Homocysteine also may make blood more likely to clot by increasing the stickiness of blood platelets. Clots can block blood flow, causing a heart attack or stroke. Increased homocysteine may affect other substances involved in clotting too. However, none of theories has so far been proven. Individuals differ in their levels of homocysteine.
Genetic factors help regulate the level of homocysteine in the blood.
The level of homocysteine in the blood also is affected by the consumption of vitamins, especially folic acid, B6, and B12. Data from the Framingham Heart Study show that only 30-40 percent of the population was getting 200 or more micrograms of folic acid in their diet. The data indicated that for many persons an intake of at least 400 micrograms was needed to keep homocysteine levels from becoming elevated. Data also indicate that homocysteine levels are higher in older persons than younger ones, and in women after menopause than in those before. But more research is needed to confirm and explain these differences.