Nutrition and Digestion

The C (Carbon) then grabs hold of the HOH to make HCOH - this is a hydrated carbon (drinking water makes you hydrated). A hydrated carbon is also known as a Carbohydrate.

The plant will link 6 of these HCOH's together to make Glucose. The Simplest of the Sugars.

This process 'captures' carbon from the atmosphere.

The Glucose can be stuck together into huge chains called Starch

If these chains have side branches (like a christmas tree) then you have a very complex carbohydrate that humans cannot digest called cellulose (cellulose is used to make the strong parts of plants (cell walls)). It is cellulose that crunches when you snap a fresh carrot

Plants are amazing. They can take glucose and use it's hydrogens, oxygens and most importantly, its carbons to make amino acids (the building blocks of proteins)

These carbons are super important. We are 60-70% water, the rest of our body is carbon based molecules. Indeed, we are carbon-based life-forms

Mr Cowley Talks Number 1 and 2 combined

Steak and Chips

Chicken and Rice

Plants make Everything

Thanks Jason and Ivan MHJC '19

From this Glucose (sugar) Plants can then make everything! (including amino acids for our proteins)

People and Potatoes

What is a Person?

If we take a person we see that they are roughly 65% water. The stuff that isn't water is mostly Fat, 15%, and Protein, 15%.

65% water - the water does, well, nothing really. It just allows movement in the body. But you need it, otherwise the movement inside your cells stops

1% carbohydrates - the energy use use when you do a short fast sprint

4% minerals - salt in your sweat and calcium phosphate in your bones

15% Fat - that is a long term store of energy, and also cushions your organs (and your bum, imagine sitting down with no fat on your bum!). This is the energy you use when you go for a long run or a very long walk

15% Protein - that is where the life is! Proteins are super important. Anything that does anything in the human body is protein. For you to walk, your muscles contract - inside your muscles proteins are moving, allowing the muscles to move.

Mr Cowley Talks Number 3

What is a Potato?

If we take a potato, we see that they are 77% Water. The stuff that isn't water is mostly Carbohydrates!

77% Water - this 'fill's' up the potatoe, giving it structure. It allows molecules to move in the cells of the potato. And importantly, the plant will use it to make Glucose!

20% Carbohydrates - these provide the structure for the cells of the potato - it also provides energy

2% Proteins - these are the enzymes that do things inside the cells of the potato. Just like in people, it is the proteins that do stuff. Its the Proteins that turn this into life!

0.1% Fat - store of energy, especially in plant seeds

Compare the Person and the Potato

What do you Notice?
Why is that important for what a Person does, compared with what a Potato does?
What could that mean for our diets?

Evolution

Early in our Evolution, we ate a lot of Plants.

The problem with eating uncooked plants is that you need to eat a lot of if. In fact, if it is uncooked you need to spend most of your day eating, like all herbivores.

This is so that you can get enough protein to meet your protein requirements

Our ancestors took opportunities when it came to their food - If they could get meat they would

Meat is high in protein, and the fat has lots of energy. So, like a Lion and other carnivores, when early humans were able to get meat, they wouldn't need to eat as much.

This ability to eat both plants and meat made us Omnivores

Watch the video to the right about why we cook :-)

Power Media Player 2020-04-01 09-11-42.mp4

The Nutrients

Mr Cowley Talks Number 4

Carbohydrates

(Carbons that have water stuck on them)

Simple Carbohydrates

Glucose
aka sugar
This is made through photosynthesis
These can move straight from the food, through the wall of your small intestine into your blood.
If you drink the sugar, like in a fizzy drink, then you don't need to digest the sugar, it will move straight through the wall of your small intestine into your blood, giving you a 'blood-sugar' spike

Complex Carbohydrates

Starch
Starch has heaps of glucose molecules stuck together in a long chain
Starch is too big to move from the small intestine into the bloodstream, it needs chemical digestion to occur first
The digestive enzyme, amylase (found in Saliva and in the Small Intestine) will cut Starch into its small glucose bits. These glucose molecules can then enter through the wall of the small intestine into the blood stream. However, this process takes time. So foods that are rich in starch are better for your blood sugar levels (and thus your pancreas) than foods that are rich in sugar. And this is why we eat potato or rice instead of chocolate for dinner.
Fiber
Fiber has heaps of glucose molecules stuck together in a different way than in starch. This makes it too hard for our digestive system to break it down. So, fiber just moves from the food, through the digestive system, to the rectum and then into the loo
Because of this, Fiber is also called roughage
Fiber is really good for our health because
- It fills us up, so we don't need to eat too many calories
- It cleans the intestines
- It stops us from having high blood sugar spikes.

Blood Sugar graph and Fiber

As you can see below, the Lowest spikes are for the foods highest in Fibre

Black Beans
Lentils

Blood sugar

The body uses Insulin and Glucagon to maintain a steady blood sugar level of about 1 gram of glucose per litre of blood (100mg/dL) when fasting (not eaten in over 8 hours)
The food eaten impacts the level of blood sugar
The higher the blood sugar level, the more Insulin the pancreas has to make to return it to normal

Blood Sugar Graphs

The graph below compares blood sugar for several foods. The glucose drink is much the same as a can of Coke

Fats (Lipids)

Carbohydrates contain lots of energy. If you feel tired, you might eat a small piece of chocolate and then you will feel re-energized.

