What are the minerals in milk?

Minerals in Milk: Essential Nutritional Components

Milk contains essential minerals including calcium, phosphorus, magnesium, potassium, sodium, and zinc, which contribute to various vital functions in the body and support overall health. 1, 2

Key Minerals in Milk

Milk provides a unique combination of macro and trace minerals that are crucial for human health:

Macrominerals

• Calcium: 220-252 μg/ml in human milk; 854-1430 μg/ml in cow's milk 3

  • Primary mineral in milk, essential for bone health
  • Contributes to metabolic health and blood pressure regulation 1

• Phosphorus: 13-16 mg/100 ml in human milk 4

  • Works with calcium for bone formation
  • Lower in proportion to calcium in human milk compared to other species

• Magnesium: 26-35 μg/ml in human milk; 87-131 μg/ml in cow's milk 3

  • Important for metabolic function
  • Contributes to glucose tolerance 1

• Potassium: Found primarily in the aqueous phase of milk 2

  • Important for blood pressure regulation
  • Contributes to metabolic health 1

• Sodium and Chloride: Primarily in the aqueous phase of milk 2

  • Essential for fluid balance

Trace Minerals

• Zinc: 1.16-3.83 μg/ml in human milk; 3.23-5.15 μg/ml in cow's milk 3

  • Higher in cow's milk than human milk
  • Essential for immune function

• Iron: 0.20-0.69 μg/ml in human milk; 0.40-0.59 μg/ml in cow's milk 3

  • Similar concentrations in both human and cow's milk
  • Primarily bound to lipid fraction in human milk (33%)

• Copper: 0.24-0.50 μg/ml in human milk; 0.06-0.09 μg/ml in cow's milk 3

  • Higher in human milk than cow's milk

• Selenium: Important trace element in milk 2

  • Contributes to antioxidant function

Distribution of Minerals in Milk

The minerals in milk are distributed differently between the aqueous and micellar phases:

• Aqueous phase minerals: Potassium, sodium, and chloride are primarily found in the aqueous phase 2

• Casein-bound minerals: In cow's milk, casein binds significant proportions of minerals (Fe 24%, Cu 44%, Zn 84%, Ca 41%, Mg 25%), whereas in human milk, casein binds smaller amounts (Fe 9%, Cu 7%, Zn 8%, Ca 6%, Mg 6%) 3

• Whey protein-bound minerals: Major proportion of minerals in human milk are bound to whey proteins 3

Clinical Significance of Milk Minerals

• Metabolic health: Calcium, magnesium, and potassium in dairy may contribute to reduced risk of type 2 diabetes and metabolic dysfunction 1

• Blood pressure regulation: Calcium and potassium in dairy products may help thwart hypertension 1

• Nutritional recommendations: The Dietary Guidelines for Americans recommend 3 cups of dairy per day (710 ml/day) for a 2000-kcal/day diet to help meet requirements for calcium, phosphorus, vitamin A, vitamin D, and potassium 1

Important Considerations

• Milk alternatives: When choosing milk substitutes, consider the mineral content. Most plant-based alternatives (except soy milk) do not match the protein content of cow's milk 1

• Bioavailability: Calcium is the only nutrient from milk substitutes tested for equivalent bioavailability to cow's milk 1

• Processing effects: Dairy product processing affects mineral content. For calcium content in cheese, the order is: milk/fermented milk/fresh cheese < soft cheese < semi-hard cheese < hard cheese 2

• Mineral binding: Milk proteins and peptides act as mineral binders or chelators, which may enhance or inhibit bioavailability of minerals 5

Milk and dairy products represent a unique combination of essential minerals that contribute significantly to human nutrition and health, with different distribution patterns between human and cow's milk reflecting species-specific nutritional needs.