Eddie Vedder
2008-10-19, 07:56
Jaha...det gäller att köpa artikeln för att se hur de kopplar mjölk till blodtrycket och därefter specifiket på de något udda tri-peptiderna med två prolin och en grenad aminosyra.
Plockade ut litegrann från vad som står i fullängdaren om du nu inte har tillgång till den. Kanske inte ger svar på allt men det är i alla fall forskarnas egna teoreir och funderingar. Tog med referenserna också.:)
A cohort study found the hazard ratio of hypertension between extreme quintiles of low-fat dairy product consumption to be 0.46 (95% confidence interval [CI] 0.26–0.84), suggesting that low-fat dairy product consumption was associated with a low risk of hypertension [12]. Although calcium in milk and dairy products generally contributes to BP control, the association between dairy products and hypertension did not significantly change after adjusting for calcium intake [12] and [13]. This suggests that other factors in milk and dairy products are responsible for this inverse association. Recently, peptides from milk protein have attracted the attention of researchers and the public because of their hypotensive ability. Biologically active peptides are produced when milk proteins are broken down by digestive enzymes, such as trypsin, or by the proteinases formed by lactobacilli during milk fermentation. The best studied milk peptides are the casein-derived tripeptides isoleucine-proline-proline (IPP) and valine-proline-proline (VPP) [14] and [15]. Nakamura et al. [16] Y. Nakamura, N. Yamamoto, K. Sakai, A. Okubo, S. Yamazaki and T. Takano, Purification and characterization of angiotensin I–converting enzyme inhibitors from sour milk, J Dairy Sci 78 (1995), pp. 777–783. View Record in Scopus | Cited By in Scopus (212)[16] first isolated them in 1995 from sour milk with a starter containing Lactobacillus helveticus and Saccharomyces cerevisiae and described their angiotensin-converting enzyme (ACE) inhibiting action. Then, IPP and VPP from milk were found to reduce BP in spontaneously hypertensive rats after a single oral administration and long-term feeding [17] and [18].
[12] A. Alonso, J.J. Beunza, M. Delgado-Rodríguez, J.A. Martínez and M.A. Martínez-González, Low-fat dairy consumption and reduced risk of hypertension: the Seguimiento Universidad de Navarra (SUN) cohort. Am J Clin Nutr 82 (2005), pp. 972–979.
[13] J.B. Ruidavets, V. Bongard, C. Simon, J. Dallongeville, P. Ducimetiere and D. Arveiler et al., Independent contribution of dairy products and calcium intake to blood pressure variations at a population level. J Hypertens 24 (2006), pp. 671–681.
[14] R.J. FitzGerald, B.A. Murray and D.J. Walsh, Hypotensive peptides from milk proteins. J Nutr 134 (2004), pp. 980S–988S.
[15] T. Jauhiainen and R. Korpela, Milk peptides and blood pressure. J Nutr 137 (2007), pp. 825S–829S.
[16] Y. Nakamura, N. Yamamoto, K. Sakai, A. Okubo, S. Yamazaki and T. Takano, Purification and characterization of angiotensin I–converting enzyme inhibitors from sour milk. J Dairy Sci 78 (1995), pp. 777–783.
[17] Y. Nakamura, N. Yamamoto, K. Sakai and T. Takano, Antihypertensive effect of sour milk and peptides isolated from it that are inhibitors to angiotensin I–converting enzyme. J Dairy Sci 78 (1995), pp. 1253–1257.
[18] M. Sipola, P. Finckenberg, J. Santisteban, R. Korpela, H. Vapaatalo and M.L. Nurminen, Long-term intake of milk peptides attenuates development of hypertension in spontaneously hypertensive rats. J Physiol Pharmacol 52 (2001), pp. 745–754.
