
and appetite and increases feelings of satiety and
satiation in all subjects, whether they be normal-
weight, overweight, or obese. However, there are
problems in designing experiments to investigate
feeding behavior, since it is very difficult to make the
control food (placebo) look and taste like the test
food. One study showed that breads containing high
concentrations of guar gum were significantly less
palatable than the control breads and this may ex-
plain why the subjects were less hungry after consum-
ing the guar-containing bread meal. The energy value
of the control and test meals should also be identical
in such experiments. Despite the positive effects of
guar gum in the short term, many of the long-term
intervention studies are contradictory and suggest
that a therapeutic role for guar gum in weight control
management has yet to be established.
Conclusions and Final Comments
0024 There is now overwhelming evidence to indicate that
guar gum has therapeutic benefits for a range of
metabolic disorders. At doses of guar gum that are
likely to be consumed for therapeutic purposes, there
is little evidence that it adversely affects human
health. On the contrary, the cholesterol-lowering
property of guar gum is of benefit to those who are
at an increased risk of CHD, including people with
hyperlipidemia and diabetes. Furthermore, the use of
guar gum in decreasing postprandial glycemia and
insulinemia and in improving long-term glycemic
control in diabetic patients is now well established.
Any improvement in glycemic control is likely to
reduce the risk of microvascular complications (e.g.,
nephropathy), which are common in people with dia-
betes, and develop over a number of years.
0025 Recent epidemiological studies have also indicated
that diets comprising low-glycemic-index foods may
have a protective effect in the development of type 2
diabetes. Guar-containing foods could play an im-
portant role in such diets and should be tested in the
future for their possible prophylactic benefits. In view
of possible beneficial effects of guar gum on insulin
resistance, which in itself is a risk factor for both
CHD and type 2 diabetes, the role of guar foods
needs to be evaluated here also. The effects of guar
gum on weight reduction in the long term have yet to
be demonstrated, although its use in maintaining
weight in weight-reduced subjects merits further
study. Obese individuals are likely to benefit however
from the consumption of guar gum in terms of im-
provements in glycemic control, insulin sensitivity,
and lipid metabolism.
0026 To assist in the development of new low-glycemic-
index foods using guar gum as a major ingredient, it
would be advantageous to have a detailed under-
standing of its behavior in the gut environment. Fun-
damental information about the way in which guar
galactomannan influences the rheological behavior of
digesta, through its effects in solution, as an entangled
network, or on the swelling of food particles, is of
paramount importance. This would need to be closely
linked to the effects of galactomannan on nutrient
digestion and absorption, including, for example,
starch and lipids.
0027The initial attempts to produce palatable guar foods
for the management of diabetes and hyperlipidemia
were disappointing. However, the technological diffi-
culties were exacerbated by the perceived need to use
high doses of guar gum (15–30 g day
1
), since the
results of early clinical trials suggested that such
doses were needed to elicit metabolic benefits. More
recent studies have shown that much lower doses (6–
12 g day
1
) and partially depolymerized guar gum are
not only clinically effective, but have significantly less
detrimental effects on sensory qualities of food. From
a food technology perspective, it is now possible to
produce guar-enriched foods that are both clinically
effective and palatable.
See also: Carbohydrates: Classification and Properties;
Cholesterol: Factors Determining Blood Cholesterol
Levels; Coronary Heart Disease: Prevention; Diabetes
Mellitus: Treatment and Management; Dietary Fiber:
Properties and Sources; Determination; Physiological
Effects; Effects of Fiber on Absorption; Glucose:
Maintenance of Blood Glucose Level; Glucose Tolerance
and the Glycemic (Glycaemic) Index; Gums: Properties of
Individual Gums; Food Uses; Dietary Importance
Further Reading
Edwards CA and Read NW (1990) Fibre and small intes-
tinal function. In: Leeds AR (ed.) Dietary Fibre Perspec-
tives, vol. 2, pp. 52–75. London: John Libbey.
Ellis PR (1999) The effect of fibre on diabetes. In: Hill M
(ed.) The Right Fibre for the Right Disease, pp. 33–42.
London: Royal Society of Medicine Press.
Ellis PR, Rayment P and Wang Q (1996) A physico-
chemical perspective of plant polysaccharides in relation
to glucose absorption, insulin secretion and the entero-
insular axis. Proceedings of Nutrition Society 55:
881–898.
Ellis PR, Wang Q, Rayment P, Ren Y and Ross-Murphy SB
(2001) Guar gum: agricultural and botanical aspects,
physicochemical and nutritional properties, and its use
in the development of functional foods. In: Cho SS and
Dreher M (eds) Handbook of Dietary Fiber, pp.
613–657. New York: Marcel Dekker.
Flourie B (1992) The influence of dietary fibre on carbo-
hydrate digestion and absorption. In: Schweizer TF
and Edwards CA (eds) Dietary Fibre – A Component
3020 GUMS/Nutritional Role of Guar Gum