Physiology Wolfgang

and pathophysiology

Final

(CHO)

a-amylase lationship

occur

digestion

after

and

system. In general, Na-dependent step of CHO absorption. The

absorption,

ofCHO

and

composition intestinal

motility.

by dietary

inhibitors.

A delay

fibers,

Final

protein

inhibitors, is achieved

hydrolysis complex

of peptides followed by absorption is the mechanism of lipid absorption:

lipolysis, cellular

micellar resynthesis, The

absorption with acids (AA) and

critical

steps

in lipid

Am

formation.

membrane

transport, absorption,

Amino

digestion, small

acids,

malabsorption, intestine, energy

diffusion, or

CHOS

With

sidering

the

resented

almost

carbohydrates,

a-glucosidases, salvage

acarbose,

major

sucrose

through

the

barrier

or lymphatic

energy

is inseparably

because starch,

the energy triglycerides,

usable intestine

fuels released to the body

stituted polymers Morphologically, portant

site

maximum The

fat

from tissues

of absorptive

process

surface

(3-fold,

area

compared

tube

(Fig

1). The

of the

folds,

villi,

10-fold,

20-fold,

with

the surface

area

area

small

surface

l992;55:299S-308S.

ofthe

is the

Printed

ofa

intestine in USA.

mechanisms:

simple

diffusion,

active transport

main

energy

g, the average

the

being

account for industrialized

50% of the countries

of CHOS,

by starch,

oligosaccharides

oligo-

follow,

the

most

and polysaccharides

CHO

in

role as dietary (Table 2) (3).

are not absorbed

to any

in the small intestine. To be absorbed they down to monosaccharides. Accordingly,

of oligo-

and

polysaccharides

assimilation.

by membrane-bound intestine.

The

in the small

specific (passive mentioning that (lactose excepted)

for

disaccharide

significant

end

enzymes products

intestine

sugars

are

are usually

assimilation

is of par-

Fundamentally,

can be distinguished. The first is cleavage amylase. The second is cleavage of short-chain

As CHO

rep-

to account

play only a subordinate to CHO supply in man

in CHO

Other

slightly

polysaccharides,

steps

small

supply.

daily calories (3). On con-

are found

of the

primarily

epithelium

proceeds

of

hydrolysis

glucose,

present

two

of starch by aoligo- or poly-

of enzymatic

are absorbed via transport routes dependent active transport and facilitated

galactose,

only in insignificant the

monosaccharides

both specific (Na4diffusion) and non-

diffusion) (3). In this connection, the monosaccharides arising from at the brush border membrane

it is worth disaccharides may have a

a in

in sur-

cylindrical available

also

diet. As not only

imthat

results

increase simple

but

the quantitatively

degradation

amounts. released

(eg, and

is obtained.

microvilli

The

representing

and fructose.

most

a way

epithelium

respectively)

lipid

I.

categories

significance

of CHOS

into

of digestion

in such and

of

the

the majority ofthe human polysaccharides, they form

exclusively

enzymatic

cells

transported from the or specially recon-

is constructed

surface

membrane

penetrate

carrier-mediated

of 250-800

different

amount be broken

the

mostly of polymers the actual absorbable

the diet and are monomers

of Kerckring’s

J C/in Nuir

the

body

assimilation

CHOs Western

appreciable must first

intestinal

of nutritional

(eg, chylomicrons) (1). the small intestine, which

face

Am

with

the

epithelial

absorption

consists whereas

in Table

quantitatively

part.

However,

from

mucosal The

associated provided proteins),

of absorption,

presence

a 600-fold

of the system.

Specific

this case. Monosaccharides components with regard

saccharides

blood

(carrier-mediated)

intake

300 g, dietary in adults in the

l992;55:299S-

absorption,

part

>

body. Absorption the

plasma

can

cells by various

represent and especially

a daily

ticular

lumen

of the

Molecules

normally

the greatest

intralymphatic are lipolysis

Nutr

of substrates

human

facilitated

(CHO)

oligo-,

Probably the most important function of the gastrointestinal tract is to transform energy from orally supplied food in such a way that absorbable and usable fuels become available for the transport

the

epithelial

are listed

mono-,

Introduction

means

than

function

pinocytosis.

Carbohydrate

the

WORDS

larger

cells.

ofthe

passive processes

308S.

