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NUTRITION
Carbohydrates
The quickest, most readily available source of energy for the body is glucose.
Carbohydrates are broken down to glucose. Between eating periods, the blood glucose
level should be maintained properly.
If there is not enough glucose available, amino acids can be broken down to glucose. The
best place to find amino acids are in proteins. The best place to find proteins is muscle,
including heart muscle. Most body cells can use other things for energy, but the brain can
only use glucose. Therefore, the body needs carbohydrates in the diet, or it will start
breaking down muscle, including cardiac muscle.
Simple carbohydrates (e.g., sugars) are “empty calories” because they contribute to
energy needs and weight gain without supplying any other nutritional requirements.
Examples of simple carbohydrates are ice cream, cakes, and cookies. Plain white
sugar from a box (called refined sugar) has no vitamins or minerals.
Dietary carbohydrates should be complex and not simple carbohydrates. Complex
sources of carbohydrates include whole grain pasta, rice, bread, and cereal. Less
desirable complex carbohydrates (for overweight people) are potatoes and corn, since
they have a lot of carbohydrates in them.
Proteins
Foods rich in protein include red meat, fish, poultry, dairy products, legumes (i.e.,
peas and beans), nuts, and cereals. When you eat protein it is broken down into amino
acids and turned into tissues like muscles, skin, hair, and nails. It’s also used to make
proteins such as hemoglobin, plasma proteins, enzymes, and hormones.
Protein formation requires 20 different types of amino acids. Of these, eight amino
acids are required from the diet in adults because the body is unable to produce
them. These are called the essential amino acids. Some protein sources, such as meat,
provide all 20 types of amino acids. But a diet of only a few types of vegetables and
grains supply us with only a few of the essential amino acids. If just one amino acid is
missing from the body, none of the other 19 work right.
Therefore, you should combine foods to acquire all the essential amino acids. For
example, the combinations of cereal with milk give a good balance of proteins. So does
combining rice with beans or peas.
Amino acids are not stored in the body, and a daily supply is needed. However, it
does not take very much protein to meet the daily requirement. Two servings of meat a
day (equal in total quantity to a deck of cards) is usually enough. Some meats (e.g.,
hamburger) are high in protein but also high in fat. Everything considered, it is probably
a good idea to depend on protein from plant origins (whole-grain cereals, dark breads,
and legumes) to a greater extent than is often the custom in the United States. Those who
get most of their protein from meat are getting about 42% fat.
Protein and/or amino acid supplements are not good because they are not digested as
well. They can also give you an excess of one amino acid or another. An excess of just
one amino acid causes a deficiency in absorption of the other amino acids.
Lipids
Fat and cholesterol are both lipids. Fat is present not only in butter, margarine, and
oils, but also in animal meats (even chicken and turkey has some fat). Not only does
it cause weight gain, but it also increases the risk of cancer and cardiovascular disease.
Cardiovascular disease is often due to arteries blocked by fatty deposits from cholesterol.
Cholesterol is carried in the blood by two types of lipoproteins: low-density lipoprotein
(LDL) and high-density lipoprotein (HDL). LDL is thought of as being “bad” because
it carries cholesterol from the liver to the cells, while HDL is thought of as being
“good” because it carries cholesterol to the liver, which takes it up and converts it to bile
salts.
Saturated fats, whether in butter or margarine, can raise LDL (bad) cholesterol levels,
while polyunsaturated fats lower LDL cholesterol levels. Examples of good
polyunsaturated fats are olive oil, canola oil, corn oil, and safflower oil. Notice that these
are all liquid at room temperature and come from plants. Saturated (bad) fats, are solids at
room temperature, usually have an animal origin, except for palm oil and coconut oil,
which are also bad fats. Red meats, although it is high in protein, also has a lot of
saturated fats; that’s why chicken, turkey, and fish are better sources of protein.
