This week, you've learned about the Minerals in your diet.
As I've mentioned, minerals are very simple substances.
They're just what you find on the periodic table of elements.
These are inorganic substances unlike our other nutrients: vitamins, carbohydrates,
fats. And proteins.
They can be broken down into the major or macro-minerals.
These are minerals we need in quantities over 100 milligrams a day; or the the
trace or micro-minerals, and those we need less than 100 milligrams per day.
We'll also have how to choose minerals. We won't be covering those in this
course. Minerals are effected by bio-availability
as you read through your text and some of the links I'm going to provide, think
bout what foods effect the bio-availability of our minerals.
Minerals need to be absorbed in their simplist form.
So anything that binds to a mineral, making it more of a compound will impair
the capacity for the body to absorb that mineral.
Minerals because they're made in such low quantities are potentially toxic and we
do store minerals so we can see problems if we consume too much.
In, in extreme circumstances we might see toxicity happening in normal food intake,
but typically when we see toxicity, that's due to supplementation.
I'm going to classify the minerals as either electrolytes, mineralizing mineral
oil, or trace minerals. Electrolytes are very important in fluid
balance, muscle contraction, conduction and transmission of nerve impulses, in
the case of hydrochloric acid, chlorides very important in that synthesis,
hydrochloric acid is made of chloride and hydrochloric acid's important for
digestion as well as immune response in the body.
We can review these electrolytes. Certainly most of us likely get enough
sodium in our diets. Sodium, sodium is primarily found in the
extra cellular structures. On the next slide we'll, few slides we'll
talk about what that means and where we see that.
While potassium is primarily intracellular.
Magnesium also primarily inter-cellular. Phosphate, again, intracellular.
As we think about where these electrolytes are we can understand how
they work together. To balance fluids and also to balance
other processes. When think about 2 major electrolytes
Sodium, Potassium. One topic I'd like to discuss in this
brief overview of the minerals. the effects of food processing on mineral
continent of food. To mention most of us get plenty of
sodium in the diet, and if you eat more processed foods, this is more so true.
Potassium however, might be lower in the diet of someone consuming significant
amounts of processed foods. This is because processing typically adds
sodium and removes potassium. Still, our nice, fresh milk turned into
Jell-o adds salt and removes Potassium. Same thing with meats, vegetables,
fruits, and grain products. Your food label is the best place to find
out how much Sodium is in your food, if you are trying to manage, if you are
trying to manage the Sodium in your diet. When we are referring to minerals, we
can't ignore water. Very crucial substance in the body.
It is the most abundant component in our body.
99 pounds of water in a 160 pound man. It makes up 62% of our body, and we can
go for only 3 to 10 days without water. We get water from what we eat and drink,
but also from metabolic processes. Water's important for maintaining these
metabolic processes, regulating body temperature, lubricating body systems and
organs, and it's part of our blood. And body tissues.
It's also essential in waste removal. We talked a little bit about digestion
and absorption and when we see constipation or diarrhea, this can be due
to either too much water in the bowel or too little.
If we look specifically at how much water we're getting from different components.
Most of our water which would probably make sense comes from beverages.
It does not have to be just plain water, we get water from everything we drink,
about 75 to 85% of our total intake. Our food does supply 22 up to 25%.
Different foods obviously having different water content.
Metabolic water is the smallest, and at only 250 to 350 mL per day.
As far as removal of water, the primary removal method, of course, is urine.
That makes sense, but there is, obviously, also water in our feces.
In our respiration and in sweat. So we think about managing water balance
if you are losing more water, if you are eating more, this might happen when you
drink caffeine for example, if you're sweating more out on a hot day, if you
have diarrhea, and are losing more water in your feces, when this happens we want
to respond by drinking more water. And we do have thirst mechanisms, that
help try to make sure that our brains tel us to do just that.
Then we are human beings, and we can't make decisions on the contrary, but not
without significant repercussion. So this water, this all important water
is primarily in the intestinal fluid. Fluid but we do have water in the
intravascular compartments as well as intricately that's between the cells, and
as I mentioned different electrolytes different minerals are found in different
body compartments. Keeping the water where it belongs is an
important role for both electrolytes and protein.
In our protein lecture we talked a little bit about the consequences of a low
protein status, and edema can result when the protein isn't there to help keep the
water in the vascular system. One way that we regulate where this water
should be, how much water comes in and how much water goes out, and our brain
telling us we're thirsty, is through the Angiotensin system and the Renin system.
This involves both the functions of our kidneys and our brains.
And influences various body organs and systems.
Take a moment to review this slide. Think about what's happening.
So, you are outside on a hot day. It's a good example of quick heat
dehydration. Perhaps you're in a very dry environment
where the air. Is going to remove more water from you
quickly. If it's humid outside, if there's a lot
of water in the air, you're actually going to lose water less rapidly.
So it's a hot day, we're out in the middle of a very dry environment, we're
losing water through respiration and through sweat, even if you don't feel
that sweat. It may be drying immediately and you may
not feel the sweat coming off your body, but you are losing water.
