Swedishstudy:folate deficnt diet incrses brstcancer risk (all bc lumped together) 44%
 

Increased folate may slash breast cancer risk [FoodNavigator.com Europe]
09/08/2007 - An increased consumption of folate may reduce the risk of breast cancer by 44 per cent, says a new study from Sweden.
Writing in the current issue of the American Journal of Clinical Nutrition, the researchers state that fruit and vegetables may be a better option to increase folate consumption, and raise questions about folic acid fortification.
"Sweden has not yet come to a decision concerning the mandatory folic acid fortification of foods," wrote the authors, led by Ulrika Ericson from Lund University.
"With regard to the contradictory results from different studies, including an American study that indicated an increased risk at total intakes much higher than in our study an increased consumption of fruit and vegetables would be a safer way to increase folate intakes."
Folate is found in foods such as green leafy vegetables, chick peas and lentils, and an overwhelming body of evidence links has linked folate deficiency in early pregnancy to increased risk of neural tube defects (NTD) - most commonly spina bifida and anencephaly - in infants.
The researchers investigated if there was an association between folate intake and invasive breast cancer risk in 11,699 postmenopausal women over the age of 50. Dietary assessments were done at the start of the study using seven-day diet records, a 168-item food-frequency questionnaire, and an interview about dietary habits.
After 9.5 years of follow-up, 392 cases of breast cancer had been diagnosed. The average folate intake for the women was 238 micrograms per day, and 19 per cent of subjects used folic acid supplements.
The researchers calculated that women in the highest average intake group (456 micrograms of folate per day) had a 44 per cent lower risk of invasive breast cancer than women in the lowest average intake group (160 micrograms of folate per day).
The benefits were still observed after the researchers took into account the intake of other B vitamins, age, physical activity, smoking, alcohol use, and the use of hormone replacement therapy.
However, when the women were divided into normal weight women (BMI of less 25 kg per sq. m) and overweight women (BMI of more than 25), the researchers report that the protective effect of folate only applied to the overweight women.
"Our findings of an association between high folate intake and lower breast cancer incidence confirm the biological hypothesis that low intakes of folate enhance the development of breast cancer," wrote the researchers.

the abstract with source
 

ABSTRACT: High folate intake is associated with lower breast cancer incidence in postmenopausal women in the Malmo Diet and Cancer cohort [American Journal of Clinical Nutrition]
Background: Epidemiologic studies of associations between folate intake and breast cancer are inconclusive, but folate and other plant food nutrients appear protective in women at elevated risk.
Objective: The objective was to examine the association between folate intake and the incidence of postmenopausal breast cancer.
Design: This prospective study included all women aged ?50 y (n = 11699) from the Malmö Diet and Cancer cohort. The mean follow-up time was 9.5 y. We used a modified diet-history method to collect nutrient intake data. At the end of follow-up, 392 incident invasive breast cancer cases were verified. We used proportional hazard regression to calculate hazard ratios (HRs).
Results: Compared with the lowest quintile, the incidence of invasive breast cancer was reduced in the highest quintile of dietary folate intake (HR: 0.56; 95% CI: 0.35, 0.90; P for trend = 0.02); total folate intake, including supplements (HR: 0.56; 95% CI: 0.34, 0.91; P for trend = 0.006); and dietary folate equivalents (HR: 0.59; 95% CI: 0.36, 0.97; P for trend = 0.01).
Conclusion: A high folate intake was associated with a lower incidence of postmenopausal breast cancer in this cohort.

