Ad libitum Mediterranean diet reduces subcutaneous but not visceral fat in patients with coronary heart disease: A randomised controlled pilot study

Background& aims

The Mediterranean diet (MedDiet) is recognised toreduce risk of coronary heart disease (CHD), in part, via its anti-inflammatoryand antioxidant properties, which may be mediated via effects on body fatdistribution. Diet efficacy via these mechanisms is however unclear in patientswith diagnosed CHD. This study aimed to determine: (1) the effect of adlibitum MedDiet versus low-fat diet intervention on adiposity,anti-inflammatory marker adiponectin, oxidative stress marker malondialdehyde(MDA) and traditional CVD risk markers, and (2) whether improvement in MedDietadherence score in the pooled cohort was associated with these risk markers, ina pilot cohort of Australian patients post coronary event.

Methods

Participants (62 ± 9 years, 83% male)were randomised to 6-month ad libitum MedDiet (n = 34)or low-fat diet (n = 31). Pre- and post-intervention, dietaryadherence, anthropometry, body composition (Dual-energy X-ray Absorptiometry)and venepuncture measures were conducted.

Results

The MedDiet group reduced subcutaneous adiposetissue (SAT) area compared to the low-fat diet group (12.5 cm² more, p = 0.04)but not visceral adipose tissue or other body composition measures. In thepooled cohort, participants with greatest improvement in MedDiet adherencescore had significantly lower waist circumference (−2.81 cm, p = 0.01)and SAT area (−27.1 cm², p = 0.04) compared to participants withno improvement in score at 6-months. There were no changes in adiponectin, MDAor other risk markers in the MedDiet compared to low-fat diet group, and nodifferences in 6-month levels between categories of improvement in MedDietscore (p > 0.05). Within the MedDiet group only, theproportion of participants taking beta-blocker medication reduced from baselineto 6-months (71% vs. 56%, p-trend = 0.007).

Conclusions

Adherence to 6-month ad libitum MedDietreduced subcutaneous fat and waist circumference which discounts themisconception that this healthy but high fat diet leads to body fat gain. Theeffect of MedDiet on body fat distribution and consequent anti-inflammatory andantioxidant effects, as well as need for medications, in patients with CHDwarrants exploration in larger studies. Clinically significant effects on thesemarkers may require adjunct exercise and/or caloric restriction.

Trialregistration

ACTRN12616000156482.