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We're going to take some time now
to talk about the trace minerals.
So we've covered the major minerals.
Keep in mind that the difference between the major
and these trace minerals is just the amount that's in your body.
When we look at the trace minerals,
we have some different recommendations.
So we have nine of these trace minerals
that we've identified that humans need.
And there are our DA's is or recommended daily intakes
or dietary intakes.
Then we also have ultra trace minerals.
And certainly you've never heard a recommendation
to seek out arsenic.
We don't want people to do that.
These are all achieved just through normal intake.
So if you're just eating foods and have a standard diet,
you're going to meet any need you have for these ultra trace
minerals.
Let's start with a conversation about iodine.
And the main interest we have in iodine
is really because it's important for the production of something
called tyrosine.
And this is a chemical that's produced by your thyroid gland.
And if you haven't taken ANP or had an anatomy class,
your thyroid gland is a small butterfly
shaped gland that resides in your neck.
And what the job really is of this gland
is to help regulate and normalize
metabolic rate or function.
So as we age, a lot of times people will say,
well, my thyroid is getting little sluggish.
And maybe that person finds it hard to lose weight
or maybe they're gaining weight.
And this is a problem that is not really related to iodine.
It's part of the normal aging process, although it can still
go wrong in people sometimes and they have to be a medications.
So when we look at iodine, the primary sourced in the US
is going to be iodized salt.
We fortify salt with iodine.
It doesn't naturally occur there.
But there are some natural sources that we can consider.
For instance, iodine is found in seafoods
or in any kinds of products in the sea.
That could be something like seaweed.
You could also find it in agricultural crops that
are grown on soil that is particularly rich in iodine.
In the US, you can imagine, because we eat a lot of salt,
we have a very high sodium diet on average,
there aren't a lot of problems in modern day
America with iodine.
That's not really been the case when we look back historically,
which is why we fortify salt now.
If you think about the US, we have the two oceans and then
right down the center in the Midwest, that was actually
historically known as the goiter belt.
And that was an area where we saw a lot of deficiency.
So we want to take a little bit of time
and look at some of the deficiency diseases
that we see related to iodine.
These occur in adults but also in children
and it's a result of deficiency during pregnancy.
So let's look at that pregnancy part of it first.
So you see cretinism or cretinism,
you could pronounce it either way.
This is a result of a woman being
deficient during pregnancy.
And the real consequence is mental retardation.
You can also see some physical deformity,
especially in the face.
The structure of the face is a little bit different.
Worldwide iodine deficiency during pregnancy
is the number one reason for preventable mental retardation.
If we look at a place like Afghanistan,
for instance, a lot of people suggest
that overall in that population there's
a reduction of 15 IQ points based
on insufficient iodine for women when they're pregnant.
So it has just disastrous consequences
for individuals but also for an entire population
when we think about ability to learn,
when we think about productivity and growth potential.
Now when someone is deficient as an adult
and she isn't pregnant, it can also occur in men,
we can see the development of something called a goiter.
And it might be a little hard to see in this picture.
It's also the picture in your textbook.
You can see this large mass right here
under the chin in the throat.
And this is an enlargement of the thyroid gland.
Because basically what's happening is the thyroid says,
"I'm going to get larger and larger
to capture any of this iodine that's passing my way."
It's not very effective.
And still this gland gets larger.
If we give someone that has a goiter some iodine,
you can see sometimes a slight reduction
in the size of the gland, but it's never
going to go back to its previous status.
The places right now in the world
where we're seeing goiter development
tend to be in Asia, particularly India and Pakistan.
So there's some interest in finding different public health
ways to kind of remedy this situation.
In the US we do have some concerns about thyroid health
related to iodine.
And if you look at my slide here,
I have a picture of the power plant in Springfield.
Maybe you recognize this if you're a Simpsons fan.
And the reason I have this picture on here
is that if there is radioactive material in the environment,
one of the problems is that that radioactive material wants
to go and reside in the thyroid.
And it causes extremely high rates of thyroid cancer.
Now in Japan they were very, very careful
about providing this potassium iodide to citizens
to help prevent thyroid cancer as a result
of this radioactive emission.
This wasn't the case back in Chernobyl,
which occurred in the 1980s.
The government denied that there had been nuclear release.
