Men with more magnesium in their blood are likely to have a higher amount of free testosterone in their body. Chemical analysts draw this conclusion in an article published in the Journal of Pharmaceutical and Biomedical Analysis.
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About two percent of the testosterone in the body is active: it is not attached to binding proteins which prevent testosterone from interacting with its receptor. About forty percent of the body’s testosterone is attached to albumin, a protein that can let go of the hormone. Free testosterone and testosterone attached to albumin are referred to as bio-available testosterone.
About sixty percent of the body's testosterone is attached to sex hormone binding globulin (SHBG) [spatial structure above]. Androgens bound to SHBG lose their anabolic effect but probably retain their androgenic effect. In the prostate, for example, there are SHBG receptors and they send error signs to the prostate cells if they attach themselves to SHBG with androgens bound to it. Androgen steroid hormones incorporated by SHBG therefore do have undesired effects, but no desirable effects.
As men get older, SHBG sweeps up more and more testosterone. This is also because older men eat less protein. Low protein consumption raises the concentration of SHBG in the blood. A higher protein intake results in more albumin, and that increases the amount of bio-available testosterone. Within limits, of course.
The researchers, linked to the Université de Franche-Comté, extracted SHBG from the blood of young men, and exposed the protein to magnesium ions. Then they measured how fast the testosterone attached itself to SHBG at increasing magnesium concentrations. The higher the magnesium concentration, the lower the attraction.
Although the researchers did not examine whether more magnesium actually leads to more free testosterone in humans, they believe their findings are meaningful at the physiological level.
"The results presented here provide evidence for an Mg2+-mediated variation of the testosterone-SHBG association, suggesting that an increase of the Mg2+-concentration inside the biological concentration range (0.75mM-1.0mM) could lead an enhancement of the bioavailable testosterone", they write.
Fifteen years ago researchers examined the effect of extremely high – and biologically improbable – magnesium concentrations. These led to a small decline in the testosterone level. [Horm Metab Res. 1993 Jan;25(1):29-33.]
The researchers have announced that they will soon be publishing their findings on the effect of plant substances on the binding of testosterone to SHBG.
Magnesium in food is found in plant products. Good sources are fibre-rich breakfast cereals, spinach, nuts and beans.
