starchy foods and glycemic index - diabetes care

Starchy Foods andGlycemic Index

David J.A. Jenkins, MD, PhDThomas M.S. Wolever, MD,

PhDAlexandra L. Jenkins, RD

Different starchy foods produce different glycemicresponses when fed individually, and there is someevidence that this also applies in the context of themixed meal. A major reason appears to relate to therate at which the foods are digested and the factorsinfluencing this. A similar ranking in terms of glycemicresponse to specific foods is seen independent of thecarbohydrate tolerance status of the groups tested.Potentially clinically useful starchy foods producingrelatively flat glycemic responses have been identified.Many of these are considered ethnic or traditional andinclude legumes; pasta; grains such as barley, parboiledrice, and bulgur (cracked wheat); and whole-grainbreads such as pumpernickel. Specific incorporationof these foods into diets has been associated withreductions in low-density lipoprotein cholesterol andtriglyceride levels in hyperlipidemia and with improvedblood glucose control in insulin-dependent diabeticpatients. To facilitate identification of such foods, it hasbeen suggested that the glycemic response should beindexed to a standard (e.g., white bread) to allowcomparisons to be made between the glycemic index offoods tested in different groups of subjects. The scopeof application of this principle is subject to furtherinvestigation. It may be used to expand the range ofpossibly useful starchy foods for trial in the diets ofdiabetic patients. Diabetes Care 11:149-59, 1988

Different carbohydrate foods produce differentglycemic responses despite an apparent lackof difference in macronutrient composition(1,2). The classification of carbohydrate foods

was first put on a systematic basis by Otto and col-leagues (3,4), who, after testing foods, allowed carbo-hydrate incorporation into the diabetic diet in propor-tion to the glycemic response they produced. In this way

the glycemic impact of the diet could be kept constantregardless of the variety of carbohydrate foods used (3,4).

Later studies by Crapo and colleagues (5-8) focusedon the differences between starchy foods of similar mac-ronutrient composition. Differences in both glucose andinsulin responses were observed, and it was postulatedthat possible differences in rates of digestion of the foodswere responsible. These differences in rates of digestionof starchy foods were subsequently confirmed (Fig. 1)and related to the glycemic responses observed in bothnormal and diabetic individuals (9,10).

From the beginning of the 1980s, many tests of singlefoods (11-28) and mixed meals (24,29-35) have beenundertaken in both normal and diabetic subjects. How-ever, because of a lack of standardization of methodsof data presentation, the results of different studies werenot always directly comparable. In 1981, the conceptof the glycemic index (Gl) was proposed as a methodof assessing and classifying the glycemic response tocarbohydrate foods (11). It was hoped that this wouldallow foods to be compared more readily. It would alsoallow the experience of different investigators to bepooled by indexing the foods tested to a common stan-dard. Initially, glucose was used, but this proved to beless acceptable for routine use than white bread of knowncomposition. The Gl was therefore defined as

incremental blood glucose area after food

corresponding area after equicarbohydrate portion of white breadx 100

From the Department of Nutritional Sciences, Faculty of Medicine, and theDivision of Endocrinology and Metabolism, St. Michael's Hospital, Universityof Toronto, Toronto, Ontario, Canada.

Address correspondence and reprint requests to David J. A. Jenkins, Depart-ment of Nutritional Sciences, Faculty of Medicine, University of Toronto, To-ronto, Ontario M5S 1A8, Canada.

DIABETES CARE, VOL. 11, NO. 2, FEBRUARY 1988 149

GLYCEMIC INDEX

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1 2 3 4Time (hours)

FIG. 1. Increase in concentration over 5h of products of starch digestion, mea-sured as glucose after acid hydrolysis,subsequent to incubation of 2 g availablecarbohydrate portions of foods withpooled human saliva and pancreaticjuice.

By applying this approach to data from different groupsof subjects and different centers (12), it has been pos-sible to begin to classify a substantial number of foodsin terms of their glycemic responses (Table 1).

Foods that have been shown to have low glycemicresponses include whole-grain (as opposed to wholemeal) cereals (15), pasta (17,36), and legumes (13,21,37).It was suggested that inclusion of such foods in the dietsof patients with diabetes might aid dietary managementby improving diabetes control.

OBJECTIONS TO GLYCEMIC INDEX

Objections to the Gl concept were raised early (38) andhave not been resolved (34,39). These objections haveresulted in a statement from the recent NIH consensusconference on diet and exercise in non-insulin-depen-dent diabetes (NIDDM) that recommended against theuse of Gl in the dietary management of diabetes (40).The concern revolves around 3 major issues: 7) largeindividual variation in responses, 2) lack of agreementamong different centers, and 3) lack of difference be-tween mixed meals. In addition, it has been pointed outthat there are no studies showing long-term benefits oflow-GI foods (38,40). For these reasons it has beenmaintained that the Gl has no clinical utility (34,38-40).Individual variation in glycemic responses. There arelarge differences among individuals with respect to theabsolute level of blood glucose achieved after meals.Factors that have been suggested to influence this in-clude the presence and type of diabetes (38,41,42), age,sex, body weight, and race (40). It has therefore beenstated that glycemic responses to foods should be testedin the specific group for which recommendations are

made (38). However, when considering the relative gly-cemic effects of different foods, i.e., the glycemic index,there is in fact some evidence for agreement amongdifferent groups (Table 1).