And the number of cases we see of thyroid cancer there
are astronomical.
So you have to provide this potassium iodide
at the exact right time, otherwise
it's not going to be very effective.
But that's kind of a therapeutic use of iodine
that maybe you weren't familiar with.
Let's turn our attention now to iron.
And iron is a trace mineral great importance,
especially to women of childbearing age.
And worldwide we see it being a problem for public health
as well.
Looking at the food sources, I really
invite you to put these into two different groups.
So you can find iron in animal products, so you meat.
And then you can also find it in plant products, which
would be beans and greens and things like this.
That's going to become really important for us
in understanding absorption rates.
Because there's a different mechanism for absorption
when it's iron from flesh or meat products
or from plant products.
If you think about the different functions of iron,
you might be a little bit familiar
with anemia, which is the result of deficiency.
But some of the characteristic symptoms
we see in that anemic state tell us
about what it does in our body.
So if you think about how people feel when they're anemic,
they often feel short of breath.
One of the things that iron does for us,
it's in this hemoglobin complex on red blood cells,
and enables us to carry oxygen around the body.
You'll also see it being very important in myoglobin,
which is in muscle cells.
And it allows those muscles to stay very oxygenated.
And those are two very critical roles.
It's also needed by some enzymes and then
in different kinds of structures.
So new cells, amino acids or proteins,
also in hormones and neurotransmitters.
Now, these two right here should kind of
give you a hint about its importance during pregnancy.
We have increased iron during pregnancy.
And it's critical women of childbearing age make sure
that they have good iron status and especially when they're
pregnant.
I mentioned anemia.
And if you think back to our conversation about vitamins,
anemia can result from B6 or B12 or folate deficiency.
Sometimes you can see it as a consequence
also for Vitamin A or Vitamin E deficiency.
Most often though when we look at anemia
it's the result of iron deficiency.
And you can be low in iron or be iron deficient
without being anemic.
But usually when we see anemia it has to do with iron status.
And there are several different symptoms.
So we have a nice list here.
Now these are symptoms that people
may experience several of them, all of them.
There can be a little bit of fluctuation there.
There are a couple here that are really important when
we start looking at specific populations.
So you think about children, lowered IQ.
They need that iron when they're growing and developing.
And it's really important that they have enough
when they're learning and in school.
And this is part of the reason that we
fortify lot of foods in the US with iron,
to make sure that kids are getting enough of this.
We also want to take a look at women's risk.
So I mentioned that children are at an increased risk and then
also pregnant women.
But women in general, even in a non-pregnant state,
need to have more iron than men.
It starts at the age of monarchy.
So when a young girl gets her first period, maybe
around 12 or 13, we see that her RDA for iron
goes from eight milligrams up to 18.
And that's really within a couple of weeks
that she has this increased need.
And that's a really particularly vulnerable time
because very often we don't see young girls
changing their diet.
So that increased need for 18 milligrams
is going to go up until menopause.
So we really, really are encouraging women to make sure
they're getting enough iron in their diet just naturally.
We also have some other groups that we're interested in.
Anyone who might be fighting some kind of an illness or
has had surgery or has experienced blood loss
where they're losing red blood cells,
we're concerned that their iron status could also be low.
An iron deficiency is a very, very common situation globally.
So I have this statistic that 1.2 billion people worldwide
are iron deficient or they have sub-clinical deficiency, which
might mean that they haven't been diagnosed
or it's below what we would consider frank or clinical iron
deficiency.
This happens for a lot of different reasons.
It very often is about blood loss.
It could be from a parasite.
It could be from an ulcer or some kind of a bleeding sore.
And it could be also from poor diet.
That's a very, very real consequence.
In the US, thankfully, we aren't anywhere near
that kind of deficiency.
On average it's about 10%, which is still very, very concerning.
We have made tremendous inroads in that number.
It had been much higher.
One of the ways that we did that, I mentioned
fortified foods.
But especially with low income populations,
we use the WIC program, Women, Infants, and Children.
And the foods that are supplied in that program
are iron fortified cereals or iron fortified formulas
for women who aren't breastfeeding.
And that has made a tremendous difference
in those populations.
Now there is potential for us to have too much iron.
And so we talk about this iron overload condition,
as hemochromatosis or hyper hemochromatosis.
