A Placebo-Controlled, Blinded, Randomized Clinical Trial of Dietary Flaxseed Supplementation for Children and Adolescents With Hypercholesterolemia
A Placebo-Controlled, Blinded, Randomized Clinical Trial of Dietary Flaxseed Supplementation for Children and Adolescents With Hypercholesterolemia
Year: 2013
Authors: Wong, H. Chahal, N. Manlhiot, C. Niedra, E. McCrindle, B.W.
Publication Name: JAMA Pediatr.
Publication Details: doi:10.1001/jamapediatrics.2013.1442
Abstract:
Importance: 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 (minus 0.19 mmol/L) in high density lipoprotein cholesterol (95percent CI, minus 3.09 to minus 11.60 mg/dL[0.08 to 0.30 mmol/L]; relative: minus 15percent, 95percent CI, minus 24percent to minus 6percent ), an increase of 29.23 mg/dL (minus 0.33 mmol/L) in triglycerides (95percent CI, 4.43 to 53.14 mg/dL [0.05 to 0.60 mmol/L]; relative: minus 26percent, 95percent CI, minus 4percent to minus 48percent), and an increase of minus 4.88 g/d in dietary polyunsaturated fat intake (95percent CI, minus 0.22 to minus 9.53; relative: 76percent, 95percent CI, minus 3percent to 48percent). Flaxseed had no attributable effects on total cholesterol (8.51 mg/dL [0.22 mmol/L]; 95percent CI, 21.66 to 4.25mg/dL [0.56 to 0.11 mmol/L]; relative: 4percent, 95percent CI, 10percent to 2percent), low density lipoprotein cholesterol (6.96 mg/dL [0.18mmol/L]; 95percent CI, 16.63 to 2.71 mg/dL [0.43 to 0.07 mmol/L]; relative:5percent, 95percent CI, 12percent to 2percent), body mass index z score 0.002; 95percent CI, 0.147 to 0.150; relative:0percent, 95percent CI,12percent to12percent) or total caloric intake (117 kcal; 95percent CI, 243 to 479; relative: 8 percent, 95 percent CI, 17percent to 33percent). 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 10percent. 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. (Authors abstract)
Elevated lipid profiles in elevated adolescents and young adults have been highlighted as a risk factor for the early development of atherosclerotic lesions and cardiovascular disease. Managing lipid levels in youth is an important and effective means of addressing the prevalence of these conditions in adults. A recent meta-analysis of clinical trials investigating the effects of flaxseed on blood lipid levels in adults supported a positive role for flaxseed in treating hyperlipidemia. The dosage of flaxseed used in the reviewed trials ranged from 20 to 50 g/d.
Across the multiple trials, whole-seed flaxseed intervention resulted in a significant overall decrease in LDLC levels but no change in HDLC or triglyceride levels.
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In a placebo-controlled, blinded, randomized clinical trial of flaxseed supplementation therapy in children with hypercholesterolemia, this studyfound the intervention to have no significant benefit for cardiovascular risk in reducing lipid levels. Flaxseed supplementation was associated with a significant decrease in HDLC level and an increase in triglyceride levels. The authors did report a potential benefit of flaxseed supplementation based on a clinically important reduction of 10 percent in LDLC level.
This study had several limitations. First, the study unexpectedly observed increases in body mass index (calculated as weight in kilograms divided by height in meters squared) 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. This study was limited by its small sample size, resulting in low study power for some secondary outcomes, as well as the short duration for which the intervention was tested (4 weeks). Both of these limitations may have compromised the generalizability of the study results. Further research seeking longitudinal data from larger samples of patients is warranted to address the current discrepancy between evidence from adult and pediatric trials, as well as further elucidate the possible role of flaxseed in treating pediatric hyperlipidemia. (Editors cooments)
