本帖最後由 goodcat1111 於 2009-4-5 08:58 編輯
作者：Eurona Earl Tilley
出處：WebMD醫學新聞
February 27, 2009 — 根據3月1日美國臨床營養學期刊的一篇研究，食用3 g的肉桂會降低餐後血清胰島素值，且增加glucagon-like peptide 1 (GLP-1)濃度，這是一種可以延遲胃排空且降低餐後飢餓感的胃腸荷爾蒙；對於血糖、葡萄糖依賴性胰島素刺激多肽(GIP)、飢餓素濃度、飽足感或者胃排空率(GER)沒有明顯效果。再者，肉桂攝取量與降低胰島素濃度之間有反比關係。
以前，在一組健康個體中，攝取6 g的肉桂顯示與降低餐後血糖濃度以及GER有關，對飽足感沒有影響。瑞典Malmo大學醫院醫學系的Joanna Hlebowicz醫師等人解釋，食物中通常不會用到6g的肉桂，因此，本研究的主要目標是確認每餐添加3g肉桂是否會改變GER、飽足感或者飯後血糖、胰島素、GIP以及 GLP-1濃度；如果的確如此，次級目標是確認每餐添加1 g肉桂是否會改變GER、飽足感或者飯後血糖、胰島素、GIP以及 GLP-1濃度。
在一篇交叉研究中，總共有15名健康的瑞典男性(n = 9)與女性(n = 6)，各給予300 g的米布丁，以及在餐後一段時間給予3 g、1 g或者0g的肉桂。以每週間隔、隨點方式供應餐食。使用即時超音波測量每位參與者的餐後GER。在事先設定的間隔中，以評分量表測量參與者餐前、餐後的飽足感。此外，以靜脈血液樣本測量相同用餐間隔下，每餐前與餐後之葡萄糖、胰島素、GIP、GLP-1以及飢餓素濃度。
作者寫道，本研究設計在於確認健康研究對象食用肉桂之後，胰島素反應之改變是否可以解釋較低的餐後血糖濃度，而GIP、GLP-1以及飢餓素反應之改變是否可以解釋胰島素分泌或者GER改變。我們也研究劑量-反應關聯與健康個體之GER、飽足感、餐後血糖、胰島素、GIP、GLP-1以及飢餓素反應的關聯。
結果顯示，在食用米布丁後，吃3g肉桂，60分鐘時，胰島素反應有最顯著的降低(邦弗朗尼修正法之後，P = .05)，120分鐘時的曲線下面積也是(邦弗朗尼修正法之後，P = .036)。同樣地，食用米布丁後吃3g肉桂，顯著增加了GLP-1反應(邦弗朗尼修正法之後，P = .0082) 以及最大濃度(邦弗朗尼修正法之後，P = .0138)。不過，食用米布丁後吃3g、1 g或者0g的肉桂，GER、飽足感、葡萄糖、GIP、飢餓素反應並無顯著差異。
Hlebowicz醫師等人解釋，肉桂在調節血糖上是最有效的藥用植物之一。我們發現肉桂降低了胰島素需求，雖然並未改變血糖濃度，但也許是因為透過刺激胰島素受體而促進葡萄糖吸收。這項發現與之前的研究結果一致。
再者，在本研究中，肉桂食用量、降低之胰島素濃度與延遲胃排空之間有關係；研究者指出，食用3 g肉桂比食用1g肉桂更可以減少飯後胰島素濃度，對於飯後血糖或者GER則沒有影響。
這項研究的一個潛在限制是，未評估餐後的升糖素濃度。升糖素是胰臟分泌的一種荷爾蒙，會刺激血糖濃度增加。
作者結論表示，肉桂對於糖尿病控制不佳的病患而言，是一種重要的飲食補充品。Hlebowicz醫師等人寫道，肉桂對於第1型和第2型糖尿病患之血糖控制的能力尚未被完整評估。顯然地，需要進行包括大量糖尿病患的長期臨床試驗，以評估肉桂補充品對第2型糖尿病的影響。
Stig and Ragna Gothon基因會之醫學研究資金支持本研究。作者宣稱沒有相關財務關係。
Cinnamon Dose-Dependently Reduces Insulin Concentration
By Eurona Earl Tilley
Medscape Medical News
February 27, 2009 — The ingestion of 3 g of cinnamon reduces serum insulin levels after mealtime and increases the concentration of glucagon-like peptide 1 (GLP-1), a gastrointestinal hormone that has been shown to delay gastric emptying and minimize the feeling of hunger after eating, according to a study published in the March 1 issue of the American Journal of Clinical Nutrition. There was no significant affect on blood glucose, glucose-dependent insulinotropic polypeptide (GIP), ghrelin concentration, satiety, or gastric emptying rate (GER). Furthermore, there appeared to be an inverse relationship between the amount of cinnamon consumed and the reduction in insulin concentration.
