Human in vivo study of the renin-angiotensin-aldosterone system and the sympathetic activity after 8 weeks daily intake of fermented milk.
OBJECTIVE
Milk fermented by lactic acid bacteria is suggested to have antihypertensive effect in humans. In vitro and animal studies have established an angiotensin-converting enzyme (ACE) inhibitor effect of peptides in fermented milk. However, other modes of action must be considered, because until today no human studies have confirmed an ACE inhibition in relation to the intake of fermented milk.


METHODS
We undertook a double-blinded randomized placebo-controlled study including 94 borderline-hypertensive persons to study the effect on human physiology of Lactobacillus helveticus fermented milk. The subjects were randomized into three groups: Cardi04-300 ml, Cardi04-150 ml or placebo. All components of the renin-angiotensin-aldosterone system were measured several times. Sympathetic activity was estimated by plasma noradrenaline and cardiovascular response to head-up tilt at baseline and after 8 weeks of intervention.


RESULTS
No ACE inhibition of the fermented milk was demonstrated, as none of the components of the renin-angiotensin-aldosteron system changed. Plasma noradrenaline response to tilt test after intervention stayed unchanged between groups (P = 0.38), but declined in the group Cardi04-300 from 2.01 +/- 0.93 nmol l(-1) at baseline to 1.49 +/- 0.74 nmol l(-1) after 8 weeks (P = 0.002). There was no change in 24-h ambulatory blood pressure or heart rate between groups.


CONCLUSIONS
Despite a known ACE inhibitory effect in vitro and in animals, milk fermented with Lb. helveticus did not inhibit ACE in humans. Our results suggest that the intake of fermented milk decreases sympathetic activity, although not to an extent mediating reductions of blood pressure and heart rate in borderline-hypertensive subjects.
Usinger
Lotte
L
Department of Clinical Physiology and Nuclear Medicine, Glostrup University Hospital Glostrup, Glostrup, Denmark. lotusi01@glo.regionh.dk
Ibsen
Hans
H
Linneberg
Allan
A
Azizi
Michel
M
Flambard
Bénédicte
B
Jensen
Lars T
LT
D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000008:administration & dosage; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D043302:Cultured Milk Products; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D052198:Lactobacillus helveticus; D008297:Male; D008875:Middle Aged; D008894:Milk Proteins / Q000008:administration & dosage*; D009638:Norepinephrine / Q000097:blood; D010455:Peptides / Q000008:administration & dosage; D012084:Renin-Angiotensin System / Q000187:drug effects* / Q000502:physiology; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000502:physiology; D018667:Tilt-Table Test
D000959:Antihypertensive Agents; D008894:Milk Proteins; D010455:Peptides; D009638:Norepinephrine