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1 DOI : /kdj REVIEW 혈당지수의재조명 부산대학교의학전문대학원내분비대사내과 김인주 Glycemic Index Revisited In Joo Kim Department of Endocrinology and Metabolism, Pusan National University School of Medicine, Busan, Korea Abstract The implementation of effective dietary strategies is important for diabetes management. Dietary carbohydrate is the main factor determining blood sugar level, especially in the postprandial period. Carbohydrate-rich diets can have deleterious effects on glycemic control in diabetic patients and may play an important role in the development of cardiovascular diseases. Low glycemic diets have been reported to have beneficial effects for diabetes control and cardiovascular risk factors. However, according to the American Diabetes Association recommendations for medical nutrition therapy, monitoring carbohydrate intake, whether by carbohydrate counting, exchange, or experience-based estimation, remains a key strategy for achieving glycemic control, with the use of the glycemic index and glycemic load recommended only as an auxiliary method that may provide a modest additional benefit for glycemic control over the effects observed when total carbohydrate is considered alone. Recently, an increasing amount of clinical evidence supports the efficacy of low glycemic diets for the management of diabetes. The development of practical methods to apply the glycemic index and glycemic load to the management of diabetes in clinical settings is warranted. (Korean Diabetes J 33: , 2009) Key words: Cardiovascular disease, Glycemic index, Hyperglycemia, Nutrition therapy 서론당뇨병환자의혈당관리에있어서당질의섭취량을모니터링하는것이매우중요하다. 특히식후혈당은포도당의혈류로의유입 ( 소화와흡수 ) 및제거에의해서일차적으로결정된다. 이때인슐린이혈당을정상적인범위내에서유지하는작용을담당한다. 인슐린의분비와작용에결함을가진당뇨병환자에서는당질섭취에따른식후혈당증가를특징적으로나타내게된다. 그러므로식사로섭취하는당질의양뿐아니라종류도식후혈당에영향을미친다. 이렇듯영양적인요소가당뇨병의혈당조절에중요하다고하지만아직까지가장적정하고보편적으로적용할만한당뇨병의식사요법은아직규정되지않았다. 일반적으로당뇨병의식 사요법에서는일일섭취열량의 45~65% 를당질로, 20~35% 을지질로, 10~35% 를단백질로각각구성하여섭취할것을권유한다. 아울러당질계수 (carbohydrate counting) 나교환 (carbohydrate exchange) 및경험적인추산등의방법으로당질섭취량을모니터링하는것을혈당조절의주된전략으로권유하며, 혈당지수 (glycemic index, GI) 나혈당부하지수 (glycemic load, GL) 를이용하면혈당조절에약간의추가적인이득이있을것이라고권고하여당뇨병환자의식사요법에서아직까지섭취하는당질의종류보다는양을더욱중요하게인지하고있다 1-3). 최근혈당지수를이용한식사요법이당뇨병환자의혈당조절등에미치는영향을분석한임상연구결과들이새롭게발표되고있지만우리나라에서는이분야에대한연구결과를찾아보기가아직어렵다. 여기 261

