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Dietary calcium alters blood pressure in neonatal spontaneously hypertensive rats
M S Muntzel1, D C Hatton, J A Metz
1Department of Medical Psychology and Medicine, Oregon Health Sciences University, Portland.
Insights
Neonatal dietary calcium intake significantly impacts blood pressure (BP) in spontaneously hypertensive rats (SHR). Early exposure to high calcium diets rapidly reduces BP, indicating heightened susceptibility in young SHR.
Area of Science:
- Nutritional Science
- Cardiovascular Physiology
- Developmental Biology
Background:
- Dietary factors significantly influence blood pressure (BP) development in young, genetically hypertensive individuals.
- Early life nutrition plays a critical role in long-term health outcomes, particularly in cardiovascular regulation.
Purpose of the Study:
- To investigate the impact of early dietary calcium intake on blood pressure development in spontaneously hypertensive rat (SHR) pups.
- To differentiate the effects of maternal milk versus solid food consumption on BP in neonatal SHR.
Main Methods:
- Spontaneously hypertensive rat (SHR) pups were fostered to dams with varying dietary calcium levels (high, low, medium).
- Experiments involved cross-fostering and controlled weaning to specific calcium diets at 21 days of age.
- Mean arterial pressures were measured at 28 days of age to assess BP development.
Main Results:
- Pups fostered to high calcium dams exhibited significantly lower mean arterial pressures at 28 days compared to those fostered to low calcium dams.
- Weaning SHR pups to a high calcium diet at 21 days resulted in lower BP at 28 days compared to weaning to a low calcium diet.
- These findings suggest that solid food consumption late in the suckling period is the primary driver of BP variations.
Conclusions:
- Neonatal spontaneously hypertensive rats demonstrate a pronounced susceptibility to the blood pressure-altering effects of dietary calcium.
- Dietary calcium intake during the late suckling period can rapidly modify blood pressure in young SHR.
- These findings highlight the critical window for nutritional interventions in managing hypertension development.
Abstract:
Dietary alterations in young genetically hypertensive rats have been shown to have a substantial impact on subsequent blood pressure (BP) development. In the present study, spontaneously hypertensive rat (SHR) pups fostered at birth to high calcium (2%) SHR dams developed significantly lower mean arterial pressures by 28 days of age than pups fostered to low calcium (0.1%) dams (93.7 v 107.7 mm Hg, P less than .01). To determine whether BP differences were due to milk ingestion or to late lactational solid diet consumption, a second experiment was performed. Pups were fostered at birth to medium calcium (1.0%) dams and weaned at 21 days to one of three calcium diets. Blood pressures were determined at 28 days after birth. Pups weaned to the high diet at 21 days had lower pressures at 28 days than pups weaned to the low diet (94.2 v 108.3, P less than .01), suggesting that the pressure variations in the first experiment were due primarily to solid food consumption by the pups late in the suckling period. This rapid BP alteration suggests that neonatal SHR have an enhanced susceptibility to the pressure effects of dietary calcium.