The Essential Minerals in Milk and Colostrum: Functional Micronutrient for Your Body

Minerals are one class of micronutrients, the other being Vitamins. Micronutrients are needed and consumed in relatively small quantities (< 1 gram per day). Dietary minerals are essential minerals that consist of major minerals (> 5 gram in the body) and trace minerals. Major minerals include Calcium, Phosphorus, Potassium, Sulphur, Sodium, Chloride and Magnesium. Trace minerals include Iron, Zinc, Copper, Manganese, Molybdenum, Fluoride, Cobalt, Iodine, Selenium, Chromium.

Minerals are bound to compounds in the foods. This limits their bioavailability, i. e., the extent to which these ingested minerals are absorbed and made available to the body. In general, plant foods have lower mineral bioavailability as compared to animal foods. Many plant foods are rich in negatively charged compounds( phytates, polyphenols, oxalate, and dietary fiber) that tightly bind positively charged elements such as calcium, iron and zinc, reducing mineral bioavailability.

Minerals in cow’s milk include potassium, calcium, magnesium, Phosphorus, sodium, chloride, zinc, iron, selenium, iodine and trace amounts of copper and manganese.

Calcium:The calcium concentration in bovine milk is about 1 g/litre. Adequate Ca intake is required for healthy bones and teeth, help prevent hypertension, decrease the chance of getting colon or breast cancer, improve weight control and reduce the risk of developing kidney stones. When Ca intake is low, the body's stored calcium is used. Bone loss occurs due to aging, and decreased estrogen produced among postmenopausal women. Over the long term, deficient Ca intake increases the risk of osteoporosis and bone fractures, especially in the elderly. .

Calcium has the potential to reduce cardiovascular disease (CVD) risk by decreasing intestinal absorption of lipids, increasing lipid excretion, lowering cholesterol levels in the blood. Findings from prospective studies of Ca’s effects on CVD risk are inconsistent. In the Iowa Women’s Health Study, higher dietary Ca and/or supplements was linked with reduced ischemic heart disease mortality in postmenopausal women. Other studies have shown no significant relation.

Many clinical trials showed inconsistent results on the relationship between increased Ca intakes and both lower blood pressure and risk of hypertension. In the Women’s Health Study, Ca intake was inversely associated with risk of hypertension in middle-aged and older women . However, other studies have found no association. Some studies showed a positive relationship between Ca supplementation and risk of kidney stones, eg., The Nurses’ Health Study. However, high intakes of dietary Ca do not appear to cause kidney stones.

Magnesium(Mg) : Milk is a good source, with about 100 mg/litre. milk. The recommended intake is 400 mg/day for men and 310 mg/day for women. Mg is a cofactor in more than 300 enzyme systems that regulate protein synthesis, muscle and nerve function, blood glucose and blood pressure. Mg is required for energy production, glycolysis, etc. Glycolysis is the enzymatic breaking down of a sugar (glucose), into simpler compounds to produce energy. Mg contributes to the structural development of bone and the synthesis of DNA, RNA, and the antioxidant glutathione. It plays an active role in transporting calcium and potassium ions across cell membranes, a process that is important to nerve impulse conduction, muscle contraction, and normal heart rhythm.

Potassium(K) : Potassium, present in all body tissues, is required for normal cell function to maintain intracellular fluid volume and movement of ions across the cell membrane. Extensive past literature showed low K intakes increase the risk of hypertension, especially when combined with high sodium intakes. In contrast, higher K intakes may help decrease blood pressure, in part by increasing vasodilation and urinary sodium excretion, thus reducing plasma volume.

Observational studies show high dietary K intakes reduces risk of kidney stones. In a cohort of 45,619 men aged 40 to 75 years with no history of kidney stones, those with the highest average K intakes (≥4,042 mg/day) had a 51% lower risk of kidney stones over 4 years of follow-up than those with the lowest intakes (≤2,895 mg/day).

Zinc(Zn) : Milk is a good source of Zinc, with about 4 mg/litre . Zn is involved in cellular metabolism and the catalytic activity of about 100 enzymes. It is involved in immune function, protein synthesis , wound healing, DNA synthesis and repair, cell growth and division, protein and lipid metabolism. Zn also supports normal growth and development during pregnancy, childhood, and adolescence. A daily intake of Zn is required by the body since there is no specialized zinc storage system.

Severe Zn deficiency depresses immune function. Mild to moderate degrees of Zn deficiency can impair macrophage and neutrophil functions and natural killer cell activity.

Zn helps to maintain the integrity of skin and mucosal membranes. Patients with chronic leg ulcers have abnormal Zn metabolism and low blood serum Zn levels. Zn supplements are often used to treat skin ulcers. Zn deficiency weakens the immune response. This contribute to increased risks of infections and mortality among children in developing countries such as acute diarrhea. Studies show that malnourished children have shorter courses of infectious diarrhea after taking 4–40 mg of Zn a day in the form of Zn acetate, Zn gluconate, or Zn sulfate. Also, Zn reduce the severity and duration of cold symptoms by directly inhibiting rhinovirus binding and replication in the nasal mucosa, and suppressing inflammation.

Copper( Cu) is a cofactor for many enzymes (cuproenzymes) involved in energy production, iron metabolism, neuropeptide activation, connective tissue synthesis, and neurotransmitter synthesis. Neuropeptides are peptides used by neurons to communicate with each other. Neurotransmitter is a chemical that is released from a nerve cell which thereby transmits an impulse from a nerve cell to another nerve, muscle, organ, or other tissue. Cu is involved in processes such as angiogenesis; neurohormone homeostasis; brain development, and immune system functioning. Angiogenesis is the process of forming new blood vessels. Also, defence against free radical damage depends mainly on the Cu-containing superoxide dismutase.

Phosphorus(P) is a component of bones, teeth, DNA, and RNA. P is a component of cell membrane structure in the form of phospholipids, and of the body’s key energy source, ATP. P functions in regulation of gene transcription, activation of enzymes, maintenance of normal pH in extracellular fluid, and intracellular energy storage.

Iron(Fe) is an essential component of hemoglobin, a red blood cell protein that transfers oxygen from the lungs to the tissues. Myoglobin, a protein that provides oxygen, contains Fe to support muscle metabolism and healthy connective tissue. Fe is necessary for physical growth, neurological development, cellular functioning, and synthesis of some hormones.

Selenium(Se) : Selenium is a component of more than two dozen selenoproteins that play critical roles in reproduction, thyroid hormone metabolism, DNA synthesis, and protection from free radicals and infection. Because of its effects on DNA repair, and the endocrine and immune systems as well as its antioxidant properties. Epidemiological studies have suggested an inverse association between selenium status and the risk of colorectal, prostate, lung, bladder, skin, esophageal, and gastric cancers as well.