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ISSFAL Policy Statement 3 |
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Page 6 of 9
Table 1 Summary of studies investigating PUFA and CHD.
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Study
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Type
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Lowest intake,
quintile
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Highest intake,
Quintile
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Benefit
|
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Ascherio et al 1996
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PC
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0.8g/d (0.36% en)
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1.5 g/d (0.68% en)7
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Yes, CHD
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Hu et al 1999
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PC
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0.71 g/d (0.32%en)
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1.36g/d (0.61%en)7
|
Yes, CHD
|
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Oomen et al 20011
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PC
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<0.45% en
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>0.58%en
|
No CHD
|
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Dolecek 1992
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PC
|
0.87g/d (0.42%en)
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2.80g/d (0.98%en)
|
Yes, CHD
|
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Djousse et al 2001
|
CS
|
0.53g/d (0.2%en)
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1.14g/d (0.5% en)7
|
Yes, CHD
|
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Bemelmans et al 2000
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CS
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1.2g/d (0.4%en)
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1.7g/d (0.6%en)
|
Yes, BP only
|
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Baylin et al 20032
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CC
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0.35% FA
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0.72% FA
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Yes, MI
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Natvig et al 19683
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PP
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0.14 g/day + baseline
|
5.5g/d + baseline
|
No, CHD4
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De Lorgeril et al 19995
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SP
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0.64g/d (0.27%en)
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1.74g/d (0.82%en)7
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Yes, CHD
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Singh et al 19976
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SP
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????
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2.9g/d (1.3%en)7
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Yes, CHD
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1 Tertiles of intake
2 Adipose fatty acids only, not diet
3 Two groups fed either sunflower oil or linseed oil; both oils effective; 4no benefit for ALA.
5 Two groups only; dietary change complex and not just change in ALA.
6 Three groups, no indication of background dietary ALA. Dietary type non-western (Indian).
7 ALA intake as % en was calculated on the basis of a diet containing 2000 kcal.
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A note for consideration on ALA and prostate cancer (A. Sinclair)
There has been interest in the literature on possible positive association between dietary intakes of ALA and prostate cancer. Two prospective and four case-control studies have been reported where dietary ALA intake has been assessed by food frequency questionnaire (see Table 1). Attar-Bashi et al (2004) have reviewed the literature on ALA and prostate cancer and the following summarises that review:
Purpose Several studies have examined the association between polyunsaturated fatty acids and prostate cancer risk. This review evaluated the evidence on the association between ALA and the risk of prostate cancer in humans.
Methods the authors comprehensively reviewed published studies on the association between ALA and the risk of prostate cancer using a MEDLINE-based literature review.
Results A number of studies (n=6) have reported a positive association between dietary, plasma or red blood cell levels of ALA and prostate cancer. Other studies (n=5) have reported either no association or a negative association. The limitations of the above studies include (1) the assumption that dietary or plasma ALA levels are positively associated with prostate tissue ALA levels and (2) measurement errors of dietary, plasma and red blood cell ALA levels (see Table 2).
Conclusions More research is needed in this area before it can be concluded there is a biologically meaningful association between ALA and prostate cancer. It is possible that dietary ALA intake is a marker of the intake of other nutrients. For example, Oomen et al. (2001) in the Zutphen elderly study reported that the intake of ALA was strongly associated with the intake of trans fatty acids.
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Lipid Matters