Background: Effects of flaxseed on serum lipids have been studied in humans, but the results are variable. Flaxseed is ineffective in lowering blood pressure in rats. Its effect on blood pressure in humans is not known. It is also not known if long-term use of flaxseed in humans has deleterious effects on the hemopoietic system, serum glucose, and renal and kidney function. We investigated the effect of short-term use of flaxseed in humans on arterial pressure and serum lipids (triglycerides, total cholesterol; high-, low-, and very-low-density-lipoprotein cholesterol [HDL-C, LDL-C, VLDL-C], hemopoietic system (red blood cells, neutrophils, hemoglobin) and the various biochemical parameters, such as serum protein, albumin, total bilirubin, aspartate aminotransferase, alkaline phosphatase, creatinine, urea, related to hepatic and renal function, and serum glucose.
Methods: Fifteen healthy men, aged 22 to 47 years, consumed three muffins daily containing 32.7 g of total flaxseed for 4 weeks, in addition to their normal daily diet. Blood pressure and blood samples for various biochemical measurements were collected before and after 4 weeks of flaxseed diet.
Results: Blood pressures, heart rate, hemoglobin, and counts of red blood cells, white blood cells, and neutrophils remained unaltered after flaxseed diet. Serum total cholesterol, HDL-C, LDL-C, and VLDL-C remained unchanged, but serum triglycerides levels were elevated. Serum total bilirubin, aspartate aminotransferase, alkaline phosphatase, protein, albumin, glucose, and urea remained unaltered, but serum levels of creatinine decreased.
Conclusion: These results suggest that 4 weeks use of flaxseed does not have deleterious effects on the hemopoietic system or renal and hepatic function and does not lower blood pressure and serum lipids. However, the level of serum triglyceride level was elevated.