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Metabolic impact of certain dietary proteins and/or amino acids - Glycaemic and hormonal responses to carbohydrate meals in healthy subject

Gunnerud, Ulrika LU (2013)
Abstract (Swedish)
Popular Abstract in Swedish

Förekomst av fetma och typ 2 diabetes ökar i Sverige, liksom globalt. Över 360 miljoner människor har diabetes och prognosen för år 2030 är drygt 550 miljoner (IDF 2011). Att arbeta med förebyggande åtgärder för att minska denna utveckling är därför nödvändigt. Något som har stor betydelse för hälsan är vilken typ av mat vi väljer att äta och dess näringsmässiga kvaliteter.

När vi äter går blodsockernivåerna upp. Återkommande höga blodsockersvar, som är vanliga vid typ 2 diabetes, ökar risken att drabbas av hjärtkärlsjukdom i framtiden. Därför är det extra betydelsefullt att kontrollera blodsockernivåerna hos typ 2 diabetiker. Även hos friska personer har låga blodsockernivåer i samband... (More)
Popular Abstract in Swedish

Förekomst av fetma och typ 2 diabetes ökar i Sverige, liksom globalt. Över 360 miljoner människor har diabetes och prognosen för år 2030 är drygt 550 miljoner (IDF 2011). Att arbeta med förebyggande åtgärder för att minska denna utveckling är därför nödvändigt. Något som har stor betydelse för hälsan är vilken typ av mat vi väljer att äta och dess näringsmässiga kvaliteter.

När vi äter går blodsockernivåerna upp. Återkommande höga blodsockersvar, som är vanliga vid typ 2 diabetes, ökar risken att drabbas av hjärtkärlsjukdom i framtiden. Därför är det extra betydelsefullt att kontrollera blodsockernivåerna hos typ 2 diabetiker. Även hos friska personer har låga blodsockernivåer i samband med måltider visat sig positiva, då risken att senare i livet drabbas av diabetes och hjärt-kärlsjukdom minskar.

Vissa komponenter i livsmedel har gynnsamma effekter som kan användas för att underlätta reglering av blodsockret. I den här avhandlingen har olika livsmedelsproteiner och aminosyrablandningar studerats. I måltidsstudier på friska försökspersoner visade det sig att om man drack vassleproteiner från mjölk tillsammans med en kolhydratrik måltid så minskade blodsockersvaret. Det visade sig också att tillsats av vissa enskilda aminosyror förstärkte denna effekt. Även sojaproteiner med tillsatta aminosyror hade en blodsockersänkande effekt. Effekten kunde förklaras av ett ökat insulinsvar. I blodet syntes också en ökning av vissa aminosyror och tarmhormoner. Att inta en liten dos av vassle/soja och aminosyror precis innan en måltid visade sig vara extra gynnsamt. Insulinet blev då effektivare och det behövdes mindre mängd insulin för att sänka blodsockret.

Resultaten från avhandlingen kan användas för utveckling av livsmedel och måltider med hälsofrämjande effekter i form av underlättad blodsockerreglering hos både friska och diabetiker. Behandling av typ 2 diabetes med vissa läkemedel kan ge oönskade biverkningar t.ex. plötsliga blodsockerfall. Användning av livsmedelsproteiner/aminosyror har troligtvis inte dessa nackdelar då den insulinstimulerande effekten bara uppkommer när blodsockret stiger efter en måltid. (Less)
Abstract
Re-occurring hyperglycaemic episodes promote subclinical low-grade inflammation and CVD in type 2 diabetes, emphasising the therapeutic role of tight blood glucose regulation. A tight blood glucose regulation is probably beneficial also in healthy subjects and mild elevations in postprandial glycaemia and triglycerides are associated with impaired flow-mediated dilation and increased markers of oxidative stress in young healthy subjects. Certain dietary proteins and amino acids (AA) have insulinogenic properties and might facilitate glycaemic regulation following a carbohydrate challenge. However, there is a lack of knowledge regarding the impact of different food proteins, and to what extent their effects can be influenced by... (More)
Re-occurring hyperglycaemic episodes promote subclinical low-grade inflammation and CVD in type 2 diabetes, emphasising the therapeutic role of tight blood glucose regulation. A tight blood glucose regulation is probably beneficial also in healthy subjects and mild elevations in postprandial glycaemia and triglycerides are associated with impaired flow-mediated dilation and increased markers of oxidative stress in young healthy subjects. Certain dietary proteins and amino acids (AA) have insulinogenic properties and might facilitate glycaemic regulation following a carbohydrate challenge. However, there is a lack of knowledge regarding the impact of different food proteins, and to what extent their effects can be influenced by supplementation with AA. Also, limited information exists with respect to influence of proteins/AA on metabolic response to carbohydrates in a composite meal.

The objective of the present thesis was to investigate the impact of whey and soy protein on postprandial blood glucose, plasma AA (p-AA) and hormonal responses when administered to healthy subjects in a glucose drink, as part of milk meals, or in combination with a composite carbohydrate meal. The effect of exchanging half of the protein for specific AA mixtures (5AA: isoleucine, leucine, lysine, threonine and valine) or (6AA: 5AA+arginine) was also examined. Additionally appetite rating in the postprandial phase was performed using VAS scales.

