The calcium requirement and factors causing calcium loss

Area of Science:

• Human Nutrition
• Calcium Metabolism
• Dietary Science

Background:

• Calcium balance is crucial for bone health and overall well-being.
• Recommended dietary calcium intake may not be sufficient for all adult males.
• Factors influencing calcium balance require further investigation.

Purpose of the Study:

• To determine the optimal dietary calcium intake for achieving a positive calcium balance in adult males.
• To investigate the effects of varying calcium, phosphorus, and protein intakes on calcium metabolism.
• To assess the impact of certain medications and high-dose calcium supplementation on calcium balance and blood pressure.

Main Methods:

• Controlled dietary studies with varying calcium intakes (800-2300 mg/day).
• Monitoring calcium balance, including dermal losses.
• Assessing the effects of increased phosphorus and protein intake.
• Evaluating the influence of aluminum-containing antacids and high-dose calcium on blood pressure.

Main Results:

• A calcium intake of 800 mg/day resulted in a slightly positive average calcium balance, with 34% of subjects in negative balance.
• Increasing calcium intake to 1200 mg/day significantly improved calcium balance.
• Further increases in calcium intake up to 2300 mg/day did not yield additional benefits.
• High phosphorus and protein intake did not adversely affect calcium metabolism.
• Aluminum-containing antacids induced calcium loss.
• High-dose calcium supplementation (200-2500 mg/day) did not lower blood pressure in normotensive or hypertensive individuals.

Conclusions:

• A dietary calcium intake of 1200 mg/day appears optimal for adult males.
• Individual calcium balance can be negative even at recommended intake levels.
• Certain medications can negatively impact calcium balance.
• High-dose calcium supplementation is unlikely to reduce blood pressure.