Low-linoleic acid diet and oestrogen enhance the conversion of α-linolenic acid into DHA through modification of conversion enzymes and transcription factors.
Level 5 - mechanism / opinion, no new human data
Preclinical animal research
PubMed 30507367 · doi:10.1017/S0007114518003252
What was done
Rats were fed a modified AIN-93G diet containing either 0% n-3 PUFA or α-linolenic acid (ALA), combined with low or high amounts of linoleic acid (LA) for 12 weeks. At week 8, rats received injections of maize oil with or without 17β-oestradiol-3-benzoate for the remaining 3 weeks. The researchers evaluated the effects on hepatic fatty acid desaturases (FADS1, FADS2), elongases (ELOVL2, ELOVL5), transcription factors (PPAR-α, SREBP-1, ER-α, ER-β), and serum and liver DHA levels.
What was found
The abstract reports directional changes without numerical values. Both the low-LA diet and estrogen significantly increased hepatic expression of PPAR-α, FADS2, ELOVL2, and ELOVL5, while decreasing SREBP-1. The low-LA diet increased FADS1 expression, whereas estrogen increased ER-α and ER-β. The low-LA diet and estrogen showed synergistic effects on hepatic PPAR-α expression and on serum and liver DHA levels.
Why it matters
This study provides mechanistic evidence in a model organism that lowering dietary linoleic acid and estrogen exposure synergistically upregulate conversion enzymes and transcription factors to enhance conversion of ALA into DHA.
Limits
This was an animal study conducted in rats, limiting direct generalizability to human nutrition and physiology. The abstract provides no sample sizes, numerical effect sizes, or confidence intervals.
Cited by
- supports Premenopausal women convert alpha-linolenic acid (ALA) into EPA and DHA more efficiently than others because estrogen activates the converting enzyme.