Vitamin E function and requirements in relation to PUFA.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing mechanistic animal models and human data without systematic review methodology
PubMed 26291567 · doi:10.1017/S000711451500272X
What was done
A narrative review evaluated published animal and human data regarding dietary vitamin E (RRR-α-tocopherol) requirements in relation to total dietary polyunsaturated fatty acid (PUFA) intake and fatty acid degree of unsaturation.
What was found
Basal vitamin E requirement on very low PUFA diets was identified as 4–5 mg/d of RRR-α-tocopherol. The requirement relative to dietary linoleic acid was calculated at 0.4–0.6 mg RRR-α-tocopherol/g linoleic acid. Based on animal data, relative vitamin E requirements scaled by degree of unsaturation in ratios of 0.3, 2, 3, 4, 5, and 6 for mono-, di-, tri-, tetra-, penta-, and hexaenoic fatty acids, respectively. Under typical dietary PUFA intakes, estimated total requirements ranged from 12 to 20 mg RRR-α-tocopherol/d.
Why it matters
As dietary guidelines promote higher PUFA intake, vitamin E consumption may need proportionate adjustment to prevent lipid peroxidation, particularly in populations where baseline vitamin E intake is already sub-optimal.
Limits
The weighting factors for highly unsaturated fatty acids rely primarily on animal studies rather than direct human trials. The abstract does not report search methodology, inclusion criteria, or the total number of studies evaluated.
Cited by
- supports Consuming higher amounts of polyunsaturated fatty acids and omega-6s increases vitamin E requirements due to lipid oxidation.