous dietary half of that,’’ he says. ‘‘We still tive effects of consuming a fiber intake and development of colon cancer in 88,757 women need to spread the word that high-fiber diet in preventing followed up for 16 years in the Nurses’ Health Study. Groups people need to base their diet divided into quintiles according to fiber intake during 1980 the incidence of colorectal and were to 1986 (indicated as first through fifth). Columns indicate on whole grains, lots of leother cancers, as well as heart number of cases of colorectal cancer in each group. Median gumes, fruits and vegetables, disease, diabetes, hyperten- daily fiber intake is indicated below each column. Similar lack of which can help to lower their was found for development of distal colorectal risk for developing a number sion, a host of diseases,’’ says correlation adenoma. of diet-related diseases.’’ Dr. Keith Ayoob of the Albert
T
Irradiation of Meat Is Approved, but Will It Be Used? he U.S. Department of Agriculture announced in February that it has authorized the use of irradiation of raw meat as a strategy to prevent food-borne illnesses, such as the recent outbreaks caused by the Escherichia coli bacteria.
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Einstein College of Medicine, a spokesperson for the American Dietetic Association. Although he has no overall qualms with the study’s methodology, Ayoob points out that subjects weren’t followed into old age, which is when colorectal cancer’s prevalence increases. Dr. Bernard Levin of the M.D. Anderson Cancer Center agrees that, although the study represents a blow to the hypothesis that dietary fiber serves as a colorectal cancer riskreducer by binding to fecal carcinogens and increasing the speed of
But there are still hurdles before low-dose irradiation, which studies have shown to be a safe and effective way to kill a wide variety of pathogens, such as E. coli, Listeria, Salmonella, and Campylobacter, is adopted on a widespread basis. Agriculture Secretary Dan Glickman proposed that producers using the technology be required to label their meats
as such, leaving consumers to decide. And consumers may prove skittish, despite the fact that irradiation has already been approved and used (albeit to a limited extent) for fruits, vegetables, pork, poultry, and spices. In addition, few companies have invested in the technology, and those that have tend to be in locations that aren’t convenient for most food-processing plants. GASTROENTEROLOGY 1999;116:785–786
Fiber and Colorectal Cancer: Poor Relations?
motility, the question can only be answered with certainty by clinical trials. ‘‘This was a large, well-done epidemiological study, but studies of this he article that appeared in the kind are only part of the scientific New England Journal of Medievidence we should use in judging cine ( January 21) and was reported the value or lack of value of compoin every major news outlet might as nents of the diet or any other lifewell have said the sky isn’t blue, style,’’ says Levin. ‘‘We need clinical although the authors were appropritrials to arrive at a more definite ately circumspect in their concluconclusion, and those are under way. sions. That’s not to say that this isn’t an ‘‘Our data do not support the exisimportant epidemiological finding. It tence of an important protective efshould make us rethink the old asfect of dietary fiber against colorectal sumptions. But it’s too early to throw cancer or adenoma.’’ away the baby with the bath water.’’ So stated, Fuchs et al. from the For Levin, the study also Dana-Farber Cancer Institute points to the fact that diets and Harvard after a prospechigh in vegetables and fruits, tive study in which they folwhich, as a result, would problowed the dietary habits of ably be high in fiber, are likely nearly 88,757 women ages to be healthier than diets that 34–59. During a 16-year folfocus solely on one particular low-up period, after adjusting component. ‘‘To use an exfor age, established risk factreme, eating a box of bran tors, and total energy intake, fiber every day in lieu of a they found no link between balanced diet would obviintake of dietary fiber and risk ously not be sensible,’’ he says. of colorectal cancer. But exAyoob says the majority of perts warn against throwing Americans fail to meet the away your cereal boxes. ADA’s recommendation that ‘‘There’s already a large they consume 25 g of fiber a body of evidence that’s accuday. ‘‘Most people get about mulated showing definite posi- Lack of dose response relationship between previous dietary half of that,’’ he says. ‘‘We still tive effects of consuming a fiber intake and development of colon cancer in 88,757 women need to spread the word that high-fiber diet in preventing followed up for 16 years in the Nurses’ Health Study. Groups people need to base their diet divided into quintiles according to fiber intake during 1980 the incidence of colorectal and were to 1986 (indicated as first through fifth). Columns indicate on whole grains, lots of leother cancers, as well as heart number of cases of colorectal cancer in each group. Median gumes, fruits and vegetables, disease, diabetes, hyperten- daily fiber intake is indicated below each column. Similar lack of which can help to lower their was found for development of distal colorectal risk for developing a number sion, a host of diseases,’’ says correlation adenoma. of diet-related diseases.’’ Dr. Keith Ayoob of the Albert
T
Irradiation of Meat Is Approved, but Will It Be Used? he U.S. Department of Agriculture announced in February that it has authorized the use of irradiation of raw meat as a strategy to prevent food-borne illnesses, such as the recent outbreaks caused by the Escherichia coli bacteria.
T
Einstein College of Medicine, a spokesperson for the American Dietetic Association. Although he has no overall qualms with the study’s methodology, Ayoob points out that subjects weren’t followed into old age, which is when colorectal cancer’s prevalence increases. Dr. Bernard Levin of the M.D. Anderson Cancer Center agrees that, although the study represents a blow to the hypothesis that dietary fiber serves as a colorectal cancer riskreducer by binding to fecal carcinogens and increasing the speed of
But there are still hurdles before low-dose irradiation, which studies have shown to be a safe and effective way to kill a wide variety of pathogens, such as E. coli, Listeria, Salmonella, and Campylobacter, is adopted on a widespread basis. Agriculture Secretary Dan Glickman proposed that producers using the technology be required to label their meats
as such, leaving consumers to decide. And consumers may prove skittish, despite the fact that irradiation has already been approved and used (albeit to a limited extent) for fruits, vegetables, pork, poultry, and spices. In addition, few companies have invested in the technology, and those that have tend to be in locations that aren’t convenient for most food-processing plants. GASTROENTEROLOGY 1999;116:785–786