An Update on Saturated Fats & Our Hearts

February 11, 2024

Welcome to Issue 77 of Science Says! Our weekly newsletter where you’ll learn the latest healthy aging and C15:0 research news that our team of doctors, scientists, and experts are most excited about—without having to go search for it.

Eric and Steph
Co-Founders, Doctors, Nerds

What Dr. Stephanie Venn-Watson, our co-founder and author of The Longevity Nutrient and over 80 peer-reviewed scientific publications, is reading.

Healthy Aging

So, are saturated fats good or bad for my heart?

In support of American Heart Month, we are covering the latest heart health science related to population trends, dietary saturated fats, LDL-cholesterol levels, and (of course) the role of C15:0 in supporting heart health.

This week, let’s clean up the somewhat messy science around saturated fats and our heart health.

But really, are saturated fats good or bad for my heart health?

Well, both. And here’s why: it’s becoming pretty darn clear that while odd-chain saturated fatty acids (especially C15:0) can protect heart health, even-chain saturated fatty acids (including C16:0 and C18:0) can harm heart health. Here are a few examples:

A study by Zheng et al. assessed links between different saturated fats and heart health among 16,000 people. They found that higher C15:0 and C17:0 levels were associated with lower total cholesterol and lower triglycerides. In contrast, higher C14:0, C16:0, and/or C18:0 were associated with higher LDL-cholesterol and triglycerides.
Similarly, Kaikkonen et al. showed that people with higher C15:0 have healthier blood pressure… and those with higher levels of even-chain saturated fats had a higher risk of poor heart health.
Taking it up a notch, Li et al. did a study of studies (aka a meta-analysis) that included data from 49 studies. They showed that people with higher even-chain saturated fat levels were linked to poor heart health. The opposite was found for odd-chain fatty acids, including C15:0. The higher the C15:0, the healthier the hearts.

So long story short, lots of studies repeatedly show that not all saturated fatty acids are created equal – and C15:0 is an odd-chain saturated fat that is on your good side.

It’s not just an association…

While the studies above showed associations between different saturated fats and heart health, Wei et al. tested the direct effects of supplementing C15:0 and C16:0 in mice with suboptimal metabolic, liver, and heart health.

Curious what they found? So were we. While perhaps not a surprise, C15:0 supported optimal all-over health in these mice. On the other hand, C16:0 was more of a “meh” and actually made angry livers angrier.

What’s going on? Why is there such a difference between odd- and even-chain saturated fatty acids?

Oh, what a difference a carbon makes! Impressively, nature has engineered our cells to respond favorably to odd fats (like C15:0) and not-so-well to even fats (that’s you, C16:0 and C18:0). For example:

Our mitochondria are core energy supporters of cellular (and heart) health. While our studies showed that C15:0 repairs mitochondrial function, Rumora et al. showed that C16:0 and C18:0 harm mitochondrial function.
Calming overactive immune responses can protect our heart health. While C15:0 has been shown to calm multiple cytokines involved in overactive immune responses to help protect our heart health, Staiger et al. have shown that C16:0 increases proinflammatory cytokines that worsen heart disease.

Differences like these help explain how odd-chain saturated fats help support our heart health, while even-chain saturated fats can work against our long-term health.

Besides, who doesn’t love being a little odd? To all of our nerdy odd (chain saturated fatty acid) science fans, Happy Valentine’s Day!