I keep hearing (not just here, most thyroid forum/sources) that low in range iron isn't optimal, that (70-90?) is optimal. Given that the range is 15-150 or 30-300 or something along those lines, 70-90 is quite a narrow portion of the range. (Also, it is interesting that the 70-90 (or whatever it is!) does not vary even when the ranges are very different - 70 in a range of 15-150 is in a very different position than 70 in a range from 30-300.)
I'm after a paper that discusses this and/or indicates some kind of optimal figure, and/or that the range may be too wide. Ideally this paper would not just relate to thyroid patients, but that's okay too since, after all, it is the situation in which we find ourselves! My google scholar skills are letting me down - perhaps I don't know the best search terms? (Optimum, ferritin, range, low-normal - various combinations of those.) I did find one article that mentioned low-normal ferritin and restless legs.
I always say that ferritin should ideally be mid-range or a little bit over. As you rightly say the range is important in determining what mid-range actually means.
The idea that ferritin should be around 70 is mentioned on STTM, although the source for the figure is not given, and nor is the range that the 70 is based on. I have always assumed that STTM is where most people get the 70 figure from.
I'll see if I can find some interesting links on the subject tomorrow.
Mine is about 80-90, but the range the lab uses is 30-300, which puts it at not very high in range! Still, I've managed to drag it up that far with dietary improvements and I'm pleased with myself. I have a history of mostly low or low in range iron, and this seems to be common with women in my family. If I have to get to 160ish, then I have a long way to go...
That's ferritin, not iron, by the way. My iron is quite high in range 25.7 (5.83-34.5) but my ferritin is very low (20 in 13-150). I've never managed to get it past 40
Here's an interesting article stating ferritin level range is too high & ferritin should be lower than what we've been told. Sorry I don't know UK lab equivalent
If left untreated, high iron can contribute to cancer, heart disease, diabetes, neurodegenerative diseases and many other health problems, including gouty arthritis. In one small study,2 100 percent of the patients achieved marked reduction in attacks or complete remission after phlebotomy was used to remove iron and maintain an iron level at near-iron deficiency — "the lowest body iron store compatible with normal erythropoiesis and therefore absence of anemia." [My emphasis]
This sounds like a recipe for disaster to me. In the past I've had ferritin which is low in range, and this was considered to be fine (by doctors). But when I bought a copy of my medical records I discovered that my serum iron was below range and had been for several years, although I never found out exactly how much below range it was.
Another consideration is that people with untreated or inadequately treated hypothyroidism have low blood volume. Perhaps we need nutrient levels to be higher than optimal for healthy people as a result? I'm only guessing though. Unfortunately, measuring blood volume is not easy, and is expensive to do it accurately.
Sorry G2G2 that the link is not useful because it is truncated and I wonder why this site does that because there is some rule against giving links. I sure hope not. So could you copy and past the entire title of the article as Dr Mercola's site is a well regarded source and this topic is important to me.
Are you in the UK? I've got blood tests results for ferritin going back to May 2010, and I've had it tested at least once a year, sometimes twice a year either by the NHS, Blue Horizon or Medichecks every year since. Every single one of the reference ranges is 13 - 150 ug/L with the exception of one result in 2013 which was 13 - 400.
Nope. In Australia, where the range - that comes from the lab we/my doctor use - is 30-300.
So, if the optimum is, say 80 (if the range is 15-150), is that really optimum. I mean - we think that the optimum TSH is (say) 1, and we don't think the range is very important as the range seems to be mostly opinion. But, other times the range is important because it reflects the method of measuring. In that case, 80 out of 15-150 is perhaps different to 80 out of 30-300...
When the ranges are that different you should go by the percentage through the range to compare results.
So if you have a (made-up) test with a range of 20 - 120 and your result is 70 then it is 50% of the way through the range. If you have the same test done a year later and the reference range has changed to 30 - 270, if your result comes out as 150 then it is still 50% of the way through the range. And in that case your level hasn't actually changed despite the fact that 150 is a lot bigger that your previous result of 70.
I convert all my test results with reference ranges into "percentages through the range". It is so much easier to detect any changes or trends that are occurring, and also means that changed reference ranges can be ignored once you have the percentages.
Normal ferritin levels for women are between 20 and 200 ng/mL. According to some experts, ferritin levels of at least 40 ng/ml are required to stop hair loss, while levels of at least 70 ng/ml are needed for hair regrowth. The optimal ferritin level for thyroid function is between 90-110 ng/ml.
The link does have some references but I haven't checked to see which ones are relevant to "optimal ferritin".
For my purpose, it will need to be something like a journal article, or official guideline. I'll plough through the Izabella Wentz references - hopefully there is something useful there.
It is possible that you won't find an official paper or guideline. It could well be a finding from patient experience that ferritin needs to be mid-range or a bit over to feel at one's best.
What I have found is that it is rare for anyone "official" to suggest that optimal ferritin is low in range, although it does pop up sometimes.
In this case, I need a journal article to give to someone.
I'll park this here to look at later (an article entitled "Iron deficiency is associated with Hypothyroxinemia and Hypotriiodothyroninemia in the Spanish general adult population: Di@bet.es study.")
And another. This one "Multiple nutritional factors and thyroid disease, with particular reference to autoimmune thyroid disease."
and specifically "In two-thirds of women with persistent symptoms of hypothyroidism despite appropriate levothyroxine therapy, restoration of serum ferritin above 100 µg/l ameliorated symptoms. "
Sigh, it's taken a long time - and dietary change - to get my iron up to just under 90... But perhaps it explains why I did poorly on levothyroxine.
• in reply to
And this quote from the abstract "AITD patients are frequently iron-deficient since autoimmune gastritis, which reduces iron absorption and coeliac disease which causes iron loss, are frequent co-morbidities."
Note to self, follow up autoimmune gastritis.
I'm not a pregnant Chinese lady, but this was interesting too: "The Relationship between Iron Deficiency and Thyroid Function in Chinese Women during Early Pregnancy."
Not a pregnant Brazilian lady either, lol. "Maternal hypothyroxinemia in the first trimester of gestation and association with obstetric and neonatal outcomes and iron deficiency: a prospective Brazilian study."
and specifically: "This prospective Brazilian study found no association between isolated hypothyroxinemia in the first trimester of gestation and obstetric or neonatal outcomes, but an association was demonstrated with iron deficiency."
The Relation Between Serum Ferritin and Goiter, Urinary Iodine and Thyroid Hormone Concentration
" Results: Total goiter rates were 80 and 20% in children with ferritin concentrations < 10 mg/dL and _ 10 mg/dL, respectively (p < 0.001). Increased serum T3 and decreased resin T3 uptake was present in those with lower serum ferritin levels; however, free T3 and T4 index, serum T4, and TSH were not significantly different between those with low and normal ferritin. Conclusion: Iron deficiency is associated with a high prevalence of goiter in Iranian schoolchildren."
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I have a history of mostly low or low in range iron, and this seems to be common with women in my family. If I have to get to 160ish, then I have a long way to go...
Low Ferritin and raised Iron 
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