1213 There were no significant improvements in Apgar scores but the babies did seem to be very active. This series is too small to justify any firm conclusions but the aerosol/tablet regimens was much more convenient and acceptable to patients and nurses than the intravenous regimen. A study of the efficacy of oral salbutamol in the long-term delay of labour and its place in the prevention of R.D.S. is con-
tinuing. Saint Mary’s
Maternity Hospital,
G. HASTWELL
Portsmouth PO3 6AD.
FOOD: INFLUENCE OF FORM ON ABSORPTION
SIR Two items in The Lancet of Nov. 8 emphasise the need for experiments to investigate the way that the form in which food is taken, as well as food composition, influence the absorption of fat and carbohydrate in the human small bowel. Dr Heaton’s letter on p. 927 draws attention to the fact that there is increasing evidence that coronary heart-disease is the result of habitual over-nutrition caused largely by eating fibredepleted foods. The ease with which refined foods (particularly
carbohydrates) are eaten and their failure to cause satiety until eaten in excessive quantities is recognised, but what influence does the refinement of a carbohydrate have on its behaviour in the bowel? Does it move faster or slower than its unrefined equivalent? We have shown that the addition of 14.5gof guar flour (a plant storage polysaccharide, undigestible in the human small bowel) to a Lundh type liquid meal (consisting of 35g Casilan, 35 g corn oil, 70 ml of 50% lactulose solution, homogenised with 350 ml of water) prolonged mouth-to-csecum transit-time by 100-125% (see figure) as judged by the first appearance of hydrogen in the breath.’1
in 10 minutes and further blood samples for glucose analysis were taken at 15-minute intervals for 2 hours from commencement of the meal. The order of the test and control meals was randomised and each subject was tested on two consecutive mornings. There was no significant rise or fall of mean blood-glucose levels after the meal containing the guar flour, whereas after the control meal there was a maximum rise of blood-glucose at 30 minutes (279+562 mg/100 ml, mean±S.E.M.) and a maximum fall (hypoglycxmia) at 120 minutes (14-1+2-5 mg/100 ml) (Student’s t test in both cases giving a P value of less than 0.02). These findings of prolonged mouth-to-caecum transit-time and reduction of postprandial glycsemia by the addition to a test meal of an undigestible plant storage polysaccharide indicate that such substances can ’have unexpected and potentially useful effects. While we wholeheartedly support the view that too much is eaten by too many, there now seems to be sufficient evidence to suggest that the physico-chemical properties as well as the composition of food are important and worthy of further study. The hypothesis of Professor Hunt and others on p. 905 stated that, in the more obese individuals of the population, the greater the ratio energy intake/volume of food and drink the greater will be the degree of obesity. While their hypothesis is restricted to obese individuals and their main concern was with the quantity of fluid taken with the food, which one feels certain will prove to be very important, it is clear that the energy intake/volume of food ratio can be reduced by including in the food undigestible substances such as dietary fibres. Although bran has been shown to accelerate rather than slow gastric emptying other dietary fibres have not yet been investigated and may have the opposite effect. Also the rate of gastric emptying may not be the only factor which influences duration of satiety; small-bowel transit-time, which may be influenced by dietary fibre, may also be important. In a study similar to the second one described above, nine subjects ascribed a value of 2-3+0-4 (mean+s.E.M.) to the sensation of hunger experienced 5 hours after a liquid test meal containing guar flour. This assessment was made on an arbitrary scale on which zero represented no hunger and 4 represented the sensation of hunger experienced 5 hours after the control meal (guar-free) (t test: p
tinuing. Saint Mary’s
Maternity Hospital,
G. HASTWELL
Portsmouth PO3 6AD.
FOOD: INFLUENCE OF FORM ON ABSORPTION
SIR Two items in The Lancet of Nov. 8 emphasise the need for experiments to investigate the way that the form in which food is taken, as well as food composition, influence the absorption of fat and carbohydrate in the human small bowel. Dr Heaton’s letter on p. 927 draws attention to the fact that there is increasing evidence that coronary heart-disease is the result of habitual over-nutrition caused largely by eating fibredepleted foods. The ease with which refined foods (particularly
carbohydrates) are eaten and their failure to cause satiety until eaten in excessive quantities is recognised, but what influence does the refinement of a carbohydrate have on its behaviour in the bowel? Does it move faster or slower than its unrefined equivalent? We have shown that the addition of 14.5gof guar flour (a plant storage polysaccharide, undigestible in the human small bowel) to a Lundh type liquid meal (consisting of 35g Casilan, 35 g corn oil, 70 ml of 50% lactulose solution, homogenised with 350 ml of water) prolonged mouth-to-csecum transit-time by 100-125% (see figure) as judged by the first appearance of hydrogen in the breath.’1
in 10 minutes and further blood samples for glucose analysis were taken at 15-minute intervals for 2 hours from commencement of the meal. The order of the test and control meals was randomised and each subject was tested on two consecutive mornings. There was no significant rise or fall of mean blood-glucose levels after the meal containing the guar flour, whereas after the control meal there was a maximum rise of blood-glucose at 30 minutes (279+562 mg/100 ml, mean±S.E.M.) and a maximum fall (hypoglycxmia) at 120 minutes (14-1+2-5 mg/100 ml) (Student’s t test in both cases giving a P value of less than 0.02). These findings of prolonged mouth-to-caecum transit-time and reduction of postprandial glycsemia by the addition to a test meal of an undigestible plant storage polysaccharide indicate that such substances can ’have unexpected and potentially useful effects. While we wholeheartedly support the view that too much is eaten by too many, there now seems to be sufficient evidence to suggest that the physico-chemical properties as well as the composition of food are important and worthy of further study. The hypothesis of Professor Hunt and others on p. 905 stated that, in the more obese individuals of the population, the greater the ratio energy intake/volume of food and drink the greater will be the degree of obesity. While their hypothesis is restricted to obese individuals and their main concern was with the quantity of fluid taken with the food, which one feels certain will prove to be very important, it is clear that the energy intake/volume of food ratio can be reduced by including in the food undigestible substances such as dietary fibres. Although bran has been shown to accelerate rather than slow gastric emptying other dietary fibres have not yet been investigated and may have the opposite effect. Also the rate of gastric emptying may not be the only factor which influences duration of satiety; small-bowel transit-time, which may be influenced by dietary fibre, may also be important. In a study similar to the second one described above, nine subjects ascribed a value of 2-3+0-4 (mean+s.E.M.) to the sensation of hunger experienced 5 hours after a liquid test meal containing guar flour. This assessment was made on an arbitrary scale on which zero represented no hunger and 4 represented the sensation of hunger experienced 5 hours after the control meal (guar-free) (t test: p
