Zinc deficiency impairs whole body accumulation of polyunsaturates and increases the utilization of [1-¹⁴C]linoleate for de novo lipid synthesis in pregnant rats

Abstract

Zinc deficiency impairs the metabolism of polyunsaturates, but the degree to which its effects are independent of food intake are still in question. Identical amounts of a semiliquid control diet (26.4 mg zinc/kg) or moderately zinc deficient diet (3.2 mg zinc/kg) were tube fed to rats for 11 days during the second half of pregnancy to evaluate the specific effects of zinc deficiency on maternal utilization and fetal accumulation of polyunsaturates. The whole body fatty acid balance method was used to determine net accumulation of polyunsaturates and their whole-body disappearance. Incorporation of 14C from [1-14C]linoleate into maternal and fetal lipid classes was also studied on days 20-21. At term, zinc-deficient rats had significantly higher whole-body disappearance of linoleate and alpha-linolenate and lower accumulation of n-6 and n-3 long-chain polyunsaturates. Zinc-deficient rats had higher 14C activity in free cholesterol, saturates, and monounsaturates in several maternal organs but not in the fetuses. We conclude that during pregnancy, moderate zinc deficiency not affecting food intake or weight gain still alters whole-body metabolism of linoleate and alpha-linolenate towards increased beta-oxidation and also increases the utilization of carbon from linoleate for de novo lipid synthesis.

Effects of Zinc and DHA on the Epigenetic Regulation of Human Neuronal Cells

“…An association between zinc and polyunsaturated fatty acids has been found in studies on zinc-deficient pregnant rats, which showed a whole-body depletion of maternal stores of both omega-3 and omega-6 polyunsaturated fatty acids (PUFA) [5]. We also demonstrated that a reduction of DHA level in the brain is associated with over expression of ZnT3, a transmembrane protein that is involved in the transport of zinc into synaptic vesicles [6].…”

Rats Allowed to Self-Select Zinc-Deficient Lard and Fish-Oil Diets Did Not Develop a Preference for Fish-Oil Diet

“…Dietary Zn and FAs are known to alter membrane and tissue FA composition (8,9). Altered FA composition may influence several processes related to insulin resistance, such as hormone binding, signal transduction, and availability of precursor molecules for lipid synthetic and catabolic pathways (25,26).…”

“…Furthermore, Zn-deficiency has been shown to alter metabolism of essential FAs towards increased ␤ -oxidation and greater utilization of linoleic acid in the de novo lipid synthesis ( 9 ). This may affect the amount and distribution of FAs in fat tissues.…”

Suckling Rats Actively Recycle Carbon from α-Linolenate into Newly Synthesized Lipids Even During Extreme Dietary Deficiency of n-3 Polyunsaturates

“…S tudies evaluating the whole body homeostasis of polyunsaturates (PUFA) in a variety of nutritional and metabolic states demonstrate that ␤-oxidation as a fuel is the quantitatively dominant route of use of both linoleate and ␣-linolenate (1,2). In addition to complete oxidation to CO 2 , studies using isotopically labeled linoleate and ␣-linolenate show that a considerable amount of partially oxidized carbon from these two fatty acids is incorporated into newly synthesized lipids rather than being fully ␤-oxidized to CO 2 .…”