2 에서는이러한내용들을요약하여당질섭취가많은우리나라의식단을고려할때혈당지수의중요성을되새겨볼수있는계기가되었으면한다. 혈당지수와혈당부하식사후의혈당반응은음식의양뿐아니라식품의종류에따라서다르게나타난다. 즉포도당으로소화되어흡수되는속도가느린식품은섭취후에혈당증가반응이느리고, 소화흡수가빠른식품을섭취한후에는혈당이급격하게증가하므로인슐린의분비도더증가시킨다. 이런다양한당질의소화흡수의속도를반영하는것이혈당지수이다. 1981년 Jenkins 등은각각 50 g의당질을함유한표준식품 ( 포도당또는흰빵 ) 섭취후의혈당반응에대한특정식품 섭취후의혈당반응정도를비교하여특정식품에포함된당질의질적인측면을나타내는혈당지수를고안하였다 4). 혈당지수는각각의식품을섭취한후의혈당반응곡선아래면적 (Area under the curve, AUC) 의비로구하며, 표준식품을 100으로한다. 혈당지수가 55 이하일때저혈당지수, 56~69이면중혈당지수, 70 이상이면고혈당지수식품으로구분된다. 밀, 귀리, 보리, 콩등의곡류가저혈당지수식품의대표적인보기이고, 흰빵과흰쌀 (short grain rice) 등은고혈당지수식품의대표적인보기이다 (Table 1) 5). 당질의흡수속도에더하여당질의양을고려하여섭취후의혈당반응을예측하는값이혈당부하지수이다. 혈당부하지수는해당식품의혈당지수와일회섭취분량에포함된당질의양을곱한값을 100으로나누어구한다. 저혈당부하지수는 10 이하, 중혈당부하지수는 11~19, 고혈당부하지수 Table 1. The average glycemic index of common foods High-carbohydrate Fruit and fruit Breakfast cereals foods products White wheat bread * 75 ± 2 Cornflakes 81 ± 6 Apple, raw Whole wheat/whole 74 ± 2 Wheat flake biscuits 69 ± 2 Orange, raw meal bread Porridge, rolled oats 55 ± 2 Banana, raw Specialty grain bread 53 ± 2 Instant oat porridge 79 ± 3 Pineapple, raw Unleavened wheat 70 ± 5 Rice porridge/congee 78 ± 9 Mango, raw bread Millet porridge 67 ± 5 Watermelon, raw Wheat roti 62 ± 3 Muesli 57 ± 2 Dates, raw Chapatti 52 ± 4 Peaches, canned Corn tortilla 46 ± 4 Strawberry jam/jelly White rice, boiled * 73 ± 4 Apple juice Brown rice, boiled 68 ± 4 Orange juice Barley 28 ± 2 Sweet corn 52 ± 5 Spaghetti, white 49 ± 2 Spaghetti, whole meal 48 ± 5 Rice noodles 53 ± 7 Udon noodles 55 ± 7 Couscous 65 ± 4 Dairy products and alternatives Milk, full fat Milk, skim Ice cream Yogurt, fruit Soy milk Rice milk 39 ± 3 37 ± 4 51 ± 3 41 ± 2 34 ± 4 86 ± 7 36 ± 2 43 ± 3 51 ± 3 59 ± 8 51 ± 5 76 ± 4 42 ± 4 43 ± 5 49 ± 3 41 ± 2 50 ± 2 Vegetables Potato, boiled Potato, instant mash Potato, french fries Carrots, boiled Sweet potato, boiled Pumpkin, boiled Plantain/green banana Taro, boiled Vegetable soup Legumes Snack products Sugars Chickpeas Kidney beans Lentils Soya beans 28 ± 9 24 ± 4 32 ± 5 16 ± 1 Chocolate Popcorn Potato crisps Soft drink/soda Rice crackers/crisps 40 ± 3 65 ± 5 56 ± 3 59 ± 3 87 ± 2 Fructose Sucrose Glucose Honey 78 ± 4 87 ± 3 63 ± 5 39 ± 4 63 ± 6 64 ± 7 55 ± 6 53 ± 2 48 ± 5 15± 4 65± ± 3 61± 3 Data are means ± SEM. * Low-GI varieties were also identified. Average of all available data (Adapted from reference 5). 262

3 김인주 : 혈당지수의재조명 는 20 이상으로구분된다. 혈당지수의의의혈당지수가높은음식을섭취하였을때나타나는혈당반응은섭취 2시간이내에혈당반응곡선의높은정점을보이고곡선아래의면적도넓다. 그리고인슐린의분비반응도더높게나타나기때문에식후 2시간이지나면혈당이식전보다더떨어질수있어오히려저혈당의위험이증가될수있다. 이에비하여혈당지수가낮은식품을섭취한후에는혈당의정점치도낮아지고, 혈당반응곡선아래의면적도더적으며인슐린분비반응도더낮으므로저혈당의위험도상대적으로감소하게된다 (Fig. 1) 6). 혈당지수에영향을미치는요인 다. 젤라틴화되어팽창한전분은빨리소화되어혈당을급속하게증가시키므로혈당지수를상승시킨다. 식품에함유된아밀로오스 (amylose) 와아밀로펙틴 (amylopectin) 의비율도중요하다. 아밀로펙틴은분지 (branching point) 를많이가지는형태로더쉽게젤라틴화되므로빨리소화된다. 