But there is a problem with carbohydrates. One that you already know

When you make a hot milo, you stir it, then dip your spoon back into the sugar pot, what happens to the sugar?

It becomes clumpy. This is because Carbohydrates attract water. So if you were to store lots of carbohydrates, you would be like an orange or a tomato, very watery.

Now, what happens if you pour melted butter onto water? It'll float on top. Fat and water do not mix, it is the opposite of carbohydrates.

Because of this, you can store a lot more Fat in a cell than you can carbohydrates. So this is what animals do!

If you eat too much chocolate and have too much sugar in your Milo, your body will turn all this excess Sugar into Fat!

It does this because it does not know that we have supermarkets, it thinks that you have to hunt for your food, and so you need to store any excess as fat in case you don't find any food for a few days.

Look at the atoms in the Fat - Carbon, Oxygen and Hydrogen... The same as that in Sugar!! This is why sugar can be turned into fat by your body!

Proteins

Proteins are the interesting guys - they do stuff!

Have a look at the videos. In the Inner Life of the Cell, the strange thing walking is a Motor Protein - its a protein

For a more complex video, try the muscle contraction... the myosin heads, and the actin filaments are both Proteins. The muscle is full of protein, this is why we eat the muscles of other animals

Proteins are made from Amino Acids.

Amino acids are like Lego blocks

There are 20 types of Amino Acids - like 20 types of Lego Blocks

The arrangement of these Amino Acids determine the shape of the Protein, and thus the function of the protein

Just like how the arrangement of Lego Blocks determines the shape of the Lego Structure and thus its function

Plants can make all 20 amino acids. When a Cow eats the grass the amino acids in the grass becomes part of the Cow's muscles. When the Human eats the Cow's muscles (steak) the amino acids become part of the Human.

The image below shows most of the Amino acids that plants can make. Notice that Glucose is at the top of the image. This is because the creation of Glucose during photosynthesis is how Carbon gets into these living systems. And everything else is made out of the carbon.

Proteins and Amino acids

By Ivan and Jason

The Video below was made by two of my students. Watch it :-) It explains the relationship between Amino Acids and Proteins

Vitamins

Plants also make Vitamins!

Think of Scurvy - sailors in the 'old days' were out at sea for months. With no fruits or vegetables to eat, their teeth would start to fall out!! This is scurvy, and it is caused by a lack of Vitamin C!!

You'll never guess what plants use to make Vitamin C (aka Ascorbic Acid) ? ?

You guessed it!! ..... Glucose.

In fact, plants can make all of the Vitamins. In the diagram below you can see tall the different Vitamins that a plant can make. (Hexose-P pool is Glucose)

Minerals

Unlike all the other nutrients, minerals are NOT made.

Minerals are elements (on the Periodic Table) that come from the earth.

The mineral Sodium Chloride is salt - It comes from the ocean. Our bodies use it to make our nerves and neurons work.

Companies make lakes of sea water, dam it, let it dry out over a couple of years, and then collect up all the salt and put it into containers and sell it to you to put on your chips.

The mineral Calcium, that is used in our bodies for our bones, comes from rocks and is found in the soil. Plants absorb the Calcium from the soil, then the sheep eats the plants and we eat the sheep, then we have the calcium.

The mineral Iron, that is used to hold oxygen in our blood and in our muscles also comes from the soil. Plants absorb the iron through their roots, then the sheep eats the plants, then we eat the sheep, then we have the iron

You'll be surprised, but most of our minerals come from plants (the rest from the ocean) :-)

Balanced Diet

So, how do we ensure that we have a balance of nutrients? And what do we mean by balance?

Well, we need to eat everything - but it is how much of each thing

If we eat a lot of Carbohydrates, out body will turn it to Fat

If we eat a lot of sweet foods with simple Carbohydrates, we increase our chances of developing diabetes

Our best bet is to eat a lot of plants!

So, vegetables, nuts and Fruits.

Lots of leafy greens and raw fruits and vegetables

Mr Cowley Talks Number 5

Importance of a balanced Diet

Excessive Nutrition

Many countries now have abundant food supplies.

Because of this, we can eat as much as we want, when ever we want.

Animals, humans included, love sugar.

Because we can eat all the sugar we want, we could. But his can have consequences.

If we eat a lot of sugar, our pancreas needs to make a lot of Insulin.

If we keep making lot's of insulin, the pancreas will get 'tired'. Some of its Insulin producing cells will die. When enough of these cells have died, the pancreas will no longer make enough insulin to get the glucose into the cells. The person now has Diabetes.

The video below The Domain of Proteins, by Jason and Ivan, explains the role of the Pancreas and Insulin in getting Sugar into your cells.