And what's happening here is that the person's body has
too much iron and it's very, very difficult to get rid
of that extra iron once it's in the body.
One of the best ways to do this, historically,
has been through blood donation.
So if people lose some of that blood,
they're also losing the iron.
Because normally the red blood cell
lasts between 90 and 120 days.
And as that red blood cell is breaking down,
the iron in that cell is being recycled.
So we're able to kind of reuse it.
So if the person has a blood donation,
they're actually going to be able to get rid
of some of that iron that normally they would hold onto.
I should also mention one of the other concerns
we have about iron toxicity or overload is with supplements.
And this is a very, very real danger for children.
And I have a lot of concern when we start giving children
vitamins, especially when they're
in fun shapes, bright colors, and they taste good.
Because children aren't savvy enough to know that
it's really a medication and not candy.
So I really encourage parents to store them very carefully
and not to tell the child it's candy.
Because it can make that product even more attractive.
And if that child takes too much,
it can be a very, very serious health situation.
OK, we have within our population in the US
a couple of special interest groups, so to speak.
And vegetarians in particular would be in this category.
Now, a vegetarian diet does not have to be low in iron
and it isn't considered low in iron when it's well planned.
We do have people that may not understand
how to have a healthy vegetarian diet.
And because of that, they may not
be using iron rich foods appropriately.
So we need to have a little discussion about that as well.
So we're going to look at those two forms of iron
that I mentioned.
So early on when we looked at food sources,
I said we have animal sources and then we have plant sources.
And this is really important for how our body absorbs them.
So when we look at those animal sources,
we call this heme iron.
And the way to kind of remember this is if it bleeds,
it has heme, it has blood.
OK?
So we have that form of iron.
And it's very, very well absorbed by your body.
Now, the book uses this percentage of 23%.
Now that can be a little bit misleading, perhaps.
Because your body has this wonderful homeostatic mechanism
that if you are low in iron, you will absorb more of it.
If you have sufficient iron status, you'll absorb less.
So this 23% really have some fluctuation to it.
That's our heme iron story.
Very easily absorbed for the most part.
Then we have non-heme.
So these are things that don't believe.
If I cut into a nice stalk of broccoli,
it's not going to bleed.
This has non-heme iron.
And the absorption rate of this is much, much lower.
Here you see this 2% figure.
And again, I provide a little bit of caution
with that because if you need more iron,
you're going to absorb it at a slightly higher rate than 2%.
But on average, these numbers should indicate to you
that we're going to absorb that non-heme or plant
iron at a much, much lower rate.
Your body is not nearly as efficient with that.
As a result of that, we actually need
to have more non-heme iron in our diet
if that's what we're going to rely on.
So if you have a non-heme iron source in your diet
and you're not eating meat, you need to take your RDA
and multiply it by 1.8 to get your new RDA of non-heme iron.
And many vegetarians aren't aware of this.
So if they read a food label and maybe it's a can of beans
and it says one serving has 10 milligrams of iron,
your body is not going to absorb all of that.
So you have to be very cautious in planning your diet
to make sure that you're actually
meeting this vegetarian RDA.
There are some things we can do to boost
our absorption of iron.
And they're very easy to do.
So you can see here I've got a bowl of chili up there.
And there are a couple things operating
in that bowl of chili.
There are beans in there and there's meat.
So I have two different sources of iron.
I have heme and non-heme.
I'm going to be able to absorb that non-heme iron at a much
higher rate in the presence of meat.
And this can be particularly important
if you think about my recommendations
to use meat as a condiment.
Not only is that a smart move for your heart and the planet
and your overall health, but also for your ability
to absorb iron.
The other thing about that bowl of chili
is that it's made with some tomatoes.
And tomatoes have Vitamin C. When
you have Vitamin C with an iron containing meal,
you're going to be able to triple
your absorption of the non-heme iron.
And that's critical.
For a vegetarian it can be as simple as squeezing
some lime juice on a meal, on some salsa that
has black beans in it or some other kind of legume.
It's a great, very, very easy thing to do.
Now I also have here on this slide
I have a picture of a cast iron pan.
And that's kind of grandmother wisdom.
It's something I've always really loved
that we can also get iron in this other form.
We call it ferrous iron or elemental iron.
