Effect of Flax in Yogurt on Blood Cyanide Levels

A Randomized, Controlled, Cross-over Trial Examining the Effect of Flaxseed on Blood Cyanide Levels in Healthy Adults

A randomized, controlled, cross-over post-prandial trial in healthy human volunteers will be conducted at the IH Asper Institute to determine the effect whole ground flaxseed, roasted then ground whole flaxseed, whole intact flaxseed and flaxseed hulls mixed into yogurt on blood cyanide levels.

Participants will receive yogurt containing the following flaxseed products in a random order:

1. 40 g ground flaxseed, untreated;
2. 40 g ground flaxseed, roasted before grinding;
3. 40 g intact whole flaxseed;
4. 28 g flaxseed hulls;
5. 0 g flaxseed.

Venous blood will be collected at the following time points: 0 (before consumption of test product), 15, 30, 45, 60, 75, 90, 120, 150, 180 min.

Urine will be collected prior to consumption of test product and 180 min.

Primary endpoints: 1) Peak blood level of cyanide and incremental area under the curve (iAUC) for cyanide in blood over a 3h postprandial period. Secondary endpoint: 1) cyanogenic glycoside and thiocyanate concentrations in plasma and urine over a 3h postprandial period.

Tertiary endpoints: 1) metabolic profile in plasma and urine over 3 h postprandial period.

Inclusion Criteria:

1. Generally healthy adult, 18 years or older;
2. Willing to provide informed consent;
3. Willing/able to comply with the requirements of the study.

Exclusion Criteria:

1. Pregnant or lactating;
2. Medical history of disease that is currently under treatment;
3. Active treatment for any type of cancer within 1 year prior to study start;
4. Presence of a gastrointestinal disorder, daily use of any stomach acid-lowering medications or laxatives (including fibre supplements) within the past month or antibiotic use within the past 6 weeks;
5. Plasma concentration of vitamin B12 < 148 pmol/L;
6. Complete blood count outside normal range;
7. Medical history of liver disease or liver dysfunction (defined as plasma AST or ALT ≥3 times the upper limit of normal (ULN));
8. Fasting blood glucose ≥6.1 mmol/L and/or HbA1c ≥6.0%;
9. Fasting plasma total cholesterol >7.8 mmol/L;
10. Fasting plasma HDL <0.9 mmol/L;
11. Fasting plasma LDL >5.0 mmol/L;
12. Fasting plasma triglycerides >2.3 mmol/L;
13. Systolic blood pressure >140 mmHg or diastolic blood pressure >90 mmHg;
14. Major surgery within the last 3 months;
15. Smoking, use of tobacco, vape or cannabis (within the last week);
16. Allergies to flaxseed or yogurt;
17. Aversion or unwillingness to eat study foods;
18. Participation in another clinical trial, current or in the past 4 weeks