KEY

epithelial

transport,

of free AA. More emulsification,

digestion

J C/in

100 times

-

is a specific

intestinal

subsequent membrane

formation, membrane translocation, chylomicron formation, and

most

micellar

is

area (1). Absorption

of absorption

digestion

mechanism: hydrolysis

and

intact peptide to free amino

of the digestion

a-amylase

by a dual intracellular

drainage.

absorption

by pancreatic

transport is the rateof absorption is de-

rate

chemical digestion,

intestinal

may be achieved

or a-glucosidase

of carbohy-

hydrolysis

mucosal membrane in close rehydrolysis and the glucalogue

termined by mode of ingestion, meal, gastric emptying, pancreatic and

absorption

intraluminal

at the surface of the between disaccharide

carrier limiting

absorption1’2

F Caspary

ABSTRACT drates

of intestinal

for

© 1992 International

Downloaded from https://academic.oup.com/ajcn/article-abstract/55/1/299S/4715344 by guest on 16 January 2018

From the Division of Gastroenterology, Department of Medicine, Johann-Wolfgang-Goethe University, Frankfurt, Germany. 2 Address reprint requests to WF Caspary, Division of Gastroenterology, Department Theodor-Stern-Kai Association

of Medicine, Johann-Wolfgang-Goethe-University, 7, D-6000 Frankfurt/Main, Germany.

for the Study

of Obesity

299S

CASPARY

300S

TABLE

Structure

Surface

area

(cm2)

1 carrier-mediated

Specific

transport

processes Nature

Substrate

Area of a simple cylinder

10.000

Kercknngs folds (Valvulae Conniventes 100.000

30

intestine

of transport

mechanism

Active transport Facilitated diffusion Active transport Active transport Active transport Active transport Active transport Active transport Active transport Active transport Active transport

Glucose, galactose Fructose Neutral amino acids Basic amino acids Imino acids Di- and tripeptides Myo-inositol Carnitine Calcium Iron Folic acid Ascorbic acid Biotin Riboflavine Thiamine Nicotinamide Choline Vitamin B-12-IF complex (ileum) Conjugated bile acids (ileum) Sulphate (ileum)

3.300

3

in the small

Active transport Active transport Facilitated diffusion Active transport Active transport Facilitated diffusion Facilitated diffusion Active transport Active transport

Microvilli C

Reprinted

commences

2,000,000

in the

Both a-l,4 FIG 1. Morphological structures ofthe mucosa ofthe small intestine. Because ofthe presence ofKerckring’s folds, villi, and microvilli a maximal contact surface between food digests and the functional elements (enzymes, carriers) of the brush border is achieved (after reference 2).

pancreatic linkages

drolysis

absorptive

advantage

monosaccharides

(3).

However,

the diet does

completely

over

not contain

absorbed after 3). Of the unavailable

cleavage CHOs,

directly

only

(so-called

carbohydrate

oftheir physicochemical on digestive-absorptive

CHOS

that

can be

agents)

like guar

TABLE

and

Thus,

amylase

a-arnylase the

main

(3).

can cleave products

only

of starch

the hy-

maltotriose

from amylose, and from a-limit dextrins. The latter cleavage ofa-l,4 linkages in the vicinity not take place at all, or with only highly the so-called

Thus,

a-limit

dextrins

are

glucose

oligosac-

2

Carbohydrate

composition

of human

diets Compos

According

Carbohydrate

because effect

testine unstirred mucosa

(5-7). It can be regarded as proven that the so-called water layer, a luminal diffusion barrier covering the of the small intestine, has a particular role in this con-

reference

Polysaccharides Starch

and

pectin, hibitory

properties, exert an inprocesses in the small in-

nection.

ition (%)

to it

According reference

64

52.6

Glycogen

0.5

-

Oligosaccharides Sucrose Lactose Maltose

26 6.5

33.2 6.6 1.8

-

to 2

Monosaccharides

Enzymatic

cleavage

Depending and amylose amylopectin, chains

salivary

in addition,

activity.

by pancreatic

by endogenous enzymes primarily polysaccharides

gelling

1.

administered

(Table are ingested with the diet. These are essentially cellulose cornplexes (plant cell walls and their residues), hemicellulose, pectins, and other fiber components (4). It now has been found that various nondegradable plant polysaccharides

and

of starch.