Previously, the ingestion of 6 g of cinnamon was shown to be associated with a reduction in blood glucose concentrations after mealtime, as well as GER, without affecting satiety among a group of healthy subjects. "Six grams of cinnamon is not a quantity ordinarily used in food," explains Joanna Hlebowicz, MD, from the Department of Medicine, Malmo University Hospital, Sweden, and colleagues. "[Thus,] the primary objective of this study was to determine whether adding 3 g cinnamon to a meal would change GER, satiety, or postprandial blood glucose, insulin, GIP, and GLP-1 concentrations. If this was the case, the secondary objective was to establish whether adding 1 g cinnamon to a meal would change GER, satiety, and postprandial blood glucose, insulin, GIP, and GLP-1 concentrations."
In a crossover study, a total of 15 healthy Swedish men (n = 9) and women (n = 6) were given 300 g of rice pudding with 3 g, 1 g, or no cinnamon after a period of fasting. Meals were served in random order at weekly intervals. Using real-time ultrasonography, GER was measured in each participant after meals. A scoring scale was used to determine satiety among the subjects before and after eating at prespecified intervals. In addition, venous blood samples were evaluated for the measurement of glucose, insulin, GIP, GLP-1, and ghrelin concentrations both before and after each mealtime according to the same prespecified intervals.
"This study was...designed to determine whether changes in insulin response explain lower postprandial blood glucose concentrations and whether a change in GIP, GLP-1, or ghrelin response could explain the change in insulin secretion or the change in GER in healthy subjects after cinnamon consumption," write the authors. "We also studied the dose-response relation with respect to the effect on GER, satiety, and postprandial blood glucose, insulin, GIP, GLP-1, and ghrelin responses in healthy subjects."
The results illustrated a significant reduction following the consumption of rice pudding with 3 g of cinnamon in the insulin response at 60 minutes (P = .05, after Bonferroni correction), as well as the area under the curve at 120 minutes (P = .036, after Bonferroni correction). Similarly, there was a significant increase following the consumption of rice pudding with 3 g of cinnamon in the GLP-1 response (P = .0082, after Bonferroni correction) and the change in the maximum concentration (P = .0138, after Bonferroni correction). However, there was no significant difference in GER, satiety, glucose, GIP, or the ghrelin response following the ingestion of the rice pudding with 3 g, 1 g, or no cinnamon.
"Cinnamon has been shown to be one of the most effective [herbs and medicinal plants] at regulating blood glucose," explain Dr. Hlebowicz and colleagues. "Our finding that cinnamon decreases the insulin demand, despite the lack of change in blood glucose concentrations, was probably due to enhanced glucose uptake via stimulation of the insulin receptor. This finding is consistent with the results of previous studies."
Furthermore, in this study, there appeared to be a relationship between the amount of cinnamon consumed, the reduction in insulin concentration, and the delay in gastric emptying. "An intake of 3 g cinnamon reduced postprandial insulin concentrations more noticeably than did the ingestion of 1 g cinnamon, without affecting postprandial blood glucose or GER," point out the researchers.
One potential limitation of the study is the fact that glucagon concentrations after eating were not evaluated. Glucagon is a hormone secreted by the pancreas that stimulates increases in the concentration of blood glucose.
The authors conclude that cinnamon could be an important dietary supplement for those with poorly controlled diabetes. "The ability of cinnamon to control blood glucose concentrations in patients with type 1 and type 2 diabetes has not yet been fully evaluated," Dr. Hlebowicz and colleagues write. "Clearly, a long-term clinical trial involving a...[large] number of diabetes patients is needed to evaluate the effects of cinnamon supplementation in type 2 diabetes."
This study was supported by the Stig and Ragna Gothon's Foundation for Medical Research. The authors have disclosed no relevant financial relationships.
Am J Clin Nutr. 2009;89:815–821. |
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