An Emerging Healthy Heart-C15:0-Gut Axis, Part I

Healthy Aging

A Prospective Look at C15:0, Heart & Gut Health, Part I

This year’s big science story is emerging as The Year of Heart & Gut Health for C15:0. This week, we’re covering a just-published prospective study by Xiao et al. that focused on circulating levels of C15:0 and the likelihood of maintaining our cardiovascular health over time. That also had a surprising link to gut health. Let’s dive in.

I’m into keeping my heart healthy. Tell me more.

The studies supporting C15:0 + heart health have been mounting:

• A few weeks back, we covered a randomized cross-over clinical trial by Arghavani et al. that showed when people increased C15:0 in their diet, their C15:0 levels increased, too. And as their C15:0 levels increased, aortic stiffness decreased within 12 weeks.
• Then, Chen et al. and Huang et al. showed in adults and kids, respectively, that higher C15:0 levels = healthier blood pressure.
• Last year, a randomized and controlled clinical trial by Chooi et al. demonstrated that daily C15:0 supplementation lowered LDL-cholesterol.
• And over the past decade, meta-analyses of prospective cohort studies have repeatedly shown that people with higher C15:0 levels have better long-term heart health.

In the latest study by Xiao et al., 1,211 adults (mean age of 58 years old) were followed over 6 years to see if C15:0 levels predicted the ability to protect arterial health.

Got it. What did they find?

There were a few key findings:

• This study re-reconfirmed baseline population C15:0 levels. This study divided the study population into those who had the lowest to highest C15:0 levels, by quartiles. Among the 1,211 participants in this study, the lowest quartile had C15:0 levels of 0.1% of total fatty acids. The middle two quartiles had C15:0 levels of 0.2%, and the highest quartile had C15:0 levels of 0.4%. As shared in our Metabolites paper, C15:0 levels ≥ 0.2% are needed to not be C15:0 deficient and maintain our baseline health. Higher C15:0 levels (aka 0.4-0.6%) are considered optimal levels, especially as it relates to heart health and longevity.
• How much dairy a person ate determined their total odd-chain saturated fatty acid levels (C15:0+C17:0). This finding was consistent with many other studies, including Chooi et al.’s controlled clinical trial, showing that the more C15:0 we ingest, the higher our C15:0 levels.
• People who had the highest quartile of circulating C15:0 levels (aka, 0.4%) had the healthiest long-term arterial health – even after 6 years. Conversely, those who had the lowest quartile C15:0 levels (0.1%), had the greatest risk of developing cholesterol plaques in their carotid arteries.

Paired with the other large prospective studies above and two clinical trials, these studies increasingly support that C15:0 is good for our cardiovascular health – by lowering LDL cholesterol, decreasing arterial stiffness, and keeping our arteries clean, clear, and functioning.

So, where does the gut come into the story?

Right. In addition to the above findings, Xiao et al. also showed that the higher a person’s C15:0 levels, the more diverse their gut microbiome and the higher their levels of certain types of good microbes – especially Christensenellaceae R-7 group. We’ll cover the gut side of C15:0’s health benefits next week.