The aim is to evaluate the effect of ingestion of a modified bovine milk protein on circulating markers of inflammation in healthy men and women aged 50-70y.The focus is healthy ageing, i.e. delaying the deterioration in health status in older adults. Loss of lean tissue mass, termed sarcopenia is a consequence of aging per se, modified by nutrition and lifestyle behaviour. Advancing the prospect of 'successful aging' a 6-month period of protein-based nutritional support has shown preservation/accrual of lean tissue. Chronic low-grade inflammation is common in ageing and is a compounding factor leading to 'anabolic blunting', i.e. a reduced sensitivity of lean tissue to enhance the synthesis of lean tissue mass in response to protein feeding. Using a simulated human gastrointestinal digestion model we have recently shown proteins to have an anti-inflammatory bioactivity in vitro. This study investigates whether the anti-inflammatory response is retained, post-digestion in vivo.

Participants to be recruited, are aged 50 to 70y from the Healthy Aging Study (EHSREC10\_45) who will attend on 4 test days (occasions) Study Design: Single blind, randomised, repeated measures design with 2 independent factor (time x treatment) Procedures: Occasion 1 Subjects will undertake a preliminary assessment as per EHSREC 10\_45 as follows; i. medical history and examination by a qualified medical doctor (\~45 min); ii. provide a blood and urine sample to be evaluated (following analysis) by a qualified medical doctor; Occasion 2 Subjects will then undertake, as per EHSREC 2013 01\_12, an assessment of body composition, dietary intake and habitual physical activity as follows; iii. habitual food intake evaluated by a qualified dietitian (\~45 min); iv. body composition (\~45 min) v. habitual physical activity level (PAL) quantified using the European Physical Activity Questionnaire (EPAQ-2; \~ 15 min). Occasion 3/4 Subjects will then undertake two controlled feeding trials, each trial separated by approximately 7 days as follows: Subjects will report to the Metabolic Laboratory (PG-052b), Physical Education and Sports Sciences (PESS) Building following an overnight fast. (i) A cannula will be inserted into a peripheral arm vein by a qualified clinician or phlebotomist; (ii) a 10ml blood sample will be withdrawn and aliquots generated for subsequent analysis; (iii) Following a 15 min rest period subjects will be given in randomised order either control (CONTROL) - a placebo nutrient drink (per kg of body mass: 0.33g protein with no anti-inflammatory bioactivity; energy \~ 160 kcal in 500ml water) or nutrient (NUTRIENT) - a nutrient drink (per kg of body mass: 0.33g protein with confirmed anti-inflammatory bioactivity; energy \~ 160 kcal in 500ml water) to be consumed within a 10 minute period. CONTROL and NUTRIENT will be reversed for the 2nd trial in randomised order. (iv) Whilst remaining sitting at rest (reading, undertaking computer work etc.) further blood samples will be withdrawn at 0, 15, 30, 45, 60 75, 90, 120 and 180 minutes post feeding. Total blood draw = 100ml per trial. Data Analysis: (i) Shapiro-Wilk test of normality, then (ii) repeated measures analysis either by ANOVA(R) if normal or Friedman Test if non-normally distributed.