Bioavailability of [alpha]-linolenic acid from flaxseed diets as a function of the age of the subject

Background: Dietary flaxseed may have beneficial cardiovascular effects. An aged population has a higher incidence of cardiovascular disease, but they may react differently to flaxseed in the diet. Objective: To investigate the response, over a period of 4 weeks, of subjects aged 18-29 or 45-69 years to a diet containing the same amount of [alpha]-linolenic acid (ALA) (6 g) introduced in the form of ground flaxseed (30 g) or flaxseed oil. Results: All subjects who received flaxseed oil showed a significant increase in plasma ALA and eicosapentaenoic acid (EPA) concentrations over the course of this study. Subjects who received ground flaxseed in the 18-29-year-old group showed a statistically significant increase in their plasma ALA levels, and although there was a trend in the same direction for the 45-69-year-old subjects, this did not achieve statistical significance. The diets induced no major changes in platelet aggregation, plasma total cholesterol, low-density lipoprotein or high-density lipoprotein cholesterol levels in any of the groups. Younger subjects showed a decrease in triglyceride (TG) values compared with older subjects. There were no significant side effects that caused compliancy issues. Conclusion: Subject age does not seem to be a major determining factor in influencing ALA absorption from a flaxseed- supplemented diet nor in the metabolism of ALA to EPA in the groups fed flaxseed oil. Concerns about side effects in older subjects administered a higher fiber load in a flaxseed-supplemented diet are not justified. However, younger but not older subjects showed a beneficial decrease in circulating TGs due to flaxseed supplementation. doi:10.1038/ejcn.2009.41; published online 8 July 2009 Keywords: omega-3 fatty acid; polyunsaturated fatty acids (PUFAs); platelet aggregation; linseed; cardiovascular disease; aging
Introduction Flaxseed contains one of the richest plant sources of the [omega]-3 polyunsaturated fatty acid, [alpha]-linolenic acid (ALA). ALA is believed to be one of the dietary factors responsible for [...]