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Plasma renin activity and plasma aldosterone concentration in infants with various sodium intakes
Insights
Infant formula sodium content significantly impacts plasma aldosterone levels, but not plasma renin activity. Adjusting dietary sodium is crucial for accurate infant aldosterone studies.
Area of Science:
- Pediatric Endocrinology
- Nutritional Science
- Renal Physiology
Background:
- Plasma renin activity (PRA) and plasma aldosterone concentration (PA) are key regulators of fluid and electrolyte balance.
- Infant nutrition, particularly sodium content in formulas, may influence these hormonal systems.
- Understanding these effects is vital for assessing infant health and development.
Purpose of the Study:
- To investigate the effect of varying sodium intake from cow's milk formulas on PRA and PA in infants.
- To determine the relationship between dietary sodium levels and hormonal regulation in early life.
Main Methods:
- 20 healthy infants (2-12 months) were studied.
- Measurements of PRA and PA were taken after consuming two different cow's milk formulas with distinct sodium concentrations (8.2 mmol/l and 12.6 mmol/l) for at least five days each.
- Mean daily sodium intake per kilogram of body weight was calculated for each formula.
Main Results:
- Mean sodium intakes were 1.20 and 1.87 mmol/kg/day.
- A highly significant decrease in plasma aldosterone concentration (PA) was observed with the higher sodium intake (603 vs. 355 pg/ml, P < 0.01).
- No significant difference was found in plasma renin activity (PRA) between the two formula groups (6.16 vs. 1.08 ng/ml·h).
Conclusions:
- Dietary sodium intake from milk formula significantly influences plasma aldosterone levels in infants.
- Plasma renin activity appears less sensitive to these variations in sodium intake within the studied range.
- Consideration of sodium content in infant formulas is essential when evaluating plasma aldosterone in infancy.
Abstract:
Plasma renin activity (PRA) and plasma aldosterone concentration (PA) were measured in 20 healthy infants 2-12 months of age, after taking a commercial modified cow's milk formula with 8.2 mmol/l sodium for at least five days, and after at least five days on a home-made, undiluted acidified cow's milk formula with 12.6 mmol/l sodium. The mean sodium intakes were 1.20 and 1.87 mmol/kg of body weight per day respectively. The arithmetic means for the corresponding PRA were 6.16 and 1.08 ng/ml . h (difference not significant) and the corresponding arithmetic means for PA were 603 and 355 pg/ml, the difference being highly significant (P less than 0.01). It is concluded that one has to consider the sodium intake in the milk formula when studying plasma aldosterone in infancy.