editorial--discusses possible unintended consequences of too much folate
 

OPEN ACCESS:(Free access just google American Jorunal of Clinical Nutrition)
EDITORIAL: Folate and cancer prevention: a closer look at a complex picture [American Journal of Clinical Nutrition]
One should be cautious about drawing strong support from the study by Ericson et al for increasing folate intakes in the general population as part of public health measures. Fortification of grain products has been mandated in several countries for the prevention of neural tube defects. The success of this policy is indisputable, given the significant decreases in neural tube defects in the United States, Canada, and Chile since the initiation of fortification (13). Folate status in the US population has increased substantially; ~40% of the US population has postfortification serum folate concentrations >40 nmol/L—a concentration that has been described as being supraphysiologic (14). At the same time, unmetabolized folic acid is detectable in the circulation of healthy individuals, with unknown physiologic consequences (4). Several European countries are currently considering the introduction of folic acid fortification for the prevention of neural tube defects, perhaps under the assumption that folic acid fortification will also aid in the prevention of cancer and of cardiovascular disease. Yet, as discussed above, there is now increasing evidence from randomized trials that high doses of folic acid can foster the growth of common precancerous lesions. The benefit of reducing a relatively small number of neural tube defects may be outweighed by the possible negative effects on tumor promotion in a substantial fraction of the population. We currently lack good quantitative information on the effects of folic acid on the growth of preneoplastic lesions or on carcinogenic progression. However, even if the extent of these adverse effects was modest, a large number of individuals with cancer precursors would be affected. Thus, a cautionary approach is warranted as we consider whether to recommend an increase in folate status for all.
Folate may play a dual role in cancer development: it may provide protection early in carcinogenesis and in individuals with a low folate status, yet it may promote carcinogenesis if administered later and potentially at very high intakes. We need to evaluate this information carefully when developing public health recommendations and should be mindful that more folate is not better in all circumstances.

editorial--discusses possible unintended consequences of too much folate
 

OPEN ACCESS:(Free access just google American Jorunal of Clinical Nutrition)
EDITORIAL: Folate and cancer prevention: a closer look at a complex picture [American Journal of Clinical Nutrition]
One should be cautious about drawing strong support from the study by Ericson et al for increasing folate intakes in the general population as part of public health measures. Fortification of grain products has been mandated in several countries for the prevention of neural tube defects. The success of this policy is indisputable, given the significant decreases in neural tube defects in the United States, Canada, and Chile since the initiation of fortification (13). Folate status in the US population has increased substantially; ~40% of the US population has postfortification serum folate concentrations >40 nmol/L—a concentration that has been described as being supraphysiologic (14). At the same time, unmetabolized folic acid is detectable in the circulation of healthy individuals, with unknown physiologic consequences (4). Several European countries are currently considering the introduction of folic acid fortification for the prevention of neural tube defects, perhaps under the assumption that folic acid fortification will also aid in the prevention of cancer and of cardiovascular disease. Yet, as discussed above, there is now increasing evidence from randomized trials that high doses of folic acid can foster the growth of common precancerous lesions. The benefit of reducing a relatively small number of neural tube defects may be outweighed by the possible negative effects on tumor promotion in a substantial fraction of the population. We currently lack good quantitative information on the effects of folic acid on the growth of preneoplastic lesions or on carcinogenic progression. However, even if the extent of these adverse effects was modest, a large number of individuals with cancer precursors would be affected. Thus, a cautionary approach is warranted as we consider whether to recommend an increase in folate status for all.
Folate may play a dual role in cancer development: it may provide protection early in carcinogenesis and in individuals with a low folate status, yet it may promote carcinogenesis if administered later and potentially at very high intakes. We need to evaluate this information carefully when developing public health recommendations and should be mindful that more folate is not better in all circumstances.

Thank Lani as usual fro your interesting posts and consistent dedication to bring this information to people.

"Folate is found in foods such as green leafy vegetables, chick peas and lentils,"

Are they measuring folate or the wider impact of a high folate from food diet green veg etc. as against supplementation (supplementation clearly prevent birth defects etc. its never simple)

What were the sources of folate of the people reported on? In other words is the benefit the folate or more green veg beans etc??

RB

This is all so very interesting... just be aware to steer clear of folic acid supplementation (multis and B complex) while on Tykerb/Xeloda. It can worsen the side effects....

Lani,

Another interesting case of one substance being both helpful and harmful at different levels and in different people. Thanks for the post.

Hopeful