Weight Loss
A woman who is about 5 feet 4 inches tall, and exercises lightly, requires about 2,100
Calories per day. For a man 5 feet 10 inches tall, who exercises lightly, the requirements
are about 2,900 Calories a day. Those who wish to lose weight need to reduce their
calories and/or increase their exercising. One pound of fat requires about 3,500
calories to be burned off. Therefore, how many days will it take to lose one pound of fat
if you eat 500 calories less per day? 7 days. If you lose more than that, it’s probably just
water loss.
Low-Carbohydrate Diets
The dramatic weight loss that occurs with a low-carbohydrate diet is not due to a loss
of fat; it is due to a loss of muscle mass and water. When a normal diet is resumed, so
is the normal weight.
Liquid Diets
Muscle is still broken down to provide energy. A few people on this regime have died,
probably because even the heart muscle was not spared by the body.
Single-Category Diets
These diets rely on the intake of only one kind of food, either a fruit or vegetable or
rice alone. However, no single type of food provides the balance of nutrients needed to
maintain health. Some dieters on strange diets suffer the consequences—in one
instance an individual lost hair and fingernails.
Vitamins
Vitamins are needed for metabolism because they make a lot of the body’s enzymes.
An enzyme is what breaks a complex molecule down into a smaller one. To break down a
carbohydrate into a sugar requires enzymes. Vitamins can have other functions, too. For
example, vitamin A makes the visual pigment that prevents night blindness. Altogether
there are 13 vitamins, which are divided into those that are fat soluble and those that are
water soluble.
There are four fat-soluble vitamins: A, D, E, and K. All the other vitamins are water
soluble. The reason this is important is that excess fat-soluble vitamins will be stored in
the body’s fat cells and can easily get to a toxic level. Water soluble vitamins can be
excreted in the kidney, and as long as the person has been drinking a good amount of
water during the day, the excess water soluble vitamins will just flush out. However, if
the person is not well hydrated, those vitamins can cause problems, too.
The liver is also a place where excess vitamin A is stored. As a matter of fact, if you eat
one polar bear liver, you will die of vitamin A poisoning!
A pregnant woman has to be especially careful about taking in too much of vitamins A,
D, E, and K because they will cross the placenta and reach the baby’s body and intoxicate
it. Where on a fetus is fat? A fetus doesn’t have any fat until it is in the last month or two
of pregnancy. Until then, the only fat is on the myelin sheath that surrounds the nerve
cells. If these vitamins lodge here, they will interfere with nerve conduction in the brain.
Vitamin C
Vitamin C is found especially in citrus fruits, such as oranges, tangerines, lemons, etc.
Vitamin D
Skin cells contain a molecule that is converted to vitamin D after UV exposure.
Vitamin D promotes the absorption of calcium by the intestines. The lack of vitamin D
leads to rickets in children. Rickets, characterized by a bowing of the legs, is caused by
defective mineralization of the skeleton. Most milk today is fortified with vitamin D,
which helps prevent the occurrence of rickets.
Antioxidants
As a cell is functioning, it generates molecules that have an extra electron, which is called
a free radical. These free radicals want to run around and get rid of their extra electron
like a hot potato, but none of the other molecules want one, either. The parts of a cell that
usually get stuck with a free radical include DNA, proteins, enzymes, and cell
membranes. This leads to damage there, and can even lead to cancer.
Substances that can deactivate this extra electron are called antioxidants. Vitamins
C, E, and A are believed to defend the body against free radicals, and therefore they
are termed antioxidants. These vitamins are especially abundant in fruits and
vegetables. We should eat at least five servings of fruits and vegetables a day.
It is not wise to take vitamin supplements instead of improving intake of fruits and
vegetables. There are many beneficial compounds in fruits that cannot be obtained from a
vitamin pill. In addition, excess vitamins can cause damage, especially the ones that are
stored in fat, which are A, D, E, and K. These four vitamins during pregnancy will also
quickly cause toxicity to the fetus, resulting in various problems with the brain. The
reason for this is that the only fat in a fetus is on the sheaths that surround the nerve cells,
so that is where the extra vitamins go.
