FLUORIDE-MAGNESIUM INTERACTION

[Guest guest]

FLUORIDE-MAGNESIUM INTERACTION (Guest Editorial)

_http://www.mgwater.com/fl2.shtml_ (http://www.mgwater.com/fl2.shtml)

by A Machoy-Mokrzynska (Institute of Pharmacology and Toxicology,

Pomeranian Medical Academy, Szczecin, Poland)

 

 

 

Fluoride (J. of the International Society for Fluoride Research), Vol. 28

No. 4; November, 1995, pp 175-177

 

 

 

It has now been fifteen years since Marier drew attention to the

significance of magnesium in biological interaction with fluorides.(1) The

toxic

effect of fluoride ion plays a key role in acute Mg deficiency. The amount of

F- assimilated by living organisms constantly increases, and Mg absorption

diminishes as a consequence of progressively advancing industrialization.

Marier gives examples of such retention of both elements in plants (e.g. in

pine and tomatoes) and in animals, for instance in bone tissue, blood and

kidneys, with the last being thought as the most probable place of Mg-F-

interaction.(1) Now, further facts have been observed, which throw a new light

on the effects of Mg-F- interaction.

 

 

The significance and distribution of Mg in living organisms are widely

known and described in textbooks.(2) Fluoride ion clearly interferes with the

biological activity of magnesium ion.(3) Present-day Mg deficiencies in

humans are the result of intensive expulsion of this element (e.g. under the

influence of extensive drinking of alcoholic beverages) or reduced Mg

content in the diet, caused, for example, by inappropriate agricultural

practices

or effects of ecotoxins.(4)

 

 

One of the prime locations of possible F- and Mg interactions is the

intestines. The increased F-supply reduces intestinal Mg resorption, owing to

high chemical affinity of both elements and production of MgF+ and MgF2.(1)

However, there are many facts to be considered, since there is a common

mechanism of transportation of both these elements through the intestinal

walls. Distinct F--Mg interaction is also observed in other cells and tissues.

Mg deficiency in plants may limit synthesis of chlorophyll, on which

photosynthesis depends. Therefore, supplementation of Mg protects plants against

toxic effects of fluoride compounds.(1) Mg deficiency in animals reduces

production of energy, relevant to the Mg-ATP system. Reduction of ATP levels

affects in an unfavourable way many metabolic processes connected with the

action of ATP (eg, metabolism of carbohydrates, proteins, nucleic acids,

lipids, and active transport).

 

 

The role of Mg and F- ions in enzymology is also well known.

Magnesium-dependant enzymes compose the biggest group in enzyme systematics.

Magnesium

is the activator of more than 300 enzymes, while fluorine is known as their

inhibitor, although the activity of some enzymes is known to be increased

by fluorine.(5) In general, Mg-F- interactions most frequently decrease

enzymatic activity.(6) The greatest practical significance of Mg-F- interaction

however, seems to be in processes of bone and tooth mineralization, and in

the formation of uroliths.(7,8)

 

 

In bone tissue magnesium stimulates the transformation of immature

(amorphic) bone into a more crystalic form. Owing to the translocation of Mg

into

mineral tissue, bone elasticity increases to help prevent fractures. Rats

on diet poor in Mg display significantly higher content of F- in femurs and

molars. This is undoubtedly related to the assimilability of both elements.

Since bioavailability of Mg and F- depends on their mutual ratio in the

diet,(9) a low-magnesium diet distinctly increases F- absorption in the

intestines.

 

 

Taking into account the mineralization of bone tissue, one also cannot

ignore the role of calcium. The basic inorganic compound of bones is

hydroxyapatite, containing calcium phosphate. The far-reaching antagonism

between

magnesium and calcium affects not only their different distribution in

tissues, but also their mutual dislodging from cells. For example, magnesium

favours blocking of calcium channels, disturbs oxidative phosphorylation,

intensifies bone decalcification and increases muscle-cell diastole, while

calcium intensifies contraction. On the other hand, hypercalcemia enhances Mg

loss or magnesiuria.(10)

 

 

Mg-F- interaction processes relating to enamel and its effect on caries

have also been investigated. Fluoride ion affects enamel hardening (11, 12)

and prevents its annealing, but this effect diminishes after administration

of Mg. Magnesium alone does not visibly affect tooth plaque, erosive enamel

damage, or the course of caries, but Mg and F- administered jointly

influence enamel hardening and reduce caries significantly, as demonstrated in

rats.(13) In interactions of F- with Mg and Ca, it should be stressed that it

is calcium rather than magnesium that intensifies mineralization processes.

