The B list The fact that high homocysteine levels can be dangerous for your heart hasn't been news to HSI members for a long time. In e-Alerts and, for over seven years in Members Alerts, we've often examined the negative role this amino acid is known to play in heart disease. Fortunately, studies have shown that homocysteine levels may be controlled with ample amounts of folate - the B vitamin also known as folic acid. Now a new study offers conclusive evidence that folate may significantly lower the risk of stroke, especially when combined with another key B vitamin. We'll check in with HSI Panelist Allan Spreen, M.D., for his insights on combining B vitamins at the right dosage to optimize folate effectiveness. Because previous studies have shown that high levels of homocysteine are associated with a deficiency of folate, vitamin B-6, and B-12, researchers at Northwestern University in Illinois designed a study to examine intakes of these three vitamins in relation to risk of the two basic types of stroke: ischemic and hemorrhagic. Ischemic stroke occurs when an artery that leads to the brain is blocked, and a hemorrhagic stroke is the result of a ruptured blood vessel in the brain. Approximately 80 percent of all strokes are ischemic. At the outset of the study in 1986, more than 43,000 men, aged 40 to 75, were enrolled. At that time, none of the subjects were diagnosed with any cardiovascular diseases or diabetes. Every four years, for a period of 14 years, researchers followed the subjects' medical records and evaluated dietary information with a detailed food frequency questionnaire. At the end of the study period, a total of 455 ischemic strokes and 125 hemorrhagic strokes were recorded. After adjusting for major lifestyle factors such as smoking and exercise, researchers found that the highest intake of folate was associated with an almost 30 percent lower risk of ischemic stroke compared to men who had the lowest folate intake. Higher intake of vitamin B-12 was also associated with a reduced ischemic stroke risk, but B-6 intake was not. And no association was found between any of the vitamins and hemorrhagic stroke. Dietary sources of folate are easy to find. Citrus fruits, tomatoes, leafy green vegetables, and pinto, navy and kidney beans are all good sources of folate. But for many people, folate and B vitamin supplements may be necessary to sufficiently lower homocysteine to levels that will help reduce the risk of stroke. When I asked Dr. Spreen to tell us a little bit about folate, he noted first of all that, "Folate isn't effective in low doses except in a limited percentage of cases." And guess what? Folate supplements are only available in very low dosages of 0.8 mg (or 800 micrograms). Dr. Spreen explains: "That's all from the conventional medical dogma that folate can mask a vitamin B-12 deficiency if you take too much folate and zero B-12." So while taking a B-12 supplement along with your folate would be an obvious solution, the FDA has mandated low doses of folate instead. Dr. Spreen recommends 1.6 mg per day of folate, although he personally believes that a dosage closer to 5 mg would probably be better for those who wish to address cardiovascular problems. As for B-12, he recommends 1 mg (1000 mcg) per day in sublingual form (dissolved under the tongue). Besides adding B-12 to a regimen of folate, Dr. Spreen also recommends that to get the most out of folate, 100 mg per day of B-6 is also necessary, as well as 400-500 mg of magnesium per day (to make the B-6 more effective). For those who are specifically trying to lower high serum homocysteine levels, Dr. Spreen also suggests taking 300-500 mg per day of trimethylglycine (TMG), depending on the severity of cardiovascular status. He says, "TMG is a powerful homocysteine-lowering agent, but it's expensive and not always necessary for use in lowering the levels. There are some people who just don't get a biologic response from the 'standard' agents, folate, B-6 and B-12, so then you'd add the TMG." In previous e-Alerts I've encouraged you to ask your doctor to check your homocysteine levels when you have a blood test. (Most doctors recommend keeping levels below 12 micromoles per liter.) This new study from Northwestern University reinforces the importance of monitoring homocysteine, while also helping to confirm past evidence that risk of cardiovascular disease and stroke may be controlled with a daily regimen of folate and B vitamins.
To Your Good Health, Jenny Thompson
Health Sciences Institute Sources:
"Folate, Vitamin B6, and B12 Intakes in Relation to Risk of Stroke Among Men" Stoke, Vol. 35, No. 1, January 2004, stroke.ahajournals.org
"Folate Reduces Stroke Risk in Men: Report" Alison McCook, Reuters Health, 1/22/04, nlm.nih.gov
"Folate Could Help Prevent Stroke" NutraIngredients.com 1/23/04, nutraingredients.com
"Dietary Intake of Folate and Risk of Stroke in US Men and Women" Stroke, Vol. 33, No. 5, May 2002, stroke.ahajournals.org
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