Minerals
In addition to vitamins, various minerals are required by the body. For example, calcium
is needed for bones, teeth, nerve conduction, and muscle contraction. Phosphorus makes
up nucleic acids and ATP, which is the body’s main energy molecule. Potassium and
sodium are important in nerve conduction and muscle contraction. Sodium and chloride
regulate the body’s water balance. Magnesium, zinc, and copper are needed for enzymes
to work. Iodine is needed for a hormone.
Iron is needed for hemoglobin, which transports oxygen around the body in the red blood
cells. Adult females need more iron in the diet than males since they lose some
hemoglobin each month during menstruation.
Calcium
Many people take calcium supplements to counteract osteoporosis, a degenerative bone
disease that many people get as they age. Calcium supplements and vitamin D foods
in addition to exercise is the best way to avoid osteoporosis because the stimulation
from using the bones will cause the body to absorb the calcium supplement better.
The best source of calcium is from dairy products and green leafy vegetables.
Sodium
You only need 500 mg a day of salt, but the average American takes in 4,000 mg every
day. Excess salt can cause high blood pressure. About one-third of the salt in out diet is
from the food; another one-third is added during commercial processing; and we add the
last one-third either during home cooking or at the table in the form of table salt.
Eating Disorders
Obesity
Obesity is about 50 pounds over the ideal weight. Moderate obesity is about 75 pounds
overweight, and severe obesity is 100 pounds overweight. Morbid obesity (close to
causing death) would be about 200 or more pounds over weight.
During childhood, some of our cells have not differentiated into specialized cells yet. If a
child eats a lot of food during infancy and childhood, most of those “blank” cells will
become fat cells. For the rest of their life, that person will have more fat cells than
average. When you lose weight, the fat cells just shrink; they don’t disappear. It’s very
important to start infants and children out in life without too much fat in their diets. The
risk of heart disease and diabetes is higher in obese individuals.
For people who are more than 100 pounds overweight, they may have a surgery that
staples the stomach into a smaller pouch so they feel full after just a few tablespoons of
food. They still need to watch their diet and make sure they get enough nutrients. They
also have to be careful about not jamming excess food in deliberately, because the
stomach can stretch out again.
Bulimia
People with this condition have the habit of eating to excess (called binge eating) and
then purging themselves by some artificial means, such as self-induced vomiting or
use of a laxative. Bulimic individuals are over-concerned about their body shape and
weight, and therefore they may be on a very restrictive diet. A restrictive diet may bring
on the desire to binge, and typically the person chooses to consume sweets, like cakes,
cookies, and ice cream. Then, a feeling of guilt most likely brings on the next phase,
which is a purging of all the calories that have been taken in.
Bulimia causes an abnormal heart rhythm, and damage to the kidneys can even
result in death. This is probably how Karen Carpenter died. Vomiting up the food
causes the stomach acids to eat away at the pharynx, esophagus, and teeth. Dental
problems are frequent, and the esophagus and stomach may even rupture and tear due to
strong contractions during vomiting.
Anorexia Nervosa
In anorexia nervosa, a morbid fear of gaining weight causes the person to be on a very
restrictive diet. Athletes such as distance runners, wrestlers, and dancers are at risk
of anorexia nervosa because they believe that being thin gives them a competitive edge.
No matter how thin they have become, people with anorexia nervosa think they are overweight, so they may not seek medical help.
Their symptoms of starvation include low blood pressure, irregular heartbeat,
constipation, being cold, and they tend to get stress fractures. Menstruation ceases
in females; the internal organs including the brain don’t function well, and the skin
dries up. Eventually, the digestive tract doesn’t function properly, so the food they
do eat cannot provide nutrients.
When death is imminent, the only recourse may he hospitalization and force-feeding. One
psychological reason behind anorexia is that it makes people feel like they have some
control over their lives.