Folic Acid May Fight Throat Cancer
Early Tests Show Promise Against Laryngeal Cancer, Researchers Report
WebMD News Archive
June 12, 2006 -- The B vitamin folic acid, also called folate, is being
studied as an anticancer agent to help prevent cancerof the
Folic acid is found in dark green, leafy vegetables (such as spinach and
turnip greens), dried beans and peas (including black-eyed peas and lentils),
and foods fortified with folic acid (including enriched grain products). Folic
acid is also available from supplements.
Doctors in Italy recently studied folic acid's effects on laryngeal
leukoplakia, which are precancerous lesions in the larynx. While more tests are
needed, early results showed laryngeal leukoplakia didn't turn into cancer
while patients were taking folic acid supplements, and – in some patients – the
precancerous lesions disappeared.
The researchers included Giovanni Almadori, MD, who works at the Universita
Cattolica del Sacro Cuore's Institute of Otolaryngology in Rome. Results appear
in the early online edition of the journal Cancer.
Almadori's team had previously reported that people with laryngeal
leukoplakia tend to have lower blood levels of folic acid than people without
Folic Acid Supplements
So the researchers gave folic acid supplements to 43 adults with laryngeal
leukoplakia for six months.
The patients had lower blood levels of folic acid than people without
laryngeal leukoplakia when the study started.
European countries don't fortify grain products with folate, according to
the nonprofit European Food Information Council's web site. And the patients
hadn't taken supplements of folic acid, or the closely-related vitamin B 12, in
the previous six months.
The patients weren't heavy drinkers, but more than 80% were smokers. Smoking
and heavy alcohol use can boost the risk of laryngeal leukoplakia, the
Checking for Cancer
Every eight hours, participants took oral supplements containing five
milligrams (mg) of folic acid.
Blood levels of folic acid rose in the patients during the study. Meanwhile,
blood levels of homocysteine – an amino acid that at elevated levels has been
associated with increased risk of cancer and heart disease-- fell, the researchers report.
Doctors checked the participants' laryngeal leukoplakia every 30 days.
The participants' laryngeal leukoplakia didn't progress to cancer during the
study. In addition, 12 patients (28%) had a "complete response,"
meaning the laryngeal leukoplakia faded away, the researchers write.
Nineteen others had a "partial response," write Almadori and
colleagues. In those patients, the laryngeal leukoplakia shrank but didn't
The remaining 12 patients had no change -- for better or worse.
During the follow-up period -- which lasted a year on average -- laryngeal
lesions returned in three patients.
The researchers caution that "definitive conclusions are far from being
drawn" since Almadori's team can't rule out the possibility that the
laryngeal leukoplakia might have gone away on its own, with or without folic
They plan a larger, longer study of folic acid supplements in people with
Upper Limit for Folic Acid Intake
Folic acid is water-soluble, which means excess amounts are usually excreted
in the urine. However, the federal Office of Dietary Supplements (ODS) notes
that the Institutes of Medicine has set an upper limit of 1 milligram per day
for adults aged 19 and older. Almadori's study used a much higher dosage of
folic acid, but it did not address any side effects.
Getting more than the upper limit of folic acid could trigger symptoms of
vitamin B12 deficiency, states the ODS. Signs of vitamin B12 deficiency include
anemia, fatigue, weakness, constipation, loss of appetite, weight loss, numbness or tingling in the hands
and feet, and depression.
Such symptoms are also seen with other conditions, so check with your doctor
about any concerns.