Chemistry Reference
In-Depth Information
Whether or not lactulose has a different impact on patients with dyslipidemia com-
pared to healthy subjects has not been addressed.
Lactulose may have hypoglycemic effects in individuals with diabetes.
7
A plau-
sible explanation was provided in an animal model showing that the disaccharide
reduced glucose absorption in an isolated jejunal loop by 40 percent.
46
In a small
study of 10 obese subjects, a biscuit prepared with fiber and lactulose blunted glucose
and insulin response to regular meals.
47
However, because commercial lactulose
syrup contains small amounts of absorbable sugar impurities, these can adversely
affect glycemic control. In fact, this is a known cautionary warning for use. Although
usually well tolerated, there is at least one report of a severe disruption of glycemic
control in a diabetic cirrhotic patient on lactulose.
48
Mineral absorption, particularly calcium and magnesium, have been shown to
be enhanced by ingestion of lactulose. In a recent double-blind, randomized trial
confined to healthy men, a dose effect of lactulose was found on the absorption of
both minerals using a stable isotope method.
49
An earlier study on postmenopausal
women also found a dose-response absorption of calcium.
50
The same enhancing
absorptive effect on calcium was shown using a dog model.
51
Mechanisms by which
lactulose and other prebiotics or probiotics and combinations of the two may enhance
mineral absorption are reviewed by Scholz-Ahreins et al.
52
As discussed above, long-term ingestion of lactulose can lead to amelioration
of symptoms and reduction of breath hydrogen measurements.
14
Adaptation to lac-
tose is discussed more in Section 5.4. However, it was reported that 10 g twice a
day of lactulose over 3 weeks led to improvement of response to lactose challenge
as shown by a reduction in breath hydrogen and symptoms with increased fecal
β-galactosidase.
53
Interestingly, in a single subject, adaptation to lactose with dairy
foods did not result in adaptation to a lactulose challenge.
54
The ability of lactulose to alter bacterial translocations has led to research in
other areas of prevention of infections as described above for obstructive jaundice.
The likely mechanism of reduced transfer of bacteria to mesenteric lymph nodes
across intestinal epithelium is through a bacterial effect on intestinal permeability.
55
However, conflicting information exists on the subject. It was already alluded to above
that lactulose increased
Salmonella
translocation in a rat model.
36
Demirogullari et
al.
56
reported that in 3-day starved rats, lactulose and lactitol both enhanced coli-
form translocations from the cecum. Alternatively, De Preter et al.
25
found decreased
intestinal permeability. In support of reduced permeability, some earlier publica-
tions reported prophylactic effects against urinary and respiratory tract infections
in elderly patients using lactulose.
7,57
Although no further trials were found for this
indication of lactulose, the concept remains of interest.
58
The other important area of research remains that of cirrhosis, where many of
the complications are attributed to such bacterial translocations.
59
In this context,
Zhang et al.
60
showed in the carbon tetrachloride rat model of cirrhosis, lactulose
prevented bacterial translocation into mesenteric lymph nodes and small bowel over-
growth compared with placebo. The postulated mechanism is enhanced intestinal
transit and improved permeability.
60
The subject of bacterial translocations is not
settled and the type of disease may determine outcome of studies.
