Change in Association Between Minerals, Fatty Acids and Oxidative Stress Parameters in Wistar Rats with Different Diets

The liver plays a central role in fatty acid (FA) metabolism, triacylglycerol synthesis, and energy homeostasis. The study aims to evaluate how a four-week dietary intervention with fish-based (EF), milk-based (EM), and standard diets (ES) affects relationships between mineral levels, FA profiles and indices, and oxidative stress parameters in female Wistar rats. Liver tissue samples were collected and analyzed for these variables. Post hoc analysis revealed significant differences in trace elements between the EM and EF and the EM and ES groups, and in toxic trace elements only between the EM and EF groups. Individual mineral differences were observed for calcium (Ca), iron (Fe), copper (Cu), zinc (Zn), arsenic (As), mercury (Hg), and lead (Pb), all showing large effect sizes (ηp2 = 0.32–0.63). The strongest mineral–FA correlations occurred mainly in the ES group (15/25) and, to a lesser extent, in EF (9/25), involving 14 minerals, while only one mineral was significant in EM. Individual mineral correlations were most frequent in ES (13/25), followed by EF (8/25) and EM (4/25). Zn was the strongest predictor of malondialdehyde (MDA) in EF (90.6%), and Cu was the main determinant in ES (72.9%). We concluded that EM showed minimal interactions, limited to Fe and oleic acid, whereas EF and ES displayed multiple strong mineral–FA correlations, with ES exhibiting the most extensive and complex interaction network.