Early studies with four starchy foods (bread, potato,rice, and corn) demonstrated the same order of rankingof the glycemic and insulin responses when these foodswere tested in nondiabetic compared with diabetic vol-unteers (6,8). Since then, several studies have shownsimilarities in the ranking of responses to a wide rangeof foods tested in nondiabetic, NIDDM (13), and insu-lin-dependent diabetic (IDDM; 15-1 7) subjects. On theother hand, many studies do not agree (Table 1).

More recently, it has been maintained that consider-ation of average glycemic responses is inadequate be-cause they may conceal large differences in response indifferent individuals (39). This objection would be ofmajor clinical importance if the variability in responsebetween patients was such that certain individuals con-sistently failed to show the expected differences in gly-cemic responses between foods. The prescription of adiet containing foods of lower Gl would certainly notresult in lower postprandial blood glucose responsesthroughout the day. Unless these individuals could bereadily identified, the clinical application of Gl datawould indeed be limited and inappropriate if the num-ber of patients who failed to show a consistent responsewas large. In view of the substantial coefficient of vari-ation often seen in the GI to single foods, this negativeoutcome is a real possibility.

We have therefore examined the individual data thatformed the basis for recently published papers. In thesestudies several low-GI foods were taken by different di-abetic patients (Table 2; 15,16). Such a range of foodsmight be exchanged for foods of higher Gl in the dietsof diabetic patients. We therefore considered it clinicallyrelevant to determine whether the overall response to

150 DIABETES CARE, VOL. 11, NO. 2, FEBRUARY 1988

D.J.A. JENKINS, T.M.S. WOLEVER, AND A.L JENKINS

TABLE 1Mean glycemic index (Gl) values of foods adjusted proportionately so that Gl of white bread = 100

Food Gl values* Subjectst Mean Gi

BreadsRye

Crispbread 90", 100 C,A 95Whole meal 89 G 89Whole grain, i.e., pumpernickel 58", 78a C,G 68

WheatWhite 100 (defined) A-K,M 100Whole meal 93", 96, 100, 104, 106 C,G,B,A,J 100 ± 2

PastaMacaroni

White, boiled 5 min 64" I 64Spaghetti

Brown, boiled 15 minWhite, boiled 15 minWhite, boiled 5 minProtein enriched

Star pastaWhite, boiled 5 min

Cereal grainsBarley (pearled)BuckwheatBulgurMillet

RiceBrown

Instant, boiled 1 minInstant, boiled 6 minPolished, boiled 5 minPolished, boiled 15 minParboiled, boiled 5 minParboiled, boiled 25 min

Rye kernelsSweet cornWheat kernels

Breakfast cerealsAll BranCornflakesMuesliPorridge oatsPuffed riceShredded wheatWeetabix

CookiesDigestiveOatmealRich teaPlain crackers (water biscuits)

Root vegetablesPotato

InstantMashedNew, boiledRussett, bakedSweet

YamLegumes

Baked beans (canned)Bengal gram dalButter beans


61"46", 59", 68", 72C

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601246

GLYCEMIC INDEX

TABLE 1(Continued)

Food Gl Values* Subjectst Mean G

Legumes (Continued)Chick peas 46% 52C B,A 49Green peas

DriedFrozen

Haricot (white) beansKidney beansRed lentilsPeanutsSoy beans

DriedCanned

FruitAppleBananaOrangeOrange juice

SugarsFructoseGlucose

HoneyMaltoseSucrose

Snack foodsCorn chipsPotato chips

Dairy productsIce creamSkim milkWhole milkYogurt

individual mean values from different groups of subjects. For significant difference from white bread (Gl = 100): aP < .05; bP < .01; CP <.001; "significance not given and unable to be calculated.tSubjects (refs.): A, normal English (11); B, predominantly NIDDM Canadian (13); C, diabetic German (4); D, normal American (6); E, NIDDMAmerican (8); F, NIDDM Canadian (14); G, NIDDM and IDDM Canadian (20); H, NIDDM and IDDM Canadian (15); I, NIDDM and IDDMCanadian (16); J, normal rural African (18); K, NIDDM Canadian (19); L, normal Australian (20); M, normal Indian (21); N, normal American(22); O, normal Canadian (23); P, NIDDM Canadian (24); Q, IDDM Canadian (24); R, impaired GTT (7); S, normal Canadian (25).^Significant difference from 100 given where >3 mean values are available.

these foods was consistent for each individual (i.e., for those foods, we believe the Gl concept can be ap-whether for each patient the mean value for the low-GI plied to individual diets composed of many foods,foods was significantly below that of bread, a higher Gl Lack of agreement between different centers. Dis-food). For each subject, the mean Gl of the foods was similarities have been observed between the glycemicsignificantly below that of bread despite the wide vari- responses to certain foods tested in different centers,ation in individual responses to a given food. It cannot notably potato and rice (5-8,11,13). However, closerbe inferred from these data whether certain individuals examination of the foods reveals that the center withconsistently show lesser changes in Gl than others. It is the consistently higher glycemic response to potatoalso not apparent to what extent the differences from fed a 317-g baked russet potato (6,8), whereas the cen-the expected values are due to intraindividual variabil- ter with the consistently lower response fed a 273-g boiledity; i.e., had each individual repeated each test on sev- new potato (11,13). The difference in weight fed, dueeral occasions, the mean would probably more closely to the use of different food tables, accounts for part ofapproximate the expected Gl value (23; unpublished the difference in glycemic response. There may also beobservations). Nevertheless, because each diabetic vol- true but unidentified differences between the more pow-unteer demonstrated a mean Gl value for the foods tested dery russet potato and the glutinous new potato. Ex-that was similar to or below the predicted mean Gl value amination of the types of rice fed indicate that the center


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D.J.A. JENKINS, T.M.S. WOLEVER, AND A.L. JENKINS

with the lower response (5-8) fed parboiled rice, whereasthe higher result was obtained in a center that fed regularrice (11,13). Subsequent testing has demonstrated thatparboiled cereals, whether rice (16) or wheat (15), arenotable in resulting in relatively flat blood glucoseprofiles. Such differences are not simply due to lackof reproducibility but represent true differences inphysiologic effects between foods that previously wereconsidered the same. Other differences have also beenreported with respect to rice. Varieties of long-grain ricemay be higher in amylose starch and consequently givea flatter blood glucose response than the more amylo-pectin-rich short-grain varieties (44).

