Table 8.

Summary renal function and kidney stones

				Association of protein/effect (in RCT)
			Number of participants (age) Men (M), Women (W)				Rating A B C
Exposure/Intervention	Outcome variable	Study		Total	Animal	Vegetable		Strength of evidence: Convincing, probable, Suggestive, no conclusion
Experimental normal (1.2 g/kg per day) or high protein intake (2.4 g/kg per day)	GFR	RC cross-over intervention study (61)	24 men, average age 24 years	POS	POS	NA	B	No conclusion
Experimental normal (1 ≈ g/kg per day) or high protein intake (≈ 2 g/kg per day) in young and elderly.	GFR	Balance study (9)	10 young (24 years), 10 elderly (70 years), 5 women in each group	POS (young) NS (elderly)	NA	NA	B
Quintiles of estimated protein intake (24-h N)	eGFR	Cohort (11)	6,000 with 24 h urinary albumin ≥ 10 mg/L. 2,592 with 24 h urinary albumin < 10 mg/L Average age: 50.	NS	NA	NA	C
Protein intake (FFQ) in gram per day and in quintiles	eGFR	Cohort (60)	1,624 W	NS INVERSE in women with mild kidney insufficiency at baseline	NA	NA	C
Experimental normal (1.2 g/kg per day) or high protein intake (2.4 g/kg per day)	Microalbuminuria	Experimental study (61)	24 men, average age: 24 years	POS	POS	NA	B	No conclusion
Experimental normal (1.5 g/kg per day) or high protein intake (3.0 g/kg per day)	Microalbuminuria	Experimental study (63)	24 men, average age: 24 years	NS	NA	NA	A
Quintiles of estimated protein intake (24 h N)	Microalbuminuria	Cohort (11)	6,000 with 24 h urinary albumin ≥ 10 mg/L. 2,592 with 24 h urinary albumin < 10 mg/L Average age: 50	NS	NA	NA	C
Protein intake (FFQ) in gram per day and in quintiles)	Microalbuminuria	Cohort (60)	1,624 W	NS	NA	NA	C
Spontaneous intake (FFQ) energy-adjusted gram per day and quintiles	Kidney stone	Cohort (64)	96,245 W (27–44 years (average: 36 years)	NA	NS	NA	C	No conclusion
Spontaneous intake (FFQ) energy-adjusted in quintiles	Kidney stone	Cohort (65)	45,619 M. Average age not given, range of age groups: 40–≥ 70 years	NA	POS (Increase in group BMI <25, not overall)	NA	C