Clinical evidence on dietary supplementation with chia seed (Salvia hispanica L.): a systematic review and meta-analysis
What this study found
Overall, current evidence does not support a health claim for chia seed supplementation, and the certainty of evidence was low to very low. Across trials, outcomes were surrogate markers rather than clinical events. Some higher-dose subgroup analyses suggested modest improvements in postprandial glucose, with pooled postprandial glucose iAUC MD -24.10 mmol/L × 2 h (95% CI -53.08 to 4.87; 4 trials; I2 = 67.9%; P = 0.025), and dose-related signals of lower postprandial glucose at medium doses (MD -33.95 iAUC mmol/L × 2 h) and high doses (MD -51.60 iAUC mmol/L × 2 h). Other pooled findings…
- Study & population
- Systematic review and meta-analysis of 14 randomized trials involving 526 participants across diverse adult populations.
- Intervention
- Chia seed (Salvia hispanica L.) was given orally, most often incorporated into food or drink, though some trials used chia seed alone, a dehydrated chia-based mixture, or chia seed oil added to water.
- Key limitation
- Evidence quality was low to very low, and all trials relied on surrogate outcomes rather than clinical endpoints.
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Open PDFOriginal abstract
Context Chia seed is a popular dietary supplement, taken mainly for its high content of alpha-linolenic acid, vegetable protein, and dietary fiber, yet information about its clinical effects is lacking. Objective This review aims to summarize the clinical evidence regarding the use of chia seed for a wide variety of health conditions. Data Sources A number of databases, including PubMed and Embase, were searched systematically. Study Selection Randomized controlled trials that assessed the clinical effects of chia seed consumption in human participants were included. The quality of trials was assessed using the Cochrane Risk of Bias Tool. Data Extraction Data on study design, blinding status, characteristics of participants, chia seed intervention, comparator, clinical assessment, duration of intake, interval of assessment, and study funding status were extracted. Meta-analysis was performed. Results Twelve trials were included. Participants included healthy persons, athletes, diabetic patients, and individuals with metabolic syndrome. Pooling of results showed no significant differences except for the following findings of subgroup analysis at higher doses of chia seed: (1) lower postprandial blood glucose level (mean difference [MD] of -33.95 incremental area under the curve [iAUC] [mmol/L × 2 h] [95%CI, -61.85, -6.05] and -51.60 iAUC [mmol/L × 2 h] [95%CI, -79.64, -23.56] at medium doses and high doses, respectively); (2) lower high-density lipoprotein in serum (MD of -0.10 mmol/L [95%CI, -0.20, -0.01]); and (3) lower diastolic blood pressure (MD of -7.14 mmHg [95%CI, -11.08, -3.19]). The quality of all evidence assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was low or very low. All trials employed only surrogate markers as outcomes. Conclusions Future trials with improved methodological quality, well-described clinical events, and validated surrogate markers as outcomes are needed to support the potential health benefits of chia seed consumption. Systematic Review Registration PROSPERO registration no. CRD42015029990.