scholarly journals Polyunsaturated fatty acids and risk of Alzheimer’s disease: a Mendelian randomization study

2019 ◽  
Vol 59 (4) ◽  
pp. 1763-1766 ◽  
Author(s):  
Yasutake Tomata ◽  
Susanna C. Larsson ◽  
Sara Hägg

Abstract Purpose Observational studies have suggested that polyunsaturated fatty acids (PUFAs) may decrease Alzheimer’s disease (AD) risk. In the present study, we examined this hypothesis using a Mendelian randomization analysis. Methods We used summary statistics data for single-nucleotide polymorphisms associated with plasma levels of n-6 PUFAs (linoleic acid, arachidonic acid) and n-3 PUFAs (alpha-linolenic acid, eicosapentaenoic acid, docosapentaenoic acid, docosahexaenoic acid), and the corresponding data for AD from a genome-wide association meta-analysis of 63,926 individuals (21,982 diagnosed AD cases, 41,944 controls). Results None of the genetically predicted PUFAs was significantly associated with AD risk; odds ratios (95% confidence interval) per 1 SD increase in PUFA levels were 0.98 (0.93, 1.03) for linoleic acid, 1.01 (0.98, 1.05) for arachidonic acid, 0.96 (0.88, 1.06) for alpha-linolenic acid, 1.03 (0.93, 1.13) for eicosapentaenoic acid, 1.03 (0.97, 1.09) for docosapentaenoic acid, and 1.01 (0.81, 1.25) for docosahexaenoic acid. Conclusions This study did not support the hypothesis that PUFAs decrease AD risk.

2003 ◽  
Vol 56 (1-2) ◽  
pp. 50-53 ◽  
Author(s):  
Vanja Ristic ◽  
Gordana Ristic

Introduction Hyperlipoproteinemia is a key factor in development of atherosclerosis, whereas regression of atherosclerosis mostly depends on decreasing the plasma level of total and LDL-cholesterol. Many studies have reported the hypocholesterolemic effect of linolenic acid. Types of polyunsaturated fatty acids (PUFA) Linoleic and ?-linolenic acids are essential fatty acids. The main sources of linoleic acid are vegetable seeds and of ?-linolenic acid - green parts of plants. ?-linolenic acid is converted to eicosapentaenoic and docosahexaenoic acid. Linoleic acid is converted into arachidonic acid competing with eicosapentaenoic acid in the starting point for synthesis of eicosanoids, which are strong regulators of cell functions and as such, very important in physiology and pathophysiology of cardiovascular system. Eicosanoids derived from eicosapentaenoic acid have different biological properties in regard to those derived from arachidonic acid, i.e. their global effects result in decreased vasoconstriction platelet aggregation and leukocyte toxicity. Role and significant of PUFA The n-6 to n-3 ratio of polyunsaturated fatty acids in the food is very important, and an optimal ratio 4 to 1 in diet is a major issue. Traditional western diets present absolute or relative deficiency of n-3 polyunsaturated fatty acids, and a ratio 15-20 to 1. In our diet fish and fish oil are sources of eicosapentaenoic and docosahexaenoic acid. Refined and processed vegetable oils change the nature of polyunsaturated fatty acids and obtained derivates have atherogenic properties.


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Nurnadia Abd Aziz ◽  
Azrina Azlan ◽  
Amin Ismail ◽  
Suryati Mohd Alinafiah ◽  
Muhammad Rizal Razman

This study was conducted to quantitatively determine the fatty acid contents of 20 species of marine fish and four species of shellfish from Straits of Malacca. Most samples contained fairly high amounts of polyunsaturated fatty acids (PUFAs), especially alpha-linolenic acid (ALA, C18:3 n3), eicosapentaenoic acid (EPA, C20:5 n3), and docosahexaenoic acid (DHA, C22:6 n3). Longtail shad, yellowstripe scad, and moonfish contained significantly higher (P<0.05) amounts of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid (ALA), respectively. Meanwhile, fringescale sardinella, malabar red snapper, black pomfret, Japanese threadfin bream, giant seaperch, and sixbar grouper showed considerably high content (537.2–944.1 mg/100g wet sample) of desirable omega-3 fatty acids. The polyunsaturated-fatty-acids/saturated-fatty-acids (P/S) ratios for most samples were higher than that of Menhaden oil (P/S=0.58), a recommended PUFA supplement which may help to lower blood pressure. Yellowstripe scad (highest DHA,ω-3/ω-6=6.4,P/S=1.7), moonfish (highest ALA,ω-3/ω-6=1.9,P/S=1.0), and longtail shad (highest EPA,ω-3/ω-6=0.8,P/S=0.4) were the samples with an outstandingly desirable overall composition of fatty acids. Overall, the marine fish and shellfish from the area contained good composition of fatty acids which offer health benefits and may be used for nutraceutical purposes in the future.


