DIET/Fiber
Dietary Fiber Not a Magic Bullet
For years, a high intake of dietary fiber has been accepted as an appropriate way to reduce the risk of colorectal cancer. This major nutrition study published in The New England Journal of Medicine calls this common practice into question.
The study employs data gathered in the Nurses' Health Study of 121,700 registered nurses age 30 to 5
Initiated in 1976, this massive study involved completion of mailed questionnaires on known or suspected risk factors for cancer and coronary heart disease.
The current study involved 88,757 women 34 to 59 who had no history of cancer, inflammatory bowel disease, or familial polyposis. Cases of colorectal cancer and adenomas were documented over the 16-year follow-up period. This study produced results that have stirred the health care and nutrition communities and the food industry. The researchers found "no evidence support the hypothesis that total dietary fiber intake is protective against colorectal cancer or adenoma."
The authors make a strong case that the long-held belief in the utility of high-fiber diets to prevent colorectal cancer was based mostly on theories and to a very small degree on substantive scientific evidence.
The study employs data gathered in the Nurses' Health Study of 121,700 registered nurses age 30 to 5
The current study involved 88,757 women 34 to 59 who had no history of cancer, inflammatory bowel disease, or familial polyposis. Cases of colorectal cancer and adenomas were documented over the 16-year follow-up period. This study produced results that have stirred the health care and nutrition communities and the food industry. The researchers found "no evidence support the hypothesis that total dietary fiber intake is protective against colorectal cancer or adenoma."
The authors make a strong case that the long-held belief in the utility of high-fiber diets to prevent colorectal cancer was based mostly on theories and to a very small degree on substantive scientific evidence.
Fiber Intake Lowers Risk of Mouth and Throat Cancers
Higher fiber intake may be protective against oral, pharyngeal and esophageal cancer. In a recent study, data from a prior study was investigated as to the correlation between consumption of various types of fiber and oral, pharyngeal and esophageal cancer.
Cases included 271 patients with oral cancer, 327 with pharyngeal cancer and 304 with esophageal cancer.Controls included 1950 subjects with acute, nonneoplastic diseases. The subjects' dietary habits were collected using a food frequency questionnaire. The researchers calculated the relative risk of sustaining one of the forms of cancer after adjusting the data for age, sex, and other confounding factors, including alcohol and tobacco consumption and energy intake.
Results: People who consumed the most fruit, vegetables and whole grain cereals had a lower risk of these cancers compared with people who consumed the least amount. Soluble fiber found in foods such as oatmeal and fruit, and insoluble fiber found in seeds and the skin of the fruit, were both protective. The results were equal for both sexes.
Conclusion: The results confirmed the findings of other studies of upper digestive tract neoplasms. Also, the authors note that high fiber intake may be a marker for a healthier lifestyle that includes lower intake of meat and foods rich in saturated fat and cholesterol, and higher intake of low-fat foods such as fruits and vegetables.
Cases included 271 patients with oral cancer, 327 with pharyngeal cancer and 304 with esophageal cancer.Controls included 1950 subjects with acute, nonneoplastic diseases. The subjects' dietary habits were collected using a food frequency questionnaire. The researchers calculated the relative risk of sustaining one of the forms of cancer after adjusting the data for age, sex, and other confounding factors, including alcohol and tobacco consumption and energy intake.
Conclusion: The results confirmed the findings of other studies of upper digestive tract neoplasms. Also, the authors note that high fiber intake may be a marker for a healthier lifestyle that includes lower intake of meat and foods rich in saturated fat and cholesterol, and higher intake of low-fat foods such as fruits and vegetables.
Regular High-Fiber Breakfast Associated With Maintaining Healthy Weight in Girls
Previous research has shown that children who consume breakfast regularly are much more likely to meet recommended intakes of vitamins and minerals than children who do not. This may be attributed to the consumption of breakfast cereals, many of which are fortified with essential nutrients, and provide dietary fiber.
Research has also shown that children who eat cereals consume significantly less fat and cholesterol than children who eat other foods for breakfast. However, less is known about the relationship between consumption of cereal and body mass index in children.
In this paper, researchers analyzed data from a 10-year longitudinal cohort study of more than 2,300 adolescent girls, all of whom were 9 or 10 years old at the start of the study. Dietary habits were tracked annually, using a three-day food questionnaire that documented the frequency of breakfast consumption and whether cereal was consumed as part of breakfast, along with intakes of dietary fiber, fat, calcium, iron, folic acid, vitamin C, and zinc.
