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mccoy

Manganese concerns?

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I noticed that yesterday my daily Mn intake has been 13 mg, red bar in cronometer, most of it from oat flakes.

 

I checked my weekly average, which was 11 mg (food only).

 

A search on tolerable upper limits, turns out it's in the region of 8.2 mg daily (60 kg bodyweight) of dietary Mn. Less in elders. Source: EFSA Europe

 

Has anyone of you guys noticed the same and are you concerned about it? My take is that nutrients in natural foods are subject to homeostatic mechanisms so naturally high dosages may be harmless. 

 

But maybe that's just a futile self-reassurance....

 

Edit: I noticed my dietary intake of copper is also exactly as the tolerable upper limit: 5 mg d-1; I take Zn supplements to prevent too much an unfavourable balance of Zn/Cu, but I don't know if the high absolute value may have drawbacks

Edited by mccoy

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From my brief Google search:

 

The  mainstream Linus Pauling Institute points to a conservative upper  limit of 11mg for adults.

 

http://lpi.oregonstate.edu/mic/minerals/manganese#toxicity

Due to the severe implications of manganese neurotoxicity, the Food and Nutrition Board (FNB) of the Institute of Medicine set very conservative tolerable upper intake levels (UL) for manganese; the ULs are listed in Table 3 according to age (4).

 

Jack Norris at the VeganHealth.org:

http://www.veganhealth.org/articles/manganese

There is a concern that manganese intakes in vegan diets can be high. To date, manganese toxicity in vegans has not been studied, but manganese toxicity usually does not occur with amounts of manganese found in the diet. However, iron deficiency can cause an increase in manganese absorption and vegans with iron deficiency should make sure they eat vitamin C at meals so that iron is absorbed instead of manganese.

 

[Cf. Manganese deficiency and toxicity: are high or low dietary amounts of manganese cause for concern?]

https://www.ncbi.nlm.nih.gov/pubmed/10475586

 

Risk of Dietary Toxicity

http://www.whfoods.com/genpage.php?tname=nutrient&dbid=77

In 2001, The National Academy of Sciences (NAS) established a Tolerable Upper Intake Level (UL) of 11 mg for total daily manganese intake for adults 19 and older. This level was based on the uppermost amount of manganese found in the diet of healthy people.. While we support the establishment of this UL recommendation from the NAS, we would also point out that it was not based on evidence about unwanted health consequences if this dietary level was exceeded. In other words, the NAS did not have evidence about health problems that might occur if dietary intake of manganese routinely exceeded this 11 mg level. The NAS only had evidence that no such problems had been observed in U.S. adults whose average daily manganese intake was as high as 11 mg. So the NAS adopted this 11 mg UL level to err on the conservative side in its public health recommendation.

 

Dietary manganese levels can be surprisingly high in some populations. In fact, unlike most required dietary minerals, it is not especially difficult to exceed the UL of 11 mg with very reasonable dietary intake. For example, if you eat one serving from each of our Top 10 manganese-rich foods in one day, you will exceed the manganese UL. As described above, we are not aware of any reason to deliberately avoid manganese-rich foods, provided that you consume an overall balanced diet with optimal intake of other minerals and do not have health problems that might compromise your body's handling of these minerals.

 

Some discussion here:
https://discourse.soylent.com/t/have-you-asked-yourself-why-upper-limit-of-manganese-is-11mg-day/7660

Edited by Sibiriak

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Manganese Bioavailability Overview

http://pubs.acs.org/doi/pdf/10.1021/bk-1987-0354.ch001  (pdf)

 

Foods vary in their contents of manganese (32,37,38). Comparisons of manganese contents of different foods are given in Table I.
Plant origin foods such as  tea, whole grain cereals , some dark green leafy vegetables, and nuts contain high amounts of manganese. However, these products often concurrently contain high amounts of tannins, oxalates, phytates and  fiber . These dietary constituents have been found to inhibit  the absorption of other minerals; hence, might have a negative  effect on manganese absorption.
Edited by Sibiriak

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Heck, guys, I hate to open a new thread when there is another one on the same topic, but I'm going to explain what happened, which is a little baffling.

 

I searched by the rapid search button in the upper RHS of the page:

post-7347-0-60646200-1498672042_thumb.jpg

 

You can try that yourself, apparently there is not thread on Manganese, besides the one I opened after my search.

post-7347-0-89275600-1498672061_thumb.jpg

 

After MR's answer, I try that again and lo, right at the bottom of the page, there sits the old thread on manganese. As far as similarity of content goes, it should have sat on top of the page AFAIK.

 

Michael, you can merge this topic to that one if you see it fit and delete whatever redundant post of mine

Edited by mccoy

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Heck, guys, I hate to open a new thread when there is another one on the same topic, but I'm going to explain what happened, which is a little baffling.

 

I searched by the rapid search button in the upper RHS of the page:

attachicon.gifCapture manganese.JPG

 

You can try that yourself, apparently there is not thread on Manganese, besides the one I opened after my search.

attachicon.gifCapture manganese2.JPG

 

After MR's answer, I try that again and lo, right at the bottom of the page, there sits the old thread on manganese. As far as similarity of content goes, it should have sat on top of the page AFAIK.

 

Michael, you can merge this topic to that one if you see it fit and delete whatever redundant post of mine

 

In your screen capture, it looks like you were careful to select to search "Forums," not "within this thread" — is that right? When I search there under "Forums," I see both your new thread and Brian's earlier one (along with Dean's and my posts in the nuts thread, which are at least as valuable as anything in the earlier Mn thread).

 

In any case, I would always encourage everyone to use the Advanced Search by clicking on the gear icon off to the right, not the basic search.

 

I'll merge this thread into the original one in a bit. People following this thread will probably need to actively begin following it in order to get updates: I don't think your 'follow' on this existing thread will automatically carry over.

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Higher manganese is actually more associated with longevity than any other nutrient [a recent study elsewhere on here] shows

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