To evaluate the effects of a Mediterranean (Med) style diet with varying quantities of lean beef on non-HDL and HDL lipid subspecies. We hypothesized that a Med diet with lean beef would confer cardiovascular benefits beyond a standard lipid panel and be superior to an average American diet (AAD).
Methods : We conducted a multicenter, 4-period controlled feeding, randomized crossover study at Penn State University and USDA-Beltsville to evaluate the effects of a Med diet (CHO 42%, PRO 17%, FAT 41%, SFA 8%, MUFA 26%, PUFA 8%) with different quantities of lean beef (0.5, 2.5 and 5.5 oz/day) compared to an average American diet (AAD; CHO 52%, PRO 15%, FAT 33%, SFA 12%, MUFA 13%, PUFA 8%) on CVD risk factors. Participants (n=66) included generally healthy normal to overweight/obese males and females (BMI= 20-38 kg/m2) 30 to 67 years. Participants were randomized to each of the 4 diets for 4 weeks with an approximate 2-week break between treatments. Fasting blood samples were collected on two consecutive days at baseline (start of study), and at the end of each diet period.
Results : All three Med diets decreased LDL-C versus AAD (-10.5 ± 2.0, -9.0 ± 2.0, -6.8 ± 2.0 mg/dL, p< 0.0001 for the 0.5, 2.5 and 5.5 oz., respectively). All Med diets elicited similar reductions in total LDL particle number and large particle number (p< 0.01 for both) compared to baseline, however only the Med diets with 0.5 oz./day (-91.2 ± 23 nmol/L) and 2.5 oz./day (-85.3 ± 23 nmol/L) were significantly decreased versus AAD (p< 0.01). There were no treatment differences for IDL or small LDL particles. All diets reduced HDL-C and HDL particle number from baseline (p< 0.01).
A healthy Med style diet containing 2.5 oz./day of lean beef elicits similar improvements in lipid subspecies compared to a traditional Med style diet containing 0.5 oz./day. The Med style diet containing 5.5 oz./day of lean beef had similar effects on lipid subspecies to the AAD, therefore our findings suggest that £ 2.5 oz./day of lean beef can be included in a Med diet and not compromise the cardiovascular benefits of a Med diet.
Funding Sources :
This study was funded by the Beef Checkoff. This study also was supported by the USDA, ARS and the Penn State Clinical and Translational Research Institute.