Background: Cardiometabolic (CMB) risk factors are major mediators of the effects of diet on health. Multiple foods are often consumed in tandem, yet CMB effects of individual dietary factors are often studied in isolation, leading to estimates that may not represent true effects as part of diet patterns.
Objective: To quantify the effects of major foods (fruits, vegetables, nuts/seeds, whole grains, fish) and dietary fiber, when consumed within the context of overall diet patterns, on systolic BP, serum lipids, and glucose-insulin homeostasis.
Methods: PubMed was searched through Oct 2015 to identify randomized controlled feeding studies evaluating effects of major dietary patterns on CMB factors. We included trials evaluating major dietary patterns including fruits, vegetables, nuts/seeds, whole grains, fish, and dietary fiber as major components and evaluating effects on systolic BP, serum lipids (total cholesterol, LDL-C, HDL-C, or triglycerides), or markers of glucose-insulin homeostasis (fasting plasma glucose, HbA1c, postprandial glucose, or fasting insulin). Multivariate metaregression was used to estimate food-specific effects on CMB factors.
Results: Among 15 included trials, diet-pattern related decreases in SBP ranged from -2.2 to -9.5 mmHg; and in LDL-C, from -5.0 to -14.7 mg/dL. Each specific food had different, independent, and additive effects on these risk factors (Figure). Results for measures of glucose-insulin homeostasis are in progress.
Conclusions: Each of these foods independently influences major CMB risk factors, even when consumed in tandem as part of overall diet patterns. Such quantification more accurately reflects the complementary effects of diverse dietary components and highlights the importance of integrated approaches to investigating dietary factors and implementing relevant dietary policies.