2020 ◽  
Vol 21 (14) ◽  
pp. 4871
Author(s):  
Francesco Bordignon ◽  
Silvia Martínez-Llorens ◽  
Angela Trocino ◽  
Miguel Jover-Cerdá ◽  
Ana Tomás-Vidal

The present study evaluated the effects of wash-out on the fatty acid (FA) composition in the muscles of Mediterranean yellowtail. After 109 days during which fish were fed either a fish oil (FO)-based diet (FO 100) or a diet (FO 0) in which FO was completely substituted by vegetable oils, all fish were subjected to a wash-out with FO 100 diet for 90 days. The FA profile of muscles in fish fed FO 0 diet at the beginning of the experiment reflected that of dietary vegetable oils, rich in linoleic acid (LA), and α-linolenic acid (ALA), and was deficient in AA (arachidonic acid), EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid). No essential FA were fully restored in fish previously fed FO 0 diet on 45th or 90th day of wash-out. At the end of wash-out, the FA composition showed that AA, EPA, and DHA in the white muscles increased by +33%, +16%, and +43% (p < 0.001), respectively. Similarly, AA and DHA in the red muscles increased by +33% and +41% respectively, while EPA remained similar to fish fed FO 0 diet exclusively. Therefore, a 90-d wash-out can partially improve the FA profile in muscles of Mediterranean yellowtail previously fed vegetable oil-based diets.


2009 ◽  
Vol 2009 ◽  
pp. 1-7 ◽  
Author(s):  
Ingeborg Hanbauer ◽  
Ignacio Rivero-Covelo ◽  
Ekrem Maloku ◽  
Adam Baca ◽  
Qiaoyan Hu ◽  
...  

Feeding mice, over 3 generations, an equicaloric diet in which α-linolenic acid, the dietary precursor of n-3 polyunsaturated fatty acids, was substituted by linoleic acid, the dietary precursor of n-6 polyunsaturated fatty acids, significantly increased body weight throughout life when compared with standard diet-fed mice. Adipogenesis observed in the low n-3 fatty acid mice was accompanied by a 6-fold upregulation of stearyl-coenzyme A desaturase 1 (Scd1), whose activity is correlated to plasma triglyceride levels. In total liver lipid and phospholipid extracts, the sum of n-3 fatty acids and the individual longer carbon chain acids, eicosapentaenoic acid (20:5n3), docosapentaenoic acid (22:5n3), and docosahexaenoic acid (22:6n3) were significantly decreased whereas arachidonic acid (20:4n6) was significantly increased. In addition, low n-3 fatty acid-fed mice had liver steatosis, heart, and kidney hypertrophy. Hence, reducing dietary α-linolenic acid, from 1.02 energy% to 0.16 energy% combined with raising linoleic acid intake resulted in obesity and had detrimental consequences on organ function.


2008 ◽  
Vol 52 (No. 7) ◽  
pp. 203-213 ◽  
Author(s):  
D. Schneideroá ◽  
J. Zelenka ◽  
E. Mrkvicová

