HOT OFF THE PRESS: C15:0 Supplementation Improves Upon the Mediterranean Diet

December 3, 2023

Welcome to Issue 70 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
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Healthy Aging

Clinical Trial Shows C15:0 Supplementation Lowers “Bad” Cholesterol (and More)

This past week, a randomized and controlled clinical trial published in the American Journal of Clinical Nutrition evaluated the added benefits of C15:0 supplementation above and beyond that of the Mediterranean diet. Let’s dive into what this clinical trial found.

What was this study about?

Glad you asked! In this study led by the Singapore Institute for Clinical Sciences, Chooi et al. included women (ages 21-45) with higher body weight and underlying metabolic abnormalities, including nonalcoholic fatty liver disease (NAFLD). These 88 women were randomly placed into one of three groups: a calorie-restricted Mediterranean diet with C15:0 supplementation (Group 1), a calorie-restricted Mediterranean diet without C15:0 (Group 2), and a standard hypocaloric diet (Control Group). All women were guided to eat a lower calorie diet of 1,000-1,500 calories per day for 12 weeks to help support weight loss. Numerous health indices were measured, including the following:

Body weight
Fasting blood samples (glucose, insulin, liver enzymes, triglycerides, total cholesterol, and LDL and HDL cholesterol)
Liver fat content
Body composition & fat distribution

I’m in. What were the results of this clinical trial?

All three groups had similar baseline health values at the beginning of the study. The results of this study after 12 weeks are best broken down into three categories:

Impacts of a low calorie diet (with and without C15:0 supplementation). In this study, all three groups lost weight by moving to a low-calorie diet. This weight loss likely caused the observed improvements in patients’ blood pressure, insulin, HOMA-IR, and HbA1c.
Impacts of the Mediterranean diet (with and without C15:0 supplementation). Those on the Mediterranean diet (with and without C15:0 supplementation) had greater reductions in body weight, BMI, and liver fat compared to the control group. These groups also had lower total cholesterol, triglycerides, and liver enzyme (GGT) levels after 3 months, which was not observed in the control group.
Unique impacts of the Mediterranean diet with C15:0 supplementation. Beyond the benefits above, the C15:0-supplemented group had significantly lower total fat mass, visceral adipose tissue, and subcutaneous adipose tissue compared to the control group. The C15:0 supplemented group also had greater reductions in LDL (the “bad”) cholesterol compared to both the Mediterranean diet only and control groups.

And the take-home message from this clinical trial with C15:0 supplementation is…

Well first, this randomized and controlled clinical trial reconfirms (yet again) that lowering one’s caloric intake has beneficial effects, including lowering body weight, blood pressure, insulin and glucose levels.
Second, the Mediterranean diet (with or without C15:0 supplementation) provides benefits of further lowering body weight and liver fat, as well as lowering lipids and HbA1c.
Finally, the Mediterranean diet with C15:0 supplementation provided the most benefits, including all the above plus the added benefits of lower total fat mass (especially around the abdomen and subcutaneous fat) and lower LDL cholesterol.

It is important to note that the restricted calorie diets used in this study (1,000-1,500 cal/day) are not considered healthy long-term, and it is currently recommended that the average adult consume 2,000 calories per day. What can be supported long-term? Hmm… higher and healthier C15:0 levels, of course!

Stay tuned for more C15:0 clinical trial updates on the horizon, including a double-blinded, randomized and placebo-controlled study at the University of San Diego, California that is looking at just C15:0 supplementation as an intervention. In the meantime, have a great week, everyone!