MYTHS AND MISCONCEPTIONS ABOUT CHRONIC CONSTIPATION
Many strongly held beliefs about constipation are not evidence-based, and have been formed from observations and studies that were not rigorously performed. This article addresses common beliefs about constipation. There is no evidence to support the theory that diseases may arise via “autointoxication,” whereby poisonous substances produced from undigested food within the intestine are absorbed. Dolichocolon, defined as an elongated colon, should not be considered a cause of constipation. While sex hormones during the menstrual cycle appear to have little effect on altering gut function, they may play a role in slowing gut transit during pregnancy. Hypothyroidism can cause constipation, but is rarely seen in patients presenting with constipation. A low-fiber diet should not be assumed to be the cause of chronic constipation. Bowel function can be improved by a fiber-rich diet, but many patients with more severe constipation acquire worse symptoms when dietary fiber intake is increased. There is no evidence that constipation can successfully be treated by increasing fluid intake unless dehydration is present. In the elderly, constipation is related to decreased physical activity, but many cofactors are likely to play a role. A broad rehabilitation program, including intervention programs to increase physical activity, may help. It is unlikely that stimulant laxatives at recommended doses are harmful to the colon. Some patients with chronic constipation are dependent on laxatives to achieve satisfactory bowel function, but this is not the result of prior laxative use. Tolerance to stimulant laxatives is uncommon. There is no indication for the occurrence of “rebound constipation” after stopping laxative intake. Laxatives may be misused, but do not appear to be addictive.

Müller-Lissner SA, Kamm MA, Scarpignato C, Wald A. Myths and misconceptions about chronic constipation. Am J Gastroenterol 2005; 100(1):232-242.

FISH CONSUMPTION AND STROKE RISK IN ELDERLY INDIVIDUALS
The relationship between fish consumption and stroke risk has been inconsistent, possibly because of the different types of fish consumed. Additionally, this correlation has not been specifically evaluated in the elderly, in whom disease burden may be high and diet may have less influence. The Cardiovascular Health Study, a population-based longitudinal cohort study, assessed the usual dietary intake of 4775 adults age 65 years or older (range, 65-98 years) who were free of known cerebrovascular disease at baseline in 1989 and 1990, using a food frequency questionnaire. In a subset of participants, consumption of tuna or other broiled or baked fish—but not fried fish or fish sandwiches (fish burgers)—was related to plasma phospholipid long-chain n-3 fatty acid levels. Incident strokes were prospectively ascertained. During 12 years of follow-up, participants experienced 626 incident strokes, including 529 ischemic strokes. In multivariate analyses, tuna or other fish consumption was inversely associated with total stroke (P = 0.04) and ischemic stroke (P = 0.02), with 27% lower risk of ischemic stroke with an intake of 1-4 times per week (hazard ratio [HR], 0.73; 95% confidence interval [CI], 0.55-0.98) and 30% lower risk with intake of 5 or more times per week (HR, 0.70; 95% CI, 0.50-0.99), compared with an intake of less than once per month. In contrast, fried fish or fish sandwich consumption was positively associated with total stroke (P = 0.006) and ischemic stroke (P = 0.003), with a 44% higher risk of ischemic stroke with consumption of more than once per week (HR, 1.44; 95% CI, 1.12-1.85), compared with consumption of less than once per month. It was also found that fish consumption was not associated with hemorrhagic stroke. Investigators concluded that among elderly individuals, consumption of tuna or other broiled or baked fish is associated with a lower risk of ischemic stroke, while intake of fried fish or fish sandwiches is associated with a higher risk. These results suggest that fish consumption may influence stroke risk late in life. Further research is needed regarding potential mechanisms and alternate explanations.

Mozaffarian D, Longstreth WT Jr, Lemaitre RN, Manolio TA, Kuller LH, Burke GL, Siscovick DS. Fish consumption and stroke risk in elderly individuals: The Cardiovascular Health Study. Arch Intern Med 2005;165(2):200-206.