I've had a lot of blood tests in the last six years. After a heart attack at 47, you get used to them. Lipid panels, metabolic panels, stress tests and echos. The full monty.

At some point, homocysteine showed up on one of them. My doctor mentioned it briefly, moved on, and I went home, and then one day I Googled it for three hours.

Turns out it's not nothing, and basically nobody talks about it.

The reason this caught my attention wasn't because I suddenly became fascinated by amino acids. It was because after my heart attack I was trying to figure out if there were gaps I wasn't seeing. Cholesterol and statins get all the attention.

Homocysteine felt like one of those things that was maybe being overlooked? There are a lot of studies about it, because, as it turns out, it is quite important to cardiovascular health.

So What Is It?

Homocysteine is an amino acid your body makes as a normal part of metabolism. The problem isn't that you have it, the problem is when it builds up.

Under normal conditions, your body converts it into harmless compounds through a process called methylation. I know a lot about methylation cycles after something we went through with my son, but that’s a post for another time. I had never thought it was something linked to my heart. Think of methylation like a waste processing system for certain byproducts. When it's running well, homocysteine stays low and clears out. When it's not, it accumulates. So? Why should I care?

Well, apparently researchers have consistently observed that people with higher homocysteine levels tend to have higher rates of heart disease and stroke. A 2002 study in JAMA that pooled data from thousands of people found that those who naturally ran about 25% lower homocysteine had about 11% lower rates of heart disease and 19% lower rates of stroke.

So, as with most large amounts of pooled data, that doesn't necessarily prove that lowering your number by itself fixes the problem.

But maybe we should think of homocysteine less like a dial you turn to fix your risk, and more like a smoke detector. A high reading doesn't mean the house is definitely on fire, but it's telling you something is going on worth paying attention to. So, what’s causing the smoke exactly?

Why Would Your Methylation Be Off?

Three reasons come up again and again, and they're all common once you're past 40.

1)    General B vitamin deficiency. The methylation cycle runs on folate (aka B9), B6, and B12. They work as a team. If any one of them is low, the system slows down and homocysteine climbs.

2)    B12 absorption gets worse with age. As you get older, your gut just gets less efficient at pulling B12 out of food. That's common after midlife, for all kinds of reasons, things like stomach acid changes, certain medications, and sometimes immune issues. But guess what? Those on a heart healthy diet (hello, that’s me) might be missing out on more of it because the standard American diet relies more on grass fed animal products that it does on fish and clams. If you are following a Vegan diet, this is an urgent issue to address. But even if you are eating spaghetti with clam sauce every week, with age you can still be running low.

3)    Genetics. You might have seen the MTHFR gene mentioned online. It's a common gene variant that can make one folate-processing step a bit less efficient. My son has it, so the whole family got tested (through MyGeneFood, if you're curious), and it turns out my wife and I both have it too. Most people with this variant still do fine, especially if they're getting enough folate, but it's one more reason I pay attention to the B vitamins I take.

So where should I get my B vitamins

The best answer is always from your diet. Lentils, black beans, edamame, and chickpeas are great sources of B6 and B9, as are leafy greens like Kale. And of course, fish (B6, B9 and B12).

But due to absorption issues and diet choices mentioned above, supplementation may be helpful. 

How do I know? What should I know?

If you do get your homocysteine tested, the result comes back as a single number, basically a measurement of how much homocysteine is floating around in your blood at the time of the draw. A lot of labs won't flag anything until that number is over about 15. But some functional heart docs and researchers get uneasy once you're up in the double digits and would rather see people closer to under 10. So you can get your results back, see a normal range checkmark, and still be sitting higher than some experts would like.

Homocysteine isn't on every routine blood panel, and it's not something everyone necessarily needs checked. But if you've had heart issues, or you're managing cardiovascular risk, or you're just curious about the fuller picture, it's worth asking your doctor about it.

What does high homocysteine do to your body?

It might contribute to hardening of arteries. And this is only when it is VERY high (hyperhomocysteinemia), but it has been shown to irritate blood vessels or cause oxidative stress, that may lead to artery hardening, bloodclots, and perhaps even dementia.  So, worth keeping an eye on, yes?

So that’s why homocysteine is important …

I'm not a doctor. I'm someone who went through a cardiac event, spent a lot of time in the research.

Look, homocysteine isn't the most important number in the world. But it's one of those markers that made me realize how much there was to learn after my heart attack. Nobody explained it to me. Maybe that's because it wasn't important for my situation. Maybe it's because doctors only have so much time. Either way, I'm glad I went down the rabbit hole.

If it were me, I'd ask about it the next time you're getting bloodwork done.

At the end of the day, the goal is to understand your health well enough that you stop feeling like you're guessing.  Because you only get one heart.  Till next time, Stephen

Source: Homocysteine Studies Collaboration. (2002). Homocysteine and risk of ischemic heart disease and stroke: A meta-analysis. JAMA, 288(16), 2015–2022. doi:10.1001/jama.288.16.2015. PMID: 12387654