February 2017 - THE NON-MEDICATED LIFE
The BENEFITS OF
By Paul E. Lemanski, MD, MS, FACP
Editor’s Note: This is the 74th in a series on optimal diet and lifestyle to help prevent and treat disease. Any planned change in diet, exercise or treatment should be discussed with and approved by your personal physician before implementation. The help of a registered dietitian in the implementation of dietary changes is strongly recommended.
Medicines are a mainstay of American life and the healthcare system not only because they are perceived to work by the individuals taking them, but also because their benefit may be shown by the objective assessment of scientific study. Clinical research trials have shown that some of the medicines of Western science may reduce the risk of heart attacks, strokes and cardiovascular death while others may reduce certain types of cancer.
In the first 74 installments of the Non-Medicated Life, informed diet and lifestyle have been shown to accomplish naturally for the majority of individuals, many, if not most of the benefits of medications in the prevention and treatment of chronic medical conditions. Moreover, as a medical intervention they may accomplish such benefits with fewer side effects, may reduce the number and amount of medication, and may allow actual discontinuation of medication.
This is especially true for dietary fiber, which can lower blood cholesterol, lower blood sugar and decrease the risk for diabetes; in addition, fiber may help in weight control and constipation, and reduce the risk for heart disease, diverticulitis of the colon, and possibly cancer of the breast.
Dietary fiber is a type of non-digestible carbohydrate found in vegetables, legumes, fruits and whole grains that can be categorized as either soluble or insoluble. Soluble fiber, which dissolves in water, is found predominately in grains (e.g., oatmeal), legumes (e.g., beans and lentils) and fruit (e.g., apples). Insoluble fiber, does not dissolve in water, is found predominately in legumes, whole grains, in vegetables (e.g., broccoli, carrots, cucumbers and tomatoes) and in fruit (e.g., prunes and dates).
In its most basic conception, maximizing soluble and insoluble fiber simply requires eating a predominately plant-based diet. However, depending on the specific condition to be benefited, certain foods provide additional advantage. By addressing each of the conditions to be benefited, it is possible to illustrate such advantage, and provide specific examples of the most effective food choices.
Elevated blood cholesterol may be improved by fiber. In a meta-analysis of 67 studies evaluating the effect of soluble fiber on cholesterol, every gram of soluble fiber consumed could reduce LDL or bad cholesterol by 2.2 mg/dl. Therefore, three grams of soluble fiber derived from oat, psyllium husk, or pectin (found in whole pears, apples, plums and oranges) could reduce LDL by about 7 mg/dl.
Elevated blood sugar may also be improved by fiber. Soluble fiber (for sources, please see above) appears to slow the absorption of glucose from the gut. While this may be beneficial for those with diabetes by offering another means of blood sugar control, it may also be important in decreasing the risk for developing diabetes. Diets low in fiber that allow a sudden rise in blood sugar have been shown to double the risk for the development of type 2 diabetes.
Conversely, higher fiber intake has been associated with a lower risk for the development of metabolic syndrome, a precursor condition to diabetes. Metabolic syndrome is defined as any three of five traits with an underlying shared metabolic mechanism. These traits are increased abdominal girth, elevated blood pressure, elevated blood glucose, elevated blood triglycerides, and low HDL “good” cholesterol. It may be that soluble fiber may exert its effects not only on blood glucose but also on other four traits by enhancing one’s sense of fullness after a meal thereby contributing to lower body weight.
The combined effect of fiber on decreasing cholesterol, blood glucose, and the risk for metabolic syndrome may also account for the effects of fiber on the lower risk of heart disease. A study of 43,000 health professionals found that for every 10 gram/day increase in total fiber, the risk for fatal or non-fatal heart attack decreased by 19%, and for every 10 gram/day increase in whole grain cereal fiber risk decreased by 29%. A meta-analysis of 10 prospective cohort studies found that every 10 gram/day increase in total dietary fiber was associated with a 14% reduction in risk for coronary death; every 10 gram/day increase in cereal, fruit or vegetable fiber was associated with a 10-16% reduction.
Seven servings of assorted vegetables and two servings of fruit (e.g., apples, pears, or berries) per day as well as daily a daily serving of non-sweetened whole grain cereal can help achieve adequate fiber intake.
Constipation may be significantly improved by dietary fiber. In this instance insoluble fiber adds non-absorbable bulk to stools making them softer, and easier to pass. The greater bulk, however, also results in lower bowel wall pressure during the sequential peristaltic contractions required to move stool toward the rectum and evacuation. This lower wall pressure means there is reduced tendency for small pockets to develop in the bowel wall. Such pockets are commonly seen in Western societies that consume inadequate daily fiber intake. Moreover, these pockets can become infected leading to a serious, potentially life threatening infection in the bowel wall called diverticulitis.
In a study of 40,000 health professionals the consumption of insoluble fiber was associated with a 40% reduction in diverticular disease. Examples of sources for insoluble fiber include whole grains, wheat bran, legumes, green beans, cauliflower, celery, zucchini, grapes and tomatoes. (It is prudent for those with known diverticular disease or a history of diverticulitis to avoid seeds and nuts, pending a discussion with your primary care physician or gastroenterologist.)
The risk for breast cancer may also be reduced by fiber. Although studies of fiber intake in older individuals does not seem to show a benefit, in a study of 90,000 pre-menopausal women, the intake of soluble fiber, insoluble fiber, and total fiber during adolescence and early adulthood decreased breast cancer risk an average of 25%. During early adulthood every 10 gram/day increase in fiber was associated with a 13% reduction in breast cancer risk, and during adolescence every 10 gram/day increase was associated with a 14% reduction in risk. Fiber may decrease breast cancer risk by decreasing plasma levels of estrogen by increasing fecal estrogen excretion.
In summary, dietary soluble and insoluble fiber when consumed in adequate amount – total 25-50 grams/day – has multiple health benefits. The benefits include reduction in cholesterol and blood glucose, as well as decreased predisposition to diabetes and better blood glucose control in those with diabetes. Fiber may provide a feeling of fullness after a meal and aid in weight control.
Such benefits may help explain the observed reduction in heart disease in those consuming adequate fiber as compared to those who do not. Fiber may significantly improve constipation and reduce the risk for diverticulitis. Finally, adequate fiber intake in adolescent and young adult women may significantly reduce the risk for breast cancer. For all these reasons, fiber as part of a predominately plant-based eating pattern, should serve as very important component of a successful non-medicated life.
Paul E. Lemanski, MD, MS, FACP (firstname.lastname@example.org) is a board certified internist at the Center for Preventive Medicine, CapitalCare Medical Group in Albany. He is medical director of the Department of Community Medicine and Population Health at CapitalCare Medical Group. Paul has a master’s degree in human nutrition. He is an assistant clinical professor of medicine at Albany Medical College, and a fellow of the American College of Physicians.