Here. As you lose this water, the volume of
your blood will actually decrease. This will simultaneously increase the
concentration of salt in your blood. In the brain the hypothalamus detects
this increase in salt concentration. And it will stimulate the pituitary
gland. The pituitary gland then releases
antidiuretic hormone, which signals our kidneys to retain sodium and water,
helping us keep, helping keep us from losing too much more water.
Now, this isn't just important for overall dehydration, but it's also
important for maintaining appropriate blood volume and pressure.
The kidneys detect that we have reduced blood flow as the water content produces
and releases renin. The control of our body fluids of the
water in our bodies and blood pressure is very important, and it happens on a
hormonal level. Both the kidneys and the brain work
together to regulate body water and blood flow.
The kidneys respond to decreased blood pressure by reducing, by releasing the
enzyme renin. Renin then activates Angiotensin, which
signals our adrenal glands to secrete Aldosterone.
This hormone then goes back to signaling the kidney to retain sodium and water,
thus increasing blood volume. In addition Angiotensin signals the blood
vessels themselves to constrict, raising blood pressure.
The brain is actually responding to increases in salt concentration, because
the volume of our blood's gone down. It stimulates pituary gland to release
antidiuretic hormone which acts like aldosterone in helping the retention of
sodium and water and thus increasing blood volume.
The details of the Renin Angiotensin system are very important on the side of
increasing blood pressure quickly the ways of constrictive power of angio
tension is important Within 20 minutes of dehydration, within 20 minutes of
dehydration, our blood vessels will constrict to ensure blood pressure is
maintained. This is essential for maintaining our
Cardiovascular System. Long term, we see the effect of hormonal
changes effecting the retention of salt and water.
The maintenance of body water is very important because as dehydration can be
deadly. Dehydration occurs when our intake is
smaller than our loss. While everyone can be dehydrated certain
groups are at a greater risk. This includes infants who might suffer
from more nausea, vomitting, and diarrhea.
Also they're more susceptible or more effected by dehydration.
Older adults are also at higher risk for becoming dehydrated as well as
individuals engaged in athletics. If you are not maintaining your water
intake while you are playing a sport You may become dehydrated.
In athletics it's also important to balance out the water loss with the
electrolyte loss. The other side of dehydration is
hyponatremia, and this can happen when we drink too much water.
So while it's very, very important to manage your water intake When we are
working out or playing sports, we don't want to consume too much.
We don't want to take in more than our kidneys can handle.
When we do still, we'll actually see an electrolyte imbalance and this too can be
deadly. Believe it or not, you can kill yourself
by drinking too much water. Finally, hot environments, especially hot
dry environments, make one more susceptible to dehydration.
So how much water do we need to drink anyway? it's been said we need to eat,
drink, 8, 8 glasses. It's been said we need to drink 8 8 ounce glasses a day.
Well, is that true? Mostly, you should be guided by thirst.
Now once you're thirsty you are already becoming dehydrated, remember the
Angiotensin System? Well, thirst is part of this entire system.
As blood volume decreases and these processes are invoked, you will become
thirsty. Now, yes, once you're thirsty, you're
already a little bit dehydrated but that doesn't mean that you need to continually
drink before you get thirsty. As long as you respond to thirst quickly,
you are not going to become further dehydrated.
Don't forget that you do get water from beverages and food, so if you are in a
hot, dry environment. Making sure that you're drinking enough.
And maybe eating higher water content foods.
getting these together to make sure that you stay hydrated.
On average, women need about 2,700 milliliters of water a day, while men
need 3,000. 700 milliliters.
On to the next group of minerals. Our bone minerals.
Our mineralizing minerals. Calcium, Phosphorous and magnesium are
very important in bone health. You'll get the opportunity to read more
about each of these in your texts, as well as going through some links that I"m
going to provide, from the Office of Dietary Components.
But I'd like to just talk a little bit about the regulation of calcium in our
body. This is very important because it happens
in a way that you might not think. Even though we obviously want to keep
minerals in our bones, to keep healthy, healthy, strong bones, it's not regulated
at the bone level. Calcium is actually regulated at the
blood level. Calcium's also very important in blood
for maintaining processes. It's an important electrolyte.
And, so, maintaining blood calcium is going to outweigh maintaining bone
calcium. Let's think a little bit about what that
means. If we don't consume enough calcium, blood
levels will drop, and our body will want to increase them.
It will do so by taking calcium from the bone.
It will also respond by absorbing more calcium With the calcium that you do get
in your diet, removing some from tissues as well as removing some from the
kidneys. Before things go out of the kidney to
produce urine, we do still have a chance to reabsorb nutrients, including calcium.
So the kidneys, like the liver, are very important to good nutrition.
Individuals in kidney failure have significant consequences of nutritional
health. And one area where you'll see dieticians
playing a vital role is in renal treatment.
All right. So do refer to your text to understand
the details of the regulation happening here, but basically, just keep in mind
that we're controlling body calcium at the blood level.
If this means removing more from the bone This will occur.
We will upper, of regulate how much we consume, we are absorbing, but we still
may take it from the bone. We continue to remove calcium from bone
over our life time. We can develop osteoporosis.
