Folic acid in multivitamins is linked to breast cancer
Women who take conventional multivitamins may be
endangering their health. A 9 year study in Sweden
found that women who took multivitamins were actually
more likely to be diagnosed with breast cancer. Why?
The researchers think that it could be the high dose of
folic acid found in most multivitamins.1
Folic acid is the synthetic form of folate, one of the B vitamins.
Natural folate, abundant in green vegetables,
is known for preventing neural tube defects during early pregnancy,
and is also important for immune function,
cardiovascular health, and cancer prevention.
Taking synthetic folic acid is not the same as
getting natural folate from plant foods.
The body processes folate and folic acid differently.
Real folate from food is protective,
fake folate from supplements may be dangerous:
A study compared breast cancer mortality rates between women who took folic acid during their pregnancy and those that did not. Thirty years later those women who followed the typical recommendations to take folic acid were twice as likely to die from breast cancer.2 A 10-year study on women taking multivitamins concluded that those who took multivitamins containing folic acid increased their breast cancer risk by 20-30%.3 A study investigating both food folate and synthetic folic acid found that only supplemental folic acid increased breast cancer risk. In other studies, women with low levels of food folate intake were more likely to be diagnosed with breast cancer.4,5 Not enough natural folate and too much folic acid both increase risk.
Not enough natural folate and too much folic acid both increase risk.
Folic acid may disrupt the normal actions of natural folate,
resulting in increased risk of several cancers, breast cancer included
(and Americans are consuming more folic acid than ever before. Between conventional multivitamins and mandatory fortification of refined grain products (white rice, white flour, etc.), Americans are exposed to excessive amounts
of folic acid on a daily basis. Many scientists have expressed concern that this excess folic acid poses serious risks of cancer to the population.6-9
Most people (including most physicians) are completely unaware
that these issues and risks exist; and this ignorance can be dangerous.
Learn more in Dr. Fuhrman's new Position Paper, Issue #45: Folate
References:
1. Larsson SC, Akesson A, Bergkvist L, et al. Multivitamin use
and breast cancer incidence in a prospective cohort of
Swedish women. Am J Clin Nutr 2010;91:1268-1272.
2. Charles D, Ness AR, Campbell D, et al. Taking folate
in pregnancy and risk of maternal breast cancer. BMJ 2004;329:1375-1376.
3. Stolzenberg-Solomon RZ, Chang SC, Leitzmann MF, et al.
Folate intake, alcohol use, and postmenopausal breast cancer risk
in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial.
Am J Clin Nutr 2006;83:895-904.
4. Sellers TA, Kushi LH, Cerhan JR, et al. Dietary folate intake,
alcohol, and risk of breast cancer in a prospective study of
postmenopausal women. Epidemiology 2001;12:420-428.
5. Kim YI. Does a high folate intake increase the risk of breast cancer?
Nutr Rev 2006;64:468-475.
6. Smith AD, Kim YI, Refsum H. Is folic acid good for everyone?
Am J Clin Nutr 2008;87:517-533.
7. Figueiredo JC, Grau MV, Haile RW, et al. Folic acid and risk
of prostate cancer: results from a randomized clinical trial.
J Natl Cancer Inst 2009;101:432-435.
8. Kim YI. Will mandatory folic acid fortification
prevent or promote cancer? Am J Clin Nutr 2004;80:1123-1128.
9. Mason JB. Folate, cancer risk, and the Greek god, Proteus:
a tale of two chameleons. Nutr Rev 2009;67:206-212.
|
No comments:
Post a Comment