Effects of Milk Protein Concentrate on Energy Restriction‐Induced Changes in Body Composition and Indices of Metabolic Syndrome

This study assessed the effects of higher protein intake achieved using milk protein concentrate (MPC) on body composition and metabolic health. We conducted a 20‐wk randomized, double blind study (4‐wk weight maintenance baseline and 16‐wk energy restricted intervention with 750 kcal/d energy deficit) with 44 subjects (12M:32F, age 52 ± 7 y, BMI 30.6 ± 3.0 kg/m 2 ) assigned to either a normal (NP, n=23) or high (HP, n=21) protein diet (0.8 vs. 1.5 g protein•kg ‐1 baseline body weight•d ‐1 ). The HP diet had 0.7 g•kg ‐1 •d ‐1 MPC. At weeks 4 and 20, body (DEXA) and muscle (MRI) composition, waist circumference (WC), morning resting blood pressure (BP), 24‐h BP, fasting plasma glucose (Glu), insulin (Ins), triglyceride (TG), LDL‐cholesterol (C), and HDL‐C were assessed. Higher protein intake did not influence changes in these parameters, except BP. 24‐h systolic and diastolic BP decreased in HP (‐5.5 ± 1.9 and ‐3.2 ± 1.1 mmHg), but remained stable in NP (1.3 ± 1.9 and 0.1 ± 1.1 mmHg). The same pattern of changes also occurred in awake (trend for diastolic), sleep and morning BPs. Over time, subjects lost weight (‐8.2 ± 2.9 kg), fat mass (FM) (‐7.0 ± 2.5 kg), FM% (‐4.6 ± 2.1%), lean mass (LM) (‐1.2 ± 1.1 kg), and gained LM% (4.3 ± 2.0%). They also lost thigh intermuscular (IMAT) and subcutaneous (SubQ) adipose tissue areas, (‐1.4 ± 1.0 and ‐22 ± 11 cm 2 ), fat area% (IMAT + SubQ, ‐3.6 ± 1.8%), muscle area (MA, ‐6.8 ± 4.6 cm 2 ), and gained MA% (3.2 ± 1.6%). WC, BP, Glu, Ins, HOMA‐IR, HOMA‐ ß, LDL‐C, TG and HDL‐C all improved over time. A MPC‐based higher protein diet supported weight loss‐induced improvements in body composition and indices of metabolic syndrome, and enhanced changes in BP. Support: National Dairy Council, NIH (UL1TR001108), Purdue Ingestive Behavior Research Center.