The New Complete Book of Food
mothers’ not having gotten adequate amounts of folate during pregnancy. The current R DA
for folate is 180 mcg for a woman and 200 mcg for a man, but the FDA now recommends
400 mcg for a woman who is or may become pregnant. Taking folate supplements before
becoming pregnant and continuing through the first two months of pregnancy reduces the
risk of cleft palate; taking folate through the entire pregnancy reduces the risk of neural
tube defects.
Possible lower risk of heart attack. In the spring of 1998, an analysis of data from the records
for more than 80,000 women enrolled in the long-running Nurses’ Health Study at Harvard
School of Public Health/Brigham and Women’s Hospital, in Boston, demonstrated that a diet
providing more than 400 mcg folate and 3 mg vitamin B 6 daily, either from food or supple-
ments, might reduce a woman’s risk of heart attack by almost 50 percent. Although men
were not included in the study, the results were assumed to apply to them as well.
However, data from a meta-analysis published in the Journal of the American Medical
Association in December 2006 called this theory into question. Researchers at Tulane Univer-
sity examined the results of 12 controlled studies in which 16,958 patients with preexisting
cardiovascular disease were given either folic acid supplements or placebos (“look-alike” pills
with no folic acid) for at least six months. The scientists, who found no reduction in the risk
of further heart disease or overall death rates among those taking folic acid, concluded that
further studies will be required to determine whether taking folic acid supplements reduces
the risk of cardiovascular disease.Adverse Effects Associated with This Food
Photosensitivity. Like celery and parsley, parsnips contain psoralens, natural chemicals that
make the skin sensitive to light. Psoralens are not inactivated by cooking; they are present
in both raw and cooked parsnips.
In laboratory animals, psoralens applied to the skin are known to trigger cancers when
the animals are exposed to light. Among human beings, their only documented side effect
is the skin inflammation common among food workers who handle and process vegetables
without wearing protective gloves. In 1981, however, scientists at the U.S. Department of
Agriculture’s Veterinary Toxicology and Entomology Research Laboratory in College Sta-
tion, Texas, suggested that detailed epidemiological studies might link physiological effects
to eating parsnips as well as handling them. The connection remains to be proved.Food/Drug Interactions
* * *