Effects of flaxseed supplementation on erythrocyte fatty acids and multiple cardiometabolic biomarkers among Chinese with risk factors of metabolic syndrome
Effects of flaxseed supplementation on erythrocyte fatty acids and multiple cardiometabolic biomarkers among Chinese with risk factors of metabolic syndrome
Year: 2013
Authors: Zong, G. Demark-Wahnefried, W. Wu, H. Lin, X.
Publication Name: Eur J Nutr
Publication Details: Volume 52; Pages 1547-1551
Abstract:
We investigated effects of ground whole flaxseed supplementation on erythrocyte polyunsaturated fatty acids (PUFAs) and serum biomarkers of inflammation,
endothelial dysfunction, oxidative stress, and thrombosis in Chinese with risk factors of metabolic syndrome (MetS). This study was a secondary analysis of a 12 week, randomized, parallel group trial in participants screened for MetS. The analysis included only those with 2 or more components of MetS before receiving either lifestyle counseling (LC, n equals 90) or LC plus 30 g per day flaxseed supplementation (LCF, n equals 83). Compared to the LC group, those in the LCF group experienced significant increases in total erythrocyte n 3 PUFAs, alpha linolenic acid, eicosapentenoic acid, and
docosapentenoic acid, while total n 6 PUFAs and n 6 to n 3 ratio decreased. Arachidonic acid increased significantly in the LC group, and serum high sensitivity C reactive protein, interleukin, soluble intracellular adhesion molecular 1, E selectin, and plasminogen activator inhibitor 1 declined significantly in both groups, but no between group differences were observed. There was no significant change in serum interleukin 6, tumor necrosis factor a, soluble vascular adhesion molecular 1, monocyte chemo attractant protein 1, and oxidized low density lipoprotein in either group. These data suggest that flaxseed supplementation increases erythrocyte n 3 PUFAs, decreases n 6 PUFAs and n 6 to n 3 ratio in participants with risk factors of MetS, but has no additional benefits beyond the lifestyle consulting for the multiple biomarkers tested in the current study. (Authors abstract)
endothelial dysfunction, oxidative stress, and thrombosis in Chinese with risk factors of metabolic syndrome (MetS). This study was a secondary analysis of a 12 week, randomized, parallel group trial in participants screened for MetS. The analysis included only those with 2 or more components of MetS before receiving either lifestyle counseling (LC, n equals 90) or LC plus 30 g per day flaxseed supplementation (LCF, n equals 83). Compared to the LC group, those in the LCF group experienced significant increases in total erythrocyte n 3 PUFAs, alpha linolenic acid, eicosapentenoic acid, and
docosapentenoic acid, while total n 6 PUFAs and n 6 to n 3 ratio decreased. Arachidonic acid increased significantly in the LC group, and serum high sensitivity C reactive protein, interleukin, soluble intracellular adhesion molecular 1, E selectin, and plasminogen activator inhibitor 1 declined significantly in both groups, but no between group differences were observed. There was no significant change in serum interleukin 6, tumor necrosis factor a, soluble vascular adhesion molecular 1, monocyte chemo attractant protein 1, and oxidized low density lipoprotein in either group. These data suggest that flaxseed supplementation increases erythrocyte n 3 PUFAs, decreases n 6 PUFAs and n 6 to n 3 ratio in participants with risk factors of MetS, but has no additional benefits beyond the lifestyle consulting for the multiple biomarkers tested in the current study. (Authors abstract)
Flaxseed is a rich source of alpha linolenic acid (ALA), plant lignans, and dietary fiber. Beyond its own benefit to metabolic disorders, ALA could be converted to long chain
N 3 polyunsaturated fatty acids (PUFAs) and induce decrease in n 6 per n 3 PUFA ratio to have further favorable effect. However, few studies have been carried out in people with or at high risk for metabolic syndrome (MetS), a condition closely associated with cardiovascular diseases and diabetes. Most studies have been conducted in western populations, and it remains unknown how n 3 PUFAs would be changed by flaxseed supplementation in Asian people who have different diet. MetS is often accompanied by inflammation, endothelial dysfunction, oxidative stress, and thrombosis which are linked with the pathogeneses of cardiometabolic diseases. Previous studies indicate that flaxseed and its derivatives have moderate protective effects on some of these biomarkers. Little is known regarding the effect of whole flaxseed in individuals who exhibit MetS risk factors. In the present study, the authors investigated effects of ground whole flaxseed supplementation on erythrocyte PUFAs, and biomarkers of inflammation, endothelial dysfunction, thrombosis, and oxidative stress in Chinese screened for MetS.
