Health experts know that the way blood flows in our blood vessels and its thickness affects the formation of blood clots and whether or not we suffer a heart attack or a stroke.

They also know that diet can have a major effect on how the blood flows and how it coagulates which means dangeous blood clots can be prevented.

What are blood clots?
Clots are formed in the blood when the body needs them. When the inside of the arteries gets damaged, platelets come to the injured area and start forming a kind of seal to prevent blood from leaking out of the blood vessels. These platelets release chemicals that activate clotting factors which ultimately will produce a blood clot.

Blood clots can form in several parts of the body
A clot can form in the arteries that supply blood to the heart. It can block the blood flow completely or partially, reducing the oxygen supplied to the heart, causing a heart attack (total blockage) or an angina (a partial supply of oxygen to the heart).

A blood clot can form in the eye, leading to permanent blindness.

A blood clot can also form in the brain, cutting the supply of oxygen. The result is a stroke.

Blood Clot Symptoms
1. A blood clot in the arteries can lead to a heart attack or angina. People experiencing a heart attack or angina may feel intense pain that appears all of the sudden in the middle of the chest or in the pit of the stomach. It usually extends to the shoulders, left arm, neck, jaw, and back. They can also feel an acceleration of pulse, a feeling of being cold, sweating, pale, anxiety and feeling of imminent death.

2. A person experiencing a stroke caused by a blood clot usually feels a loss of sensation on one side of the face which can result in paralysis of that area. The person may experience difficulty in talking if the left side of the brain is affected. Other symptoms of blood clots in the brain include severe headaches, confusion or loss of balance and coordination.

3. Blood clots in the veins may cause swelling, pain, redness and a sensation of warmth. Blood clots in the veins can travel to other parts of the body such as the lungs and cause pulmonary embolism.

Blood clots, the triggering factor of heart attacks
Cardiologists used to think that the triggering factor for heart attacks was the alteration of the cardiac rhythms due to the narrowing of the arteries. Now they know that blood clots are the immediate cause in 80 to 90% of heart attacks and that diet can influence some factors that influence the formation of blood clots in the following manner:

Diet can influence platelet aggregation. Platelets are the smallest blood cells and they tend to group or adhere to blood vessel walls, promoting blood clots.
Diet can influence fibrinogen. Fibrinogen is a blood-clotting factor. A high level of fibrinogen in the blood is a high risk for blood clot formation.

Diet can affect the fibrinolytic factor, a system charged with breaking down and dissolve dangerous blood clots. The intensity of this activity along with the amount of fibrinogen is the main risk factor for cardiovascular disease.

How to control blood coagulation
Doctors always advise us not to take aspirin before surgery because this drug can thin the blood and reduce blood clotting, increasing the length of bleeding and the possibility of complications.

But have you ever heard a doctor advising a patient before surgery not to eat garlic or onions? Well, these two foods are anticoagulants that can slow down the tendency of blood clots to form through the same mechanisms as aspirin does.

On the other hand, foods like cheese or red meat make blood flow slower because they increase platelets stickiness and its capacity to form blood clots. There is no doubt that if you regularly eat the right foods, even in small quantities, you can affect substantially the tendency of the blood to coagulate, protecting yourself from blood clots, whether in the legs, lungs, heart, and brain.

Garlic and onions as blood tonics
Papyrus in ancient Egypt already described garlic and onions as powerful blood tonics and the first American doctors prescribed onions to “purify” the blood. French farmers give garlic and onions to horses to dissolve blood clots. And now modern research has confirmed what our ancestors believed about garlic: that it can have a positive effect on our blood flow.

The anti-clotting properties of garlic
Eric Block, Ph.D., leading researcher at Department of Chemistry, University of Albany, isolated a compound in garlic named ajoene, a compound that has antithrombotic (anti-clotting) properties. It helps prevent platelets in the blood from forming blood clot. Its anti-thrombotic activity is equal or superior to aspirin.

Actually, aspirin works through one single mechanism, preventing the production of thromboxane, but ajoene, not only does the same but also blocks the aggregation of platelets in seven more ways. Medical researchers at the George Washington University have identified three very important anticoagulants compounds in garlic and onions, one of them being adenosine.

The anti-thrombotic activity of garlic in humans has been documented in several studies. A study conducted in India with 50 medicine students, showed that three garlic cloves a day reduced the time of coagulation by about 20 percent.

An investigation carried out in Germany showed that garlic compounds speeds up the breakdown of blood clots and improves blood flow. According to the researchers of Saarland, Homburg/Saar, this simultaneous action improves blood flow and helps purify the blood eliminating blood debris.

How much garlic?
One or two garlic cloves is enough to have a beneficial effect on the coagulation activity, according to British Dr. David Roser. Garlic can be eaten raw or cooked because heat does not destroys the anti-thrombotic compounds. In fact, it heat helps release them.

Onions block fat in food
Dr. Victor Gurewich, professor of medicine at Harvard University, advises patients with a cardiovascular condition to eat onions every day because their components prevent the aggregation of platelets and speed up the dissolution of blood clots.

Doctor N. N. Gupta. Professor at the K. G. Medical College of Lucknow, India, fed a group of men with foods rich in the type of fat found in butter and cream and observed a substantial decrease in the activity of blood clot formation.

Then, he fed the same group with the same foods rich in fat but he added 60 grams of raw onion, cooked or fried. A blood test conducted four hours after the group had eaten, he observed that the onion had completely blocked the tendency of fat to form blood clots; less than half a cup of onions was enough to accomplish this result.

The bottom line
Better not to eat too many foods that have saturated fat, but if you do, always add onions. Pieces of onions on your hamburger or pizza could be the solution to prevent the fat in these foods from forming blood clots. And remember to add garlic to your meals to reinforce the onions effect.

To your health!

Emilia KIapp, R.D.,B.S.

Author's Bio: 

Emilia Klapp has a Bachelor in Nutrition Science and is certified as a Registered Dietitian. She is the author of The Diabetes Club, a blog dedicated to inform people how to prevent and control diabetes through nutrition and exercise. To obtain a list of calories, fat, sodium, and carbohydrates contained in fast food served at Fast Food Restaurants as well as weekly information on “Food Combining” go to