Looking at the nutritional labels of the Plenny Shake varities, magnesium ranges from 166-176 mg/meal. With five meals a day, that gives you a magnesium intake of 830-880 mg/day.
In 2015 the European Food Safety Authority published a paper titled Scientific Opinion on Dietary Reference Values for magnesium (link). In it they recommend an Adequate Intake of 350 mg/day for adult men and 300 mg/day for adult women. Also, under section 184.108.40.206, they reference a 2001 study that established an Upper Intake Level of 250 mg/day, basically saying that at this level no adverse effects should occur. The 2015 paper’s authors did not conduct their own study, and they couldn’t gather enough evidence to support the establishment of an Average Requirement or a Population Reference Intake, so they settled with establishing an Adequate Intake, which is used when data is lacking. The paper also recommends further research into determining an Upper Intake Level, which suggests the referenced 2001 study isn’t comprehensive enough.
However, with a previously suggested Upper Intake Level of 250 mg/day and a recommended Adequate Intake of 350 mg/day for adult men, how does this support Plenny Shake supplying up to 880 mg/day?
There is currently no evidence to suggest that dietary magnesium is toxic, however, there is evidence to suggest that higher amounts of nonfood/supplementary magnesium lead to diarrhea. For one, that is what the 2001 study suggested. Another paper from 1997 (link) suggested an Upper Intake Limit of 350 mg/day, noting that previous studies had shown wildly varying results. Diarrhea was observed for 6 of 21 participants getting 360 mg/day, 5 of 25 getting 384 mg/day and 18 of 50 getting 470 mg/day. In contrast, no diarrhea was observed at 452 mg/day, average of 576 mg/day and up to 1200 mg/day (reference the paper for more details).
I think it’s fair to say that high amounts of magnesium doesn’t affect everyone equally. Sadly, I have been experiencing loose stools/diarrhea at times when I’ve been consuming Plenny Shake exclusively. I’m starting to suspect the magnesium, but I don’t have any conclusive evidence.
Yeah, but still, why does Plenny Shake have such high amounts of magnesium?