And if I cook an acidic food in that frying pan,
maybe I even put my chili in there,
I'm going to leach a little bit of that iron into the food.
And this is a particularly good way for us
to actually increase iron status.
And so I'll just give you a couple statistics on this.
If I were to simmer some spaghetti
sauce with tomatoes in it in a glass dish.
And maybe you don't use glass dishes,
but maybe you're using stainless steel, for instance.
You're going to have about three milligrams
of iron in that spaghetti sauce.
But if I did it in the cast iron skillet, 87 milligrams.
Now, we don't have to worry about poisoning ourselves
with iron or having iron overload using
a skillet pan like this.
It's going to be absorbed according to your need.
So it'll be just fine.
And you wouldn't really even have
to have an acidic dish in there.
If you use one of these cast iron skillets
or some kind of a cook top, you could have pancakes in there,
you could have anything else, fry a piece of fish in it,
you're still going to get some of that iron.
So I recommend to a lot of people
who have teenage girls that this is a great way
to actually increase their iron and decrease
their risk of deficiency.
Let's move onto another divalent metal.
So this one is zinc.
And you've probably heard about zinc, especially in relation
to the common cold.
A lot of people will take zinc lozenges.
And we'll talk about that might be a good or bad situation.
Now, the food sources of zinc are very similar to the ones
that we see for iron.
Some exceptions would be yogurt.
Generally speaking, foods that are rich in calcium
are very low in iron and other kinds of metals.
But yogurt is actually a good source of zinc,
so that's a little bit of a shift.
And then we can see fortified cereal.
So these ready to eat cereals the kids
might choose through the WIC program
or just at the supermarket, and also meats.
So in general meats are a very, very good source of zinc.
And zinc has a lot of different roles in the body.
And so what I've done is I've gone
through all the different roles that you might see or talk
about and I've categorized them and highlighted
a few that I want to talk about.
So you can see the ones that are a little bit bold, gene
expression in protein synthesis.
This should give you a little tip
off that zinc is very, very important during pregnancy,
when we are growing this whole other human.
That fetal development is a time when
we need to have enough zinc.
Also immune function.
And this is part of the reason that someone might take a zinc
lozenge when they have a sore throat
or they have a little bit of a cold.
It's important for wound healing.
Also I mentioned growth and development in children.
A couple that I'll talk about that I haven't bolded.
I have *** production up here.
So in men, zinc is very important for fertility.
But also in women.
So normal reproduction and fertility
tends to be a little bit enhanced
as long as someone has enough zinc.
Also taste perception.
Some studies have shown that women who are zinc deficient
and you actually give them a zinc containing food,
to them it tastes horrible.
And this is kind of weird twist of nature.
You would think that if you're deficient in zinc
those foods might taste good to you
to encourage you to eat them.
But your taste is thrown off a little bit
when you're low in zinc.
So it's just kind of a little interesting trivia for you
about this.
Now when we see deficiency, you're
going to see some of those functions of zinc
kind of co-opted in some way.
So you see that there's problems with immunity.
And I also mentioned that abnormal taste,
which can further the deficiency sometimes.
And it's also related a little bit
to night blindness, which we talked about Vitamin A
being a big player.
Iron and zinc also have a role to play in that.
Now when there's too little zinc,
one of the things that we see in some populations
is diminished growth in children.
And your book talks about a particular case
in the Middle East in Egypt.
And the reason that this occurs in this population
is because they're using unleavened breads.
So these don't contain yeast.
Yeast normally, through its metabolism
of different kinds of products, is
going to break down phytates.
Really the problem with the phytates
is that they bind this zinc and we're not
going to be able to absorb it.
So that can be a problem in certain populations,
especially if that population doesn't
have a whole lot of meat products
or is low in some whole grains and legumes and things
like that.
As a result of those deficiencies in the Middle
East, you can look at this picture here.
I have a young boy and he looks like he's probably
about eight or 10, but I think he's actually 16 or 17.
And so you see that he's much shorter for his age.
And then also if you looked at his *** maturation
and development, he's not going to look
like your typical 16 or 17-year-old boy.
So we see that there's going to be alterations
in normal physical growth, but in particular
in *** maturation when there's zinc deficiency.
You can also have some problems with
the normal immune function.
Infections can be worsened.
And again, that has to do with your immune response.