We studied the effect of different levels of linseed oils made either of the flax cultivar Atalante with a high content of &alpha;-linolenic acid (612 g/kg) or of the cultivar Lola with a predominating content of linoleic acid (708 g/kg) in a chicken diet upon the fatty acid pattern in meat. Cockerels Ross 308 were fed the diets containing 1, 3, 5 or 7 per cent of oil in the last 15 days of fattening. Breast meat (BM) and thigh meat (TM) without skin of 8 chickens from each dietary group were used for analyses. The relative proportions of fatty acids were expressed as percentages of total determined fatty acids. When feeding Atalante oil, the proportions of n-6 fatty acids were highly significantly lower while those of n-3 fatty acids were higher; the ratio of n-6/n-3 polyunsaturated fatty acids in meat was narrower (<i>P</i> < 0.001) than in chickens fed oil with a low content of &alpha;-linolenic acid. In BM and TM, the relative proportions of &alpha;-linolenic and &gamma;-linolenic acids were nearly the same, the proportion of linoleic acid in BM was lower, and the proportions of the other polyunsaturated fatty acids in BM were higher than in TM. In BM, the ratio of n-6/n-3 polyunsaturated fatty acids was significantly (<i>P</i> < 0.001) more favourable than that found in TM. The relative proportions of total saturated and monounsaturated fatty acids in meat decreased and those of polyunsaturated fatty acids increased significantly (<i>P</i> < 0.01) in dependence on the increasing level of dietary oils. When feeding Atalante oil, a significant increase in the proportion of linoleic acid in BM but not in TM was observed. The proportions of the other n-6 fatty acids decreased and those of all determined n-3 fatty acids, with the exception of docosahexaenoic acid, significantly increased with the increasing level of oil in the diet. When feeding Lola oil, its increasing content in the diet increased the relative proportion of linoleic acid as well as its elongation to &gamma;-linolenic acid; however, the proportions of arachidonic and adrenic acid did not change significantly (<i>P</i> > 0.05). The proportion of &alpha;-linolenic acid increased in both BM and TM. The proportion of eicosapentaenoic and clupanodonic acids in BM significantly decreased. The ratio of n-6 to n-3 polyunsaturated fatty acids ranged from 0.9 to 13.6 and from 1.0 to 17.2 in BM and TM, respectively. An increase in the level of Lola oil in the diet by 1% caused that the n-6/n-3 polyunsaturated fatty acid ratio extended by 1.00 and 1.19 units in BM and TM, respectively. Dependences of n-6/n-3 ratio on the level of Atalante oil were expressed by equations of convex parabolas with minima at the level of oil 5.8 and 5.9% for BM and TM, respectively. By means of the inclusion of linseed oil with a high content of &alpha;-linolenic acid in the feed mixture it would be possible to produce poultry meat as a functional food with a very narrow ratio of n-6/n-3 polyunsaturated fatty acids.


Nutrients ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 301
Author(s):  
Andrew J. Sinclair ◽  
Xiao-Fei Guo ◽  
Lavinia Abedin

The retina requires docosahexaenoic acid (DHA) for optimal function. Alpha-linolenic acid (ALA) and DHA are dietary sources of retinal DHA. This research investigated optimizing retinal DHA using dietary ALA. Previous research identified 19% DHA in retinal phospholipids was associated with optimal retinal function in guinea pigs. Pregnant guinea pigs were fed dietary ALA from 2.8% to 17.3% of diet fatty acids, at a constant level of linoleic acid (LA) of 18% for the last one third of gestation and retinal DHA levels were assessed in 3-week-old offspring maintained on the same diets as their mothers. Retinal DHA increased in a linear fashion with the maximum on the diet with LA:ALA of 1:1. Feeding diets with LA:ALA of 1:1 during pregnancy and assessing retinal DHA in 3-week-old offspring was associated with optimized retinal DHA levels. We speculate that the current intakes of ALA in human diets, especially in relation to LA intakes, are inadequate to support high DHA levels in the retina.


2017 ◽  
Vol 86 (3) ◽  
pp. 293-301 ◽  
Author(s):  
Gordana Kralik ◽  
Zlata Kralik ◽  
Eva Straková ◽  
Manuela Grčević ◽  
Danica Hanžek

The aim of the research was to enrich eggs with n-3 polyunsaturated fatty acids by using plant oils and fish oil as dietary supplements in laying hens’ feed. The focus was put on the effect of the daily consumption of 100 g of egg yolk, i.e. 100 g of egg mass, on the human health. The 1st group of laying hens was fed a diet containing soybean and fish oil, and the 2nd group was given feed containing a combination of linseed, rapeseed, soybean, and fish oils. Eggs laid by the 2nd group contained 4.73% α-linolenic acid, 0.20% eicosapentaenoic acid and 2.37% docosahexaenoic acid (% of total fatty acids in yolk lipids, P < 0.001), which marks an increase of × 4.04 for α-linolenic acid, × 3.33 for eicosapentaenoic acid, and × 1.75 for docosahexaenoic acid compared to eggs laid by the 1st group. Total n-3 polyunsaturated fatty acids in eggs of the 2nd group were × 2.8 higher than in the 1st first group. Calculated per 100 g of eggs of the 2nd group, the intake for the human body corresponds to 435 mg α-linolenic acid, 18.43 mg eicosapentaenoic acid, and 218.2 mg docosahexaenoic acid.


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