## **Core Concept**
High calcium intake can have several effects on the body, particularly on the cardiovascular and renal systems. Calcium plays a crucial role in various physiological processes, including bone mineralization, muscle contraction, and nerve function. However, excessive intake can lead to adverse effects.

## **Why the Correct Answer is Right**
The correct answer, , suggests that high calcium intake leads to decreased absorption of iron. This is accurate because high levels of calcium can interfere with the absorption of non-heme iron, which is primarily found in plant-based foods. The mechanism involves the formation of insoluble calcium-iron complexes in the intestine, which reduces the bioavailability of iron.

## **Why Each Wrong Option is Incorrect**
- **Option A:** - This option is incorrect because while calcium is crucial for bone health, high intake doesn't directly lead to increased excretion of calcium in the urine; instead, it can lead to an increased risk of kidney stones.
- **Option B:** - This option is incorrect because high calcium intake does not directly result in increased absorption of fats; rather, it can affect the absorption of other minerals.
- **Option D:** - This option is incorrect because high calcium intake does not directly lead to decreased excretion of phosphate; instead, it can affect phosphate metabolism indirectly.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that while calcium is essential for health, excessive intake, especially from supplements, can increase the risk of cardiovascular events and kidney stones. It's crucial to balance calcium intake with other dietary components to avoid adverse effects.

## **Correct Answer: C. Decreased absorption of iron.**