# Functional and Evolutionary Role of Reproductive Hormonal Dysregulation Following Dietary Exposure to Singed Meat

## TL;DR

Eating meat singed with certain fuels harms rat hormones and health, suggesting risks to fertility and evolution.

## Contribution

Identifies reproductive hormonal disruption as a novel biomarker of dietary toxicant exposure.

## Key findings

- Firewood- and tyre-singed meat caused dose-dependent toxicity and hormonal disruption in rats.
- Reproductive hormones like testosterone dropped while FSH, LH, and prolactin increased.
- LPG-singed meat caused minimal health effects compared to other singeing methods.

## Abstract

Consumption of meat singed with non-standard fuels is a common practice in many low- and middle-income settings, yet it may introduce combustion-derived toxicants with serious health consequences. While the toxicological effects of pollutants such as polycyclic aromatic hydrocarbons and heavy metals are well documented, the specific impact of singed meat consumption on endocrine regulation remains poorly understood. Of particular concern is the reproductive hormonal network, which not only serves as a sensitive biomarker of systemic disruption but also represents an evolutionary safeguard of fertility and generational continuity. Our study addresses this knowledge gap using male Wistar rats fed for 90 days (week 0 to week 12) on diets containing increasing proportions (25%, 50%, 75%) of meat singed with firewood, liquefied petroleum gas (LPG), or tyres. Firewood- and tyre-singed meat induced dose- and source-dependent toxicity, including hepatocellular injury, impaired protein metabolism, elevated blood urea nitrogen and creatinine, organ hypertrophy, and pronounced oxidative stress. Hormonal analysis revealed reduced testosterone alongside increased FSH, LH, and prolactin, indicating hypothalamic–pituitary–gonadal axis disruption and reproductive risk. In contrast, LPG-singed meat caused only minor alterations. These findings highlight reproductive hormones as sensitive biomarkers, underscoring the health risks of singeing practices and their evolutionary implications for fertility and population fitness.