Tc Beard

A population-based study of the relationship between salt intake, bone resorption and bone mass

Objective: To explore the relationship between urinary sodium (the best measure of salt intake), urinary calcium, urinary deoxypyridinoline (DPYR) and bone mass. Design: Cross-sectional study. Setting: Population based sample of healthy Hobart residents. Subjects: One hundred and fifty-four (M=34, F=120) subjects invited to take part from a systematic sample of the electoral roll and a single newspaper advertisement. Results: In both sexes, urinary sodium correlated moderately with urinary DPYR (r=0.32, P<0.0001) and urinary calcium (r=0.37, P<0.0001). In multivariate analysis, the combination of urinary sodium, total body bone area, age and sex explained 22% of the variation in log-transformed DPYR (P<0.00001). In univariate analysis, both urinary sodium and urinary DPYR were strongly associated with bone mineral content and bone mineral density at all sites but this association disappeared after adjustment for confounders particularly body weight. Conclusions: This study has shown that salt intake is associated with markers of bone resorption in a population-based sample of males and females and appears likely to be a risk factor for osteoporosis despite the lack of a demonstrable association between bone mass and a single measure of urinary sodium excretion. Further studies are needed to define the effect of salt intake on bone mass and fractures more clearly. These studies will need to be either longitudinal or interventional in design with repeated measures of urinary sodium so that habitual sodium intake can be accurately assessed and regression dilution bias can be minimised. Sponsorship: Arthritis Foundation of Australia, Royal Hobart Hospital Acute Care Program.

Calcium diglutamate improves taste characteristics of lower-salt soup.

Objective: To ascertain (1) whether the taste characteristics of a conventionally-salted (150 mM NaCl) soup can be reproduced in soups of substantially lower NaCl level with the help of added glutamate, and (2) whether calcium diglutamate (CDG) is equivalent to monosodium glutamate (MSG) in its effect on the taste of soup.Design: Cross-sectional, with multiple measurements on each subject.Setting: Healthy university students.Subjects: A total of 107 volunteers, recruited by on-campus advertising.Methods: Subjects tasted 32 soups, with all possible combinations of four NaCl concentrations (0–150 mM), four glutamate levels (0–43 mM), and two glutamate types (MSG, CDG).Main outcome measures: Ratings of each soup on six scales (liking, flavour-intensity, familiarity, naturalness of taste, richness of taste, saltiness).Results: A 50 or 85 mM NaCl soup with added CDG or MSG is rated as high as, or higher than, a 150 mM NaCl soup free of added glutamate on five of the six scales (the exception being saltiness). CDG and MSG have equivalent effects.Conclusions: Addition of glutamate allows substantial reductions in Na content of soup, without significant deterioration of taste. CDG and MSG have equivalent effects, but use of CDG permits a greater reduction in Na intake.Sponsorship: We acknowledge the financial support of the International Glutamate Technical Committee (IGTC).