Nutritional recommendations... one size fits all?

18 mg of what?

deannalfisher wrote: »

18mg of what???

I'm going to guess iron after Googling "RDA 18 mg" and scrolling through the results.

If you want to go on a rant about a blanket daily recommendation of 18 mg iron for women age 19-49, you'd be far better off quibbling about the hard and fast age delimiters than about the lack of variation by size -- the reason for the specific recommendation is related to replacing iron lost due to menstrual cycles, and variation in that is not related to a woman's size. There are women in that age cohort who don't have monthly cycles for a variety of reasons, and there are women older than 49 who still have monthly cycles, but the RDA cuts back to 12 mg when you hit 50, presumably because that's some average age for menopause or covers 2 standard deviations of the mean, or something of that sort.

Ready2Rock206 wrote: »

What are we even discussing? 18 mg of what???

It has to be iron. It's the only vitamin or mineral with an RDA of 18 mg for adult women under 50.

If you actually need iron replacement (as oppossed to taking a general multi vitamin as a catch-all 'just in case') then you are much better off taking a specific replacement, like FGF or Ferro_grad, rather than a multi vitamin - the amount of iron in multi vitamins is not sufficient to treat iron deficiency anemia.

Re OP's question - of course, RDA's put out by governments or medical organisations are a simplified general guideline, based on the average, not a tailored individual list specific to you.

Some things will have more variation in requirements than others - iron being one of them. So men and women are recomended different amounts, mainly because women lose iron through blood loss of menstruation and men do not.
Hence the age difference between women's recomendations - again it is an average - obviously not every woman goes through menopause at exactly 50.
And of course they start menstruating before 19 - but I am guessing the RDA was only for adults hence that lower age limit.

The height of the woman would have very little to do with it.

what you are missing is that RDA's for specific age ranges aren't just pulled out of a hat - they are established through years of stats/test results/studies to provide a recommendation and they can/are updated as evidence requires that indicates they need to be changed

if your doctor is blowing you off, it might be because your blood work doesn't indicate a need for any customized recommendations

Janneson27 wrote: »

paperpudding wrote: »

If you actually need iron replacement (as oppossed to taking a general multi vitamin as a catch-all 'just in case') then you are much better off taking a specific replacement, like FGF or Ferro_grad, rather than a multi vitamin - the amount of iron in multi vitamins is not sufficient to treat iron deficiency anemia.

Re OP's question - of course, RDA's put out by governments or medical organisations are a simplified general guideline, based on the average, not a tailored individual list specific to you.

Some things will have more variation in requirements than others - iron being one of them. So men and women are recomended different amounts, mainly because women lose iron through blood loss of menstruation and men do not.
Hence the age difference between women's recomendations - again it is an average - obviously not every woman goes through menopause at exactly 50.
And of course they start menstruating before 19 - but I am guessing the RDA was only for adults hence that lower age limit.

The height of the woman would have very little to do with it.

As I said iron was just an example. If you are focusing slowly on that then you are missing the point of the post.

No. What I said applies to other recomendations as well.
But some, like iron have more variation in people requirements than others.

Janneson27 wrote: »

I just think it would be nice if we were more educated in this department. I think better education helps women understand their needs and meet them better. I just wish I knew. What if someone is being overlooked because they are just scared to tell us it's okay to eat less?

I'm just curious. Feel free to discuss. Please do not personally attack me. I am not trying to promote an unhealthy under nourished diet. I'm just wanting to experience an educated and thought provoking discussion.

I totally agree that more information about how individual we all are when it comes to our nutritional needs, based on how our bodies work and what they require to function, would be optimal. Heck, it could be crucial, even.

But one thing I think it's important to know is that the medical community needs to figure out what ARE women's needs first, before we can even begin to try and get the numbers disseminated to the public at large. There is actually a lot about the female body that the medical community has guessed at, but quite literally has never studied (in women), tested (in women), or knows much about, honestly.

At this point, 80% of medical studies done - on drugs, how the body works, etc... - are done on males, but NEVER done on females. Or the studies may use both sexes but don't break down their results along sex lines so if there ARE differences between the sexes, they are not noted. Many times it has simply been assumed that women will be the same as men, so it doesn't matter.

But as some research entities ARE doing more studies with females included, or with sex breakdowns included, it's being discovered that there can be some major differences. And one reason this matters is because a lot of our information about the basics on human physiology, how our bodies work and what their needs are? Those tended to be done early on in our researching history, when women were less likely to be included than they are now. And the results are often still used today, even if they are tweaked now and again by newer studies.

As some examples, men build more muscle if they increase their protein intake above the normal needed amounts. Men have higher performance if they carb load before an athletic event. It was assumed this was the same for women - in sports medical literature it was stated like this was universal for ALL people - until the studies were done on women too. Turns out, women get no benefit at all for muscle building when they increase their protein intake. And if women carb load, it has either no effect, or it actually causes lower performance during the following athletic event.

So based on this, it seems as though something as basic as how our bodies process carbs and protein, or how they build muscle utilizing protein, may be different between men and women. We don't know how or why, though. It hasn't even been studied past these couple of studies, to my knowledge (I've been trying to find the study, but couldn't find my own links, unfortunately).

But the odds are good that, when calculating out how much protein and carbs women should have, there are assumptions made on how the body processes carbs and protein, and these are based on studies that in all likelihood were done on males only. So...they could be accurate for women, or they could be inaccurate, and we honestly have no way to tell except the slightly fuzzier method of each individual seeing what seems to work for themselves best.


There's also been some very interesting research - not much, as it's pretty new - on the fact that individuals, regardless of sex, actually can process foods in ways that seem completely opposite to each other. A study on blood sugar levels was aiming to look at how foods affected people blood sugar levels. It was expected that some people might have differences in degree. But what actually happened was that some people could have blood sugar spikes to a food that would cause a huge drop in blood sugar levels in another.

The conclusion at the end of the study was that nutritional guidelines probably need to be a lot more individualized than the medical community ever suspected. ( An article on the study: https://www.sciencedaily.com/releases/2015/11/151119133230.htm )

So I guess what I'd say is, yes, education would definitely help, IMHO. But the lack of information we have on details about what our bodies need seems to be more rooted in a lack of information, period, rather than the doctors trying to withhold information, if that makes sense?