그러므로아밀로오스 / 아밀로펙틴의비율이높을수록더천천히소화되고혈당지수도더낮다. 섬유소의경우에도점성이낮아야전분과소화효소의작용을둔화시켜당질의소화와흡수를지연하여혈당지수를낮추는효과를나타낸다. 곡류의도정정도도혈당지수에영향을미친다. 도정되지않은곡류의외층 ( 겨, bran) 은소화효소에대한방어역할을하므로도정을많이할수록소화흡수속도가빨라지고혈당지수도높아진다 7). 혈당지수와당뇨병 식품별혈당지수를결정하는요인으로가장중요한것은식품에포함된당질의소화흡수속도라고할수있다. 이전에는복합당질즉전분은그화학적성질때문에느리게분해되고단당류와이당류는빠르게분해되어흡수되는당질이라고단순하게생각하였으나위배출시간, 인슐린의반응을비롯한매우다양한요인들이섭취후혈당반응에영향을미친다. 혈당지수에영향을미치는대표적인요인들로는섭취하는식품의형태, 식품입자의크기, 식품의가공및요리과정, 식품에함유된전분의특징, 섬유소의함량과특성, 단백질과지질의함량등이잘알려졌다. 이중전분의물리적형태가혈당지수를결정하는가장중요한요인으로알려졌 당뇨병은인슐린의부족이나작용이상에의해초래되는대사질환으로고혈당을특징적으로나타낸다. 당질은인슐린의분비와식후혈당을결정하는가장중요한영양소이다. 당질의섭취량뿐만아니라종류도식후인슐린분비와식후혈당에크게영향을미친다. 혈당지수가높은음식을섭취하면식후혈당, 혈중유리지방산, 인슐린등이증가되고인슐린저항성이유발될수있으며, 혈당지수가낮은음식은혈당의변동을최소화하고, 일중인슐린의분비량도감소시켜인슐린감수성을개선할수있다고알려졌다 8-10). 혈당지수를고려하는식사요법이당뇨병의예방, 치료및합병증관리에도움이될것이라는관심이지속되어왔고, 최근주목할만한결과들이많이소개되었다. Fig. 1. Glycemic and insulinemic responses after ingestion of carbohydrates (Adapted from reference 6). 263

4 1. 혈당지수와당뇨병예방혈당부하의증가는여러기전을통해당뇨병의발병을증가시킬것으로생각된다 (Fig. 2). 그러므로저혈당지수및저혈당부하지수의음식을섭취하는것은당뇨병의위험을감소시킬것으로기대된다. 심혈관질환암, 및당뇨병이없는 65,173명의성인여성을 6년간관찰하였을때, 915명의새로운당뇨병환자가발견되었는데, 혈당지수의최상위오분위군과최하위오분위군사이에당뇨병발생의비교위험도는 1.37 (95% confidence interval [CI], 1.09~1.71, P trend =.005) 로나타나혈당지수와당뇨병의위험사이에양의상관성을보이는것으로보고되었고 11), 남성에서도유사한결과가관찰되었다 12). 최근발표된 Barclay 등의메타분석에따르면혈당지수와혈당부하지수가가장높은사분위와가장낮은사분위그룹사이에당뇨병발생의비교위험도는각각 1.40 (95% CI, 1.23~1.59) 과 1.27 (95% CI, 1.12~1.45) 로나타났다 13). 또한, 85,509명의미국인여성을 20년간관찰한 Nurses' Health Study의결과에서모두 4,670예의제2형당뇨병이발생하였고, 저당질식이점수가가장높은십분위그룹과가장낮은십분위그룹사이에당뇨병발생의다중비교위험도는총당질, 식물성단백질및식물성지질을기준으로했을때 0.82 (95% CI, 0.71~0.94, P for trend = 0.001) 이었고, 혈당부하지수가가장높은십분위그룹의당뇨병발생의비교위험도는 2.47 (95% CI, 1.75~3.47, P for trend < ) 이었으며, 당질의섭취량에따라당뇨병의발생이증가되어가장높은십분위그룹의비교위험도가 1.26 (95% CI, 1.07~1.49, P for trend = 0.003) 으로보고되었다 14). 이러한연구들을종합해보면혈당지수가높은음식을계속섭취하는것은당뇨병의발생위험을증가시키며, 혈당지수와혈당부하지수가낮은음식을섭취하면당뇨병의위험을감소시킬수있다는것을시사하는일관적인결론을도출할수있다고생각된다. 하지만임상적인근거를갖춘결론을도출하기위해서는관찰연구보다는전향적인중재연구가수행되어야할것이다. 2. 혈당지수와당뇨병치료당뇨병환자는인슐린분비와작용에장애가있으므로당질섭취에의한식후혈당의증가반응이더두드러지게나타난다. 따라서저혈당지수식사에따른이점이당뇨병환자에서더욱두드러진다 15). 당뇨병환자에서저혈당지수식사가혈당조절에미치는효과에대하여다양한연구결과가보고되었고, 미국당뇨병학회에서는이러한연구결과들에근거하여혈당지수와혈당부하지수를고려한식사요법이당질의섭취량만을계산하는식사요법에비하여중등도의추가적인효과가있다고계속제시해왔다 1-3). 최근에소개된대표적인무작위배정임상연구를살펴보면, Ma 등은조절이불량한제2형당뇨병환자 40명을각각저혈당지수식사군과미국당뇨병학회 (American Diabetes Association, ADA) 식사군에무작위배정하고 12개월동안관찰한결과 HbA1C의감소정도에는양군간에차이가없었으나저혈당지수식사군에서혈당조절을개선하기위해서당뇨병치료제를추가하거나증량시킨경우가저혈당지수식사군에서유의하게적었다고보고하였다 ( 교차비 0.26, P = 0.01) 16). 비록대상환자수가적어서 HbA1C의작은차 Fig. 2. Hypothesis on the potential mechanisms linking a high glycemic load with the development of type 2 diabetes. 264

