Effects of fish-oil supplementation on myocardial fatty acids in humans.
BACKGROUND
Increased fish or fish-oil consumption is associated with reduced risk of cardiac mortality, especially sudden death. This benefit putatively arises from the incorporation of the long-chain n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) into cardiomyocyte phospholipids.


OBJECTIVE
The study examined the kinetics of incorporation of n-3 fatty acids into human myocardial membrane phospholipids during supplementation with fish oil and alpha-linolenic acid-rich flaxseed oil.


METHODS
Patients with low self-reported fish intake (<1 fish meal/wk and no oil supplements) accepted for elective cardiac surgery involving cardiopulmonary bypass were randomly allocated to 1 of 6 groups: no supplement; fish oil (6 g EPA+DHA/d) for either 7, 14, or 21 d before surgery; flaxseed oil; or olive oil (both 10 mL/d for 21 d before surgery). Right atrial appendage tissue removed during surgery and blood collected at enrollment and before surgery were analyzed for phospholipid fatty acids.


RESULTS
Surgery rescheduling resulted in a range of treatment times from 7 to 118 d. In the fish-oil-treated subjects, accumulation of EPA and DHA in the right atrium was curvilinear with time and reached a maximum at approximately 30 d of treatment and displaced mainly arachidonic acid. Flaxseed oil supplementation yielded a small increase in atrial EPA but not DHA, whereas olive oil did not significantly change atrial n-3 fatty acids.


CONCLUSIONS
The results of the present study show that dietary n-3 fatty acids are rapidly incorporated into human myocardial phospholipids at the expense of arachidonic acid during high-dose fish-oil supplementation.
Metcalf
Robert G
RG
Rheumatology Unit, Royal Adelaide Hospital, Adelaide, Australia. rmetcalf@mail.rah.sa.gov.au
James
Michael J
MJ
Gibson
Robert A
RA
Edwards
James Rm
JR
Stubberfield
John
J
Stuklis
Robert
R
Roberts-Thomson
Kurt
K
Young
Glenn D
GD
Cleland
Leslie G
LG
D000368:Aged; D002315:Cardiopulmonary Bypass; D002318:Cardiovascular Diseases / Q000378:metabolism* / Q000401:mortality / Q000601:surgery; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000008:administration & dosage / Q000493:pharmacokinetics; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage / Q000493:pharmacokinetics; D015525:Fatty Acids, Omega-3 / Q000378:metabolism / Q000493:pharmacokinetics*; D005260:Female; D005395:Fish Oils / Q000008:administration & dosage / Q000737:chemistry*; D006801:Humans; D008043:Linseed Oil / Q000008:administration & dosage / Q000737:chemistry; D008297:Male; D008563:Membrane Lipids / Q000737:chemistry / Q000378:metabolism; D008875:Middle Aged; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D000069463:Olive Oil; D010743:Phospholipids / Q000737:chemistry / Q000378:metabolism*; D010938:Plant Oils / Q000008:administration & dosage / Q000737:chemistry; D012307:Risk Factors
D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D008563:Membrane Lipids; D000069463:Olive Oil; D010743:Phospholipids; D010938:Plant Oils; D004281:Docosahexaenoic Acids; D008043:Linseed Oil; D015118:Eicosapentaenoic Acid