Results: "Compared with girls who ate cereal on 0 days, girls who ate cereal on 1, 2, or 3 days were 0.93, 0.90, and 0.87 times as likely to be at risk of overweight; that is, eating cereal on 1 or more days resulted in a reduction in risk of overweight," the scientists wrote. In addition, "a similar trend was seen for breakfast consumption, with those consuming breakfast on 3 days having lower BMIs than girls who skipped breakfast on all or most days."
In the study's conclusion, the authors stated that their analysis "clearly demonstrated that cereal consumption was predictive of lower BMI" in adolescent females. They added that cereal consumption "had positive effects on nutrient intake in girls, resulting in diets significantly lower in fat and cholesterol."
In this paper, researchers analyzed data from a 10-year longitudinal cohort study of more than 2,300 adolescent girls, all of whom were 9 or 10 years old at the start of the study. Dietary habits were tracked annually, using a three-day food questionnaire that documented the frequency of breakfast consumption and whether cereal was consumed as part of breakfast, along with intakes of dietary fiber, fat, calcium, iron, folic acid, vitamin C, and zinc.
Results: "Compared with girls who ate cereal on 0 days, girls who ate cereal on 1, 2, or 3 days were 0.93, 0.90, and 0.87 times as likely to be at risk of overweight; that is, eating cereal on 1 or more days resulted in a reduction in risk of overweight," the scientists wrote. In addition, "a similar trend was seen for breakfast consumption, with those consuming breakfast on 3 days having lower BMIs than girls who skipped breakfast on all or most days."
In the study's conclusion, the authors stated that their analysis "clearly demonstrated that cereal consumption was predictive of lower BMI" in adolescent females. They added that cereal consumption "had positive effects on nutrient intake in girls, resulting in diets significantly lower in fat and cholesterol."
Fiber May Benefit Diabetes Patients
Recent American Diabetes Association (ADA) dietary guidelines for patients with diabetes mellitus recommend that dietary composition be based on individualized nutritional assessments and target individual desired outcomes.
Among these recommendations is an increase in dietary fiber intake from 20 to 35 grams per day as a means of regulating cholesterol levels.
The effects of dietary fiber on glycemic control were considered inconsequential, and the ADA expert panel determined that it would be difficult for one to consume adequate dietary fiber unless food sources were supplemented or fortified with fiber. The present study determined the effects of increasing dietary fiber in type 2 diabetes patients solely through the consumption of foods not fortified with fiber, to a fiber level beyond that recommended by the ADA.
Thirteen patients were assigned to follow two diets for six weeks each: a diet containing moderate amounts of fiber (24 grams total - 8 grams soluble, 16 grams insoluble), and a diet containing high amounts of fiber (50 grams total - 25 grams soluble, 25 grams insoluble). Both diets contained identical macronutrients and energy content, and were compared with regard to their influence on glycemic control and plasma lipid concentrations.
High daily fiber intake improved glycemic control, evidenced by decreases in average daily preprandial and 24-hour plasma glucose concentrations. In addition, the high-fiber diet lowered urinary glucose excretion and 24-hour plasma insulin concentrations. The authors note that fiber intake was not achieved by consuming fiber-fortified foods and that patients reported few side effects from the high-fiber diet. They suggest that dietary guidelines for patients with diabetes include an overall increase in dietary fiber without relying on the use of fiber
The effects of dietary fiber on glycemic control were considered inconsequential, and the ADA expert panel determined that it would be difficult for one to consume adequate dietary fiber unless food sources were supplemented or fortified with fiber. The present study determined the effects of increasing dietary fiber in type 2 diabetes patients solely through the consumption of foods not fortified with fiber, to a fiber level beyond that recommended by the ADA.
Thirteen patients were assigned to follow two diets for six weeks each: a diet containing moderate amounts of fiber (24 grams total - 8 grams soluble, 16 grams insoluble), and a diet containing high amounts of fiber (50 grams total - 25 grams soluble, 25 grams insoluble). Both diets contained identical macronutrients and energy content, and were compared with regard to their influence on glycemic control and plasma lipid concentrations.
High daily fiber intake improved glycemic control, evidenced by decreases in average daily preprandial and 24-hour plasma glucose concentrations. In addition, the high-fiber diet lowered urinary glucose excretion and 24-hour plasma insulin concentrations. The authors note that fiber intake was not achieved by consuming fiber-fortified foods and that patients reported few side effects from the high-fiber diet. They suggest that dietary guidelines for patients with diabetes include an overall increase in dietary fiber without relying on the use of fiber
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