14 replies to this topic

[Lufega]

Magnesium gluconate? Really? I was a bit surprised, but it seems so. I looked at a couple mag. gluconate products online but none tell me how much actual elemental magnesium there is per serving. I also found none of the more common packers make this type. I wonder why.

Study of magnesium bioavailability from ten organic and inorganic Mg salts in Mg-depleted rats using a stable isotope approach.

Centre de Recherche en Nutrition Humaine d'Auvergne, Laboratoire des Maladies Métaboliques et Micronutriments, INRA de Theix/Clermont-Ferrand, Saint-Genès-Champanelle, France. coudray@ensam.inra.fr

Literature data on the bioavailability of various Mg forms provide scarce information on the best Mg salt to be used in animal and human supplementation. This study aimed to investigate the bioavailability of different forms of Mg in rats using Mg stable isotopes. Eighty male Wistar rats aged 6 weeks were fed a semi-purified Mg-depleted diet for three weeks. The rats were then randomised into ten groups and received, for two more weeks, the same diet repleted with Mg (550 mg Mg/kg) as: oxide, chloride, sulphate, carbonate, acetate, pidolate, citrate, gluconate, lactate or aspartate. After 10 days of Mg-repleted diet, the rats received orally 1.8 mg of an enriched 26Mg. Faeces and urine were then collected for 4 consecutive days. Isotope ratios in faeces and urine were determined.

The Mg absorption values obtained varied from 50% to 67%. Organic Mg salts were slightly more available than inorganic Mg salts. Mg gluconate exhibited the highest Mg bioavailability of the ten Mg salts studied. Urinary 26Mg excretion varied from 0.20 mg to 0.33 mg, and feeding with the organic pidolate, citrate, gluconate and aspartate salts resulted in higher urinary 26Mg excretion than with inorganic salts. Ultimately, 26Mg retention was higher in the rats receiving the organic salts such as gluconate, lactate and aspartate than in those receiving the inorganic salts. Taken together, these results indicate that 26Mg is sufficiently bioavailable from the ten different Mg salts studied in the present experiment, although Mg gluconate exhibited the highest bioavailability under these experimental conditions.

Magnesium citrate still seems to work, however, so it will likely remain the favorite..

Short-term oral magnesium supplementation suppresses bone turnover in postmenopausal osteoporotic women.

Department of Internal Medicine, Section of Endocrinology and Metabolism, Yeditepe University Hospital, Devlet Yolu Ankara Cad. No: 102, Kozyatagi, Istanbul, 34752, Turkey. haydin@yeditepe.edu.tr

<h3 class="abstract_label">Abstract</h3>Magnesium has been shown to increase bone mineral density when used in the treatment of osteoporosis, yet its mechanism of action is obscure. In this study, the effects of daily oral magnesium supplementation on biochemical markers of bone turnover were investigated. Twenty postmenopausal women have been divided into two groups. Ten patients were given magnesium citrate (1,830 mg/day) orally for 30 days. Ten postmenopausal women of matching age, menopause duration, and BMI were recruited as the control group and followed without any medication. Fasting blood and first-void urine samples were collected on days 0, 1, 5, 10, 20, and 30, respectively. Total magnesium, calcium, phosphorus, iPTH and osteocalcin were determined in blood samples. Deoxypyridinoline levels adjusted for creatinine were measured in urine samples. Thirty consecutive days of oral magnesium supplementation caused significantly decrease in serum iPTH levels in the Mg-supplemented group (p < 0.05). Serum osteocalcin levels were significantly increased (p < 0.001) and urinary deoxypyridinoline levels were decreased (p < 0.001) in the Mg-supplemented group. This study has demonstrated that oral magnesium supplementation in postmenopausal osteoporotic women suppresses bone turnover.

Edited by Lufega, 15 June 2010 - 08:03 PM.

[Lufega]

[Comparative study of magnesium salts bioavailability in rats fed a magnesium-deficient diet]

Vestn Ross Akad Med Nauk. 2010;(2):29-37.

Abstract

The purpose of this study was to compare efficiency of compensation of alimentary Mg deficiency after administration of 12 organic and 8 inorganic magnesium salts and to evaluate the ability of vitamin B6 to accelerate their effect. Two hundred eighty rats were placed on a Mg-deficient diet (Mg content (15 mg/kg) and demineralized water for 7 weeks. Twelve control rats were fed a basal diet (Mg content 500 mg/kg). Starting from day 49 of the Mg-deficient diet, the rats were given magnesium salts (50 mg magnesium and 5 mg pyridoxine per kg): Mg chloride, Mg sulphate, Mg oxide, M nitrate, Mg thiosulphate, Mg hydrophosphate, Mg carbonate, Mg trisilicate, Mg (L-, D- and DL-) aspartate, Mg (L- and DL-) pyroglutamate, Mg succinate, Mg glycinate, Mg orotate, Mg taurate, Mg lactate or their combination with vitamin B6 (5 mg/kg b.w.). Erythrocyte and plasma Mg levels were measured by spectrophotometry following the colour reaction between Mg and titanium yellow. Mg L-aspartate compensated for magnesium deficit more effectively and faster than all other salts. Mg chloride showed the highest efficiency among inorganic magnesium salts. Both Mg chloride and Mg L-aspartate in combination with vitamin B6 caused statistically significant compensation of magnesium deficit.


