This study is single site, double-blind, randomized, cross-over study designed to compare the effects of flax oil and fish oil supplementation on the oxylipin profile in healthy males and females. Eligible participants will complete two (2) Supplementation Phases (flax oil versus fish oil) and will be asked to attend 6 in-person clinic visits (0, 1, 3, 7, 14 and 28 days) for blood and urine collection during each phase. Participants will consume 8 capsules a day for 28 days containing either A) Flax Oil at 4 grams of ALA per day ,in one phase and B) Fish Oil at a dose of 4 grams DHA + 0.8 grams EPA per day in the next phase. Participants will be randomized and blinded and will therefore no know what supplement they are taking in either phase.

This is a single site, double-blind, randomized, crossover study designed to compare the effects of dietary omega-3 fatty acids from flax oil versus fish oil supplementation on oxylipin profiles over time (0 to 4 weeks) and between healthy males and females.

Recruitment will consist of a total of six (6) male and six (6) female participants. Participants will be recruited through advertisement from the local community. The study will be conducted at the Asper Centre for Clinical Research, St. Boniface Hospital. Participants will be asked to provide written informed consent prior to participation in the study. Participants who have provided written consent will be asked to attend an in-patient visit to provide a fasting blood sample. Should the participant be eligible to participate, they will be scheduled for a minimum 6 week Run-in Period, a 4 week Supplementation Phase, a minimum 6 week Wash-out Period and then a second 4 week Supplementation Phase; each Supplementation Phase will have 6 in-person visits (0, 1, 3, 7, 14 and 28 days) to obtain fasting blood and urine samples and for completion of the Study Checklist. During each 4 week Supplementation Phase, participants will consume capsules containing flax oil and at a dose of 4 grams of ALA/day, or capsules containing fish oil and at a dose of 4 grams DHA + 0.8 grams EPA/day. A 3-Day Food Record and Activity Questionnaire will be completed before the Day 0 visit and during week 3 of each Supplementation Phase.

Provision of flax oil or fish oil in capsules will allow this study to be double-blinded. Blinding will reduce potential bias during data collection and evaluation of study endpoints. Both the research team and the participant are blinded from the time of randomization and for the duration of the study. Randomization will be used to avoid bias in the assignment; to increase the likelihood that known and unknown participant characteristics are evenly balanced across the various test groups; and to enhance the validity of statistical comparisons across test groups.

Inclusion Criteria:

Participants must meet the following criteria to be eligible for participation in the study:

1. Male, or non-pregnant, non-lactating premenopausal female, ≥18 and ≤50 years of age;
2. Normal blood lipid profile (total cholesterol <5.2 mmol/L, LDL-cholesterol <3.4 mmol/L, HDL-cholesterol >0.9 mmol/L, triglycerides <1.7 mmol/L), plasma creatinine <1.5× upper limit of normal (ULN) where the normal range is 50-97 µmol/L, and glycated hemoglobin <6%; aspartate transaminase (AST) <2× ULN where the normal range is 10 - 32 U/L, and alanine transaminase (ALT) <2× ULN where the normal range is <25 U/L;
3. Blood pressure <140/90;
4. Body mass index (BMI) of 18 to 28;
5. Stable regime if taking vitamin and mineral/dietary/herbal supplements for the past 1 months and while participating in the study;
6. Willing to maintain a stable level of activity while participating in the study;
7. Willing to maintain dietary routine and to refrain from consuming omega-3 supplements or omega-3 rich foods (>0.3 grams ALA/serving, or >0.1 grams EPA + DHA/serving) from acceptance into the study until the final study visit;
8. Females must have normal menses and can be on birth control;
9. Agrees to not donate blood while participating in the study and for 2 months after participation in the study.
10. Willing to comply with the protocol requirements and procedures;
11. Willing to provide informed consent.

Exclusion Criteria:

Participants will be excluded if they have any of the following:

1. Presence of a clinically diagnosed disease affecting the circulatory, respiratory, immune, skeletal, urinary, muscular, endocrine, digestive, nervous or reproductive system, or a disease condition that has required or currently requires medical treatment;
2. Taking any prescribed medication, regular use of acetylsalicylic acid (e.g. Aspirin), ibuprofen (e.g. Advil) or acetaminophen (e.g. Tylenol) within the last 3 months;
3. Allergy or sensitivity to any of the study product ingredients, such as flax, flax oil, or marine source oils such as fish or shellfish.
4. Cigarette/cigar smoking or use of tobacco products within the past 12 months or during the study;
5. Body weight has not been stable (±3 kg) over the past 6 months;
6. Consumption of >15 alcoholic beverages per week (according to Canada's Low-Risk Alcohol Drinking Guidelines, 2012) within the last 3 months or while participating in the study;
7. Current (within the past 30 days) bacterial, viral or fungal infection;
8. Unable to obtain blood sample at the screening and/or week 0 visit.
9. Donated or had blood collected in the 2 months prior to participation the study.