5 김인주 : 혈당지수의재조명 Table 2. The impact of carbohydrate-rich foods on metabolic and cardiovascular disease risk in nondiabetic persons Low GI Soluble fiber Insoluble fiber Epidemiologic observations Reduced risk of diabetes Reduced risk of CHD Controlled clinical trials Reduced risk of diabetes Reduced risk of CHD Plausible mechanisms Blood glucose regulation CHD risk factor profile ꠏ ꠏ CHD, coronary heart disease; GI, glycemic index., strong evidence;, weak evidence; ꠏ, no evidence (not tested) (Adapted from reference 15). 이를증명하기에는부족하고, 지질강하제의사용에따른영향을고려하지못했고, 당뇨병치료제의변경에대한이유를완전히규명하지못한등의제한점을지닌연구이지만저혈당지수식사가 ADA 식사를대체할만한식사요법으로서가치가있음을제시할연구결과로생각된다. 한편, Jenkins 등은경구혈당강하제로치료중인제2형당뇨병환자 210명을저혈당지수식사군과고곡류섬유식사군으로각각무작위배정하여 6개월간관찰한결과를보고하였다 17). 고혈당지수식사군에서 HbA1C는 7.14% 에서 6.64% 로, 고곡류섬유식사군에서는 7.07% 에서 6.89% 로각각감소하여저혈당지수식사군에서혈당조절의개선효과가더유의한차이를보였다 (P < 0.001). 또, 저혈당지수식사군에서고밀도지단백콜레스테롤 (high density lipoprotein, HDL) 의유의한증가도관찰되었고 (1.7 mg/dl; 95% CI, 0.8~2.6 mg/dl, P = 0.005), 체중도감소하는경향을나타내었다. 이연구에서저혈당지수식사의혈당조절개선효과는이미그효과가잘알려진고식이섬유식사의효과에비하여우월하다는것이입증되어당뇨병환자의치료에서혈당지수및혈당부하지수등당질의질적인면을고려해야할필요성이다시금확인되었다고생각된다. 또한, Thomas 등은저혈당지수식사와고혈당지수식사의효과를 4주 ~12개월동안관찰한무작위배정비교임상연구 11개의연구결과를메타분석하여보고하였다 18). 저혈당지수식사군에서 HbA1C는평균 0.5% 감소하여유의한개선효과를보였고 (95% CI, -0.9~0.1, P = 0.02), 저혈당의발생도유의하게감소하였다. 이러한연구결과들을종합해보면저혈당지수식사는당뇨병환자의치료에서혈당조절의개선효과를일관적으로기대할수있는유용한방법으로생각된다. 아울러저혈당지수식사로얻어지는식후혈당의감소, 인슐린저항성의 개선과이상지혈증의개선및체중감소등은당뇨병의중요한치료목적인심혈관질환의예방에도기여할수있는효과라고생각된다. 결론저혈당지수식사는당뇨병에서혈당조절을개선할뿐만아니라 HDL의증가, triglyceride, Plasminogen Activator Inhibitor 1 (PAI-1) 및 C-reactive protein (CRP) 의감소, 당뇨병의발병감소및심혈관질환의발생을감소시키는효과가있다고알려졌으며, 잘알려진식이섬유의효과와비교한저혈당지수식사의효과는 Table 2와같이요약된다. 그러므로, 당뇨병환자의식사요법에서당질의총섭취량과더불어혈당지수의개념을반영하여어떤당질을어떻게섭취할것인가하는내용이반드시고려되어야할것이다. 특히, 당질식품이주식이며, 선호되는당질식품과요리과정등이서구와는다른우리나라의실정을제대로반영한혈당지수의연구개발과적용에대한관심과노력의필요성이재고되어야할것이다. 참고문헌 1. American Diabetes Association: Standards of medical care in diabetes Diabetes Care 30(suppl 1):S4-41, American Diabetes Association: Nutrition recommendations and interventions for diabetes. Diabetes Care 31(suppl 1):S61-78, American Diabetes Association: Standards of medical care in diabetes Diabetes Care 32(suppl 1): 265

6 S13-61, Jenkins DJ, Wolever TM, Taylor RH, Barker H, Fielden H, Baldwin JM, Bowling AC, Newman HC, Jenkins AL, Goff DV: Glycemic index of foods: a physiological basis for carbohydrate exchange. Am J Clin Nutr 34:362-6, Atkinson FS, Foster-Powell K, Brand-Miller JC: International Tables of Glycemic Index and Glycemic Load Values: Diabetes Care 31:2281-3, Granfeldt Y, Bjorck I, Hagander B: On the importance of processing conditions, product