The effect of modifying dietary LA and ALA intakes on omega-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) status in human adults: A systematic review and commentary

Abstract

The effect of modifying dietary LA and ALA intakes on omega-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) status in human adults: a systematic review and commentary

Effects of a low and a high dietary LA/ALA ratio on long-chain PUFA concentrations in red blood cells

“…This is in line with the observations of the systematic review of Wood et al 26 who state that a combination of a decrease of LA and a simultaneous increase of ALA intake is most effective in improving the n3 PUFA status.…”

“…However, the timeframe of 14 days may be too short to observe significant changes in DHA concentrations. Wood et al 26 concluded that ALA supplementation studies with decreased LA intake -as our study -were able to increase DHA concentrations. Our results cannot confirm this observation, on the one hand possibly due to the short intervention time and on the other hand also due to the high ALA dose in this study.…”

“…20,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] According to a current review from Wood et al, 26 the majority of these studies, exhibited some or several methodological weaknesses such as studying males and females together, [28][29][30][31][32][33][34][35][36] 13 Therefore, it is suggested that males and females are either stratified or studied separately. 26 The aim of our study was to compare the effects of two different dietary LA/ALA ratios on fatty acid concentrations in RBC with special emphasis on LC n3 PUFAs. A homogenous study collective of healthy, non-smoking men within a narrow range regarding age (mean age 26.1 ± 4.53 years) and BMI (24.0 ± 1.65 kg m ) was chosen to prevent/minimize the influence of gender, smoking, age, and BMI on PUFA metabolism.…”

“…Also other studies that increased the total ALA intake to 1.1-6.3 en% observed significantly higher EPA amounts, albeit with great variability [27][28][29]36,38,[40][41][42][43][44] reviewed by Wood et al 26 The efficiency of ALA conversion is, besides other factors, mainly dependent on the ALA dose, which essentially explains the fluctuations of the studies cited above. 26 In a similar study, a 6-week intervention with ALA from linseed oil (LA/ALA ratio of 1 : 1) resulted in a 47.2% increase of relative EPA amounts in RBCs. 33 The reason for this comparatively small increase after 6 weeks of intervention may be the lower ALA dose of 8.7 ± 2.2 g d −1…”

Dietary Fiber Intake Modifies the Positive Association between n–3 PUFA Intake and Colorectal Cancer Risk in a Caucasian Population

“…The latter may influence eicosanoid signaling, which has been reported to be associated with the development and progression of CRC (49). In addition, contrary to common beliefs, the current evidence does not support that an increase in ALA intake can enhance DHA synthesis (50). In fact, recently, it was reported that a higher ALA intake was associated with decreased tissue DHA concentrations (51), because of the feedback inhibition that controls DHA synthesis (52).…”