title: Change in salt intake affects blood pressure of chimpanzees: implications for human populations.
abstract: BACKGROUND
  Addition of up to 15.0 g/d salt to the diet of chimpanzees caused large rises in blood pressure, which reversed when the added salt was removed. Effects of more modest alterations to sodium intakes in chimpanzees, akin to current efforts to lower sodium intakes in the human population, are unknown.
  
  
  RESULTS
  Sodium intakes were altered among 17 chimpanzees in Franceville, Gabon, and 110 chimpanzees in Bastrop, Tex. In Gabon, chimpanzees had a biscuit diet of constant nutrient composition except that the sodium content was changed episodically over 3 years from 75 to 35 to 120 mmol/d. In Bastrop, animals were divided into 2 groups; 1 group continued on the standard diet of 250 mmol/d sodium for 2 years, and sodium intake was halved for the other group. Lower sodium intake was associated with lower systolic, diastolic, and mean arterial blood pressures in Gabon (2-tailed P<0.001, unadjusted and adjusted for age, sex, and baseline weight) and Bastrop (P<0.01, unadjusted; P=0.08 to 0.10, adjusted), with no threshold down to 35 mmol/d sodium. For systolic pressure, estimates were -12.7 mm Hg (95% confidence interval, -16.9 to -8.5, adjusted) per 100 mmol/d lower sodium in Gabon and -10.9 mm Hg (95% confidence interval, -18.9 to -2.9, unadjusted) and -5.7 mm Hg (95% confidence interval, -12.2 to 0.7, adjusted) for sodium intake lower by 122 mmol/d in Bastrop. Baseline systolic pressures higher by 10 mm Hg were associated with larger falls in systolic pressure by 4.3/2.9 mm Hg in Gabon/Bastrop per 100 mmol/d lower sodium.
  
  
  CONCLUSIONS
  These findings from an essentially single-variable experiment in the species closest to Homo sapiens with high intakes of calcium and potassium support intensified public health efforts to lower sodium intake in the human population.
authors.affiliation: Department of Epidemiology and Public Health, Imperial College London, Faculty of Medicine, St. Mary's Campus, Norfolk Place, London W2 1PG, UK. p.elliott@imperial.ac.uk
authors.forename: Paul
authors.initials: P
authors.lastname: Elliott
authors.forename: Lesley L
authors.initials: LL
authors.lastname: Walker
authors.forename: Mark P
authors.initials: MP
authors.lastname: Little
authors.forename: John R
authors.initials: JR
authors.lastname: Blair-West
authors.forename: Robert E
authors.initials: RE
authors.lastname: Shade
authors.forename: D Rick
authors.initials: DR
authors.lastname: Lee
authors.forename: Pierre
authors.initials: P
authors.lastname: Rouquet
authors.forename: Eric
authors.initials: E
authors.lastname: Leroy
authors.forename: Xavier
authors.initials: X
authors.lastname: Jeunemaitre
authors.forename: Raymond
authors.initials: R
authors.lastname: Ardaillou
authors.forename: Francoise
authors.initials: F
authors.lastname: Paillard
authors.forename: Pierre
authors.initials: P
authors.lastname: Meneton
authors.forename: Derek A
authors.initials: DA
authors.lastname: Denton
mesh_terms: D000818:Animals; D001794:Blood Pressure; D004039:Diet, Sodium-Restricted; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D006973:Hypertension / Q000178:diet therapy* / Q000209:etiology*; D008297:Male; D002679:Pan troglodytes; D017673:Sodium Chloride, Dietary / Q000494:pharmacology*; D013045:Species Specificity