In addition, the ripeness of fruits will determine theirsugar content, a factor shown to be especially importantin the case of bananas (45). Cooking will enhance thedegree of gelatinization of starch (46) and hence thedegree to which it raises the blood glucose (47). Theseand many other food-related factors determining post-prandial glycemia and insulin response are emerging(48).

Substances such as phytates (49,50) and lectins (51)and indeed the dietary fiber content (52) are all knownto influence glycemic response and are altered by dif-ferent growing conditions (53). Finally, the absoluteamounts fed by different investigators may depend onthe food tables used or whether a direct analysis wasperformed. If so, the method used to determine dietaryfiber content will influence the available carbohydratecontent. To some, the field might appear to be too vari-able to allow meaningful interpretation. An alternativeview would be that much knowledge is being acquiredthat will change our perception of food systems but willallow predictions to be made based on knowledge ofphysiologic responses to foods. A surprising fact is that,despite all these unknowns, there is a broad measure ofagreement on the relative glycemic effect of many car-bohydrate foods tested in different centers (Table 1).Lack of difference between mixed meals. The mosttopical criticism of the Gl concept is that, when indi-vidual carbohydrate foods are taken as part of a mixed

mg/100 ml

300

250

200

150

100

50

0

=3

60 120

Time (min)

180

FIG. 2. Mean plasma glucose levels of 8 NIDDM subjectsfed standard test meals containing baked potato ( •—•) ,rice ( •—•) , spaghetti (O—O), or lentil (O—O) as majorsource of carbohydrate (34).

meal, differences in glycemic responses between thefoods are abolished. Several studies fail to show anydifference in glycemic response to mixed meals(33,34,54,55). With the first study to apply Gl in thissituation (Fig. 2), a major problem in interpretation wasthe use of total rather than incremental areas for com-parison of postprandial responses (56).

The suggestion that clinically there may be no greatadvantage from using the Gl to achieve a modest re-duction in postprandial glycemia when the fasting bloodglucose value is grossly elevated is uncontested. Theprimary concern must be the reduction of the fastingblood glucose level. However, if Gl is to be used torank the postprandial glucose responses to differentmeals, then the method of assessment would seem im-portant. The fasting blood glucose is not influenced bythe subsequent meal. However, if the total blood glu-cose area is chosen, a large variation in starting valuecould obscure differences between meal responses whenexpressed as absolute postprandial levels. The Gl clas-sification has therefore been based on incrementalresponses. Similar treatment should be given if Gl is tobe used to predict the mixed-meal response.

In addition, if absolute values are used to calculate

TABLE 2Variability of individual glycemic indexes (Gl) for 6 low-GI cereal foods compared with white bread testedin 8 diabetic patients

Food

BreadBulgurPumpernickelParboiled riceBarleyWheat kernelsRye kernelsMean ± SESignificance

vs. bread (P)

Gl

100657867316347

58.5 ± 6.8

<.01

1

100496952283631

44.2 ± 6.3

<.001

NIDDM patients

2

100557077314841

53.7 ± 7.1

<.OO5

3

100387957294727

46.2 ± 8.0

<.005

4

100709873165743

59.5 ±11.4

<.02

5

100825557489351

64.3 ± 7.6

<.01

IDDM patients

6

100637059305759

56.3 ± 5.6

<.001

7

100317664

74633

42.8 ± 10.1

<.005

8

100629049318176

64.8 ± 9.0

<.01

Mean ±

100.0 i56.0 i75.9 i61.0 i27.5 i58.2 i45.1 i53.9 i

<.001

SE

05.94.73.54.26.85.85.8


GLYCEMIC INDEX

Gl, then the higher the fasting blood glucose value, thesmaller the contribution of the postprandial response tototal glycemia. This can be demonstrated by analyzingdata from a different study. Figure 3 illustrates both theabsolute (top) and incremental {bottom) glycemic re-sponses of 15 NIDDM subjects who ate meals of bread,rice, spaghetti, and barley to which the same amountof fat and protein as cheddar cheese had been added(57). The incremental areas for rice, spaghetti, and bar-ley were 23, 44, and 59% less, respectively, than thatfor bread, whereas the total areas for these meals wereonly 2, 19, and 25% less than that of bread. Thesereduced figures further diminished the chance of a re-lationship between the Gl for single foods and mixedmeals (39). Furthermore, we consider it important thatthe foods tested in a mixed meal should also have beentested singly before conclusions are drawn relating to

300

200

0)

o

Oo

100

0

200

100

0 1 2 3Time (hours)

FIG. 3. Mean blood glucose concentrations {top) and bloodglucose increments {bottom) of 15 NIDDM subjects fedtest meals containing 50 g carbohydrate from white bread(A), polished rice (O), spaghetti (•), or pearled barley (O).To each food, 32 g cheddar cheese and 100 g cooked to-mato were added (57).

the validity of applying the Gl in this situation. Wherethis has been done, a degree of predictability has beenfound (Fig. 4; 58).