And sometimes zinc can also disturb or disrupt
thyroid function.
And this is independent of iodine.
So sometimes you see these minerals work in concert.
So they have this synergistic relationship.
And sometimes they're going to work independently.
And this is one of those independent cases where
the zinc can actually cause some abnormalities
in the functioning of your thyroid.
Now we have a couple of risk groups
that I'm just going to highlight.
And I talked about people with certain kinds
of dietary practices related to unleavened
breads and low proteins and things like this.
But we also are concerned about pregnant women
and young children, the elderly.
And this can be for several reasons with aging adults.
In particular, that they tend to have
kind of a dampened immune response,
maybe that they're a little bit more
susceptible to catching every little common cold or things
like this.
So we want to make sure that they're getting enough zinc.
And then people that are considered low income or maybe
in developing countries, poorer populations because they can't
afford the foods that are rich in zinc,
those meats and different kinds of protein sources.
You can also have too much zinc.
So as much as those zinc lozenges
make your throat feel better, you
want to be careful not to overuse them.
And they tend to taste kind of good
and they make you feel better, so you use them
for several days beyond what's recommended.
You want to be pretty careful with that
because when we get into a situation
where there's too much zinc, we can actually
block the absorption of other metals.
I mentioned that we had iron and zinc
and that they were what we call divalent metals.
We can also see that with copper.
Copper kind of falls into this classification.
And what happens is there's too much zinc in the system
and it doesn't allow that iron and these other metals
to be absorbed in appropriate amounts.
So you're going to see some kind of fluctuation
in normal levels of these metals.
Now I also said that zinc and iron
tend to be found in the same foods.
And that can be somewhat helpful to people,
especially if you're eating a vegetarian diet.
Again, vegetarian diets don't have to be low in these metals,
but we see that for folks who are
kind of having an unplanned or poorly planned vegetarian diet,
that's a consequence.
So it's about making strategic choices in the diet.
You can also use a lot of fortified foods.
When you look at a lot of soy proteins now,
they're actually adding a lot of these minerals to them.
Things like soy milk.
And then also ready to eat cereals
can be a good source as well.
Let's turn our attention to selenium now.
And this a little bit different when we look at our minerals
because this is an antioxidant mineral,
which is really nice because we have two of these.
We have zinc.
It acts as an antioxidant.
And then we have selenium.
And the role here really is the same
as our antioxidant vitamins.
So we talked about A, C, and E. So the job of an antioxidant
is to disable those free radicals that
would cause cellular damage.
We also see a role for selenium in activating thyroid hormone.
So it's going to help to maintain normal metabolic rate
and functioning.
There are lots of different sources of selenium.
We don't really have to worry about it too much in our diet.
Shellfish and meat are very good sources.
Also Brazil nuts are a good source.
About 1/3 of a cup is a serving and you
can have that a few times a week and that's a good choice.
You could also find it in different kinds
of agricultural products that are
grown on selenium rich soil.
So that can be grains, that can be vegetables, and even fruits.
It naturally makes its way into those.
In terms of toxicity, we can see toxicity
with long term supplementation.
Sometimes people hear that some of these antioxidants
are good for them and so they take supplements
and they tend to take these supplements in higher doses
than are recommended.
So if you look at our upper tolerable limit,
we see that it's set at 400 micrograms.
This is a very, very small amount.
We're looking at just a tiny, tiny bit.
So outside of this, RDA in this upper limit is not recommended.
It won't make you healthier.
It can actually start to cause some problems.
Let's look at fluoride.
Now fluoride is little bit different
because we've talked about these essential minerals.
When we look at fluoride, it's not considered essential.
It's considered to be a healthful choice,
but it's not something that's absolutely
required for normal human functioning.
You've probably heard about fluoride quite a bit.
We use it in toothpaste and things like this.
So its primary role is to help prevent
cavities or dental carries, we call them.
And they are different kinds of sources that we might use.
So fluoridated drinking water is probably the number one source.
And we see about 65% of the population
has access to fluoridated water.
Not in every location is this going to be available.
And certainly we see this trend for increased use
of bottled water.
And bottled water by and large probably 99% of it
does not contain fluoride.
So for populations that are relying on bottled water,
it might, especially when children are involved,
it might be a little clue to us that we
need to seek out another source.
You can also use fluoride tablets.
