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- van Vught, A. J. A. H., et al.
(author)
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The effects of dietary protein on the somatotropic axis : a comparison of soy, gelatin, alpha-lactalbumin and milk
- 2010
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In: European Journal of Clinical Nutrition. - : Springer Science and Business Media LLC. - 0954-3007 .- 1476-5640. ; 64:5, s. 441-446
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Journal article (peer-reviewed)abstract
- BACKGROUND/OBJECTIVES: Growth hormone (GH) is an important regulator of growth and body composition. It has been shown that GH release can be promoted by administration of various amino acids (AAs), such as arginine and lysine, that are present in soy protein. We previously showed that oral ingestion of soy protein stimulates the GH release, it is not known however to which extent other proteins stimulate the GH secretion.SUBJECTS/METHODS: Ingestion of soy protein (soy), gelatin protein (gelatin), alpha-lactalbumin protein (alpha-lactalbumin) and milk protein (milk) were compared on their GH-stimulating capacity. After oral ingestion of protein (0.6 g protein per kg bodyweight), blood was sampled every 20 min for 5 h to analyze GH, AA, insulin and glucose concentrations. The study was performed in eight healthy women (aged 19-26 years; body mass index 19-26 kg/m(2)) in a randomized, single blind, placebo-controlled crossover design.RESULTS: GH responses were more increased after ingestion of gelatine (8.2+/-1.1 microg/l) compared with ingestion of soy, alpha-lactalbumin and milk (5.0+/-0.8, 4.5+/-0.6 and 6.4+/-1.0 microg/l, respectively) (P<0.05). After ingestion of each protein, GH responses were higher compared with placebo ingestion (P<0.05). Simultaneously ingestion of gelatin resulted in the highest serum-arginine concentrations (ARG) compared with after ingestion of the other proteins (P<0.05). Insulin as well as glucose concentrations were not different after ingestion of the various proteins (P<0.05).CONCLUSIONS: The GH-promoting activity of protein depends on the protein source, in that, gelatin protein is the most potent GH stimulator. Arginine may be the responsible AA in the GH-promoting effect of gelatin, although each protein may have its own specific AA-spectrum involved in the stimulation of the somatotropic axis.
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| 2. |
- van Vught, A. J. A. H., et al.
(author)
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The effects of protein ingestion on GH concentrations in visceral obesity
- 2010
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In: Hormone and Metabolic Research. - : Georg Thieme Verlag KG. - 0018-5043 .- 1439-4286. ; 42:10, s. 740-745
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Journal article (peer-reviewed)abstract
- Growth hormone (GH), a hormone originating from the anterior pituitary gland, is an important regulator of metabolism and body composition. Low GH secretion is associated with features of the metabolic syndrome, in particular increased visceral body fat and decreased lean body mass. It has been shown that GH release can be promoted by ingestion of protein, in particular gelatin protein. The question remains; is the GH-promoting effect of gelatin protein also present in a population with blunted GH response, such as visceral obesity? 8 lean women (age: 23 +/- 3 years, BMI: 21.6 +/- 2.0 kg/m(2)) and 8 visceral obese women (age: 28 +/- 7 years, BMI: 33.8 +/- 5.5 kg/m(2)) were compared with regard to their 5-h GH response after oral ingestion of gelatin protein (0.6 g protein per kg bodyweight), placebo (water), or injection of growth hormone releasing hormone (GHRH) (1 mu/kg body weight), in a randomized crossover design. GH response after placebo, gelatin protein, or GHRH was higher in lean subjects than in visceral obese subjects (p < 0.05). Ingestion of gelatin protein increased GH response compared with placebo in both visceral obese (182.1 +/- 81.6 mu g/l.5h vs. 28.4 +/- 29.8 mu g/l.5h) and lean (631.7 +/- 144.2 mu g/l.5h vs. 241.0 +/- 196.8 mu g/l.5h) subjects (p < 0.05). GH response after ingestion of gelatin protein in visceral obese did not differ from that in lean, placebo-treated subjects (p = 0.45). GH concentrations after GHRH injection correlated significantly with GH concentrations after gelatin ingestion (AUC; r = 0.71, p < 0.01, Peak; r = 0.81, p < 0.01). Further research is needed to investigate if gelatin protein is able to improve metabolic abnormalities in hyposomatotropism in the long term or to investigate the relevance of protein as diagnostic tool in hyposomatotropism.
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