a narrow opening produced by cleavage or separation of parts. 2. cleavage (def 1). 3. Anatomy. a natural division or groove in an organ, as in the brain. verb (used with object), fissured, fissuring. 4. to make fissures in; cleave; split.
A diet rich in potassium helps to counterbalance some of sodium's harmful effects on blood pressure. Foods that are good sources of potassium are listed in the Food Sources of Potassium table on the next page.
More recently, there has been a focus on trying to help prevent atherosclerosis (clogging of the arteries) and heart disease by lowering blood plasma levels of homocysteine. This can usually be accomplished by increasing the intake of vitamins B12, B6, and folic acid. If you take the prescription drug warfarin to prevent blood clots (itâs also used as rat poison!), do not eat natto or take nattokinase. 2  Natto has a high vitamin K content, which may impede the effectiveness of warfarin.