 

 

Urolith formation is considered to be pathological. Mineral content

analysis of uroliths shows that they always contain Mg and F- (besides

phosphates, calcium and other inorganic and organic components).(8) Formation

of

uroliths follows crystallization rules. Mg ion reduces the rate of superficial

crystal nuclei formation, whereas F- ion accelerates the process. The

former reduces and the latter accelerates growth of calcium phosphate

crystals.(7) In the formation of uroliths, calcium is the promotor, and

magnesium

plays the role of the inhibitor.

 

 

It also should be pointed out that uroliths always contain more Ca than

Mg. Fluoride on the other hand, favours formation of uroliths and accelerates

their production.(8)

 

 

In summary, it can be stated that in intoxication with fluorine compounds,

magnesium plays a protective role by countering and reducing the toxic

effects of F-.

 

 

----------

----

 

References:

 

1 Marier J R. Observations and implications of the (Mg F) interrelations

in bio-systems: a review and comments on magnesium intake and fluoride

intake in the modern-day world. Proceedings of the Finnish Dental Society 76.

82-92, 93-102, 1980. (Abstracted in Fluoride 14, 142 1981).

 

2 Durlach J. Le magnesium en pratique clinique. Editions Medicales

Internationales. Paris 1991.

 

3 Guminska M. The effect of magnesium on metabolism in living organisms

and medical consequences of its deficiency in man. Folia Medica Cracoviensia

26 1-2, 5-28, 1985.

 

4 Markiewicz J. Environmental factors decreasing magnesium content in

alimentary chain. Folia Medica Cracoviensia 26 1-2, 5-28, 1985.

 

5 Strochkova L S, Zhavoronkov A A. Fluroide as an activator of enzymatic

systems. Fluoride 16, 181-186 1983.

 

6 Chlubek D, Machoy Z. Significance of the effect of fluorine dose on

enzymes activity in vivo and in vitro studies. Bromatologia i Chemia

Toksykologiczna 22 3-4, 235-242, 1989.

 

7 Okazaki M. Mg2+-F- interaction during hydroxyapatite formation.

Magnesium 6 (6) 296-301, 1987.

 

8 Machoy P, Bober J. Fluorine-constant component of urinary calculi,

Environmental Sciences 2 1 11-15, 1993.

 

9 Cerklewski F L. Influence of dietary magnesium on fluoride

bioavailability in the rat. American Insitute of Nutrition 117 (3) 456-500,

1987.

 

10 Machoy Z. Biochemical mechanisms of fluorine compounds action. Folia

Medica Cracoviensia 28 1-2, 61-81, 1987.

 

11 Collys K, Slop D, Coomans D. Interaction of magnesium and fluoride in

the rehardening and acid resistance of surface-softened bovine enamel in

vitro. Magnesium Trace Element 9 (1) 47- 53, 1990.

 

12 Luoma A R, Luoma H, Raisanen J, Hausen H. Effect of magnesium and

fluoride on the fermentative dissolution of enamel by a streptococcal layer as

measured by mircrohardness tester and a proton probe microanalysis. Caries

Research 17 430-438, 1983.

 

13 Sorvari R, Koskinen-Kainulainen M, Sorvari T, Luoma H. Effect of a

sports drink mixture with and without addition of fluoride and magnesium on

plaque formation, dental caries and general health of rats. Scandinavian

Journal of Dental Research 94 483-490, 1986.

 

 

----------

----

 

FLUORIDE: published by the International Society for Fluoride Research

Editorial Office: 81A Landscape Road, Mt Eden, Auckland 4, NZ Subscription

Rate: $40. U.S. Funds per year (quarterly publication)