It is an excellent video, I recommend watching it :-)

Ivan and Jason, MHJC class of 2019

Malnutrition

Famines and starvation cause a disease called Kwashiorkor disease. This is when the mothers milk and the solids that the child eats contains insufficient protein. Because of this the child's muscles cannot develop. The child's growth is stunted.

Lets explain it another way.

If a person dies you can ... yum... eat them.. as can be seen in the movie 'The heart of the Sea'

You can eat them because they are made of water, protein and fat

In the body water does... well nothing

Fat it does well... not much

The thing that does everything is protein!!!

So to make your muscles and everything else that does stuff in your body you need protein

But in the time of famine - when there is very little food - then the kids can't eat meat or protein rich food

So they cant make the parts of their body which needs protein

Which is why they have no muscle

There belly's swell as their ab's haven't developed

Any protein that they get goes straight to their brain and the organs in their torso

Its a horrible way to die ... which is why it is important to donate to organizations that reduce starvation .

Treatment for Kwashiorkor

In order:

Give Water = hydration - as they will also be dehydrated
Give Carbohydrates = their body's have been burning protein as there is no carbohydrates to eat
Give Protein = Rebuild the muscle

Digestion

Teeth

There are 3 main types of teeth.

Incisors - these are the front teeth. They cut.

Canines - these are pointy teeth. They stab and are used for tearing meat

Molars - (and pre-molars) - these are big flat teeth. They are used for mashing.

You can tell what an animal eats by looking at its teeth

My Dog likes meat - you can tell by his big canine teeth (his incisors are pointy and sharp, as are his molars)

Horses don't eat meat, they eat grass. So they have big incisors and molars, but don't have Canine's

Mr Cowley Talks Number 6

The Tooth

Our Teeth have 3 main parts.

Enamel

This is very hard
It is the hardest substance in the human body and is 96% Calcium Phosphate
It can be damaged by acid
it is the only part of the tooth exposed in the mouth

Dentin

this is layer is also hard, but can flex
It is 70% Calcium Phosphate and the rest collagen (like your nose and ears)
Calcium Phosphate is found in milk

This structure makes the tooth kind of like reinforced concrete, which has the hard concrete on the outside and the flexible metal beams on the inside

Pulp

this layer contains the blood vessels that supply oxygen and nutrients to the cells contained in the Dentin and the Enamel
this layer also contain nerves that will signal if too much pressure is being applied to the tooth, and will also signal if the tooth is severely damaged

A few other things

The part of the tooth that you can see is called the crown

The part hidden by the gums. The gums are also called the gingiva

The Tooth is held in the Jaw bone by Cementum

Cementum is 50% Calcium Phosphate and the rest collagen.

The bit of the tooth below the gum is called the Root

Tooth Decay

Bacteria feed off sugar.
As they do this they make acid
The acid dissolves the enamel
This leads to a cavity

......So... brush and floss your teeth

Digesting Digestion

Mr Cowley Talks Number 7

Once we've chewed our food with our teeth, and mixed it with Saliva creating a bolus, whats next?

Ingestion

putting food into your mouth

Digestion

Teeth (Incisors, Canines, Molars)
Saliva
Peristalsis in the esophagus
1. With the Epiglottis moving to close the trachea and open esophagus
Stomach with its acid
Digestive enzymes
1. Amylase in the saliva
2. Pepsin in the Stomach
3. Lipase in the Small intestine from Bile
Small intestine neutralization of the Stomach acid - using Bicarbonate from the Pancreas

Absorption

Small Intestine
1. 6 meters long
2. Covered in Villi - increases surface area to that of a tennis court
3. Place where amino acids, sugars and fats are absorbed
Large Intestine
1. Bacteria help to release vitamins from the food for absorption
2. Water is absorption

Egestion

Waste stored in Rectum
Exits through anus (Defecation)

Mr Cowley Talks Number 9

Digestive Enzymes = Chemical Digestion

Digestive enzymes cut bit molecules into the small molecules

Absorption

The small intestine is covered in tiny finger like projections called Villi

These increase the surface are of the surface of the small intestine - like the bristles on your toothbrush

Mr Cowley Talks Number 8

Liver

Once the nutrients move from the small intestine, through the villi and into the blood stream, they go to the Liver.

All of the blood from the Intestine goes to the Liver for processing.

The liver's jobs

Any toxins in the food are removed (from bacteria or man-made)
Sugar can be stored as glycogen and glycogen can be turned back into sugar
Old blood cells are broken down and some of their components used to make bile
Sugar can be turned into Fat
Fats can be turned into sugar
Amino acids (protein) can be turned into sugar
Amino acids (protein) can be turned into Fat
The liver can turn some amino acids, into other amino acids

So the liver removes toxins from the blood, and then it assesses nutrient input and checks with nutrient levels in the blood and will convert some nutrients into others to meet the demand of the body

That's pretty amazing! That's why its the biggest organ in the body!

Watch the Ted-Ed "How does the liver work" clip, then watch it again! It's really good.