Clogged Arteries? Your Diet Might Not be the Problem
The plaques that clog our arteries and raise the risk of a heart attack or stroke may come from bacteria living in our mouths and guts, not from food.
This surprising finding by researchers at the University of Connecticut may explain why gum disease is often linked to atherosclerosis – a condition where fat, calcium, cholesterol and other compounds in the blood form plaques on the walls of arteries.
As plaques build up, they narrow the arteries and restrict the flow of blood and oxygen to vital organs in the body. This can lead to heart attacks, strokes, and other serious health problems – and ultimately, death.
The immune system also plays a role.
Immune cells can attach to the artery wall, feed on the fat deposits in the plaques, and multiply. This causes inflammation, which results in thickening of the muscle in the artery wall.
In a vicious cycle, the thickening from the inflammation further helps the formation of plaques and growths known as atheromas.
Diet may not be the culprit
For the longest time, it was assumed that the fatty molecules (lipids) in our diet (from foods such as eggs, butter, meat and fatty fish) were the main source of the fat found in the artery-blocking plaques.
However, new evidence suggests that this is not the case – or at least not the whole story.
There are people who can eat all the fat and cholesterol they like and never develop heart disease.
In a new study, published in the Journal of Lipid Research, researchers analyzed the plaques from patients being treated in hospital.
They found that the growths contained specific types of fat molecules that could not have come from animals. They looked much more like fat molecules made by bacteria!
Bacteria belonging to the Bacteroidetes family make funny looking fat molecules that are distinct from animal-based fats.
The researchers think that these subtle differences might trigger an immune response. Immune cells encountering the fatty deposits will recognize them as not being human and attack them – causing inflammation.
The researchers also found an enzyme in the plaques that breaks down the bacterial fat molecules into substances that cause inflammation.
They suggest that bacterial fats have a dual effect on the arteries. First, the immune system spots them and raises the alarm, and then the enzyme breaks down the fats into molecules that promote inflammation.
The researchers note that the bacteria themselves are not invading the blood vessels and causing problems.
Bacteroidetes bacteria normally colonize the human body without causing any harm, but under certain conditions, they can cause gum disease. Again, the bacteria do not invade, but the fat molecules they make can pass through cell walls and into the bloodstream.
The research team now plans to carry out more detailed analyses to find out exactly where the bacterial fats accumulate and how significant these bacteria are in causing heart disease.