Modifying dietary LA and ALA leads to favourable increases in n3 status: A systematic review
Modifying dietary LA and ALA leads to favourable increases in n3 status: A systematic review
Year: 2014
Authors: Mantzioris, E.
Publication Name: ISSFAL International Congress, Stockholm, Sweden June 28 – July 1
Publication Details: ID# Tuesday M6.01
Abstract:
Background: It has been suggested that increased ALA (18:3 n3) and or decreased intake of LA (18:2 n6) may improve n3 LCPUFA status by increasing the availability of substrate for conversion and/or reducing competition for desaturation and cellular incorporation, however data from human studies have not been closely evaluated. Aim: To systematically review human studies evaluating the effect of altering ALA and or LA intake on EPA and DHA status.
Methods: Studies were eligible if they included adult, nonpregnant participants, specifically altered dietary intake of LA and/or ALA and reported the effects on EPA and DHA status. Results: Nineteen studies (18 randomised controlled trial and 1 open label study) met the inclusion criteria. Four different dietary patterns were identified: 1) Increased ALA (1.16.3 percent E) with unchanged LA (4.37.3 percent E) 2) Decreased LA (2.43.9 percent E) with unchanged ALA (0.41.4 percent E) 3) Increased ALA (0.86.3 percent E) with unchanged LA (2.5 percent 4.6 percent E) 4) Decreased ALA (0.01 0.5 percent E) and decreased or unchanged LA (2.0 percent 6.0 percent E) 6 of 9 studies that increased ALA without changing LA reported increases in EPA status, but none reported increased DHA status. 4 of 5 studies that maintained ALA and decreased LA reported increases in EPA, and 2 of 5 also reported increases in DHA. Increasing ALA intake in conjunction with decreased LA intake appeared to be the most effective strategy for increasing n3 LCPUFA status, with 5 of 7 studies reporting increased EPA and 2 of 7 increases in both EPA and DHA. Conversely, only 1 of 6 studies which reduced ALA intake reported increases in EPA and DHA status. However, the majority of these studies had small sample sizes, mixed sex groups and some omitted a runin period before the intervention. Conclusion: The majority of human studies evaluating the effects of altering ALA and LA intake have shown that it is possible to increase n3 LCPUFA status by increasing the availability of substrate (ALA) and/or reducing competition for conversion by limiting LA intake. (Authors abstract)
Methods: Studies were eligible if they included adult, nonpregnant participants, specifically altered dietary intake of LA and/or ALA and reported the effects on EPA and DHA status. Results: Nineteen studies (18 randomised controlled trial and 1 open label study) met the inclusion criteria. Four different dietary patterns were identified: 1) Increased ALA (1.16.3 percent E) with unchanged LA (4.37.3 percent E) 2) Decreased LA (2.43.9 percent E) with unchanged ALA (0.41.4 percent E) 3) Increased ALA (0.86.3 percent E) with unchanged LA (2.5 percent 4.6 percent E) 4) Decreased ALA (0.01 0.5 percent E) and decreased or unchanged LA (2.0 percent 6.0 percent E) 6 of 9 studies that increased ALA without changing LA reported increases in EPA status, but none reported increased DHA status. 4 of 5 studies that maintained ALA and decreased LA reported increases in EPA, and 2 of 5 also reported increases in DHA. Increasing ALA intake in conjunction with decreased LA intake appeared to be the most effective strategy for increasing n3 LCPUFA status, with 5 of 7 studies reporting increased EPA and 2 of 7 increases in both EPA and DHA. Conversely, only 1 of 6 studies which reduced ALA intake reported increases in EPA and DHA status. However, the majority of these studies had small sample sizes, mixed sex groups and some omitted a runin period before the intervention. Conclusion: The majority of human studies evaluating the effects of altering ALA and LA intake have shown that it is possible to increase n3 LCPUFA status by increasing the availability of substrate (ALA) and/or reducing competition for conversion by limiting LA intake. (Authors abstract)