Lite från diskussionen:
The mechanism that has been studied most in relation to the antihypertensive effects of milk tripeptides is ACE inhibition. All of the studies in this meta-analysis attributed the hypotensive effects of milk tripeptides to ACE inhibition [24] K. Aihara, O. Kajimoto, H. Hirata, R. Takahashi and Y. Nakamura, Effect of powdered fermented milk with Lactobacillus helveticus on subjects with high-normal blood pressure or mild hypertension, J Am Coll Nutr 24 (2005), pp. 257–265. View Record in Scopus | Cited By in Scopus (16)[24], [25], [26], [27], [28], [29], [30], [31] and [32]. ACE catalyzes the conversion of angiotensin I to angiotensin II, which is a strong vasoconstrictor that induces the release of aldosterone and therefore increases the sodium concentration and increases BP. ACE inhibitors not only decrease the production of angiotensin II but also inhibit the degradation of bradykinin, a potent vasodilator [14],[15] and [16]. The chemical structure for food-derived ACE inhibitors has not been established. It is likely that the hydrophobic amino acid proline at the C-terminal position influences ACE activity [34]. Furthermore, the stability of IPP and VPP under gastrointestinal conditions due to the C-terminal proline makes the ACE-inhibiting action possible [35]. IPP and VPP were detected in the abdominal aorta when spontaneously hypertensive rats were given sour milk containing the two peptides [36]. Recently, Foltz et al. [37] found that healthy people who drank an IPP-enriched beverage had 2.1-fold the plasma IPP level of those who received a placebo. Moreover, the concentration of IPP in plasma was significantly increased above baseline after the intake of a whey protein–containing placebo [37]. This suggests that, aside from escaping intestinal degradation and entering the circulation, IPP is generated in the intestinal tract by luminal and brush peptidases.
Hypotensive peptides from milk protein are not limited to IPP and VPP. More and more peptides from casein (casokinins) and whey (lactokinins) protein have been demonstrated as potent inhibitors of ACE [14]. Most of them have not been verified by RCTs. However, most recently, a RCT found that the intake of a casein hydrolysate C12 peptide consisting of 12 amino acids for 4 wk significantly decreased BP in prehypertensive subjects [38]. A recent study conducted in 10 hypotensive subjects found a lower BP that was observed as soon as 6 h after a single administration of C12 peptide [39]. Pins and Keenan [40] observed hypotensive effects of bioactive peptides from whey, in what is the first RCT for whey-derived peptides. In another RCT, however, a milk drink supplemented with whey peptides that had ACE-inhibitory activity did not significantly affect BP in mild hypertensive subjects [41]. However, not all the hypotensive effects of fermented milk are related to ACE inhibition. Inoue et al. [42] found a significant decrease in BP when hypertensive subjects consumed milk fermented by Lactobacillus casei and Lactococcus lactis. In this RCT, milk peptides and ACE-inhibitory activity were not detected in the fermented milk and the hypotensive effect was responsible for the presence of γ-aminobutyric acid.
[24] K. Aihara, O. Kajimoto, H. Hirata, R. Takahashi and Y. Nakamura, Effect of powdered fermented milk with Lactobacillus helveticus on subjects with high-normal blood pressure or mild hypertension. J Am Coll Nutr 24 (2005), pp. 257–265.
[25] T. Jauhiainen, H. Vapaatalo, T. Poussa, S. Kyronpalo, M. Rasmussen and R. Korpela, Lactobacillus helveticus fermented milk lowers blood pressure in hypertensive subjects in 24-h ambulatory blood pressure measurement. Am J Hypertens 18 (2005), pp. 1600–1605.
[26] S. Mizuno, K. Matsuura, T. Gotou, S. Nishimura, O. Kajimoto and M. Yabune et al., Antihypertensive effect of casein hydrolysate in a placebo-controlled study in subjects with high-normal blood pressure and mild hypertension. Br J Nutr 94 (2005), pp. 84–91.
[27] J. Sano, K. Ohki, T. Higuchi, K. Aihara, S. Mizuno and O. Kajimoto et al., Effect of casein hydrolysate, prepared with protease derived from Aspergillus oryzae, on subjects with high-normal blood pressure or mild hypertension. J Med Food 8 (2005), pp. 423–430.
