Energy-Rich Carbohydrates
Fresh fruits, whole grains, and
vegetables—especially legumes such as peas and beans—provide abundant complex
carbohydrates . The body breaks the starch in these foods into glucose, your
primary source of energy. These foods also provide essential vitamins and
fiber. Eating foods high in soluble fiber helps lower one's cholesterol level
and may reduce the risk of heart disease. A diet high in insoluble fiber helps
prevent constipation.
Foods rich in processed carbohydrates such as white
flour, refined sugar, and corn syrup are sometimes said to be lull of
"empty calories/' This is a way of saying that these foods provide little
in the way of vitamins or fiber.
You may have noticed breads and other grain-based
foods labeled as "gluten-free." Gluten is a protein found in wheat and many other grains. An estimated 1
percent of the population has a genetic disorder called celiac disease, in
which gluten causes an autoimmune reaction that harms the small intestine's
villi. Celiac disease is treated by eliminating gluten from the diet.
Good Fat, Bad Fat
Your body uses lipids to build cell membranes, as
energy stores, and as a reservoir for fat-soluble vitamins.
Linoleic acid and alpha-linolenic acid arc essential
fatty acids, meaning the human body needs them but cannot make them, so they
are required in the diet. Both are polyunsaturated fats; their long carbon
tails include two or more double bonds. Unsaturated fats are liquid at room
temperature.
We divide the polyunsaturated fatty acids into two
categories: omega-3 fatly acids and omega-6 fatty acids. Omega-3 fatty acids,
the main fat in oily fish such as sar dines, seem to have special health
benefits. Studies suggest that a diet high in omega-3 fatty acids can reduce
the risk of cardiovascular disease, lessen the inflammation associated with
rheumatoid arthritis, and help diabetics control their blood glucose. Oleic
acid, the main fat in olive oil. may also have health benefits. It is
monounsaturated, which means its carbon tails have only one double bond. A diet
in which olive oil is substituted for saturated fats helps prevent heart
disease.
Dairy products and meats are rich in saturated fats
and cholesterol. Overindulging in these foods increases one's risk for heart
disease, stroke, and some cancers.
Trans fatty acids, or trans fats, are manufactured
from vegetable oils. However, they have a molecular structure that makes them
even worse for the heart than saturated fats. All food labels are now required
to show the amounts of trans fats, saturated fats, and cholesterol per serving.
Body-Building Proteins
Amino acids are building blocks of proteins. Your
cells can make some amino acids but you must get eight essential amino acids
from food.Most proteins in meat are "complete," meaning their amino
acid ratios match a human's nutritional needs. By contrast, most plant proteins
are "incomplete," meaning they lack one or more amino acids essential
for the human diet.
The American Dietetic Association states that, with
careful planning, a vegetarian diet can provide all essential nutrients for
people in any stage of life. To obtain all the required amino acids from plant
sources alone, one must combine foods so that the amino acids missing from one
component are present in some oth ers. As an example, rice and beans together
provide all necessary amino acids, but rice alone or beans alone do not. You do
not have to eat the two complementary foods at the same meal, but both should
be consumed within a 24-hour period.
Vitamins and Minerals
Vitamins are organic substances that are essential
in very small amounts; no other substance can carry out their metabolic
functions. At a minimum, human cells require the thirteen vitamins. Minerals
are inorganic substances that are essential for growth and survival because no
other substance can serve their metabolic functions. Red blood cells require
iron to make oxygen-transporting hemoglobin. Iodine is essential for
development of a healthy nervous system and to make thyroid hormone.
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Pancreas - Makes
enzymes. Empties into small intestine