thickness and egg addition for the glycaemic and hormonal responses to pasta: a comparison with bread made from pasta ingredients. Eur J Clin Nutr 45:489-99, Bjorck I, Granfeldt Y, Lilijeberg H, Tovar J, Asp NG: Food properties affecting the digestion and absorption of carbohydrates. Am J Clin Nutr 59: , Crapo PA, ReavenG, Olefsky J: Postprandial plasma -glucose and -insulin responses to different complex carbohydrates. Diabetes 26: , Wolever TM: Dietary carbohydrates and insulin action in humans. Br J Nutr 83(suppl 1):S97-102, Livesey G, Taylor R, Hulshof T, Howlett J: Glycemic response and health a systematic review and meta -analysis: relations between dietary glycemic properties and health outcomes. Am J Clin Nutr 87:258S-68S, Salmerón J, Manson JE, Stampfer MJ, Colditz GA, Wing AL, Willett WC: Dietary fiber, glycemic load, and risk of non-insulin-dependent diabetes mellitus in women. JAMA 277:472-7, Salmeron J, Ascherio A, Rimm EB, Colditz G, Spiegelman D, Jenkins DJ, Stampfer MJ, Wing AL, Willett WC: Dietary Fiber, Glycemic Load, and Risk of NIDDM in Men. Diabetes Care 20:545-50, Barclay AW, Petocz P, McMillan-Price J, Flood VM, Prvan T, Mitchell P, Brand-Miller JC: Glycemic index, glycemic load, and chronic disease risk a meta-analysis of observational studies. Am J Clin Nutr 87:627-37, Halton TL, Liu S, Manson JE, Hu FB: Low-carbohydrate -diet and risk of type 2 diabetes in women. Am J Clin Nutr 87:339-46, Riccardi G, Rivellese AA, Giacco R: Role of glycemic index and glycemic load in the healthy state, in prediabetes, and in diabetes. Am J Clin Nutr 87(suppl 1):S269-74, Ma Y, Oldendzki BC, Merriam PA, Chiriboga DE, Culver AL, Li W, Hebert JR, Ockene IS, Griffith JA, Pagoto SL: A randomized clinical trial comparing low glycemic index versus ADA dietary education among individuals with type 2 diabetes. Nutrition 24:45-56, Jenkins DJ, Kendall CW, McKeown-Eyssen G, Josse RG, Silverberg J, Booth GL, Vidgen E, Josse AR, Nguyen TH, Corrigan S, Banach MS, Ares S, Mitchell S, Emam A, Augustin LS, Parker TL, Leiter LA: Effect of a low-glycemic index or a high-cereal fiber diet on type 2 diabetes: a randomized trial. JAMA 300: , Thomas D, Elliott EJ: Low glycaemic index, or low glycaemic load, diets for diabetes mellitus. Cochrane Database of Syst Rev. 21:CD006296,

5-7.indd

5-7.indd http://dx.doi.org/10.4093/jkd.2012.13.1.33 식후고혈당의식사요법 건국대학교병원영양팀유정아 Diet Therapy for Postprandial Hyperglycemia in Patients with Diabetes Jeong-a Yoo Nutrition Care Service Team, KunKuk University Hospital,