PMID: 20364677 [PubMed - in process]

This study compared a lot of the more common formulas we use. Can anyone access the full study ?

Edited by Lufega, 15 June 2010 - 11:04 PM.

[KimberCT]

Full Text

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[Lufega]

nice kimberCT, thanks !

[24 Is Ours]

I wonder why orotate wasn't involved in the study?

[Lufega]

I wonder why orotate wasn't involved in the study?

There's a study in post #2 that compares orotate as well as glycinate and taurate. The full study should give us these details.

[KimberCT]

I wonder why orotate wasn't involved in the study?

There's a study in post #2 that compares orotate as well as glycinate and taurate. The full study should give us these details.

Wish I could find the full PDF for that one.  It'll probably be more difficult since it was originally written in Russian.

[outsider]

I believe it is ionised magnesium which is the best.

[Lufega]

I believe it is ionised magnesium which is the best.

Do you know of a particular product? I've tried magnesium fizz a few times but it also has other nutrients so it's hard to measure what's doing what.

[niner]

I believe it is ionised magnesium which is the best.

Like magnesium chloride? It's an ionic salt. It's the best of the inorganic magnesium salts, but the organic salts seem to have better bioavailability.

[chrono]

I almost started a thread on mag gluconate last week. PureBulk sells the bulk powder, but after I'd typed a huge post, I calculated the molar ratio and found out that it's actually more expensive than bulk taurate or malate.

Elemental magnesium comprises 5.3% of the total compound weight.

I think that bioavailability is a bit of a non-issue with magnesium (as long as it's not something like the oxide, which is much lower). I think the various absorption and homeostasis mechanisms make the issue of bioavailability more complex than it is for things like pharmaceuticals. From the full text:

Our results clearly showed that Mg organic salts are better sources of Mg than Mg inorganic salts, and suggest that Mg gluconate is the best source of Mg because it exhibited the highest Mg absorption and Mg retention values in the ten studied groups (66.5% and 48.7%, respectively). It is important to stress that Mg inorganic salts remain a good source of Mg because the absorption and the retention of Mg observed with these salts were perfectly acceptable (more than 50% and 39%, respectively).
...
However, the administration of different organic and inorganic Mg salts did not result in any significant differences in these intestinal and caecum parameters. This may explain why there is no major difference in intestinal Mg absorption between the different Mg salts investigated in this study.
...
Indeed, the statistical analysis failed to show any trend or significant difference between the ten groups for the three Mg status parameters measured in this study, i.e. plasma Mg, erythrocyte Mg and bone Mg levels.

Though I do find intriguing the possibility that gluconate is slightly more effective at raising magnesium levels in CSF and brain (see this post in the threonate thread).

Also, gluconic acid (and malic, for that matter) might be something to reconsider if you have any aluminum exposure:

Effect of various dietary constituents on gastrointestinal absorption of aluminum from drinking water and diet.
Domingo JL, Gomez M, Sanchez DJ, Llobet JM, Corbella J.

The influence of some frequent dietary constituents on gastrointestinal absorption of aluminum from drinking water and diet was investigated in mice. Eight groups of male mice received lactic (57.6 mg/kg/day), tartaric (96 mg/kg/day), gluconic (125.4 mg/kg/day), malic (85.8 mg/kg/day), succinic (75.6 mg/kg/day), ascorbic (112.6 mg/kg/day), citric (124 mg/kg/day), and oxalic (80.6 mg/kg/day) acids in the drinking water for one month. At the end of this period, animals were killed and aluminum concentrations in liver, spleen, kidney, brain, and bone were determined. All the dietary constituents significantly increased the aluminum levels in bone, whereas brain aluminum concentrations were also raised by the intake of lactic, gluconic, malic, citric, and oxalic acids. The levels of aluminum found in spleen were significantly increased by gluconic and ascorbic acids, whereas gluconic and oxalic acids also raised the concentrations of aluminum found in kidneys. Because of the wide presence and consumption of the above dietary constituents, in order to prevent aluminum accumulation and toxicity we suggest a drastic limitation of human exposure to aluminum.
PMID: 8480083 [PubMed - indexed for MEDLINE]

[stephen_b]

Interesting tip from "Rapid recovery from major depression using magnesium treatment", PMID 16542786 (full text here):

The main side effect reported from high-dose magnesium and low calcium intake as treatment for depression was diarrhea. This results mainly from the attachment of each magnesium ion to about 800 molecules of water in the intestinal tract. Any treatment to terminate diarrhea, including lowering magnesium intake, was deemed essential to promote proper absorption of nutrients. One gram of arginine with each meal helped prevent magnesium-induced diarrhea, while 3 g per meal caused severe constipation, perhaps due to the effect of excessive arginine-induced nitric oxide on nonadrenergic, noncholinergic inhibitory nerves of the colon.

Edited by stephen_b, 05 August 2010 - 07:47 PM.

[zorba990]

I still prefer magnesium lactate.

[shaggy]

Interesting stuff..

How available is Magnesium amino acid chelate?

[albedo]

I am using citrate (prescribed/reimbursed) as I have an issue with RBC Magnesium not in the norm. I have no particular symptoms though, so it is a bit of a struggle to get prescription from my MD. I am checking is I find a good local and inexpensive source of gluconate. Do you have a take on Albion's glycinate. As I am asymptomatic, what I should look at in my tests to see a possibly deficiency in magnesium? Was reading about high homocysteine for example.