Heart disease is the leading cause of death for men and women in the United States. According to the CDC, in 2017, it was responsible for 21.8% of all female deaths and 24.2% of all male deaths. The most common cause of heart disease is a narrowing or blockage of the coronary arteries, the vessels that pump blood to your heart.

The villain in this story for years has been cholesterol. Several decades ago, when they started doing open heart surgery, they noticed that patients in the worst condition had high cholesterol levels. Every time they opened a heart attack or stroke victim up, they saw cholesterol clogging everything. So the natural response was to blame cholesterol and look for ways to reduce it.

The problem with that idea is called correlation versus causation.

Let's say a house in your neighborhood catches on fire. The fire trucks rush to put the fire out. Another house catches on fire a week later, so the fire trucks run to put out that one. If you're driving by those fires, the common thing or "correlation" between them is that fire trucks were at the scene both times. You might mistakenly assume that fire trucks cause house fires.

There is a similar problem with cholesterol. As researchers studied the issue, the cause appeared to be something else entirely; an amino acid called homocysteine. The discovery that homocysteine may be one of the primary causes of heart disease happened in 1969.

Doctors were studying children with an inherited disorder of homocysteine metabolism. An 8-year-old boy died of complications from hardening of the arteries. He was far too young to have it build up over time. His extremely high levels of homocysteine triggered the flood of cholesterol.

They also discovered that people with normal cholesterol levels were at significantly higher risk of a future problem if their homocysteine levels were elevated. Here's what they think is happening.

Homocysteine moves through your blood vessels like a spur. As it builds up, it can damage and scar the lumen, the inside of the blood vessel. Then cholesterol does its job, showing up like a fire truck to deal with the damage. But as the scarring continues, the cholesterol plaques continue to accumulate. Imagine lots of fire trucks starting to block the streets because of all the house fires.

Yes, cholesterol buildup was the thing that created the blockage, but the CAUSE of that cholesterol dam was the higher homocysteine levels.

Here's where we run into a problem. Even though decades of research tell us that higher homocysteine levels can be an early indicator of a problem, no drugs are specifically designed to reduce it to safe levels. Without an easy prescription to deal with the problem, many doctors won't test homocysteine levels, and some insurance companies won't pay for it. But knowing what your homocysteine level is can be extremely important.

So what causes homocysteine to get out of control?

The Framingham Heart Study showed that the homocysteine levels of elderly participants are related to dietary deficiencies. Three things in particular. A deficiency of vitamin B6 or folate and reduced absorption of vitamin B12. About two-thirds of participants were deficient in one of these three B vitamins.

But taking vitamin pills wasn't the answer. When clinical studies gave subjects vitamins to reduce their homocysteine levels, it didn't reduce their chance of having heart disease.

Most doctors consider a normal level of homocysteine in the blood to be less than 15 micromoles per liter (mcmol/L) of blood. But that number may be too high. The Finland study of stored blood samples from the 1970s showed that countries with homocysteine levels below 8 mcmol/L, such as France, Spain and Japan, have a significantly lower risk of mortality than countries in the 10-11 mcmol/L range, such as Finland, Germany and Ireland. Based on that data, your goal should be to get below 8 mcmol/L.

Here's what research has shown can help reduce those levels.

Talk to your doctor or healthcare provider about getting a test if you have a vitamin B6, B12, or folate deficiency. You may also want a test if you have risk factors for heart disease. Once you have the results, talk to your doctor about a plan to deal with it. You also want to find out the best time for a follow-up test to track the progress of your actions.

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Reference Links:

Homocysteine and thrombosis: from basic science to clinical evidence

Anetta Undas, Jan Brożek and Andrzej Szczeklik
Thieme Thrombosis and Haemostasis, 11 August 2005 - Published Online 14 December 2017

Click Here for the Study: https://www.thieme-connect.de/products/ejournals/abstract/10.1160/TH05-05-0313

 

Homocysteine and the pathogenesis of atherosclerosis

Kilmer S McCully
Expert Review of Clinical Pharmacology, Published online: 05 Feb 2015

Click Here for the Study: https://www.tandfonline.com/doi/abs/10.1586/17512433.2015.1010516?journalCode=ierj20

 

Homocysteine and Heart Disease

Kilmer S McCully
US Cardiology, 2004;1(1):1-4

Click Here for the Study: https://www.uscjournal.com/articles/homocysteine-and-heart-disease

 

Role of homocysteine in the development of cardiovascular disease

Paul Ganguly and Sreyoshi Fatima Alam
Nutrition Journal BMC, Published online 2015 Jan 10. doi: 10.1186/1475-2891-14-6

Click Here for the Study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4326479/

 

When HDL cholesterol doesn’t protect against heart disease

Harrison Wein, Ph.D.
NIH Research Matters, March 22, 2016

(Original paper no longer available. Paper archived for reference.)

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