Lactulose
- consists of the monosaccharides fructose and galactose
- In the colon, lactulose is broken down primarily to lactic acid, and also to small amounts of formic and acetic acids, by the action of via evolved-beta galactosidase from colonic bacteria, which results in an increase in osmotic pressure and slight acidification of the colonic contents.
- This in turn causes an increase in stool water content and softens the stool.
- In treating heptic diseases (hepatic encephalopathy) it is thought that lactulose draws out ammonia from the body in the same way that it draws out water into the colon.
Affect on Sugar level
- The interaction of lactulose and diabetes is categorised as ‘moderate’
- Product information states that there is a possibility of affected glycaemic control
- Lactulose may contain more than 5 g lactose/galactose/epilactose depending upon the dose taken. This should be taken into account in patients with diabetes mellitus. [15 ml of Lactulose contain 42.7 KJ (10.2 kcals) = 0.21 BU]
Glycaemic Index
- In terms of glycaemic Index, comparatively lactose (45) and galactose (25) has lower index compared to glucose (100).
- However do keep in mind that GI value represents the type of carbohydrate in a food but says nothing about the amount of carbohydrate typically eaten. Thus, a higher consumption of lower index food is still able to increase the sugar level
Studies: Galactose
- Following galactose ingestion, there was a modest transient increase in peripheral glucose and insulin concentrations. This was associated with a modest increase in the glucose Ra (rate of glucose appearance)
- conversion of galactose to glucose in the liver may have been greater than suggested by the increase in glucose appearance in the circulation due to substitution for other gluconeogenic substrates
- Oral galactose is a relatively potent insulin secretagogue, and the insulin response is also additive to that following glucose ingestion
Studies: Lactose
- decrease in the glucagon area response observed with 25 g galactose + 25 g glucose or 50 g lactose was less than that with ingestion of 25 g glucose alone. The latter suggests inhibition of the glucagon response to glucose by the added galactose
Studies : Lactulose
- In a study to test the effects of a preparation containing fibre and lactulose in the form of biscuits on glucose and insulin levels in obesity, they found a contradicting trend that glucose and insulin in response to breakfast and to lunch were blunted by dietary fibre and lactulose, without any trend towards post-meal hypoglycaemia
- However, there is also a single case report that reported a case of a patient with diet-controlled diabetes and cirrhosis who experienced a marked deterioration in glycemic control, requiring insulin use, when he began using a different brand of lactulose syrup. The hyperglycemia resolved and insulin was discontinued after use of the original brand of lactulose syrup was resumed
Recommendations
- Most references suggest of being cautious to the addition of lactulose. However this is not a contraindication
- While may affect the sugar level, most likely it will not affect levels significantly to the extent of impacting diabetes control
- Based on guidelines and data from published literature, food and dietary change with exercise and lifestyle change should be the first step in management. For patients recalcitrant to these changes, laxatives should be the next step of treatment. Treatment should begin with bulking agents such as psyllium, bran or methylcellulose followed by osmotic laxatives if response is poor
References:
- https://www.drugs.com/disease-interactions/lactulose.html
- https://www.ncbi.nlm.nih.gov/pubmed/11172481
- http://www.metabolismjournal.com/article/0026-0495(93)90151-D/pdf
- https://www.medicines.org.uk/emc/medicine/25597
- https://beta.nhs.uk/medicines/lactulose/
- https://www.ncbi.nlm.nih.gov/pubmed/9145450
- https://www.ncbi.nlm.nih.gov/pubmed/7716610
- https://www.ncbi.nlm.nih.gov/pubmed/27987136
