Key Findings
Ongoing controversy surrounding the safety and benefits of the long-term use of lipid lowering drugs warrants greater research into possible alternative therapies for the clinical management of pediatric hyperlipidemia. In this placebo-controlled, blinded, randomized clinical trial of flaxseed supplementation therapy in children with hypercholesterolemia, flaxseed had no significant benefit for cardiovascular risk in reducing lipid levels. However, flaxseed supplementation was associated with a significant decrease in HDL-C level and an increase in triglyceride levels. On the basis of a 95% CI, there was a potential benefit of flaxseed supplementation based on a clinically important reduction of –10% in LDL-C levels. An explanation for the negative results seen may be that palatable delivery of oral interventions is often more difficult in pediatric patients; it is possible that the formulations of the ground flaxseed in the muffin and bread necessary for palatability to pediatric patients, influenced the efficacy of the intervention vs standard methods used in adults, such as whole flaxseed or purified lignans. The study unexpectedly observed increases in body mass index and daily caloric intake in both study groups during the trial. The results may have been confounded by the inherent difficulty of confirming adherence and compliance to the study protocol since assessment of compliance was based on consumption reports from patient-completed intake logs. Compliance may have been affected by the unconfirmed palatability of the study breads and muffins, as well as the long period (4 weeks) between the pre- and post treatment
assessment visits. The study was limited by its small sample size (n = 32), resulting in low study power for some secondary outcomes, as well as the short duration for which the intervention was tested (4weeks). These limitations may have compromised the generalizability of the study results.
ABSTRACT
Nonpharmacological management of hypercholesterolemia in children is challenging with few available options. OBJECTIVES To determine the safety and efficacy of dietary flaxseed supplementation in the management of hypercholesterolemia in children. DESIGN Four-week placebo-controlled, blinded, randomized clinical trial. SETTING: Specialized dyslipidemia clinic at a tertiary pediatric care center. PARTICIPANTS Thirty-two participants aged 8 to 18 years with low-density lipoprotein cholesterol from 135 mg/dL (3.5 mmol/L) to less than 193 mg/dL (5.0 mmol/L). INTERVENTION: The intervention group ate 2 muffins and 1 slice of bread daily containing ground flaxseed (30 g flaxseed total). The control group ate muffins and bread substituted with whole-wheat flour. MAIN OUTCOME AND MEASURE Attributable change in fasting lipid profile. RESULTS Dietary flaxseed supplementation resulted in an attributable decrease of -7.35 mg/dL (-0.19 mmol/L) in high-density lipoprotein cholesterol (95% CI, -3.09 to -11.60 mg/dL[-0.08 to -0.30 mmol/L]; relative: -15%, 95% CI, -24% to -6%; P = .001), an increase of 29.23 mg/dL (+0.33 mmol/L) in triglycerides (95% CI, 4.43 to 53.14 mg/dL [+0.05 to +0.60 mmol/L]; relative: +26%, 95% CI, +4% to +48%; P = .02), and an increase of +4.88 g/d in dietary polyunsaturated fat intake (95% CI, +0.22 to +9.53; relative: +76%, 95% CI, +3% to +148%; P = .04). Flaxseed had no attributable effects on total cholesterol (-8.51 mg/dL [-0.22 mmol/L]; 95% CI, -21.66 to 4.25 mg/dL [-0.56 to +0.11 mmol/L]; relative: -4%, 95% CI, -10% to +2%; P = .20), low-density lipoprotein cholesterol (-6.96 mg/dL [-0.18 mmol/L]; 95% CI, -16.63 to 2.71 mg/dL [-0.43 to +0.07 mmol/L]; relative: -5%, 95% CI, -12% to +2%; P = .15), body mass index z score (+0.002; 95% CI, -0.147 to +0.150; relative: +0%, 95% CI, -12% to +12%; P = .30), or total caloric intake (+117 kcal; 95% CI, -243 to +479; relative: +8%, 95% CI, -17% to +33%; P = .52). An attributable change in total and low-density lipoprotein cholesterol failed to exclude a potential benefit of flaxseed supplementation based on a prespecified minimum clinically important reduction of 10%. No concerns were noted regarding safety. CONCLUSIONS AND RELEVANCE:
The use of dietary flaxseed supplementation, while safe, was associated with adverse changes in the lipid profile of children with hypercholesterolemia, although a potential benefit of low-density lipoprotein cholesterol lowering could not be excluded. The use of flaxseed supplementation in children with hypercholesterolemia might not be a viable option for lipid management in this population.