[28] S. Mizushima, K. Ohshige, J. Watanabe, M. Kimura, T. Kadowaki and Y. Nakamura et al., Randomized controlled trial of sour milk on blood pressure in borderline hypertensive men. Am J Hypertens 17 (2004), pp. 701–706.
[29] J. Tuomilehto, J. Lindstrom, J. Hyyrynen, R. Korpela, M.L. Karhunen and L. Mikkola et al., Effect of ingesting sour milk fermented using Lactobacillus helveticus bacteria producing tripeptides on blood pressure in subjects with mild hypertension. J Hum Hypertens 18 (2004), pp. 795–802.
[30] L. Seppo, T. Jauhiainen, T. Poussa and R. Korpela, A fermented milk high in bioactive peptides has a blood pressure-lowering effect in hypertensive subjects. Am J Clin Nutr 77 (2003), pp. 326–330.
[31] L. Seppo, O. Kerojoki, T. Suomalainen and R. Korpela, The effect of a lactobacillus helveticus LBK-16 H fermented milk on hypertension—a pilot study on humans. Milchwissenschaft 57 (2002), pp. 124–127.
[32] Y. Hata, M. Yamamoto, M. Ohni, K. Nakajima, Y. Nakamura and T. Takano, A placebo-controlled study of the effect of sour milk on blood pressure in hypertensive subjects. Am J Clin Nutr 64 (1996), pp. 767–771.
[33] M.P. Dent, S. O'Hagan, W.H. Braun, P. Schaetti, A. Marburger and O. Vogel, A 90-day subchronic toxicity study and reproductive toxicity studies on ACE-inhibiting lactotripeptide. Food Chem Toxicol 45 (2007), pp. 1468–1477.
[34] M.A. Ondetti and D.W. Cushman, Angiotensin-converting enzyme inhibitors: biochemical properties and biological actions. CRC Crit Rev Biochem 16 (1984), pp. 381–411.
[35] S. Mizuno, S. Nishimura, K. Matsuura, T. Gotou and N. Yamamoto, Release of short and proline-rich antihypertensive peptides from casein hydrolysate with an Aspergillus oryzae protease. J Dairy Sci 87 (2004), pp. 3183–3188.
[36] O. Masuda, Y. Nakamura and T. Takano, Antihypertensive peptides are present in aorta after oral administration of sour milk containing these peptides to spontaneously hypertensive rats. J Nutr 126 (1996), pp. 3063–3068.
[37] M. Foltz, E.E. Meynen, V. Bianco, C. van Platerink, T.M. Koning and J. Kloek, Angiotensin converting enzyme inhibitory peptides from a lactotripeptide-enriched milk beverage are absorbed intact into the circulation. J Nutr 137 (2007), pp. 953–958.
[38] J.A. Cadee, C.Y. Chang, C.W. Chen, C.N. Huang, S.L. Chen and C.K. Wang, Bovine casein hydrolysate (c12 Peptide) reduces blood pressure in prehypertensive subjects, Am J Hypertens 20 (2007), pp. 1–5. Article | PDF (253 K) | View Record in Scopus | Cited By in Scopus (3)
[39] R.R. Townsend, C.B. McFadden, V. Ford and J.A. Cadée, A randomized, double-blind, placebo-controlled trial of casein protein hydrolysate (C12 peptide) in human essential hypertension. Am J Hypertens 17 (11, pt 1) (2004), pp. 1056–1058.
[40] J.J. Pins and J.M. Keenan, Effects of whey peptides on cardiovascular disease risk factors. J Clin Hypertens 8 (2006), pp. 775–782.
[41] Y.M. Lee, T. Skurk, M. Hennig and H. Hauner, Effect of a milk drink supplemented with whey peptides on blood pressure in patients with milk hypertension. Eur J Nutr 46 (2007), pp. 21–27.
[42] K. Inoue, T. Shirai, H. Ochiai, M. Kasao, K. Hayakawa and M. Kimura et al., Blood-pressure-lowering effect of a novel fermented milk containing γ-aminobutyric acid (GABA) in mild hypertensives. Eur J Clin Nutr 57 (2003), pp. 490–495.
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