# Measuring Peripheral Tissue DHA Turnover Using a Novel 13C Enrichment Technique

## TL;DR

This study uses a new 13C enrichment method to measure how quickly DHA turns over in peripheral tissues of mice, providing insights into DHA metabolism.

## Contribution

The novel 13C enrichment technique allows precise measurement of DHA turnover in peripheral tissues.

## Key findings

- DHA half-lives in red blood cells, muscle, and heart were measured using 13C enrichment.
- The method revealed distinct turnover rates in various peripheral tissues of mice.
- Future applications could explore DHA metabolism changes due to genetics and environmental factors.

## Abstract

Recently, through the use of compound‐specific isotope analysis (CSIA), our lab validated the utility of 13C enrichment (δ
13C) of docosahexaenoic acid (DHA) by using a very high δ
13C in a diet switch study by measuring brain, liver, and plasma DHA turnover and half‐lives via high‐precision gas chromatography combustion isotope ratio mass spectrometry (GC/C/IRMS). Using this novel enrichment technique, the present study extends measures of DHA turnover in the peripheral tissues, including red blood cells (RBC), perirenal adipose tissue (PRAT), muscle, heart, and skin. Mice were fed a low δ
13C diet (fish‐DHA control) for 3 months, then switched to either a high δ
13C treatment diet (algal‐DHA) or a very high δ
13C treatment diet (13C enriched‐DHA), while some remained on the fish‐DHA control diet as a reference group for the remainder of the study time course. In mice fed the algal and 13C enriched‐DHA diets, the RBC DHA half‐life was 22.8 and 19.5 days, the PRAT DHA half‐life was 6.0 and 8.2 days, the muscle DHA half‐life was 38.2 and 42.2 days, the heart DHA half‐life was 12.4 and 10.5 days, and the skin DHA half‐life was 13.6 and 13.0 days, respectively. Future studies could employ the 13C enrichment method to examine how DHA metabolism is altered in peripheral tissues according to genetics, stress, and development.