In so-called hypoallergenic (HA) infant formulas, the allergenic potential of milk proteins is reduced by using more or less intensively hydrolysed casein or whey proteins as constituent. Further studies showed the high inhibitory effect of these products mediated by angiotensin-converting enzyme (ACE) inhibiting peptides included in these formulas. Beside other peptides, we have detected and quantified the highly potent ACE-inhibitor Ile-Trp (IC50= 0.7 mM) for the first time in a number of HA samples, representing the most effective ACE-inhibiting peptide which has ever been detected in food items. The effect of long-term (15 weeks) intake of HA infant milk formula containing the potent inhibitory peptide was studied with respect to the development of hypertension and myocardial remodelling in spontaneously hypertensive rats (SHR). 12-week-old SHR (n= 48) were divided into four groups to receive orally ad libitum water and different supplements in their food pellets. Experimental groups studied were a placebo group receiving food pellets without any supplement (PL), a captopril (CA) group, a hypoallergenic (HA) infant milk formula group, and a conventional infant milk (CM) formula group (with intact milk protein). The calculated intake of Ile-Trp was approximately 1.60 mg/d and kg body weight for the HA group. Blood pressure was monitored non-invasively via tail cuff throughout the study. At week 15 coronary dilator reserve was determined (adenosine i.c. 1 mM, reactive hyperemia after 15 s flow stop) in isolated heart preparations. At the beginning of the feeding period systolic blood pressure was similar in all groups (230 – 235 mmHg) and increased in the typical time-dependent manner in the placebo- and CM-groups. A significant decrease in systolic blood pressure was shown for the CA- (mean: -28 4.0 mmHg) and the HA-group (mean: -17 4.2 mmHg). At week 15 heart mass was lower in HA- (92 1%) and CA-group (83 2%, both p < 0.05 vs. CM). Coronary flow reserve was improved in CA- and HA- versus CM-group.

In summary, the effect of HA formula intake is similar to that of established ACE-inhibitors. Amelioration of arterial hypertension is associated with myocardial remodelling. We conclude that milk products containing the dipeptide Ile-Trp are interesting nutrition additives as functional food that may support arterial blood pressure reduction in mildly hypertensive patients.