Homocysteine is one of the most important biomarkers for heart health, yet it's left unchecked by most primary care physicians.
Having too-high levels of homocysteine is often a result of being low on certain B vitamins — and B vitamin deficiency just happens to be pretty common in the U.S. Elevated levels of homocysteine are linked to cardiovascular issues and can even impact your brain health and mood.
That's why it's so important to monitor your levels and make sure they're at an optimal range.
Here's what you need to know about the vital role homocysteine plays in your body, and how to optimize your levels of this important chemical.
What Is Homocysteine?
Before we get into what homocysteine is, it's important to understand what amino acids are and the role they play in the body. Amino acids are what proteins are made up of, which is why they're often referred to as the "building blocks of protein." Your body needs proteins to build and repair your cells and tissues, keep your immune system functioning, and produce hormones, among other essential functions.
There are 20 main amino acids. Homocysteine is a chemical in the blood that's produced as a result of the breakdown of one specific amino acid called methionine, per a 2005 report in Circulation.
But your body needs B vitamins to make use of that homocysteine.
Specifically, vitamins B2 (riboflavin), B6 (pyridoxine), B9 (folate or folic acid), and B12 (cobalamin) are needed to break down homocysteine into other key chemicals in your body through a process called methylation.
"Homocysteine is a key biomarker that reflects both one’s intake of B vitamins as well as a genetic ability to put the B vitamins in a methylated form," says Lifeforce Physician Julia Afridi, DO, ABIHM.
Why Is Homocysteine Important?
Homocysteine plays many important roles in the body, but it's especially vital because it acts as a precursor to a very important antioxidant called glutathione, Dr. Afridi says.
Glutathione is a powerful antioxidant that your body naturally makes, and it helps neutralize free radicals, supports your immune system, and breaks down nutrients. Low glutathione levels are linked to serious health conditions, such as neurological diseases (Alzheimer's and Parkinson's), cancer, heart attack, stroke, and diabetes, according to a 2004 study in the Journal of Nutrition.
Not only that, but your homocysteine levels give you an inside look into your body's B vitamin status. High homocysteine levels usually indicate that you're not getting enough B vitamins.
"When homocysteine levels get too high either due to low intake of B vitamins or the body's inability to methylate them, then there is less of this antioxidant activity occurring in the body," Dr. Afridi says. Less antioxidant activity puts you at a higher risk for chronic health conditions.
OK, so you're well aware of how important it is to maintain healthy homocysteine levels. But how high is too high, and what should you aim for?
Here's a breakdown of homocysteine levels and what they mean:
Homocysteine and Cardiovascular Disease
Having high levels of homocysteine in the blood irritates the blood vessels, and can increase the risk of heart disease, stroke, and blood clots, says Lifeforce Physician Cono Badalamenti, MD, MHSA.
Here's how it manifests: Elevated levels of homocysteine can potentially harden the arteries (a condition called atherosclerosis), which raises your risk of heart attack and/or stroke. High homocysteine levels can also contribute to blood clots in the veins (a condition called venous thrombosis), per the Circulation report.
Maintaining healthy homocysteine levels is key to keeping your heart healthy, so much so that reducing total homocysteine by 3 µmol/L is associated with a 24% reduced risk of stroke and a 16% reduced risk of heart disease, per a 2004 JAMA study.
Other Risks of High Homocysteine
High homocysteine in the blood can even increase the risk of dementia, says Dr. Badalamenti. According to a 2018 study in the Journal of Alzheimer's Disease, a homocysteine level of 10.8 umol/L (which is just above the optimal level but within the normal level) is linked to an increased risk of dementia.
Plus, "the inability to methylate B vitamins may also have negative impacts on mood and cognition," Dr. Afridi says.
High homocysteine levels are also associated with osteoporosis as it reduces bone blood flow and causes bones to become more fragile, per a 2017 study in the Journal of Cellular Physiology.
How to Optimize Your Homocysteine Levels
A homocysteine level of less than 13 μmol/L is considered normal — however, you'll want to aim for a bit lower than that, according to Lifeforce Medical Director Vinita Tandon, MD. “Optimal levels of homocysteine are around 5-10 umol/L,” says Dr. Tandon.
You can get your homocysteine levels checked through a basic blood test, but it's not always offered by PCPs. And while "you can also test for B vitamin levels, these [numbers] don’t tell you how well you methylate [B vitamins], so they won't necessarily reflect your homocysteine level," Dr. Afridi says. So your best bet is to get your homocysteine levels specifically checked.
The two main risk factors for high homocysteine levels include low B vitamin intake and genetics. And the so-called "solution" depends on the root cause of your high homocysteine levels.
Here's what you can do to help optimize your levels:
1. Load Up on B Vitamin-Rich Foods
B vitamin deficiency is fairly common, especially as we age. About 6% of adults younger than 60 years old and about 20% of adults older than 60 have vitamin B12 deficiency, per the National Institutes of Health.
If your high homocysteine levels are a result of not getting enough B vitamins, you'll want to load up on vitamin B-rich foods, Dr. Afridi says.
Make sure to include the following in your diet:
Vitamin B6: Foods high in B6 include salmon, chicken breast, fortified tofu, pork chops, beef, and sweet potatoes.
Vitamin B9 (folate): Top sources of B9 include edamame, lentils, dark leafy greens, asparagus, broccoli, and avocado.
Vitamin B12: You can get B12 from clams, fish, crab, low-fat beef, fortified cereal, fortified soy products, low-fat dairy, cheese, and eggs.
2. Consider a Supplement
"Certain genetic influences such as having one or two copies of the MTHFR gene will limit the ability to methylate B vitamins and make one at a higher risk for having elevated homocysteine," Dr. Afridi says.
"If you have genetic influences that prevent you from forming methylated B vitamins, you can take a methylated B vitamin like Lifeforce Methylation to support optimal homocysteine." However, always speak to your doctor before starting a new supplement regimen.
This article was medically reviewed by Julia Afridi, DO, ABIHM Board Certified in Family and Osteopathic Medicine.