April 12, 2018
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BACKGROUND
The cardioprotective properties of linoleic acid (LA), a major n-6 (ω-6) polyunsaturated fatty acid (PUFA), have been recognized, but less is known about its associations with other causes of death. Relatively little is also known about how the minor n-6 PUFAs-γ-linolenic acid (GLA), dihomo-γ-linolenic acid (DGLA), and arachidonic acid (AA)-relate to mortality risk.
OBJECTIVE
We investigated the associations of serum n-6 PUFAs, an objective biomarker of exposure, with risk of death in middle-aged and older men and whether disease history modifies the associations.
DESIGN
We included 2480 men from the prospective Kuopio Ischaemic Heart Disease Risk Factor Study, aged 42-60 y at baseline in 1984-1989. The stratified analyses by baseline disease status included 1019 men with a history of cardiovascular disease (CVD), cancer, or diabetes and 1461 men without a history of disease.
RESULTS
During the mean follow-up of 22.4 y, 1143 deaths due to disease occurred. Of these, 575 were CVD deaths, 317 were cancer deaths, and 251 were other-cause deaths. A higher serum LA concentration was associated with a lower risk of death from any cause (multivariable-adjusted HR for the highest compared with the lowest quintile: 0.57; 95% CI: 0.46, 0.71; P-trend < 0.001) and with deaths due to CVD (extreme-quintile HR: 0.54; 95% CI: 0.40, 0.74; P-trend < 0.001) and non-CVD or noncancer causes (HR: 0.48; 95% CI: 0.30, 0.76; P-trend = 0.001). Serum AA had similar, although weaker, inverse associations. Serum GLA and DGLA were not associated with risk of death, and none of the fatty acids were associated with cancer mortality. The results were generally similar among those with or without a history of major chronic disease (P-interaction > 0.13).
CONCLUSIONS
Our findings showed an inverse association of a higher biomarker of LA intake with total and CVD mortality and little concern for risk, thus supporting the current dietary recommendations to increase LA intake for CVD prevention. The finding of an inverse association of serum AA with the risk of death needs replication in other populations.
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Journal Abstract
The American Journal of Clinical Nutrition
Written by
Polyunsaturated fatty acids (PUFA) – Do they reduce death?
There have been many headlines saying fat is bad, fat is good, polyunsaturated fat is good but not all are good, so the confusion continues. One of the problems is how we determine how much PUFA a patient is getting. Many studies do it with a food diary. Now, imagine trying to predict your LDL levels based on your diet history? It would be impossible.
This study actually measured the blood levels instead of going based on dietary history. The researchers measured linoleic acid (LA), a major n-6 (ω-6) PUFA, γ-linolenic acid (GLA), dihomo-γ–linolenic acid (DGLA), and arachidonic acid (AA).
They did this on 2480 men from the Kuopio Ischaemic Heart Disease Risk Factor Study in Finland, and they followed them for over 22 years.
They found that patients with the highest LA levels compared with the lowest quintile had a 43% reduction in death from any cause (HR, 0.57; 95% CI, 0.46–0.71; P < .001). CVD deaths were reduced by 46% when comparing the highest and lowest quintiles (HR, 0.54; 95% CI, 0.40–0.74; P < .001). For non-CVD or non-cancer death, the reduction was 52% (HR, 0.48; 95% CI, 0.30–0.76; P = .001).
Serum AA had a weaker but similar pattern of results. The serum GLA and DGLA did not show any benefit.
This study basically shows in these men in Finland a clear reduction in mortality with higher levels of LA. Hence, perhaps increasing our intake of LA could reduce mortality risks.