Chia seed enrichment in high-fat-high-sugar diet-induced obesity: a strategy to increase DHA levels in maternal tissues and in fetal placenta and brain during pregnancy

OBJECTIVES: An appropriate nutritional environment is crucial for both the mother's health and that of the developing fetus. Alpha-linolenic acid (ALA) serves as a precursor to docosahexaenoic acid (DHA), a n-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) required for placentation and fetal brain development. Chia seeds are particularly rich in ALA, however, although its benefits to offspring's health are well established, the extent to which ALA is converted into fetal n-3 LCPUFA, particularly DHA, remains unclear. The high-fat, high-sugar Western diet is a major contributor to obesity and typically contains low levels of n-3 LCPUFA and DHA. Using a rat model of diet-induced obesity, we investigated whether supplementing chia seeds to a high-fat-high-sugar (HFS) diet enhances DHA levels in maternal tissue and circulation, and increases its availability in the placenta and fetal brain at gestational days 15 (G15) and 20 (G20). METHODS: Female Wistar rats were fed an HFS diet for 6 weeks before mating. They were then divided into two groups during gestation until G15 or G20. One group continued on the HFS diet (n=7), while the other group was fed a HFS diet supplemented with chia seeds (HFSChia, n=7-9). RESULTS: We demonstrated that the HFSChia diet increased ALA, eicosapentanoic acid (EPA) and DHA levels in the liver at G15 and G20. This increased the incorporation of DHA into lipid complexes in the maternal liver, adipose tissue, and peripheral circulation. Furthermore, placental enrichment of n-3 LCPUFA, accompanied by enhanced expression of lipid transporters suggested an increased capacity of n-3 LCPUFA transfer to the fetus, as did enhanced DHA concentrations in fetal brain phospholipids from mid-gestation onwards. CONCLUSION: Supplementing a HFS diet with chia seeds increased maternal n-3 LCPUFA levels and enhanced the placental transfer capacity of DHA to the fetal brain, which may support optimal neurodevelopment in a context of obesity.