C15:0 Supports Metabolic Health: Another Study

Healthy Aging

Evidence of C15:0’s 360° Metabolic Support

When it comes to glucose, our metabolic health is dependent on maintaining healthy 1) insulin sensitivity and 2) pancreatic beta cell function. An impressively robust prospective cohort study was just published in Clinical Nutrition to evaluate associations between different dairy-derived fatty acids (including C15:0) and maintained healthy insulin sensitivity + beta cell function over a period of 9 years. Let’s dive into what this study found.

I’m in. But first, what made this study so robust?

A total of 418 adults from the Prospective Metabolism Islet Cell Evaluation (PROMISE) cohort were included in this study. People with type 2 diabetes at baseline were excluded.

Each participant had 4 in-depth evaluations over a 9 year period, including fasting blood samples and oral glucose tolerance tests (OGTT) with additional blood samples and insulin measurements at 30 and 120 minutes per visit.

Specifically, the following measurements were used to assess insulin sensitivity and beta cell function throughout the study:

• Insulin sensitivity (measured as log ISI, logISSI2, and logIGI/IR)
• Fasting glucose
• Glucose at 120 minutes (logGlucose)
• Glucose area under the curve (LogGlucose AUC)

Additionally, baseline fasted serum dairy-based fatty acids were measured, including:

• C15:0
• Trans-16:1n9
• Trans-18:1n11
• C9 trans-11 conjugated linoleic acid (CLA)

Yehia et al. evaluated longitudinal associations between these fatty acid levels and metabolic health using covariate-adjusted generalized estimating equations with false discovery adjusted P values (that’s just a fancy way of saying they applied a strong statistical model).

Got it. What did they find?

As seen in the figure below, higher phospholipid C15:0 levels were associated with:

• Healthier insulin sensitivity, as measured by ISSI2
• Healthier insulin sensitivity, as measured by IGI/IR
• Lower fasting glucose
• Lower glucose at 120 minutes in a glucose tolerance test
• Overall healthier glucose tolerance

Dairy-based fatty acids trans-16:1n9 and trans-18:1n11 were also positively associated with various measures of metabolic health.

Incremental Protection of Metabolic Health

By using generalized estimating equation models, Yehia et al. were also able to show that for every standard deviation (SD) increase in phospholipid C15:0 levels, there was a percentage improvement in both insulin sensitivity and beta cell function.

All in, this study shows that specific dairy-based fatty acids, including C15:0, have a potential role in positively influencing insulin sensitivity and beta cell function in adults without pre-existing type 2 diabetes.

These results indeed add to the growing number of prospective cohort studies, including meta-analyses from Huang et al. and Li et al., repeatedly showing links between higher C15:0 and better long-term metabolic health.