Use of the Linoleic Acid: Dihomo-γ-Linolenic Acid (LA:DGLA) Ratio, Gut Microbiome Composition, and Function to Assess the Biological Impact of Zinc Biofortified Maize on Women and Children in Guatemala

Background: The linoleic acid (LA) and dihomo-γ-linolenic acid (DGLA) ratio (LA/DGLA) is a potential biomarker of zinc physiological status that may overcome the limitations of previous zinc biomarkers. However, it has not been extensively tested in at-risk rural populations. Additionally, while biofortified maize has been shown to reduce zinc deficiencies in efficacy trials, its biological impact in at-risk rural populations has not yet been thoroughly investigated in effectiveness trials.

Objective: In a randomized pilot study, we aimed to assess the impact of biofortified maize (with at least 35% higher zinc content compared to conventional maize) on a rural population in eastern Guatemala (50% of the population is zinc deficient). Blood and stool samples were collected. We examined baseline, midpoint, and endpoint data in relation to zinc status and physiological biomarkers.

Population: Total of 51 women (30±6 years) and 55 children (35±14 months) were studied for zinc status using fasting blood samples to determine the LA:DGLA ratio, and stool samples for microbiome and short-chain fatty acids (SCFA) analyses.

Results: At baseline, the LA:DGLA ratio was significantly higher (p< 0.05) in the child cohort (7.21±0.3%) compared to the women cohort (4.91±0.4%). In general, there was a clear downward trend following biofortified maize treatment. Overall, the assessment revealed that biofortified maize improved zinc status in both cohorts. Additionally, microbial and SCFA analyses indicated shifts in microbial composition and function, as well as changes in SCFA production.


Conclusion: The LA:DGLA ratio was significantly different between the women and child cohorts, which correlates with previous population studies showing low zinc intake in the same region. Zinc status was also found to affect microbial composition, function, and SCFA production. Follow-up studies will further investigate the utility of the LA:DGLA ratio as a biomarker in the context of a nutrition and agriculture intervention for at-risk populations