Consuming large amounts of folic acid and vitamin B6 may sharply reduce the risk of heart attack, according to a major study released. The 14-year study found that women whose diets contain high levels of the two vitamins are significantly less likely to develop-heart disease. The findings suggest that the nation's heart disease rate could be cut if people simply ate more green leafy vegetables and other foods containing those nutrients. Eric B. Rimm of the Harvard School of Public Health in Boston led the study.