Folate Update

Which "Five-A-Day" is Best for Health?

Despite strong evidence that shows eating regular daily servings of "powerhouse" fruits and vegetables can reduce the risk of chronic disease, new research says our intake of them is extremely low, and that overall fruit and vegetable intake is leveling off. Writing in the March issue of the Journal of the American Dietetic Association, Dr. Marilyn S. Nanney of St. Louis University, says that although many of us recognize the need to consume at least 5 fruits and vegetables daily, we aren't making the most nutritious choices because of unclear dietary recommendations from health organizations (1). According to Dr. Nanney, the fruits and vegetables that do the best job in reducing health risks include dark green leafy vegetables (e.g. spinach and greens), yellow/orange fruits (e.g. carrots and winter squash), citrus fruits (e.g. oranges) and cruciferous vegetables (e.g. broccoli, cauliflower and brussels sprouts).

In addition to its role in preventing birth defects in newborns, studies have identified folic acid (also called folate), as one component of dark green leafy vegetables that's directly linked to reduced risk of several chronic diseases including cardiovascular disease, and cancers of the colon and breast. Recent findings from Stockholm's Karolinska Institute and the Centers for Disease Control (CDC) underscore the importance of folic acid and the need to put more greens on our daily menu.

Folate May Help Protect Against Ovarian Cancer

In addition to the mounting evidence for a protective effect of folic acid on breast and colorectal cancer, a high dietary intake of folic acid may also play a role in reducing the risk of ovarian cancer, especially among women who consume alcohol. While the incidence of ovarian cancer is not as high as some other reproductive cancers, it's dangerous because it can often be at an advanced stage before symptoms appear and it is detected.

This study, conducted in a group of 61,000 women, found that women who consumed the highest amount of folate reduced their risk of ovarian cancer by 1/3 compared to women eating lesser amounts of this B-vitamin (2). Alcohol interferes with folic acid metabolism but a Harvard team previously demonstrated that the increased risk of major chronic diseases associated with heavy drinking was greatly reduced among women with higher folic acid consumption (3).

Folate Reported To Be Cutting Deaths From Stroke

Research has shown that folic acid, B6 and B12 can lower homocysteine - a risk factor for heart disease and stroke when levels are too high. Now researchers are examining whether giving folic acid or a combination of these B-vitamins can cut the risk of death or further cardiovascular events in people who already have heart disease. At the American Heart Association conference in March, researchers from the CDC announced evidence that deaths from stroke are falling 3 times faster than expected in both women and men, and that this dramatic drop coincides with folic acid fortification of the nation's food supply (4), and increased publicity about the benefits of taking supplemental folate.

For a variety of reasons both stroke and heart attacks had been declining gradually during the 1990's - more so for men than women. But the rate of decline dramatically sped up after folate fortification of flour began in 1996. That accelerated decline translates into an estimated 31,000 less stroke deaths each year. While the effects on heart attack were less pronounced, it still will result in an estimated 17,000 fewer deaths yearly. Since stroke and heart disease are leading causes of death, small changes translate into large public health numbers. While this report suggests an important effect of folic acid in the general population, some groups - younger Afro-American women for example - still do not appear to be getting adequate amounts (5).

References

1. Nanney MS et al. Rationale for a consistent "powerhouse" approach to vegetable and fruit messages. J Am Diet Assoc 104:352-6, 2004
2. Larrson SC et al. Dietary folate intake and incidence of ovarian cancer: the Swedish Mammography Cohort. J Natl Cancer Inst.96:396-402, 2004.
3. Jiang R et al. Joint association of alcohol and folate intake with risk of major chronic disease in women. Am J Epidemiol 158:760-71, 2003.
4. Botto LD et al. Improvement in CVD and stroke mortality after flour fortification with folic acid. LB 27, AHA 44th Annual Conference on CVD Epidemiology and Prevention, San Francisco, March, 2004.
5. Patrick TE et al. Homocysteine and folic acid are inversely related in black women with preeclampsia. Hypertension April 19, 2004 (Epub ahead of print).