There are at least five other published studies thathave examined the effects of mixed meals (32,33,35,59,60). Only two of these are generally quoted (39).In one, it was concluded that the glycemic responses tothe meals "were similar except for one meal" (33). Thedifferent meal (meal B) had a significantly greater gly-cemic response than two of the other meals (meals Aand C), as predicted by the Gl of meal B, and was 21and 27 Gl units greater than meals A and C (23). Inaddition, although Bantleetal. (32) concluded that fruc-tose-containing meals were not always lower than thosecontaining other carbohydrates, they were able to dem-onstrate a significant difference in NIDDM subjects (whoare less variable than IDDM subjects) (23). In a laterstudy by this group, small but significant differences be-tween meals of differing predicted glycemic effect werefound in normal subjects, but they were not seen inNIDDM subjects (54).

Three less-known studies show good predictive abilitywith Gl. Parillo et al. (59) found the expected differencebetween bread and spaghetti when incorporated into amixed meal (Fig. 5). Slama et al. (60,61) also found thatblood glucose and insulin responses for different foodsin a mixed meal ranked as expected. Finally, Collier etal. (35) fed five different mixed meals to NIDDM sub-jects (Fig. 6). These resulted in a range of differences ofalmost 100 mg/dl in postprandial blood glucose levels.The close correlation between the expected Gl of themeals and the observed glycemic responses was prob-ably a reflection of the fact that the foods fed had beentested previously and were known to have glycemic re-sponses equivalent to their published Gl values (Fig. 7).Therefore, before concluding that differences in gly-cemic response to individual foods are lost when theyare combined in a mixed meal, it appears important topretest the individual carbohydrate components of themixed meal.

EFFECTS OF DIETARY CHANGE

Only two studies have been published of the effect ofincorporating carbohydrate foods that cause relativelylow rises in blood glucose into the diet. In one, diabeticchildren reduced the glycemic impact of their diets for6 wk by eating carbohydrate foods known to raise bloodglucose minimally instead of more conventional car-bohydrate foods (67). This change resulted in improvedglucose tolerance and a fall in serum cholesterol after astandard meal. Although no significant fall was seen inHbA1c levels, there was a significant fall in glycosylatedalbumin, probably due to the much shorter half-life ofthis protein, which makes it a more suitable marker forrelatively short dietary studies (63). In the second studythe same dietary maneuver was undertaken by a groupof hypertriglyceridemic, predominately glucose-intol-



FIG. 4. Mean plasma glucose and insu-lin levels of NIDDM subjects fed test mealscontaining white beans processed in 2different ways: O, A, damaged cell walls;• , undamaged cell walls. Left panel, re-sponses to bean products fed alone. Rightpanel, responses when bean productswere consumed as part of mixed meal(58). *P < .05, **P < .01.

350

300

250

200

0

60

50

40

30

20

II 200

PLASMA INSULIN

30 60 120

TIME Imin)

180

erant individuals over 1-mo periods (14). This dietaryexchange was accompanied by falls in serum triglyc-eride and total and low-density lipoprotein cholesterollevels. In these studies, there were small to modest in-creases in dietary fiber, which seemed unlikely to pro-vide the whole explanation.

A Blood glucose(mmol/l)

• ' L.

0 30 60 90 120 150 180 210 240 270 300

Time (min)

FIG. 5. Mean ± SE blood glucose increments of 7 diabeticsubjects fed mixed meals containing white bread (O), newpotato (•), or spaghetti (•) as major carbohydrate source(59). *P < .05, **P < .025, ***P < .01 vs. spaghetti.

The conclusion is supported by some of the most suc-cessful dietary studies to show improvement in glucosecontrol in diabetic patients (64-69) or reductions in bloodlipids in hyperlipidemic individuals (66,70). Althoughthe thrust of such studies was to increase fiber intake, itwas achieved with foods with a lesser impact on bloodglucose than many of the foods they displaced. Dietary-fiber studies where this has not been the case have re-

Q

CD300

GOCD 200

(JD

CDCD—JPQ

100

0 1 2 3

TIME (HOURS)

FIG. 6. Mean blood glucose responses of 6 NIDDM sub-jects fed mixed meals containing instant potato (•), whitebread (A), polished rice (Q), white spaghetti (D), or mix-ture of red lentils and barley (O) as major carbohydratesource. Values that differ by >37 mg/dl are significantlydifferent. P < .05 (35).

DIABETES CARE, VOL. 11 , NO. 2, FEBRUARY 1988 155

GLYCEMIC INDEX

1OOO

UJ

UJ 500CO©

C5

20 40 60 80 100MEAL G.I.

FIG. 7. Correlation between mean incremental blood glu-cose response areas for meals illustrated in Fig. 6 withexpected meal glycemic index. P < .01, r = .9875.

suited in much lesser benefits (71-75), and the benefitsseen in lipid and carbohydrate metabolism may havebeen largely attributable to the accompanying reductionin the proportion of fat in the diet.

UNANSWERED QUESTIONS

The major question that still remains is: what clinicalgains can be expected through tighter control of post-prandial glycemic excursions? This can be resolved bydietary trials where low-GI foods are fed. However, ifthese trials are to be undertaken with the necessary de-gree of compliance, then an expanded list of classifiedfoods is required.

