Breast Cancer Prevention (cont.)
Are there other breast cancer prevention measures?
Free radicals
Free radicals are electrically charged chemicals that can attack and damage
proteins and DNA, thereby altering genetic information. If enough damage occurs
to the DNA segments of a cell that controls cell division and growth, cancer can
develop from that single cell.
Free radicals can be formed by the normal metabolic
activity in the body. The cells in the body chemically transform nutrients
(sugars, fats, and proteins)
into substances that the muscles, brain, and other organs can use as energy.
Such transformations involve many chemical reactions and multiple energy
transfers between chemicals. During this metabolic process, free radicals can be
formed.
Free radicals also occur when cells are exposed to radiation. The body is
regularly exposed to low levels of radiation in the atmosphere. The body also
receives radiation during mammography and other x-ray tests. Theoretically,
these low levels of radiation can lead to the formation of free radicals. (The
amount of radiation in the atmosphere and in carefully performed x-rays tests is
generally considered safe.)
Fortunately, a healthy body is well equipped to destroy free radicals and
prevent cells with damaged DNA from becoming cancerous. The body is capable of
quickly recognizing and destroying free radicals. For example, the body has an
enzyme called superoxide dismutase that regularly cleans up free radicals and
prevents them from damaging cells and proteins. The body can repair DNA damage
caused by radiation or free radicals. The body is also capable of quickly
destroying cells that have irreparable DNA damage to prevent them from turning
cancerous. The immune system also seeks out cells with DNA damage and destroys
them.
However, an overload of free radicals can cause damage
to the system that destroys free radicals and damage to DNA repair systems. This
damage or a weakened immune system can contribute to cancer development.
Antioxidants
Antioxidants are chemicals that prevent a type of chemical reaction
called oxidation. Oxidation is a major source of free radical formation. Antioxidants
also mop up the free radicals that are formed. Superoxide dismutase is one
example of an enzyme that acts like an antioxidant. Other naturally occurring
antioxidants include beta carotene, vitamin E, and
vitamin C. Fruits and
vegetables are safe and rich sources of antioxidants. A somewhat controversial
substance is caffeine. In several laboratory studies, caffeine acted like an
antioxidant that cleans up free radicals. At present, there is no evidence that
caffeine or coffee affects breast cancer risk. Also, some caffeine-containing
substances, such as tea, have apparently been shown to decrease cancer risks.
The relationship between meats, fats, and breast cancer
Early epidemiological studies suggested that high-fat
diets might be
associated with increased risks of breast cancer. But this relationship has not
been confirmed, and it is clear that some fats may be protective rather than
harmful. There are, however, some theoretical concerns about eating overcooked
meats and fats.
From person to person, there are many "normal" variations in individual
metabolic systems (sequences of enzymes and proteins). Some of these variations
lead to different risks from potential cancer-causing exposures. Examples of
systems with the potential for individual variation in management of these
potential toxins are:
- NAT-2 is a well-studied enzyme in the body that converts substances from
overcooked meats into active agents that can damage DNA. There are two forms of
NAT-2 enzyme—fast- or slow-acting. When an individual with the fast-acting
NAT-2 enzyme consumes overcooked meat, the agents that damage DNA can accumulate
rapidly.
- Another enzyme in the body is lipoxygenase. Fats in the diet are converted
into fatty acids, linoleic acid, and arachidonic acid. Lipoxygenase further
converts linoleic and arachidonic acids into chemicals that are potent
stimulators of cell growth. These chemicals not only increase the risk of
developing cancers, they also promote the growth of cancers and encourage cancer
cells to metastasize.
- Even though we cannot change our individual NAT-2 or lipoxygenase enzyme
activities, we can reduce the consumption of fats and overcooked meats.
- There also appear to be certain types of fats such as
omega-3 fatty acids that protect against the formation and activation of
injurious fatty products. These are found in higher concentration in many fish. There are both
epidemiological and laboratory studies which show these benefits.
Diet to reduce breast cancer risk
Theoretically, there are dietary measures that can decrease free-radical
formation and reduce the risk of developing breast and other types of cancer. These measures are:
- diets rich in vegetables and fruits,
- diets low in fats, and red and overcooked meats,
- reasonable intake of anti-oxidants such as vitamins E and C,
- regular exercise and weight reduction, and
- avoiding cigarettes.
Evidence that these measures reduce the chances of developing breast cancer
is largely based on epidemiological data. Epidemiological evidence is derived
from comparing two large populations with similar characteristics that have
different diets or levels of exercise. Epidemiological evidence can only be
suggestive, not conclusive. In fact, concrete proof that diet and exercise
actually reduce the risk of developing breast cancer will be difficult to
attain.
When firm scientific data is lacking and is unlikely to be available for the
foreseeable future, the doctor has to weigh the risks of his/her recommendations
against the potential benefits. Long-term risk and benefit considerations are
especially important in advising young, healthy women about preventing a disease
that they may or may not develop.
In the case of diets low in fat and overcooked meats, diets high in
vegetables and fruits, avoiding smoking, and regular exercise, there is enough
known benefit and very little known risk, which makes it easy for doctors to
recommend them to their patients.
Doctors are also comfortable with recommending one multivitamin a day.
However, there is no clinical evidence that taking mega-doses of vitamins are of
any benefit. Mega-doses of certain vitamins can have adverse side effects.
Exercise
There is epidemiological data which show that women who exercise regularly
have a lower incidence of breast cancer than women who do not exercise. The
reason for such a benefit is unknown, but it may be related to the fact that
obese individuals have
higher levels of estrogen in the body than non-obese people. The higher levels
of estrogen may increase the risk of breast cancer in obese women. For
additional information, please visit the Fitness Center.
Next: Conclusion »
- tamoxifen, Nolvadex -
- Breast Biopsy - Learn about the different types of breast biopsy procedures, which are used to remove suspicious breast growth and examined for the presence of cancer.
- Breast Cancer - Get the facts on breast cancer symptoms, signs, stages, types, research, risk factors, diagnosis, prevention information and treatment options: mastectomy, chemotherapy, radiation therapy.
Latest Medical News
Cancer RSS