Whereas daily protein intake is generally well above the recommended dietary allowance in community-dwelling and frail elderly people, a significant proportion of institutionalized elderly showed an intake below the current protein requirement, making them an important target population for dietary interventions. Particularly at breakfast, there is scope for improving protein intake.

Introduction: Sufficient high quality dietary protein intake is required to prevent or treat sarcopenia in elderly people. Therefore, the intake of specific protein sources as well as their timing of intake are important to improve dietary protein intake in elderly people. Objectives: to assess the consumption of protein sources as well as the distribution of protein sources over the day in community-dwelling, frail and institutionalized elderly people. Methods: Habitual dietary intake was evaluated using 2- and 3-day food records collected from various studies involving 739 community-dwelling, 321 frail and 219 institutionalized elderly people. Results: Daily protein intake averaged 71 ± 18 g/day in community-dwelling, 71 ± 20 g/day in frail and 58 ± 16 g/day in institutionalized elderly people and accounted for 16% ± 3%, 16% ± 3% and 17% ± 3% of their energy intake, respectively. Dietary protein intake ranged from 10 to 12 g at breakfast, 15 to 23 g at lunch and 24 to 31 g at dinner contributing together over 80% of daily protein intake. The majority of dietary protein consumed originated from animal sources (≥60%) with meat and dairy as dominant sources. Thus, 40% of the protein intake in community-dwelling, 37% in frail and 29% in institutionalized elderly originated from plant based protein sources with bread as the principle source. Plant based proteins contributed for >50% of protein intake at breakfast and between 34% and 37% at lunch, with bread as the main source. During dinner, >70% of the protein intake originated from animal protein, with meat as the dominant source. Conclusion: Daily protein intake in these older populations is mainly (>80%) provided by the three main meals, with most protein consumed during dinner. More than 60% of daily protein intake consumed is of animal origin, with plant based protein sources representing nearly 40% of total protein consumed. During dinner, >70% of the protein intake originated from animal protein, while during breakfast and lunch a large proportion of protein is derived from plant based protein sources.

Renal involvement was evaluated in 62 patients with primary Sjögren's syndrome, classified according to criteria proposed by The European Classification Criteria Group. Urine concentration capacity was tested using intranasal 1-desamino-8-D-arginine-vasopressin. For patients with urine pH>5.5 without metabolic acidosis (n=28), an acidification test with ammonium chloride was performed. Urinary citrate, albumin, NAG, ALP and beta2-microglobulin were measured and creatinine clearance was calculated. Maximum urine concentration capacity and creatinine clearance were reduced in 13 (21%). Albumin excretion was >30 microg/min in only one patient (1.6%). Seven patients (11.3%) had complete or incomplete distal renal tubular acidosis (dRTA), four had reduced creatinine clearance and five had reduced maximum urine concentration capacity. The ratio of citrate/creatinine in spot urine was below the 2.5 percentile in all patients with complete or incomplete dRTA. The prevalence of dRTA was lower than in previous studies. There were also few patients with signs of glomerular disease (1.6%). The use of citrate:creatinine ratio in spot urine can be a helpful method in identifying patients with complete or incomplete dRTA.

Increasing protein intake above habitual intake levels (0.9 g kg(-1) per day) does not preserve lean body mass, strength or physical performance during prolonged energy intake restriction in overweight older adults.