This study was initiated to see if the insulin resistance, hyperinsulinemia, and hypertension that follow feeding normotensive Sprague-Dawley rats a fructose-rich diet could be prevented by letting rats run spontaneously in exercise wheel cages. Blood pressure in sedentary rats increased from (mean +/- SEM) 125 +/- 2 to 148 +/- 3 mm Hg in response to 2 weeks of a high fructose diet, and this increment was significantly (p less than 0.001) attenuated in exercising rats (from 121 +/- 1 to 131 +/- 2 mm Hg). In addition, mean (+/- SEM) plasma insulin concentration was lower in fructose-fed rats allowed to run spontaneously (44 +/- 2 vs 62 +/- 5 microU/ml; p less than 0.01). Finally, resistance to insulin-stimulated glucose uptake was assessed by determining the steady state plasma glucose response to a continuous glucose and exogenous insulin infusion during a period in which endogenous insulin secretion was suppressed. The results of these studies indicated that the mean (+/- SEM) steady state plasma glucose concentration was significantly lower in the exercise-trained rats (127 +/- 5 vs 168 +/- 6 mg/dl; p less than 0.001), despite the fact that the steady state plasma insulin levels were also lower in rats allowed to run spontaneously (75 +/- 4 vs 90 +/- 5 microU/ml; p less than 0.05). Thus, the ability of exercise-trained rats to stimulate glucose disposal was enhanced as compared with that of sedentary rats fed the same fructose-rich diet. These data demonstrate that the insulin resistance, hyperinsulinemia, and hypertension produced in normotensive rats by feeding them a high fructose diet can be attenuated if rats are allowed to run spontaneously.(ABSTRACT TRUNCATED AT 250 WORDS)

BACKGROUND AND AIM:Functional gastrointestinal symptoms are common and their management is often a difficult clinical problem. The link between food intake and symptom induction is recognized. This review aims to describe the evidence base for restricting rapidly fermentable, short-chain carbohydrates (FODMAPs) in controlling such symptoms.

METHODS:The nature of FODMAPs, their mode of action in symptom induction, results of clinical trials and the implementation of the diet are described.

RESULTS:FODMAPs are widespread in the diet and comprise a monosaccharide (fructose), a disaccharide (lactose), oligosaccharides (fructans and galactans), and polyols. Their ingestion increases delivery of readily fermentable substrate and water to the distal small intestine and proximal colon, which are likely to induce luminal distension and induction of functional gut symptoms. The restriction of their intake globally (as opposed to individually) reduces functional gut symptoms, an effect that is durable and can be reversed by their reintroduction into the diet (as shown by a randomized placebo-controlled trial). The diet has a high compliance rate. However it requires expert delivery by a dietitian trained in the diet. Breath hydrogen tests are useful to identify individuals who can completely absorb a load of fructose and lactose so that dietary restriction can be less stringent.

CONCLUSIONS:The low FODMAP diet provides an effective approach to the management of patients with functional gut symptoms. The evidence base is now sufficiently strong to recommend its widespread application.