Comparison of the impact of trans fatty acids from ruminants and industrial sources on human cholesterol homeostasis

Abstract

This double‐blind randomized crossover study compared the impact of dietary trans fatty acids (TFA) from ruminants (rTFA) and from industrial sources (iTFA) on surrogate markers of cholesterol absorption (β‐sitosterol and campesterol) and synthesis (lathosterol) in healthy men. Thirty‐eight men consumed 3 experimental isoenergetic diets in a random order for 4 weeks each. The 3 diets were 1) high in rTFA (10.2g/2500 kcal), 2) high in iTFA (10.2g/2500 kcal) and 3) control diet low in TFA from any source (2.2g/2500 kcal). Plasma LDL‐C concentrations were increased to a similar extent in the iTFA (+4%) and rTFA (+6%) diets compared with the control diet. Plasma concentrations of β‐sitosterol, campesterol and lathosterol were significantly reduced after the iTFA diet compared with the control diet (−11%, −26% and −17% respectively, P < 0.05), but not after the rTFA diet. Analyses were also performed according to baseline concentrations of absorption markers. Low absorbers on the control diet had a 29% increase in plasma LDL‐C concentrations after the rTFA diet (P = 0.01 vs. the control diet) but showed no significant change in LDL‐C after the iTFA diet (+11%, P = 0.23). While very high intakes of rTFA and iTFA appear to have comparable LDL‐C raising effects, our data suggest that underlying mechanisms may be different between the two sources of TFA. Financial support: Dairy Farmers of Canada, Novalait Inc and NSERC