Gl studies have drawn attention to the agreement anddisagreement between investigators in terms of the bloodglucose responses observed after both single foods andmixed meals. The similarities provide hope that a systemof classification, if comprehensive, may be feasible, usefulas an adjunct to food tables in designing therapeuticdiets, and a stimulus to studies of mechanism. The dis-agreements indicate there is much more to learn in termsof processing and the effect of food components andfood form on physiological processes (e.g., digestion,transit time, endocrine responses) before the most effec-tive use can be made of the knowledge.

The Gl approach to classification has also highlightedthe urgent need for uniform food tables giving true avail-able or absorbable carbohydrate (starch and sugars) anddietary fiber separately so that known amounts of car-bohydrate are fed. Different portion sizes are used bydifferent investigators, and differences in results maysimply be due to the amounts of food fed.

APPLICATION OF GLYCEMIC INDEX

Strict application of Gl exchange principles is only pos-sible in a research setting, where the Gl of diets may becalculated (23,56). After standard dietary advice, thecontrol or "normal" diet for most diabetic and hyper-lipidemic patients has a Gl of 85-90 (14,63,76) (whitebread = 100). This may be reduced by a mean 11-13(14,62). These changes are not large numerically butrequire a considerable change in the nature of the car-bohydrate foods eaten (Fig. 8). Thus, lower-GI foodssuch as pumpernickel bread will be increased from vir-tually nonexistent levels, and regular wheat breads willbe substantially reduced (Fig. 8). Nevertheless, for thosenot in a research setting, it may be possible to make use

20

0

40

20

20

RYEBREAD

OATBRAN BULGUR BEANS BARLEY SPAGHETTI

POTATO RICEBREAKFAST

CEREALS

FRUIT

BAKEDGOODS SUCROSE

FIG. 8. Intakes of different carbohydrate foods expressedas proportion of total dietary carbohydrate. Open bars,control; solid bars, periods of low glycemic index (Gl).Upper panel, foods that increased during low Gl; middlepanel, foods that decreased during low Gl; lower panel,foods that remained unchanged during low Gl.

156 DIABETES CARE, VOL. 11 , NO. 2, FEBRUARY 1988


of Gl data by selecting foods to incorporate into patients'diets that have the desired nutritional profile, complyingwith current guidelines, and yet have a lower glycemicimpact. Many of these are traditional or ethnic foods,e.g., pasta, lentils, beans, parboiled rice, barley, bulgur,and pumpernickel bread, which, rather than constrict-ing the patients' eating habits, may in effect introducethe patients to new foods.

Current recommendations by several agencies con-cerned with health (including heart foundations andcancer institutes in addition to diabetes associations)support the increased use of carbohydrate foods. Overthe last decade, the overall aim has been to reduce con-sumption of saturated fat, which is implicated in raisingserum cholesterol levels, and total dietary fat, which isassociated epidemiologically with colon and breast tu-mors. It has not been suggested that the increased car-bohydrate that replaces fat should come from sugars.Nevertheless sugar may not raise the blood glucosemore than many starchy foods (32), and fructose sub-stitution actually results in significantly flatter postpran-dial glucose responses (77). Therefore, modest amountsof sugars may be used as sweeteners. However, theiruse as a source of calories is still a matter of debate.There is concern that in susceptible individuals, fructosemay raise serum triglyceride levels (78,79). Further-more, when sucrose replaces starch in diets higher insaturated fats or very high in carbohydrate, it may in-crease the levels of both cholesterol and triglyceride(80,81). Thus, despite the fact that high fat or fructose-containing foods may cause relatively flat blood glucoseresponses, they cannot be recommended solely on thebasis of their lower acute glycemic response. The Glclassification may therefore be most appropriately usedto rank starchy foods. These starchy foods would alreadyhave been chosen for possible inclusion in the diet onthe basis of their nutritional attributes. In this setting theGl would allow selection of foods that have the addedadvantage of producing lower postprandial glycemic ex-cursions.

ACKNOWLEDGMENTS

These studies were supported by the National Sci-ences and Engineering Research Council, Canada.

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2. Conn JW, Newburgh LH: The glycemic response to iso-glucogenic quantities of protein and carbohydrate. / ClinInvest 15:665-71, 1936

3. Otto H, Bleyer G, Pennartz M, Sabin G, Schauberger G,Spaethe K: Kohlenhydrataustausch nach biologischenaquivalenten. In Diatetik bei Diabetes Mellitus. Otto H,Spaethe R, Eds. Bern, Huber, 1973, p. 41-50

4. Otto H, Niklas L: Differences d'action sur la glycemied'aliments contenant des hydrates de carbone: conse-quences pour le traitment dietetique du diabete sucre.Med Hyg 38:3424-29, 1980

5. Crapo PA, Reaven G, Olefsky J: Plasma glucose and in-sulin responses to orally administered simple and com-plex carbohydrates. Diabetes 25:741-47, 1976

6. Crapo PA, Reaven G, Olefsky J: Postprandial plasma-glu-cose and -insulin responses to different complex carbo-hydrates. Diabetes 26:1178-83, 1977

7. Crapo PA, Kolterman OG, Waldeck N, Reaven GM, Olef-sky JM: Postprandial hormonal responses to different typesof complex carbohydrate in individuals with impairedglucose tolerance. Am ) Clin Nutr 33:1723-28, 1980

8. Crapo PA, Insel J, Sperling M, Kolterman OG: Compari-son of serum glucose, insulin, and glucagon responses todifferent types of complex carbohydrate in non-insulin-dependent diabetic patients. Am J Clin Nutr 34:184-90,1981

