Nattokinase is an enzyme that is included in natto and other natural food products. Natto is a traditional Japanese food that is made from fermented soybeans. The nattokinase enzyme is also found in products with other names, including soy natto, fermented soybeans and natto extract. These natural products have an unusual odor that resembles the smell of a strong cheese and a flavor that tends to be salty and nutty. A dried form of natto does not have the strong odor or flavor of the original form of natto and is generally easier for most people to eat.
Fermented soybeans often have a blood-thinning effect that reduces the ability of a person’s blood to form clots. The blood-thinning effect of this enzyme may help to protect people against medical conditions that are caused by excessive clotting. Abnormal blood clot formation typically inhibits healthy blood circulation.
People have used products with nattokinase to help with the treatment of several health conditions, although scientific research does not generally support the effectiveness of this enzyme in the treatment of any disease. Some users of natto have sought to prevent medical conditions such as angina, stroke and cardiovascular disease by eating this natural food. Atherosclerosis, deep vein thrombosis and peripheral vascular disease are other conditions that some individuals have attempted to treat with a fermented soybean product. People with hemorrhoids, varicose veins and hypertension have also tried to improve their health with natto. Pain, chronic fatigue syndrome and muscle spasms have been treated with this natural food as well.
The general safety of nattokinase has not been thoroughly evaluated by medical or scientific researchers. Pregnant women and breastfeeding mothers may want to refrain from using products that contain nattokinase until they have discussed their use with a physician. Nattokinase may cause an increased risk of bleeding. Doctors typically recommend that patients avoid products with a blood-thinning effect prior to a planned surgical procedure to avoid excessive surgical bleeding.
People who use blood-thinning medications such as antiplatelet drugs or anticoagulant medications may develop an increased risk of abnormal bleeding or bruising if they eat natto. Aspirin, warfarin and heparin are some common drugs that have a potential blood-thinning effect and can interact with nattokinase. Ibuprofen and naproxen users may also want to exercise caution with their use of natto. In some cases, people who are considering the use of natto may benefit from discussing the product with a doctor. Physicians often provide general guidance to their patients about the safe consumption of such foods.