By Karen Collins, American Institute for Cancer Research
Q: What causes pancreatic cancer? Is diet involved?
A: While there's no way to say what ``causes'' any individual
case of the disease, researchers are beginning to find risk factors
that may identify those most and least likely to develop pancreatic
cancer. Smoking clearly increases risk of the disease. The
strongest link named in a major report on diet and cancer risk from
the American Institute for Cancer Research is that eating more
fruits and vegetables probably helps prevent pancreatic cancer.
Diets high in red meat, especially meats that are smoked or cooked
by high-temperature frying or grilling, may increase risk. This
seems to be not so much due to meat's fat, but to substances formed
when meats are processed or cooked in these ways. Both the AICR
report and a new study in the Journal of the National Cancer
Institute identify high-calorie intake as possibly related to
pancreatic cancer. In the new study, those who were the most
overweight and ate the most calories had almost twice the
pancreatic cancer as those with lowest weight and calorie
consumption. The AICR report also notes that while more research is
needed, some studies have found that diets high in sugar could
increase risk, too.
Q: What's the nutritional value of the vegetable called jicama?
A: Jicama, with a crunchy texture like that of water chestnuts,
is easy to just peel, slice and serve raw. It is a good source of
vitamin C as well as dietary fiber. The amount of other nutrients
is negligible, and we don't yet know of any phytochemicals present
in significant amounts. Jicama itself is low in calories -- just 23
in a half cup -- but that doesn't count the dips commonly used in
serving it. Rather than worrying about choosing only the ``best''
vegetables, current research emphasizes simply making a wide
variety of fruits and vegetables a major part of our diet.
Q: Is zinc important for healthy eyes? Where is it found?
A: It's not clear why zinc is important for eye health, although
it is present there in concentrated levels, and zinc seems to be
necessary for the function of several important enzymes. When zinc
supplies are extremely low, vision problems can develop. Some
research has shown that getting enough zinc may help prevent a
disorder called macular degeneration that can lead to blindness,
but other studies have found zinc unrelated to this problem.
However, zinc is also essential for immune function, wound healing,
and overall tissue growth and maintenance. The main sources of zinc
in our diets are lean meats and seafood, dairy products, whole
grains and dried beans. A balanced diet should provide all you
need. While zinc is needed for immune function, too much can
actually hurt the immune system. To avoid this and other toxic
effects (such as anemia and copper deficiency), experts recommend
that if you take nutritional supplements, the total amount of zinc
should not be more than 15 milligrams, which is 100 percent of
Daily Value.
