blueberries, and strawberries; among
vegetables, garlic, red and yellow onions,
asparagus, green beans, and beets.
Fiber
Fiber is defined as the material in our plant
foods that our digestive enzymes can’t break
down into absorbable nutrients. These
substances therefore aren’t absorbed in the
small intestine, and pass intact into the large
intestine, where some are broken down by
intestinal bacteria, and the rest are excreted.
The four main components of fiber come from
plant cell walls (p. 265). Cellulose and lignin
form solid fibers that don’t dissolve in our
watery digestive fluids, while pectins and
hemicelluloses do dissolve into their
individual molecules. Minor components of
fiber include uncooked starch and various
gums, mucilages, and other unusual
carbohydrates (e.g., mushroom chitin,