Whey protein (4.5-18g) reduced postprandial glycaemia, and increased insulinaemia and p-AA in a dose dependent way to a glucose challenge, and the p-5AA (iAUC 0-60 min) correlated to the insulin response (iPeak; P < 0.009). Lactose-equivalent amounts of bovine and human milk resulted in similar postprandial glycaemia and insulinaemia. A rapid response in GIP, GLP-1 and p-AA correlated to an early insulinogenic effect that was associated to reduction of glycaemia (iAUC 0-90 min; P < 0.001). Hydrolysed and intact whey had similar effects on glycaemic responses when co-ingested with glucose, although hydrolysed way tended to be more insulinogenic, possible due to its higher early insulin and faster p-AA response compared with intact whey. Exchanging half of the intact or hydrolysed whey protein for 5AA magnified the insulinogenic effect and reduced postprandial glycaemia (iAUC 0-120min; P < 0.05).

Intake of whey or soy protein with or without addition of 5AA or 6AA, as a pre-meal protein drink (PMPD) prior a composite meal, considerably attenuated postprandial blood glucose incremental peak value (iPeak; P < 0.05). Also, all whey PMPDs with or without added AA reduced glycaemia (iAUC 0-120min; P < 0.05) and increased the Glycaemic Profile (GP; P < 0.05). Arginine had no additional effect on glycaemic responses when added to the 5AA mixture. Early GLP-1 and p-AA responses (iAUC 0-15 min) were associated with early insulin response (iAUC 0-15min). Early increment in insulin possibly explain the attenuation of over-all course of post-prandial glycaemia to the composite carbohydrate meal post the PMPDs. Interestingly, the lowering of glycaemic excursions was observed in the absence of elevated insulinaemic peak. Intake of a PMPD prior a composite meal had no effects on appetite rating (VAS) or plasma ghrelin. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor Gannon, Mary, Departments of Medicine and Food Science and Nutrition, University of Minnesota, Minneapolis, USA
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Amino acids, dietary protein, glycaemic regulation, insulin, incretins
defense location
Lecture Hall B, Chemical Centre, Getingevägen 60, Lund University, Faculty of Engineering
defense date
2013-03-22 09:15
ISBN
978-91-7422-317-0
language
English
LU publication?
yes
id
f3d26bd3-dcf6-4b4f-a351-db270e710300 (old id 3516049)
date added to LUP
2013-02-28 11:27:09
date last changed
2016-09-19 08:45:17
@phdthesis{f3d26bd3-dcf6-4b4f-a351-db270e710300,
  abstract     = {Re-occurring hyperglycaemic episodes promote subclinical low-grade inflammation and CVD in type 2 diabetes, emphasising the therapeutic role of tight blood glucose regulation. A tight blood glucose regulation is probably beneficial also in healthy subjects and mild elevations in postprandial glycaemia and triglycerides are associated with impaired flow-mediated dilation and increased markers of oxidative stress in young healthy subjects. Certain dietary proteins and amino acids (AA) have insulinogenic properties and might facilitate glycaemic regulation following a carbohydrate challenge. However, there is a lack of knowledge regarding the impact of different food proteins, and to what extent their effects can be influenced by supplementation with AA. Also, limited information exists with respect to influence of proteins/AA on metabolic response to carbohydrates in a composite meal.<br/><br>
The objective of the present thesis was to investigate the impact of whey and soy protein on postprandial blood glucose, plasma AA (p-AA) and hormonal responses when administered to healthy subjects in a glucose drink, as part of milk meals, or in combination with a composite carbohydrate meal. The effect of exchanging half of the protein for specific AA mixtures (5AA: isoleucine, leucine, lysine, threonine and valine) or (6AA: 5AA+arginine) was also examined. Additionally appetite rating in the postprandial phase was performed using VAS scales.<br/><br>
Whey protein (4.5-18g) reduced postprandial glycaemia, and increased insulinaemia and p-AA in a dose dependent way to a glucose challenge, and the p-5AA (iAUC 0-60 min) correlated to the insulin response (iPeak; P &lt; 0.009). Lactose-equivalent amounts of bovine and human milk resulted in similar postprandial glycaemia and insulinaemia. A rapid response in GIP, GLP-1 and p-AA correlated to an early insulinogenic effect that was associated to reduction of glycaemia (iAUC 0-90 min; P &lt; 0.001). Hydrolysed and intact whey had similar effects on glycaemic responses when co-ingested with glucose, although hydrolysed way tended to be more insulinogenic, possible due to its higher early insulin and faster p-AA response compared with intact whey. Exchanging half of the intact or hydrolysed whey protein for 5AA magnified the insulinogenic effect and reduced postprandial glycaemia (iAUC 0-120min; P &lt; 0.05). <br/><br>
Intake of whey or soy protein with or without addition of 5AA or 6AA, as a pre-meal protein drink (PMPD) prior a composite meal, considerably attenuated postprandial blood glucose incremental peak value (iPeak; P &lt; 0.05). Also, all whey PMPDs with or without added AA reduced glycaemia (iAUC 0-120min; P &lt; 0.05) and increased the Glycaemic Profile (GP; P &lt; 0.05). Arginine had no additional effect on glycaemic responses when added to the 5AA mixture. Early GLP-1 and p-AA responses (iAUC 0-15 min) were associated with early insulin response (iAUC 0-15min). Early increment in insulin possibly explain the attenuation of over-all course of post-prandial glycaemia to the composite carbohydrate meal post the PMPDs. Interestingly, the lowering of glycaemic excursions was observed in the absence of elevated insulinaemic peak. Intake of a PMPD prior a composite meal had no effects on appetite rating (VAS) or plasma ghrelin.},
  author       = {Gunnerud, Ulrika},
  isbn         = {978-91-7422-317-0},
  keyword      = {Amino acids,dietary protein,glycaemic regulation,insulin,incretins},
  language     = {eng},
  school       = {Lund University},
  title        = {Metabolic impact of certain dietary proteins and/or amino acids - Glycaemic and hormonal responses to carbohydrate meals in healthy subject},
  year         = {2013},
}