Minerals

 All 22 minerals considered to be essential to the human diet are present in milk. These include three families of salts:

  1. Sodium (Na), Potassium (K) and Chloride (Cl):These free ions are negatively correlated to lactose to maintain osmotic equilibrium of milk with blood.
  2. Calcium (Ca), Magnesium (Mg), Inorganic Phosphorous (P(i)), and Citrate: This group consists of 2/3 of the Ca, 1/3 of the Mg, 1/2 of the P(i), and less than 1/10 of the citrate in colloidal(nondiffusible) form and present in the casein micelle.
  3. Diffusible salts of Ca, Mg, citrate, and phosphate: These salts are very pH dependent and contribute to the overall acid-base equilibrium of milk.

The mineral content of fresh milk is given below. A wide range is shown, based on variability due to intrinsic (lactogenesis in the secretory cell of individual animals) and extrinsic factors (mainly feed and season/climate adaptation, but also contaminants). 

Mineral Content per litre
Sodium (mg) 250-640
Potassium (mg) 1100-1500
Chloride (mg) 800-1200
Calcium (mg) 1100-1300
Magnesium (mg) 70-140
Phosphorus (mg) 800-1000
Iron (ug) 100-700
Zinc (ug) 2500-7000
Copper (ug) 100-350
Manganese (ug) 10-50
Iodine (ug) 50-600
Fluoride (ug) 20-80
Selenium (ug) 20-40
Cobalt (ug) 0.5-1.3
Chromium (ug) 0.5-20
Molybdenum (ug) 20-100
Nickel (ug) 0-50
Arsenic (ug) 20-60
Aluminum (ug) 50-1600
Lead (ug) tr-20

This information is consolidated from C. D. Hunt and F. H. Nielsen, Chap. 10.1 in McSweeney, P.L.H. and P.F. Fox, 2009. Advanced Dairy Chemistry, Vol. 3, Lactose, water, salts and minor constituents, 3rd edn., Springer, pp. 392-8; and from, Cristina Sola-Larranaga; Inigo Navarro-Blasco. 2009. Chemometric analysis of minerals and trace elements in raw cow milk from the community of Navarra, Spain . Food Chemistry, 112 (1), 189-196.