9. Jenkins DJA, Ghafari H, WoleverTMS, Taylor RH, BarkerHM, Fielden H, Jenkins AL, Bowling AC: Relationshipbetween the rate of digestion of foods and post-prandialglycemia. Diabetologia 22:450-55, 1982

10. Jenkins DJA, Wolever TMS, Thome MJ, Jenkins AL, WongGS, Josse RG, Csima A: The relationship between gly-cemic response, digestibility, and factors influencing thedietary habits of diabetics. Am I Clin Nutr 40:1175-91,1984

11. Jenkins DJA, Wolever TMS, Taylor RH, Barker HM, Fiel-den H, Baldwin JM, Bowling AC, Newman HC, JenkinsAL, Goff DV: Glycemic index of foods: a physiologicalbasis for carbohydrate exchange. Am) Clin Nutr 34:362-66, 1981

12. Jenkins DJA, Wolever TMS, Jenkins AL, Josse RG, WongGS: The glycemic response to carbohydrate foods. Lancet2:388-91, 1984

13. Jenkins DJA, Wolever TMS, Jenkins AL, Thome MJ, LeeR, Kalmusky J, Reichert R, Wong GS: The glycemic indexof foods tested in diabetic patients: a new basis for car-bohydrate exchange favouring the use of legumes. Dia-betologia 24:257-64, 1983

14. Jenkins DJA, WoleverTMS, Kalmusky J, Giudici S, Gior-dano C, Wong GS, Bird JH, Patten R, Hall M, BuckleyGC, Little JA: Low glycemic index foods in the man-agement of hyperlipidemia. Am J Clin Nutr 42:604-17,1985

15. Jenkins DJA, Wolever TMS, Jenkins AL, Giordano C, Giu-dici S, Thompson LU, Kalmusky J, Josse RG, Wong GS:Low glycemic response to traditionally processed wheatand rye products: bulgur and pumpernickel bread. Am IClin Nutr 43:516-20, 1986

16. Wolever TMS, Jenkins DJA, Kalmusky J, Jenkins AL, Gior-dano C, Giudici S, Josse RG, Wong GS: Comparison ofregular and parboiled rices: explanation of discrepanciesbetween reported glycemic responses to rice. Nutr Res6:349-57, 1986

17. Wolever TMS, Jenkins DJA, Kalmusky J, Giordano C, Giu-dici S, Jenkins AL, Thompson LU, Wong GS, Josse RG:Glycemic response to pasta: effect of food form, cookingand protein enrichment. Diabetes Care 9:401-404, 1986

18. Walker ARP, Walker BR: Glycemic index of South Africanfoods determined in rural blacks—a population at lowrisk to diabetes. Hum Nutr Clin Nutr 36:215-22, 1984

19. Wolever TMS, Wong GS, Kenshole A, Josse RG, Thomp-son LU, Lam KY, Jenkins DJA: Lactose in the diabetic diet:


GLYCEMIC INDEX

a comparison with other carbohydrates. Nutr Res 5:1335-45, 1985

20. Brand JC, Nicholson PL, Thorburn AW, Truswell AL: Foodprocessing and the glycemic index. Am J Clin Nutr42:1192-96, 1985

21. Dilawari JB, Kamath PS, Batta RP, Mukewar S, RaghavanS: Reduction of postprandial plasma glucose by bengalgram dal (Cicer arietnum) and rajmah (Phaseolus vul-garis). Am j Clin Nutr 34:2450-53, 1981

22. Potter JG, Coffman KP, Reid RL, Drall JM, Albrink MJ:Effect of test meals of varying dietary fiber content onplasma insulin and glucose response. Am j Clin Nutr34:328-34, 1981

23. Wolever TMS, Nuttall FQ, Lee R, Wong GS, Josse RG,Csima A, Jenkins DJA: Prediction of the relative bloodglucose response of mixed meals using the white breadglycemic index. Diabetes Care 8:418-28, 1985

24. Jenkins DJA, Wolever TMS, Wong GS, Kenshole A, JosseRG, Thompson LU, Lam KY: Glycemic responses to foods:possible differences between insulin-dependent and non-insulin-dependent diabetics. Am ) Clin Nutr 40:971-81,1984

25. Wolever TMS, Cohen Z, Thompson LU, Thorne MJ, Jen-kins MJA, Prokipchuk EJ, Jenkins DJA: Heal loss of avail-able carbohydrate in man: comparison of a breath hydro-gen method with direct measurement using a humanileostomy model. Am / Gastroenterol 81:115-22, 1986

26. Vaaler S, Hanssen KF, Aagenaes O: Plasma glucose andinsulin responses to orally administered carbohydrate-richfoodstuffs. Nutr Metab 24:168-75, 1980

27. Vaaler S, Wiseth R, Aagenaes O: Increase in blood glu-cose in insulin-dependent diabetics after intake of variousfruits. Ada Med Scand 212:281-83, 1982

28. Tappy L, Wursch P, Randin JP, Felber JP, Jequier E: Met-abolic effect of pre-cooked instant preparations of beanand potato in normal and in diabetic subjects. Am J ClinNutr 43:30-36, 1986

29. Jenkins DJA, Wolever TMS, Taylor RH, Barker HM, Fiel-den H, Jenkins AL: Effect of guar crispbread with cerealproducts and leguminous seeds on blood glucose con-centrations of diabetics. Br Med I 281:1248-50, 1980

