Copper absorption from human milk, cow's milk, and infant formulas using a suckling rat model

Area of Science:

• Nutritional Science
• Biochemistry
• Pediatrics

Background:

• Copper deficiency is a concern in infants.
• Accurate assessment of copper bioavailability from infant diets is essential for nutritional guidance.

Purpose of the Study:

• To evaluate copper uptake from various infant diets using a rat model.
• To compare the bioavailability of copper from human milk, cow's milk, cow's milk formulas, cereal/milk formula, and soy formula.

Main Methods:

• Utilized a suckling rat model with extrinsically labeled infant diets (using 64Cu).
• Employed ultracentrifugation, ultrafiltration, and gel filtration to validate radiocopper binding.
• Administered labeled diets via intubation to 14-day-old rats and measured tissue copper uptake after 6 hours.

Main Results:

• Liver copper uptake varied significantly across diets.
• Human milk demonstrated the highest copper uptake (25%), followed by cow's milk formula (23%).
• Soy formula exhibited the lowest copper uptake (10%).

Conclusions:

• The suckling rat model provides a reliable method for assessing copper bioavailability in infant foods.
• Dietary copper bioavailability differs substantially among various infant formulas and human milk.
• Findings highlight the importance of diet composition in determining copper absorption during infancy.