because hydrolytic branching does

ofa-1,6 restricted

so-called

duodenum

are maltose

amylopectin, occur

reference

sites

enzymatic ronment 600

from

arise from a-l,6 linkages. Amylase has optimal activity at pH 7 and is inactivated in the acid enviof the stomach, so that breakdown of starch only re-

branching Villi

with permission

on

of starch its origin,

of varying a branched

are composed

starch

is a mixture

of amylopectin

S

composition. The majority consists of glucose polymer in which the individual of a- 1 .4-linked

glucose

residues

and

the

Downloaded from https://academic.oup.com/ajcn/article-abstract/55/1/299S/4715344 by guest on 16 January 2018

Glucose

-

Fructose

3

Reprinted

with permission

from

4.2 1.6 reference

3.

t 1. Oreaves IP, Hollingsworth DF. Proc Nutr Soc l964;23: 136. t 2. Reiser S. In: Berdanier CD, ed. Carbohydrate metabolism. New York:

John

Wiley

and Sons,

l976;45-78.

TABLE

MECHANISMS

OF

INTESTINAL

diet according

to their

3

ABSORPTION

sequently,

Classification of carbohydrates digestibility5

in the human

Type

ion.

30 1S

are subjected

We

have

to bacterial

to consider

that

fermentation

starch

can

within

become

the co-

resistant

to a-

amylase as a result ofprocessing(storage, freezing). Other possible causes of incomplete digestion of starch in the small intestine may be due to the resistance of nongelatinized starch granules,

of carbohydrate

Free sugarst Glucose Fructose

the presence

of natural

large hard

amounts grains)

of poorly (8-10).

a-amylase

Final

CHO

inhibitors,

digestible

or the ingestion

forms

of starch

(seed

of coats,

Galactose

Disaccharides Sucrose Lactose Trehalose Maltose Maltotriose

and oligosaccharidest

The

from

and

proximity and into

the

with

from

Raffinose Stacchyose Lactulose Sorbitol

the

are

complex

has been

purification

with permission

from

reference

4.

in the small

of low residues,

(isomaltose-linkage). this

primary

glucose end

Only

breakdown

endoenzyme

that

chains,

made up of an average of six are uncleaved a- 1 .6 linkages little

ofstarch

free

since

glucose

no

results

a-amylase

of hydrolysis

exhibits

only

activity

so that

from

represents

an

in the middle

of

as regards

cleavage

of

Type

of starch

the

three

proceeds

hydrolytic

very end

rapidly

products,

investigations

indicate

that

the

so-called

physiological

Table are

not

same

manner

intestine.

subjected

fermentation

predigestion

of starch

Sucrase

of an

and

enzyme

purified,

isolated,

in a mutually

isomaltase

complex.

the human

were

of classification

capable

breakdown of glucose activities This

and characterized

that,

maltase

enzyme

on the basis

enzyme

(1 1). After

complex

of their

could

substrate

as sucrase

and glucoamylase (-y-amylase)

that are not completely

and

iso-

are far less well charcleaves

absorbed

Positive H2 breath testt

of carbohydate

glucose

under

from

the

physiological

Estimated proportion of nonabsorbed material

Both

within

as dietary

fiber,

unavailable

the colon

which starch

to bacterial

is undigestible and

dietary

fiber

breakdown

and

(8).

4 lists some completely

S

ofthe absorbed

starch from

products the

small

and other intestine

CHOS

that

and,

con-

Downloaded from https://academic.oup.com/ajcn/article-abstract/55/1/299S/4715344 by guest on 16 January 2018

Starch(i00 g) White flour Rice flour Oatmeal

17/18 0/6 ?

Corn flour

?

6

? ?

13 18

Potatoes Beans Sucrose lOOg Fructose 50g 25g

malab-

of CHOS also exists for certain starch products, ie, a certain amount of orally ingested CHO in the form of starch (eg, wheat-meal products) enters the large intestine in undigested

are then

are,

%

sorption

in the

form

for the various effect the release

in the maltose,

‘‘

form

mass,

They

of the brush border membrane, a three enzymes (previously called

(3).

Glucoamylase

TABLE 4 Carbohydrates conditions5

maltotriose, and a-limit dextrins, are present in roughly equal portions 10 mm after entry ofthe starch (3). Formerly, it was assumed that even complex starch-containing polysaccharides were completely absorbed by the small intestine (4). However,

in the small

lumen.