In this study, flaxseed supplementation in Chinese with risk factors of metabolic syndrome significantly increased total n 3 PUFAs, and ALA, EPA and DPA, but not DHA, in consistent with most of previous studies conducted in western people. In fact, few studies reported changes of DHA status in humans. This might be explained by the fact that ALA prevents downstream desaturation by monopolizing delta 6 desaturase, the enzyme desaturates not only ALA to C18: 4n 3, but also C24: 5n 3 to DHA in the pathway of n 3 PUFA biosynthesis. Increased ALA may competitively suppress conversion of LA and accumulation of long chain n 6 PUFAs, which could be reflected by unchanged AA in the LCF group in comparison with increased erythrocyte AA in the LC group. Flaxseed supplementation lead to a preferable change in n 6 per n 3 ratio which has been suggested to be associated with lower risks of many chronic diseases including cardiovascular diseases and diabetes. Despite the changes in erythrocyte PUFA status, no significant effects of flaxseed supplementation were noted for all measured cardio metabolic biomarkers. It has been suggested that at least 10 g per day of ALA is needed to ameliorate inflammation, which is higher than the dose used in the present trial. Although the duration of this intervention was longer than many previous studies, it still may not be sufficient to observe complete changes in erythrocyte PUFAs which might happen if flaxseed supplementation had continued. Second, the n 3 PUFAs in whole flaxseed may have relatively low digestibility due to the high fiber content, though, in a previous study, it was suggested that ground flaxseed can still induce significant increases in AL. In conclusion, supplementation with 30 g per day whole flaxseed for 12 weeks increased total erythrocyte n 3 PUFAs, ALA, EPA, and DPA, while decreased total n 6 PUFAs and n 6 per n 3 ratio. However, flaxseed did not exert additional benefit on biomarkers of inflammation, endothelial dysfunction, thrombosis, and oxidative stress. (Editors comments)
N 3 polyunsaturated fatty acids (PUFAs) and induce decrease in n 6 per n 3 PUFA ratio to have further favorable effect. However, few studies have been carried out in people with or at high risk for metabolic syndrome (MetS), a condition closely associated with cardiovascular diseases and diabetes. Most studies have been conducted in western populations, and it remains unknown how n 3 PUFAs would be changed by flaxseed supplementation in Asian people who have different diet. MetS is often accompanied by inflammation, endothelial dysfunction, oxidative stress, and thrombosis which are linked with the pathogeneses of cardiometabolic diseases. Previous studies indicate that flaxseed and its derivatives have moderate protective effects on some of these biomarkers. Little is known regarding the effect of whole flaxseed in individuals who exhibit MetS risk factors. In the present study, the authors investigated effects of ground whole flaxseed supplementation on erythrocyte PUFAs, and biomarkers of inflammation, endothelial dysfunction, thrombosis, and oxidative stress in Chinese screened for MetS.
In this study, flaxseed supplementation in Chinese with risk factors of metabolic syndrome significantly increased total n 3 PUFAs, and ALA, EPA and DPA, but not DHA, in consistent with most of previous studies conducted in western people. In fact, few studies reported changes of DHA status in humans. This might be explained by the fact that ALA prevents downstream desaturation by monopolizing delta 6 desaturase, the enzyme desaturates not only ALA to C18: 4n 3, but also C24: 5n 3 to DHA in the pathway of n 3 PUFA biosynthesis. Increased ALA may competitively suppress conversion of LA and accumulation of long chain n 6 PUFAs, which could be reflected by unchanged AA in the LCF group in comparison with increased erythrocyte AA in the LC group. Flaxseed supplementation lead to a preferable change in n 6 per n 3 ratio which has been suggested to be associated with lower risks of many chronic diseases including cardiovascular diseases and diabetes. Despite the changes in erythrocyte PUFA status, no significant effects of flaxseed supplementation were noted for all measured cardio metabolic biomarkers. It has been suggested that at least 10 g per day of ALA is needed to ameliorate inflammation, which is higher than the dose used in the present trial. Although the duration of this intervention was longer than many previous studies, it still may not be sufficient to observe complete changes in erythrocyte PUFAs which might happen if flaxseed supplementation had continued. Second, the n 3 PUFAs in whole flaxseed may have relatively low digestibility due to the high fiber content, though, in a previous study, it was suggested that ground flaxseed can still induce significant increases in AL. In conclusion, supplementation with 30 g per day whole flaxseed for 12 weeks increased total erythrocyte n 3 PUFAs, ALA, EPA, and DPA, while decreased total n 6 PUFAs and n 6 per n 3 ratio. However, flaxseed did not exert additional benefit on biomarkers of inflammation, endothelial dysfunction, thrombosis, and oxidative stress. (Editors comments)