30. Coulston AM, Greenfield MS, Enger F, Tokey T, ReavenGM: Effect of source of dietary carbohydrate on plasmaglucose and insulin responses to test meals in normal sub-jects. Am j Clin Nutr 33:1279-82, 1980

31. Coulston AM, Greenfield MS, Kraemer FB, Tobey TA,Reaven GM: Effect of differences in source of dietary car-bohydrate on plasma glucose and insulin responses tomeals in patients with impaired carbohydrate tolerance.Am I Clin Nutr 34:2716-20, 1981

32. Bantle JP, Laine DC, Castle GW, Thomas JW, HoogwerfBJ, Goetz FC: Postprandial glucose and insulin responsesto meals containing different carbohydrates in normal anddiabetic subjects. N Engl J Med 309:7-12, 1983

33. Nuttall FQ, Mooradian AD, DeMarais R, Parker S: Theglycemic effect of different meals approximately isoca-loric and similar in protein, carbohydrate, and fat contentas calculated using the ADA exchange lists. Diabetes Care6:432-35, 1983

34. Coulston AM, Hollenbeck CB, Liu GC, William RA, Star-ich GH, Mazzaferri EL, Reaven GM: Effect of source ofdietary carbohydrate on plasma glucose, insulin, and gas-tric inhibitory polypeptide responses to test meals in sub-jects with non-insulin-dependent diabetes mellitus. Am )Clin Nutr 40:965-70, 1984

35. Collier GR, Wolever TMS, WongGS, Josse RG: Predictionof glycemic response to mixed meals in non-insulin-de-pendent diabetic subjects. Am j Clin Nutr 44:349-52,1986

36. Jenkins DJA, Wolever TMS, Jenkins AL, Lee R, Wong GS,Josse R: Glycemic response to wheat products: reducedresponse to pasta but no effect of fiber. Diabetes Care6:155-59, 1983

37. Jenkins DJA, Wolever TMS, Taylor RH, Barker H, FieldenH: Exceptionally low blood glucose response to driedbeans: comparison with other carbohydrate foods. Br MedI 2:578-80, 1980

38. Coulston AM, Hollenbeck CB, Reaven GM: Utility ofstudies measuring glucose and insulin responses to var-ious carbohydrate-containing foods. Am } Clin Nutr 39:163-65, 1984

39. Hollenbeck CB, Coulston AM, Reaven GM: Glycemiceffects of carbohydrates: a different perspective. DiabetesCare 9:641-47, 1986

40. Kolata G: Diabetics should lose weight, avoid fad diets.Science 235:163-64, 1987

41. Simpson RW, McDonald J, Wahlqvist ML, Atley L, OutchK: Food physical factors have different effects in non-diabetics and diabetics. Am j Clin Nutr 42:462-69, 1985

42. Simpson RW, McDonald J, Wahlqvist ML, Atley L, OutchK: Macronutrients have different metabolic effects in non-diabetics and diabetics. Am J Clin Nutr 42:449-53, 1985

44. Goddard MS, Young G, Marcus R: The effect of amylosecontent on insulin and glucose responses to ingested rice.Am / Clin Nutr 39:388-92, 1984

45. Englist HN, Cummings JH: Digestion of the polysaccha-rides of banana in the human small intestine (Abstract).Int Congr Nutr, 13th, Brighton, UK, 1985, p. 70

46. Booher CE, Behan I, McNeans E: Biologic utilization ofunmodified and modified food starches (Abstract), j Nutr45:75, 1951

47. Collings P, Williams C, MacDonald I: Effect of cookingon serum glucose and insulin responses to starch. Br Med7 282:1032-33, 1981

48. Thorne MJ, Thompson LU, Jenkins DJA: Factors affectingstarch digestibility and the glycemic response with specialreference to legumes. Am J Clin Nutr 38:481-88, 1983

49. Yoon JH, Thompson LU, Jenkins DJA: The effect of phyticacid on in vitro rate of starch digestibility and blood glu-cose response. Am ) Clin Nutr 38:835-42, 1983

50. Thompson LU, Yoon JH, Jenkins DJA, Wolever TMS,Jenkins AL: Relationship between polyphenol intake andblood glucose response of normal and diabetic individ-uals. Am ) Clin Nutr 39:745-51, 1984

51. Rea RL, Thompson LU, Jenkins DJA: Lectins in foods andtheir relation to starch digestibility. Nutr Res 5:919-29,1985

52. Jenkins DJA, Wolever TMS, Leeds AR, Gassull MA, Di-lawari JB, Goff DV, Metz GL, Alberti KGMM: Dietaryfibers, fiber analogues and glucose tolerance: importanceof viscosity. Br Med) 1:1392-94, 1978

53. Al-Nouri FF, Siddiqi AM: Biochemical evaluation of twelvebroad bean cultivars. Can Inst Food Sci Technol) 15:37—40, 1982

54. Laine DC, Thomas JW, Bantle JP: Comparison of the pre-dictive capabilities of the diabetic exchange lists and theglycemic indices of foods (Abstract). Diabetes 35 (Suppl.1):43A, 1986

55. Coulston A, Hollenbeck C: Comparison of plasma glu-cose and insulin responses to mixed meals of predicted



high, medium, and low glycemic response (Abstract). Di- 68.abetes 35 (Suppl. 1):43A, 1986

56. Wolever TMS, Jenkins DJA: The use of the glycemic indexin predicting the blood glucose response to mixed meals.Am ) Clin Nutr 43:167-72, 1986 69.

