Milk fermented by Lactobacillus helveticus, a lactic acid bacterium with potent proteolytic activity, had an antihypertensive effect in animal model studies. During the culture process, the biogenic peptides valyl-prolyl-proline and isoleucyl-prolyl-proline were derived from milk protein. These two peptides have been shown to have an inhibitory effect on angiotensin-converting enzyme, which converts angiotensin I to angiotensin II, a strong vasoconstrictor. Preclinical and in vitro studies suggest that a portion of the orally ingested dose of these peptides can be absorbed in the intact form from the gastrointestinal tract, can inhibit the tissue renin-angiotensin system, and can produce significant reductions in blood pressure. In clinical studies, fermented milk containing biologically active peptides significantly decreased systolic and diastolic blood pressure in hypertensive subjects. In contrast, no significant effect on blood pressure was observed in normotensives. Based on these observations, it is possible that fermented milk containing valyl-prolyl-proline and isoleucyl-prolyl-proline which could provide a non-pharmacological approach to the management of hypertension. This report reviews a series of studies on antihypertensive peptides in milk fermented with Lactobacillus helveticus and also describes the results of clinical trials including the latest information.
To elucidate the effect of fermented milk containing Lactobacillus johnsonii La1 (LC1®) on defecation, a double blind placebo controlled study was conducted. Healthy Japanese adults (24-67 years of age, n=57, male: 31, female: 26) were randomly divided into two groups, and the subjects in the LC1 group (n=30) consumed LC1 fermented milk containing L. johnsonii La1 at 1×109 cfu/90 g (90 g per day) for 21 days and the subjects in the control group (n=27) consumed placebo fermented milk without the La1 strain in the same manner. In the subjects of the LC1 group with mild constipation (n=9), less than one defecation per day in the 3 weeks observation period, defecation frequency both in times per week and days per week significantly increased during consumption of LC1 compared to before consumption (p<0.05), and the frequency recovered to normal status with at least one defecation per day in 4 out of 9 of subjects (44%) after 3 weeks LC1 consumption. Subjects with mild constipation in the control group (n=7) showed no significant changes in defecation frequency. The frequency in the subjects with normal defecation did not change in either group. L. johnsonii La1 was found in all feces from 10 subjects in the LC1 group participating in fecal collection, suggesting that La1 strain efficiently reached the gastrointestinal tract as a viable form. Excess amount (360 g per day) of LC1 intake for 2 weeks in the other healthy subjects (n=10) caused an increase in defecation frequency, which was kept at the normal level of less than twice per day. These results suggest that LC1®, a probiotic fermented milk containing L. johnsonii La1, is beneficial for improving mild constipation without any safety concerns.
The physiologic effects of kefiran, a water-soluble exopolysaccharide, were investigated in the animal studies by oral administration of kefiran. The results in this study showed that kefiran had a hypoglycemic effect in KKAy mice and could improve defecation in the levels of fecal moisture and wet weight of feces in constipated SD rats induced by a low-fiber diet.