Fibra dietaria

perspectives

in nutrition

Definition
is a protective
Hugh Trowel!2

of dietary
factor

fiber

and

hypotheses
diseases’

that

it

in certain

ABSTRACT followed hydrolysis these CF these
Wales

Crude
by dilute by human are plus 2%. of DF alkali. not

fiber

(CF)

is the fiber

residue DF tables. term,

of plant term, instance, is composed For naturallystarchy dietary

food is the

left

after

extraction of plant hemicellulose, has food

by dilute resistant and DF about include

acid to lignin; I I %, all and food is a three years. and 29: certain

Dietary reported that CF and as

(DF),

a new

residue

alimentary

enzymes. in food a new compounds supplies
from

of cellulose, whole complex with, wheat from 1970. asmellitus, during fall
diseases.

constituents about

wheatmeal (DFC), and to and 1860 potato,

It is suggested all chemical
stationary

fiber associated staples,

should concentrated in rose

substances
were

around, England during fiber and These

structural in 1942 factor diseases, had
and

polymers. to 1953, against such of
an

from 1770 to slightly heart mortality
of theprobably

1860, from disease, rates

fell greatly 1954 such diabetes in by England
three

1910, disease,

controls protective metabolic diseases
vegetables

declined colonic of
prevalence

to

It is postulated and the from Am. obesity. food J. starchy

that

certain ischemic diets trends

disorders,

diverticular

changing African
increased

control foods Nutr.Clin.

Westernization 417-427, 1976.

is accompanied

a large

in CF

same

Preliminary hypothesis

statement of colonic

of the fiber disorders

In 1960 it was postulated “as an interesting hypothesis that the pattern of (noninfective) colonic disease in Africans (was largely due to the protection of) natural African diets usually high in their fibre content (causing) soft,bulky, high-residue stools (and) the colon was large in volume” (1). Africans south of the Sahara rarely suffered from constipation, diverticular disease, irritable colon, ulcerative colitis, appendicitis, hemonnhoids, polyp, and cancer of the large bowel (1). The experimental studies of Walker on Bantu in South Africa (2) prompted this suggestion; he had recognized basic studies such as those in theUnited States on fiber and laxation (3). Slowly many studies of diseases characteristic of Western-type living (4, 5) produced more epidemiological evidence of difference in disease patterns but failed to grapple with the problem of defining fiber. In 1972 a decision was made to adopt a
. . . . . .

physiological definition, and a new term, dietary fiber (DF), was introduced and defined asthe residue derived from plant cell walls that is resistant to hydrolysis by human alimentary enzymes (6-8). The existing literatune has been examined in the light ofthis concept.

Estimation dietary fiber

of crude

fiber

and

Crude fiber (CF) is the food left after sequential solvent, dilute aqueous acid,

residue of plant extraction with and dilute aque-

ous alkali, and isreported in food tables. On average 80% of hemicelluloses and 50 to 90% of lignins are removed before the residue is estimated, and cellulose recovery is only 50 to
‘Supported tion. 2Formerly Consultant Physician, Department of Medicine and Pediatrics, Makerere University, and Uganda Government, Uganda. Present address: Woodgreen, Fordingbridge SP6 2AZ, Hampshire, England. by a grant from the BritishHeart Founda-

The

AmericaniournalofClinical

Nutrition

29: APRIL

1976,

pp.

417-427.

Printed

in U.S.A.

417

418

TROWELL 2. Lignins

80% (9). Dietary fiber contains cellulose, hemicellulose, and lignin (10), but food tables do not report these constituents of plant foods. CF is estimated by internationally agreed methods, but there is not agreement concerning...