When we look at bone development age matters, when we were very young we are
actually growing bones. The osteopaths and the osteoclads, the 2
types of cells responsible for bone growth and turn over act in different
ribs in different ages So during growth, up until in our twenties, we have active
growth. In our late teens to mid-thirties, we
reach peak bone mass. So about up until you're 18, you're
accruing bone, and then from your late teens to your mid-year life years, you're
maintaining bone. Thereafter, you actually start to have
bone loss. So if we think about calcium intake, for
the purposes of maintaining solid, strong, healthy bones, we have different
strategies over our lifetime. When we're young, we want to get our
bones as strong as possible. Which means, eating calcium rich foods.
As we get older, we want to maintain that mass.
So we still want to eat calcium rich foods.
And then as we're getting older, we want to minimize the amount of bone we loose,
by again still eating calcium rich foods. Trace minerals include iron, zinc,
selenium, magnesium, fluoride and copper. in this introductory lecture, I'm going
to only review some key elements of Iron and Zinc.
But I have supplied links at the end of this lecture to some very informative
articles from the Office of Dietary Supplements on trace minerals.
Iron is the most abundant mineral in the Earth's crust.
It's a crucial. Mineral for the transport of oxygen
throughout our body. And the transport of oxygen exists in a
form of hemoglobin and myoglobin. This concept of hemoglobin's actually
very important when we're identifying types of dietary iron.
So, iron in the human body, as I just mentioned, can be in the form of
hemoglobin, and that is, goes the same for the livestock that we consume.
So iron that's obtained from meats for example, is termed heme iron, and iron is
obtained from plants and eggs and cheese is non-heme iron.
Right so, if we think about hemoglobin as being in the human body.
We can parallel that hemoglobin is also in livestock.
Hemoglobin and Myoglobin do the same job in animals as they do in us.
So when we're trying to eat iron, the iron that we get from meat is heme iron
and the iron that we get from non meat sources Is non-heme iron.
There's some differences between this and this can be important if you're a
vegetarian. Especially if you're a vegetarian female
who has significant blood loss on a regular basis.
The main way that we actually lose body iron is through regular blood loss.
Non-heme iron means less absorbable, less available than heme.
And it's also affected by other food components, such as fiber and phytates.
The Iron will be bound by fiber and phytates, and decrease the amount that we
are able to absorb. Heme iron is not affected by this.
On the flip side, non-heme iron is also affected by ascorbic acid.
Ascorbic acid when we're drinking orange juice with an iron containing food will
actually boost non heme iron absorption. But it won't affect heme iron.
Lastly, you can also obtain some non heme iron through an iron skillet.
So cooking with an iron skillet will increase your amount of Iron intake.
Zinc. Zinc is also a very important trace
mineral. You probably heard a lot about Zinc in
it's relationship to the immune system, and it's often marketed as being a cure
for the common cold. And while it is very important in
immunilogical processes, it's not exactly a cure.
And we have a little project for you. to do and look at why that's true, what
Zinc's role really is in the immune system, relative to why again, it's not a
cure for the common cold. Zinc's another mineral that we primarily
only get from eat sources, we do The zinc can be affected by other things in our
foods, by phytates for example. And so vegetarians may be more
susceptible to developing insufficiencies in zinc.
Again, not only are they getting less zinc because they're not eating meat, but
also the zinc that they are getting Is going to be effected by these other
compounds. Actually, the deterients sometime require
as much as 50% more of the RDA for zinc because of this.
They also might actually benefit from food preparation techniques that reduce
the bonding of Zinc by phytate. Making it more bio available.
You can do this by soaking beans or grains and seeds in water several hours
before cooking them, then letting them sit after soaking until sprouts form.
You can then make been sprouts. This is 1 food that vegetarians use,
sometimes consume and it is a way to get more zinc from those foods.
Other foods that can provide more zinc for vegetarians are leavened grain
products versus unleavened products. the leavening actually breaks down parts
of the phytates and thus makes the Zinc more bio-available.
Down here I've listed the link, as previously I've also listed a link, for
more information about these amazing little trace minerals.
The absorption of Iron and Zinc is unique and very interesting.
The links that I have provided here are helpful in that they show you animations
on the processes of zinc and iron absorption.
Put simply, both Iron and Zinc actually have an additional storage site, your
intersite, your gut cell. When you eat foods with Iron and Zinc,
break them down, you free the iron and zinc and these minerals then enter the
gut cells. Then they can actually be stored in the
gut cell until you need them in the body. Over time, when you lose those gut cells
through sloughing off, of course, you also lose the Iron and Zinc.
So, someone who has a lot of gastrointenstinal upset and has more
sloughing of these cells, actually loses more Iron and Zinc than someone with a
healthy gut. Please go to these animations to see
first hand how these processes occur. Lastly, because these a complex concepts,
there's a lot of information about your minerals.
Go ahead and visit the Office of Dietary Supplements in addition to your reading
to learn more about these nutrients. Please note that I've actually provided
you two links for health professionals rather than for consumers.