Perhaps the most important health benefit of a
high-fiber diet is its potential to protect against heart
disease. Multiple large, well-designed studies have
shown that soluble fiber can lower blood cholesterol
levels.
High levels of cholesterol can lead to the build
up of plaque, a hard, waxy substance, on the walls of
arteries. This can block blood flow and result in stroke
or heart attack.
The mechanism for lowering cholesterol
appears to be connected to the fact that cholesterol
binds with soluble fiber in the intestine and can
then be eliminated from the body or bile acids.
Soluble
fiber in oats and oat products appears to be more
effective in lowering cholesterol than soluble fiber
from other grains. This finding has been accepted by
the American Heart Association which recommends a
high-fiber diet to maintain or improve heart health.
A high-fiber diet can prevent digestive system
problems such as constipation, hemorrhoids, and
diverticulitis by keeping stool soft and easy to expel.
Hemorrhoids are swollen veins around the anus
caused by straining to eliminate stool. Diverticulitis
is a disease in which, sections of the intestine bulge out
to form pockets called diverticuli that collect food and
become infected.
Increased bulk and moisture from dietary fiber helps materials move more easily through
the intestine and not become trapped in these pockets.
Claims have been made that a diet high in fiber
reduces the risk of colon cancer. The theory is that
fiber speeds up the elimination of waste from the
colon. This decreases the time that cells lining the
intestinal wall are exposed to potential cancer-causing
agents.
However, in the mid-2000s, a study that followed
80,000 nurses for 16 years found no relationship
between dietary fiber and colon cancer. More research
remains to be done in this area.
Fiber should be increased in the diet gradually. If
fiber intake increases suddenly, abdominal pain, gas,
and diarrhea may result.
Also, when eating a highfiber
diet, it is important to drink at least 8 glasses
(64 oz or 2 L) of water or other fluids daily. People
whose fluid intake must be restricted for medical reasons
should avoid a high-fiber diet.