(3). hydrolysis

duodenum

very

is capable but

molecules Enzymatic

weight, there

membrane of their

hydrophilic substrates. The defto the digestive function in hu-

two subunits

The enzymes

molecular in which

are anchored

ofthe

most

intestinal

an

maltase.

intestine.

acterized. charides glucose

layer and

form

2.

to homogeneity,

into

specificities, or indigestible

to their in relation

of the

in the

they

and functional

(I, 3). They

center

of the

manner

united

be split

catalytic

small

enterocytes

where

protein

Their specificities overlap. They

products

comprehensive

ofthe

in close structural

the a-glucosidases is made between in man. of starch

membrane

in the lipid

in Figure

disaccharides

in maturing

membrane,

medium

accessible pattern

is shown

maltases) products

Misceilaneou$

apical

their

aqueous

Among distinction

form

border

membrane component

accordingly, mite enzyme

mans

brush

to the glucose-carrier

project,

are provided

and from dietary

are synthesized

in the

part ofthe

by a hydrophobic

Lignin

t Easily digestible. f Poorly digestible § Crude fiber.

ofthe

disaccharidases

for absorption

products

enzymes

embedded

integral

Cellulose.

Reprinted

These

border

necessary

enzymes

intestine.

Dextrins Starch Glycogen Resistant starchj Oats (eg) Nonstarch polysaccharide$ Gums (eg, guar) Alginates Pectins Hemicellulose Polysaccharides in structural

by brush

degradation

starch

by specific

Polysaccharidest

S

digestion

monosaccharides

Reprinted

t A positive bacterial

10-20 -

8

0/6

-

? ?

7/15 5/7 with permission

H2 breath

fermentation

from

reference

test after ingestion

of the carbohydrate.

4.

of carbohydrate

indicates

CASPARY

302S

across

sodium

widely

accepted

sites:

one

for glucose,

The

binding

both Maltose

-s

The

inwardly

a.Limjt

dium

-.

dextrin

force

pump

sites

downhill

Na

epithelial

cells,

Sucrose

system

requiring

pumping

Inhibition uanides) port

(14,

inhibition

nutrients

(amino

transporter

lumen

Mucosa

end-terminal

position

predigestion.

The

of starch

enzyme

amounts

Lactase is an important tion. Its activity is absent ofthe world population. quent in Caucasians. In and absorption, the rate rate-limiting step. The always

higher

transport plained

than

system. on these

Intestinal

epithelial molecular a carrier propriate

substances

a carrier

amino

seems

by cardiac

other

glucose

however, actively

capacity

The

and

intestinal

predictions

much

more

is administered

at doses

This

of fructose of

glucose

sluggishly. >

25 g (16).

is the reason

when Figure

Lumen

of starch

ofthe

(1, 3, 12). From the

pioneering

through

bifunctional

carrier,

absorption

and

experimental

transport.

Mucosa

Serosa

Glucose Phioretin

can

be cx-

a lipid

#{188}..-. Ouabain

membrane

it is possible saturation analogues,

processes

good

agreement

of both between

findings

is in favor

to explain

phenomena

of

characteristics, competand counter-transport

FIG 3. Schematic representation of the glucose-transport system in the mucosal epithelial cells ofthe small intestine. Simple diffusion occurs along a concentration gradient at the brush border membrane (I) and basolateral membrane (4). Facilitated diffusion also occurs along a concentration gradient at the brush border membrane (2) and the basOlateral membrane (5) by means ofa specific carrier. Active transport: transport of glucose against a concentration gradient through the brush border membrane is coupled via a earner with an influx of Na4 ions along an electrochemical gradient (3). Through maintenance of the inwardly directed Nat-gradient by Na4-K4-ATPase in the basolateral membrane (6), monosaccharide transport, which is not directly energy dependent, is linked to an energy-requiring process. Glucose thus can accumulate intracellularly

work responsible

sub-

glucose-galactose of milk

substances. The permeation the membrane of intestinal

3, 12). The

specificity, by substrate

this

3 depicts

Na

( 1, Thus,

glucose

D-galactose;

diet only in minimal

index

pass

hydrophilic through

to

leads transported

vitamins).

