Help on accessing alternative formats, such as Portable Document Format (PDF), Microsoft Word and PowerPoint (PPT) files, can be obtained in the alternate format help section.

(PDF Version - 187 K)
Bureau of Nutritional Sciences
Food Directorate, Health Products and Food Branch
Health Canada

January 2014

Background

In March 2012, Health Canada's Food Directorate received an application for a therapeutic claim about ground flaxseed and blood cholesterol lowering. The information below is a summary of Health Canada's review based on the Guidance Document for Preparing a Submission for Food Health Claims.

Health Canada has recently reconsidered the classification of food products with disease risk reduction claims or therapeutic claims in light of clarified principles for the classification of foods at the Food-Natural Health Product interface. Health Canada's position is that when food products are marketed for a disease risk reduction or therapeutic benefit, which comes as a result of the food's normal use as part of the diet, these products may be classified and regulated as foods. In other words, the use of a disease risk reduction claim or a therapeutic claim alone is not sufficient to classify the product as a natural health product.

Scientific Evidence Supporting the Claim

The petitioner provided a literature review up to May 2011 to substantiate the proposed health claim. The petitioner's literature review was updated by Health Canada's Food Directorate to June 2013, bringing the total number of relevant studies to 8.

All relevant studies were clinical trials conducted in normo- and hypercholesterolemic males and females ranging from 8 to 75 years of age. Treatment duration ranged from 4 weeks to 12 months and the quantity of ground flaxseed consumed ranged from 30g/day to 50g/day. Ground flaxseed was used in all studies except one (Simbalista et al., 2010), which used partially defatted flaxseed meal at a dose equivalent to 25g/day of whole seed. The smallest study included 10 subjects, while there were 179 subjects in the largest study. The main endpoints considered were total cholesterol and low-density lipoprotein (LDL) cholesterol. These are recognized as risk factors or biomarkers for heart disease.

The direction of effect was highly consistent towards a reduction in total cholesterol (100%) and LDL cholesterol (100%) levels when flaxseed was consumed. However, a very low proportion of studies showed a statistically significant reduction in total cholesterol (25%) and LDL cholesterol (0%) levels. These conclusions were similar when only higher quality studies were taken into account.


The petitioner conducted a meta-analysis which was reproduced and expanded by Heath Canada's Food Directorate. Pooled estimates of both meta-analyses were similar. The estimates from the Food Directorate meta-analysis are reported here. All 8 studies identified as part of the systematic review were included. Baseline and final values for the control and treatment groups were extracted from the studies to calculate the change for each group, except when change was already provided. The pooled effect was -0.21mmol/L (p=0.0001) for total cholesterol levels and -0.22mmol/L (p