Plain language summary
Metabolic syndrome is a cluster of 5 risk factors, including waist circumference, blood pressure, and serum concentrations of glucose, triglycerides, and high-density lipoprotein (HDL) cholesterol in the fasting condition. These often occur in concert and predispose people to type 2 diabetes and cardiovascular disease. The aim of this study was to evaluate whether current evidence supports the idea that Paleolithic nutrition improves risk factors for chronic disease more than do other dietary interventions in people with one or more components of the metabolic syndrome. The study is a systematic review and meta-analysis of 4 randomized controlled trials that compared Paleolithic nutrition with any other dietary intervention in participants with one or more of the 5 components of the metabolic syndrome. Results indicate that Paleolithic nutrition resulted in greater short-term pooled improvements on each of the 5 components of metabolic syndrome than did currently recommended guideline-based control diets. However, the greater pooled improvements did not reach signiﬁcance for 2 of the 5 components (i.e., HDL cholesterol and fasting blood sugar). Authors conclude that the available data warrant additional evaluations of the health beneﬁts of Paleolithic nutrition.
BACKGROUND Paleolithic nutrition, which has attracted substantial public attention lately because of its putative health benefits, differs radically from dietary patterns currently recommended in guidelines, particularly in terms of its recommendation to exclude grains, dairy, and nutritional products of industry. OBJECTIVE We evaluated whether a Paleolithic nutritional pattern improves risk factors for chronic disease more than do other dietary interventions. DESIGN We conducted a systematic review of randomized controlled trials (RCTs) that compared the Paleolithic nutritional pattern with any other dietary pattern in participants with one or more of the 5 components of metabolic syndrome. Two reviewers independently extracted study data and assessed risk of bias. Outcome data were extracted from the first measurement time point (≤6 mo). A random-effects model was used to estimate the average intervention effect. The quality of the evidence was rated with the use of the Grading of Recommendations Assessment, Development and Evaluation approach. RESULTS Four RCTs that involved 159 participants were included. The 4 control diets were based on distinct national nutrition guidelines but were broadly similar. Paleolithic nutrition resulted in greater short-term improvements than did the control diets (random-effects model) for waist circumference (mean difference: -2.38 cm; 95% CI: -4.73, -0.04 cm), triglycerides (-0.40 mmol/L; 95% CI: -0.76, -0.04 mmol/L), systolic blood pressure (-3.64 mm Hg; 95% CI: -7.36, 0.08 mm Hg), diastolic blood pressure (-2.48 mm Hg; 95% CI: -4.98, 0.02 mm Hg), HDL cholesterol (0.12 mmol/L; 95% CI: -0.03, 0.28 mmol/L), and fasting blood sugar (-0.16 mmol/L; 95% CI: -0.44, 0.11 mmol/L). The quality of the evidence for each of the 5 metabolic components was moderate. The home-delivery (n = 1) and dietary recommendation (n = 3) RCTs showed similar effects with the exception of greater improvements in triglycerides relative to the control with the home delivery. None of the RCTs evaluated an improvement in quality of life. CONCLUSIONS The Paleolithic diet resulted in greater short-term improvements in metabolic syndrome components than did guideline-based control diets. The available data warrant additional evaluations of the health benefits of Paleolithic nutrition. This systematic review was registered at PROSPERO (www.crd.york.ac.uk/PROSPERO) as CRD42014015119.