Abstract
BackgroundThe 2015–2020 Dietary Guidelines for Americans recommend a Mediterranean-type diet as one of three healthful eating patterns. However, only one previous trial has evaluated the effects of a Mediterranean diet intervention in a US sample population.MethodsTo address this gap, we conducted a pilot, non-blinded, 8-week randomized controlled trial on the comparative efficacy of consumption of a Mediterranean diet or a diet supplemented with fish oil, walnuts, and grape juice versus controls. Participants (overweight or obese US adults; 73% female and mean age 51 years) were randomly assigned to one of three groups: (1) Mediterranean diet; (2) habitual high-fat American-type diet supplemented with fish oil, walnuts, and grape juice; or (3) habitual high-fat American-type diet (controls). Intent-to-treat analysis of within-subject differences (Student’s paired t-test or Wilcoxon sign ranks test) and between-subject differences (mixed-effects models with a group-by-time interaction term, adjusted for baseline health outcome) was conducted.ResultsParticipants in the Mediterranean diet arm (n = 11) had significantly greater weight loss despite no significant change in total caloric intake, and lower plasma cystine, indicative of decreased oxidative stress, compared to controls (n = 9) at both 4 and 8 weeks. Compared to controls, they also had significantly lower total cholesterol and low-density lipoprotein cholesterol levels at 4 weeks. Participants in the supplement arm (n = 10) had significantly lower adiponectin levels compared to controls at 4 weeks. No significant improvements in endothelial function or inflammatory biomarkers were observed in either intervention group compared to controls.ConclusionThese results suggest that adopting a dietary pattern reflecting a Mediterranean diet improves weight and cardio-metabolic health among overweight or obese US adults, and may be more beneficial than supplementing habitual American diets with fish oil, walnuts, and grape juice.Trial registrationClinicalTrials.gov NCT00166088. Registered 14 September 2005.
Highlights
The 2015–2020 Dietary Guidelines for Americans recommend a Mediterranean-type diet as one of three healthful eating patterns
We report results of a pilot, non-blinded, 8-week randomized controlled trial to test whether a Mediterranean diet or a habitual high-fat American-type diet supplemented with several key components of the Mediterranean diet reduces cardiovascular disease (CVD) risk factors compared to a habitual high-fat American-type control diet among overweight or obese adults
Effects of Mediterranean diet Among participants who were assigned to the Mediterranean diet arm, there was a significant decrease from baseline to 8 weeks in body weight (− 2.2 [2.6] kg, p = 0.03), total cholesterol (− 24.9 [19.8] mg/dl, p = 0.003), Low-density lipoprotein (LDL) cholesterol (− 24.9 [17.3] mg/dl, p = 0.003), and Circulating pro-angiogenic cell activity (CFU-A) (− 40.3 [36.4] cfu, p = 0.01)
Summary
The 2015–2020 Dietary Guidelines for Americans recommend a Mediterranean-type diet as one of three healthful eating patterns. Despite new recommendations in the 2015–2020 Dietary Guidelines for Americans suggesting that a Mediterranean-type diet is healthful [6], only one trial, to our knowledge, has evaluated the effects of a Mediterranean diet intervention in a US population [7]. Compared to the control group following a habitual diet, no changes in blood lipids, except for an increase in plasma monounsaturated fatty acids, were noted in the Mediterranean diet group [7]. It is unclear from previous studies whether the Mediterranean diet as a whole is necessary to see improvements in health, or if habitual diets can be supplemented with key components of the Mediterranean diet with similar benefit. Especially the phytochemicals found in wine, is thought to provide cardio-metabolic benefit [10, 11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