D-glucose

glytrans-

to be a rudimentary

in human

glycemic

normally

acids

mechanism.

as substrate inhibition

malabsorption of active

pump,

for

3).

cells is much faster, as could be anticipated from the size and structure of sugars. Suggestions that there is system in the membrane have proved to be most ap-

theoretical

which

physiological

mechanism

pump

cell

as by big-

accepted by the carrier binding sites seems to occur by a different transport

for the the

the

such

of monosaccharides

for explaining and

products

at the

glucose-

to an energy

ofactive

several

of

against

enzyme responsible for lactose digesor markedly reduced in the majority Lactase deficiency is, however, less frethe overall process of lactose digestion of hydrolysis oflactose by lactase is the activity of a-glucosidases is, however,

the transport

transport

Lipophilic

such itive

trehalase

The low grounds.

significantly faster than rate of monosaccharides

sugar

or hydrolytic

because trehalose appears (mushrooms) (3).

enzyme

and disaccharides (from reference

Na

ofall

system, strate

FIG 2. Digestion and absorption of oligobrush border membrane of the small intestine

the

bile acids,

operates

interior

membrane.

chain,

to inhibition

as substrates not

the

by depriving

of the Na

accept

from

basolateral

oftransport

fructose is, however, (3). Fructose absorption

Intestinal

lead

acids,

will

so-

to accumulate

of respiratory

Inhibition

15).

unspecific

provides maintains

is coupled

either

inhibiting

will

Na

membrane

pump

inhibition

(ouabain)

sub-

ofNa4

membrane

glucose

at the

Na

or by directly

cosides -5

system

of the

when

(1, 3, 12, 13). The facilitated

at the apical

(anoxia;

energy

Lactose

gradient

transport -.s

allowing

optimally appropriate

An energy-requiring

basal-lateral by ejecting

thus

It is binding

gradient

transport.

gradient

an electrochemical

by the

downhill

at the

has two (13).

operates

are occupied

for glucose

the

for Na4 step

directed

has emerged.

transporter

one

translocation

located

the

membrane,

the glucose

a second

and binding

strates.

border

that

carrier

the driving Maltotriose

the brush

now

of Crane

(12)

for translocation

the

concept ofglucose

of the and

Downloaded from https://academic.oup.com/ajcn/article-abstract/55/1/299S/4715344 by guest on 16 January 2018

and

flow

out

by

facilitated

membrane (5). The specific actions curved arrows (from reference 3).

of some

diffusion

inhibitors

at

the

basolateral

are indicated

by

MECHANISMS Monosaccharide The ride

transport

and

Michaelis-Menten transport

transport

allow

measurement

represents

The

the rate

of Km and layer

of the

represents

phenomenon

essentially

takes

up

based only

on

dissolved

reduces

the thickness

and

intestine reduces thus accelerates

strate concentrations ( 17, revealed that the carbohydrate well, disaccharide hydrolysis transport thickness

Km . Thus

testinal

of the

guar unstirred

absorption

(6-10).

Fate ofCHOs CHOS

fact

that

substrates

Km

.

rapid

perfusion

be completely hurry,

enzymatic

transporters)

absorbed

reasons

an increased the rate of in-

decreased activity,

will eventually

in the

(malabsorption, absorptive or

reach

lack

surface,

of

the colon

where

they

usually

the

result

lack

of a phosphorylation

reaction.

Reprinted

24.7t

with permission

t 24.7 kcal

=

62% ofthe

by fermentation

from

energy

and absorption

portant

and

plete

especially

fermentation

of

breath, for the

H2

by

Fermentation is

mmol

be considered

here

fermentation,

of 57.5

H2, and

of glucose and thus

and

mmol

be reused

also

influence

with

CHO

hydrolases

disaccharidases

malabsorption

(10.35

95 mmol

CO2.

and

_____ : Foat’

:

025

H2.

C02.

CH41

to a high

reabsorptive

extent

not

change

in the

5). The

effectiveness

absorbed

CHOS

as well is also massive

form

fecal

Downloaded from https://academic.oup.com/ajcn/article-abstract/55/1/299S/4715344 by guest on 16 January 2018

in an

Bacterial

mechanism

fer-

for SCFAs

symptoms

by Figure

of patients

5. Minimal

pH and

weight,

CHO

no caloric

occur due to the fermentation of SCFA will take place.

as an

of SCFAs thus CHO load in the

increased

increased. watery

explains

colon

why

caloric

CHOs to salvage

patients

under

responsiblefor

massive the rate

of absorption (Table

after 6) (1).

CHO

The

malab-

a considerable and

SCFAs

(Fig

energy

from

mal-

treatment

will not lose weight. Caloric only be achieved with very

induce

load.