And these are prescribed by the physician, by pediatrician,
and they're usually administered up until the age of about five
with children.
Toothpaste also contains fluoride.
And if children are first learning to brush their teeth,
they're not very good at spitting,
so they actually swallow some of that.
So that can be another place that they're
getting some of the fluoride.
It does naturally occur in the food supply,
but in very, very tiny amounts.
It's in different kinds of ocean products.
So seafood and seaweed and things like this.
If we look at deficiency with this, what we're really seeing
is that an increased risk of dental cavities.
So again, it's going to be widespread in the population.
There are other kinds of practices
that are going to reduce risk of poor dental health
just as much.
So brushing teeth and things like this, good oral hygiene.
Fluoridation, I just want to have a quick note about that.
Because there's a lot of controversy about
whether or not communities should fluoridate their water.
And even when they fluoridate their water,
sometimes people choose to drink bottled water or spring
water because they're nervous about that chemical being
in the water supply.
It's a very, very practical and safe choice for communities
and it's cost effective.
If you consider that for low income populations
and many, many populations that aren't considered
at poverty level in the US, they don't have access
to good dental care.
On the average low income child doesn't visit the dentist
until they're 12 years old.
So from a public health perspective,
we really, really want to provide fluoride in this way.
And there's absolutely no evidence linking fluoride
at this level of supplementation in the water with cancer.
Now, if someone was taking huge fluoride supplements,
that may cause problems and adverse health effects.
But in terms of fluoridated water,
it's a very, very good choice.
With toxicity we do see some results
that are particularly sad, in a way.
So one of the things that we see,
you can look at this picture here, we see a child.
There's some kind of brown spots on the teeth.
This is an indication of toxicity.
This is something called fluorosis.
And what's happened here is that maybe this child
has been given fluoride tablets from the pediatrician
or has had a lot of toothpaste exposure
and maybe has access to fluoridated water.
For most folks that are experiencing
a little bit of toxicity, it doesn't get to this point.
Instead they might have a few characteristic white spots
on their teeth.
And this is quite common, really, and very,
very harmless.
It doesn't really affect the health of the tooth.
It's just more of the appearance of it.
We're going to talk a little bit about chromium.
And you've never heard of chromium.
Maybe you've heard of chrome if you really like your car,
you have an old car that you're restoring.
Chromium is really important when
we start looking at the way that our body handles
insulin and glucose.
It's widespread in the diet.
So we don't have to worry too much about seeking it out.
It's in naturally whole foods.
It naturally occurs.
So it's in meat products and whole grains, nuts, cheeses.
So if you're eating a fairly well rounded diet and not
all completely processed food, you
shouldn't have any problem with it.
Where we do see a potential problem
is with folks who are relying on a lot of simple carbohydrates
and highly refined grains and not very many whole foods.
They may be lower in chromium.
As I said, the function here really
is that it's going to help us to regulate and handle
glucose and insulin.
It makes that insulin action a little bit more efficient.
When people are low in chromium though,
you can see kind of a shift in diabetic condition.
So it might be a little bit worse.
So supplements for someone who's low in chromium
are going to be helpful to restore their normal balance.
But beyond that, chromium supplements
aren't going to cure diabetes and they
aren't going to reverse the condition in any way.
So you only really need as much as you need.
And unfortunately, Harvard has done
a lot of studies in this area and found
it to be really ineffective in terms of supplementation
beyond normal RDA levels.
And one of the other concerns I have
in particular about chromium, sometimes bodybuilders
will be using this.
They've heard that it might reduce body fat
or increase lean muscle mass and that's not true.
There are concerns with supplement use and toxicity,
so people need to be very, very careful with that.
So when I mentioned toxicity, we're
more often going to see toxic situations resulting
from industrial processes or industrial exposures.
Because chromium is a carcinogen.
One of the things that I'll just note here
is that with supplements sometimes
you can see dermatitis and different kinds of acne
and just really poor skin health.
This is kind of an indicator that
for an athlete who has this physical presentation that they
may be taking chromium supplements beyond their RDA.
But we also see these kinds of problems
in athletes who are taking anabolic steroids
and other kinds of substances to increase performance
or increase muscle mass.
So just a couple of cautions there
for folks who are bodybuilders.
So those are our trace minerals.