The aim of this study is to determine if thirty grams per day of flaxseed consumption for 4 weeks could potentially reduce the serum lipid levels in children and adolescents with familial or severe hypercholesterolemia compared to those on placebo.

The proposed study is a 4 week randomized, double-blind, placebo-controlled clinical trial. Participants will be recruited from the pediatric lipid disorder clinic at the Hospital for Sick Children, which provides consultations to and management of children with primary lipid abnormalities. Patients that meet the study criteria will be approached during their routinely scheduled clinic visits, until the sample size (N=30) be reached. Patients will randomly be assigned to the intervention or the placebo group. The intervention group will be given muffins and breads containing ground flaxseed. Two muffins and one slice of bread will be consumed per day to provide a total of 30g flaxseed to the experimental group. The control group will be given muffins and breads containing whole wheat flour in place of flaxseed. Participants will be instructed to eat one muffin for breakfast, one muffin as an afternoon snack, and one slice of bread as an evening snack every day for a 4-week period. The muffins and breads use in the study will be baked by an independent baker.

Inclusion Criteria:

• age 8 to 18 years
• positive first-degree family history of hypercholesterolemia or premature atherosclerotic cardiovascular disease
• elevated LDL level above 3.5 mmol/L and less than 5.0 mmol/L
• entered in the National Cholesterol Education Program Step II diet for at least 6 months

Exclusion Criteria:

• patients with secondary causes of hyperlipidemia
• history of major illness or surgery 3 months or less prior to enrollment
• taking lipid-lowering medications
• history of gastrointestinal problems
• allergies towards flaxseed