CHO

High-grade diarrhea and

of unfermented of the

which

factors

results

CHOs.

the clinical

as shown

loss,

loss

rate

C atoms

rapid fermentation exceeding the reabsorptive will lead to an acid fecal pH, increased water

sorption

The

ofthe

fermentation

process and reabsorption load of the colon. If the

caloric

by various

27.5%

these

the effective

of flatulence will induce

Factors

in 140

efficiently

malabsorption,

inhibitors,

results

acids(SCFAs),

is shown in Table 5. can reabsorb SCFAs very

glucosidase inhibitors weight reduction can FIG 4. The fate of carbohydrates in the large intestine: bacterial hydrolysis of polysaccharides. Phosphorylation of by bacterial disaccharidases and fermentation under anaerobic conditions leading to formation of short-chain fatty acids (SCFAs), hydrogen (H2), bicarbonate (C02), and methane (CH4) (from reference 4).

test)

(C02) result

of the fermented

electrolyte

degree

in the

products energetic

of 62%

colon is increased, process for SCFAs

diffusion

inert 1 9). The

Bacterial

fermentation the osmotic

rapid

(breath-hydrogen (4, 19).

only

energetically.

does

of CHOs

appearance

fatty

Thus,

in detail

breakdown

g) of glucose

ofshort-chain

loss occurs, slight flatulence may process, and effective reabsorption The reduce

test

of corn-

ofbacterial CHO lactate, hydro(CH4). The proits

subsequent

are converted to metabolically lost as an energy source (4,

Bacterial

enzymes

salvage

cannot

The main products propionate, n-butyrate, (C02), and methane

of 100 mmol

energy salvage mentation and

Monosaccharides

to the

(4, 19). The

wall

of CHO fermentation Because the colon

L

respect diarrhea

bacterial

intestinal

production met-

with

have been used as a sensitive diagnosis of CHO malabsorption

Bacterial

[cetate]

to the body

ofosmotic

process

should be given attention. fermentation are acetate, gen (H2), carbon dioxide the

pectin)

Bacterial

is returned fatty acids.

(see reference 3); Figure 4 depicts the overall bacterial of CHOs within the colon. The energetic consequence of bacterial fermentation

can

Disaccharides Monosaccharides

4.

glucose

of short-chain

the prevention

through

Disaccharides

Oligosaccharides

reference

from

ofCHOs, which is an anaerobic proprocess of CHOs in the colon is an im-

phenomenon,

energy

duction

are sub-

final

abolic step is fermentation cess. The fermentation

of

will break Starch and

The

S

or

by bacterial amylases. of disaccharides by bacteria

Carbohydrate polymers (st1arch. glycogen. cellulose.

in-

diges-

disaccharidases

to bacterial degradation. Bacterial hydrolases CHO polymers into smaller molecules (4).

glycogen can be broken down The intracellular breakdown

small

poor

39.8 28.7 4.0

100 mmol

of

studies have will reduce, as by affecting

to act by inferring that will reduce

in the colon

a

the thickness ofthe unstirred rates especially at low sub-

18). Transport kinetic gelling agent guar as glucose transport seems layer

of various

intestinal

pancreatic jected down

cannot

because

tibility,

decreases

as well absorption

fermentation

Glucose, 10.35 g Short-chain fatty acids, Loss in feces Total

the

from

in the intestine

that

testine

thus

carbohydrate

kcal

and is able to unstirred layer the

from

303S

maximal a diffusion

liquid medium. The thickness of the unstirred layer, which in kinetic transport studies affects K,. but not Vmax , can be manipulated in vitro and in vivo: stirring ofthe incubation medium the small layer and

ABSORPTION

TABLES Energy salvage

monosaccha-

mucosa of the small intestine of transport (17, 18). The

a physical

intestine

of active

unstirred

INTESTINAL

layer

characteristics

rate (V,,,)(l).

barrier covering determine the

unstirred

OF

with

a-

loss and thus high doses of

malabsorption.

of absorption food The

ingestion mode

may of food

be affected ingestion

is

304S

CASPARY Carbohydrate

malabsorption

Minimal

Medium-grade

CHO

CHO

.

Aipha-glucosidase High-grade

The terminal

CHO

R

U CHO

at the

E 3

digestion

surface

glucosidases absorption

H2

SCFA’

inhibitors

of the

would thus from starch,

pH:

Normal