57. Wolever TMS, Jenkins DJA, Josse RG, Wong GS, Lee R:The glycemic index: similarity of values derived in insu-lin-dependent and non-insulin-dependent diabetic pa-tients. I Am Col Nutr 6:295-305, 1987 70.

58. Golay A, Coulston AM, Hollenbeck CB, Kaiser LL, WurschP, Reaven GM: Comparison of metabolic effects of whitebeans processed into two different physical forms. Dia- 71.betes Care 9:260-66, 1986

59. Parillo M, Giacco R, Riccardi G, Pacioni C, RivelleseA: Different glycaemic responses to pasta, bread, andpotatoes in diabetic patients. Diabetes Med 2:374-77, 72.1985

60. Slama G, Bornet F, Blayo A, Costagliola D, Haardt MJ,Tchobroutsky G: Insulinogenic and glycaemic indexes of 73.various starch-rich foods taken in a mixed meal or aloneby type 2 diabetics (Abstract). Diabetes 34 (Suppl. 1 ):48A,1985

61. Bornet FRJ, Costagliola D, Blayo A, Fontvieille A, Haardt 74.MJ, Letanoux M, Tchobroutsky G, Slama G: Insulinogenicand glycemic indices of six starch-rich foods taken aloneand in a mixed meal by type 2 diabetics. Am j Clin Nutr45:588-95, 1987 75.

62. Collier GR, Kalmusky J, Giudici S, Helman G, GiordanoC, Ehrlich RM: Effects of slowly digested carbohydratesin type I diabetic children (Abstract). Diabetes 34 (Suppl. 76.1):33A, 1985

63. Jones IR, Owens DR, Williams S, Ryder REJ, Birtwell AJ, 77.Jones MK, Gicheru K, Hayes TM: Glycosylated serumalbumin: an intermediate index of diabetic control. Dia-betes Care 6:501-503, 1983 78.

64. Kiehm TG, Anderson JW, Ward K: Beneficial effects of ahigh carbohydrate high fiber diet in hyperglycemic men.Am J Clin Nutr 29:895-99, 1976 79.

65. Anderson JW, Ward K: High carbohydrate, high fiber dietsfor insulin treated men with diabetes mellitus. Am j ClinNutr 32:2312-21, 1979 80.

66. Anderson JW, Chen WL: Plant fiber: carbohydrate andlipid metabolism. Am J Clin Nutr 32:346-63, 1979

67. Kinmonth AL, Angus RM, Jenkins PA, Smith MA, BaumJD: Whole foods and increased dietary fiber improve blood 81.glucose control in diabetic children. Arch Dis Child57:187-94, 1982

Simpson HRC, Simpson RW, Lousley S, Carter RD, GeekieM, Hockaday TDR, Mann Jl: A high carbohydrate le-guminous fibre diet improves all aspects of diabetic con-trol. Lancet 1:1-5, 1981Rivellese A, Riccardi G, Giacco A, Pancioni D, GenoveseS, Mattioli PL, Mancini M: Effect of dietary fiber on glu-cose control and serum lipoproteins in diabetic patients.Lancet 2:447-50, 1980Anderson JW, Chen WJL, Sieling B: Hypolipidemic effectsof high carbohydrate, high fiber diets (Abstract). Metab-olism 29:551, 1980Simpson HCR, Carter RD, Lousley S, Mann Jl: Digestiblecarbohydrate—an independent effect on diabetic controlin type 2 (non-insulin-dependent) diabetic patients? Dia-betologia 23:235-39, 1982Manhire A, Henry CL, Hartog M, Heaton KW: Unrefinedcarbohydrate and dietary fiber in treatment of diabetesmellitus. I Hum Nutr 35:99-101, 1981Hollenbeck CB, Riddle MC, Connor WE, Leklem JE: Theeffects of subject-selected high carbohydrate, low fat dietson glycemic control in insulin dependent diabetes mel-litus. Am I Clin Nutr 41:293-99, 1985Hollenbeck CB, Coulston AM, Reaven GM: To what ex-tent does increased dietary fiber improve glucose and lipidmetabolism in patients with non-insulin-dependent dia-betes mellitus (NIDDM)? Ami Clin Nutr 43:16-24, 1986Lindsay AN, Hardy S, Jarrett L, Rallinson ML: High-car-bohydrate, high-fiber diet in children with type I diabetesmellitus. Diabetes Care 7:63-67, 1984Wolever TMS, Jenkins DJA: Application of the glycaemicindex to mixed meals (Letter). Lancet 2:944, 1985Crapo PA, Scarlett JA, Kolterman OG: Comparison of themetabolic responses to fructose and sucrose in sweetenedfoods. Am ) Clin Nutr 36:256-61, 1982Crapo PA, Kolterman OG, Henry RR: Metabolic conse-quences of two-week fructose feeding in diabetic sub-jects. Diabetes Care 9:111-19, 1986Hallfrizch J, Reiser S, Prather ES: Blood lipid distributionof hyperinsulinemic men consuming three levels of fruc-tose. Am I Clin Nutr 37:740-48, 1983Antar MA, Little JA, Lucas C, Buckley GC, Csima A: Inter-relationship between the kinds of dietary carbohydrateand fat in hyperlipoproteinemic patients. Atherosclerosis11:191-201, 1970Albrink MJ, Ulrich IH: Interaction of dietary sucrose andfiber on serum lipids in healthy young men fed carbo-hydrate diets. Am ) Clin Nutr 43:417-28, 1986


starchy foods and glycemic index - diabetes care

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