Summary
Bone meal is essentially finely crushed processed bone. It was used as an ingredient in calcium supplements, but lost popularity after a study in 1980 proved it had toxic elements. Today, organic versions are available for supplement use. Generally, it is known to promote bone health and overall nutrition. It can also be used as a fertilizer and an ingredient in pet food.
Description
Bone meal is used as a supplement for calcium and phosphorus. It is composed of finely crushed, processed bone, usually from cattle but sometimes also from horses. Bone marrow may also be added to the product. Calcium in bone meal occurs as a calcium phosphate compound known as hydroxyapatite or hydroxylapatite. Hydroxyapatite is an inorganic compound found in the matrix of bone and the teeth; it confers rigidity to these structures. The formula of hydroxyapatite is (Ca3 (PO4)2)3·Ca (OH) 2 or Ca10 (PO4) 6 (OH)2.
Bone meal was at one time a popular nutritional supplement for calcium. It is still marketed as a nutritional supplement, but it is no longer as popular. The reason for this is that in the 1980s analysis of bone meal supplements revealed them to contain substantial amounts of lead, as well as other toxic elements, such as arsenic, mercury and cadmium. A second-generation ""bone meal'' product called microcrystalline hydroxyapatite, or MCHA, is being marketed as a calcium supplement and is claimed to be free of contaminants.
Bone meal is also used as a high-phosphorus fertilizer and in some pet foods.
Actions & Pharmacology
Mechanism of Action
See Calcium and Phosphorus.
Pharmacokinetics
See Calcium and Phosphorus.
Hydroxyapatite is apparently well-absorbed from the gastrointestinal tract.
Indications & Usage
Bone meal is still sold as a ""natural'' source of calcium. Its use should be avoided owing to potential toxic-metal contamination.
Overdosage
There are no known reports of overdosage of bone meal.
Dosage
No recommended dose. Second-generation ""bone meal'' supplements known as microcrystalline hydroxyapatite, or MCHA, are available as calcium supplements and are claimed to be free of contaminants.
Literature
Boulos FM, von Smolinski A. Alert to users of calcium supplements as antihypertensive agents due to trace mineral contaminants. Am J Hypterten. 1988; 1(3 Pt 3):137S-142S.Bourquin BP, Evans DR, Cornett JR, et al. Lead content of 70 brands of dietary calcium supplements. Am J Public Health. 1993; 83:1155-1160.Groschup MH. [Bovine spongiform encephalopathy in ruminants and the new variant of Creutzfeldt-Jakob disease in humans.] [Article in German.] DTW Dtsch Tierarzl Wochenschr. 1999; 106:329-331.Roberts HJ. Potential toxicity due to dolomite and bone meal. South Med J. 1983; 76:556-559.Whiting SJ. Safety of some calcium supplements questioned. Nutr Rev. 1994; 52:95-97.Research & Summary
The use of bone meal as a calcium and phosphorus source is no longer recommended. Several researchers have reported that many bone meal preparations are contaminated with toxic metals. In one study, bone meal samples were contaminated with significant amounts of lead, arsenic, mercury and other metals. Dolomite and calcium carbonate supplements labeled ""oyster shell'' or ""natural source'' have also been found to be contaminated with these metals.
One researcher has advised that ""physicians must consider the possibility of unrecognized self-poisoning from the consumption of such substances, especially in the context of unexplained neurologic, gastrointestinal, cutaneous and hematologic disorders.''
The feeding of meat and bone meal to cattle, contaminated with bovine spongiform encephalopathy (BSE) tissue, led to an epidemic of BSE in the British cattle population in the 1990s.
Contraindications, Precautions & Adverse Reactions
Contraindications
Bone meal is contraindicated in those with hypercalcemia. Conditions that cause hypercalcemia include hyperparathyroidism, hypervitaminosis D, some granulomatous diseases, sarcoidosis and cancer. Bone meal is also contraindicated in those with calcium pyrophosphate dihydrate (CPPD) deposition disease.
Precautions
Bone meal is no longer recommended as a calcium and/or phosphorus supplement because of possible presence of toxic substances, such as lead. Children are especially sensitive to the effects of lead. Children, pregnant women and nursing mothers should absolutely avoid bone meal supplements.
Adverse Reactions
See Calcium. Prolonged use of bone meal contaminated with toxic elements, such as lead, may cause the typical toxic effects of these substances. Lead may produce abdominal pain, anemia and central nervous system damage.
