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The prolonged coronavirus pandemic has once again put Vitamin C in the spotlight for its endless health benefits.

Japanese researchers have recently found that vitamin C has anti-aging effects, such as preventing dementia, as well as strengthening bones and preserving muscle mass.

And today we're going to look at vitamin C and its amazing benefits for both health and longevity.

In Japan, around one-third of the population is age 65 or over.

Exercise classes are offered across the country to help these seniors stay healthy.

I'm 80. I come here to gain muscle.

I'm 78. I am working hard here so that
I can keep doing my favorite sport.

One of the keys to staying healthy is keeping bones strong.

Japanese researchers have found that vitamin C has a major impact on the bones.

This X-ray image is from an experiment by a Japanese research team.

It shows a mouse that is deficient in vitamin C.

Its spine is brittle and curved significantly.

Compared with a healthy mouse of the same age, the difference is obvious.

The vitamin-C-deficient mouse also has a broken thigh bone.

Its bones grew so brittle that it couldn't withstand the pressure from walking.

Details of the functions of vitamin C are a mystery.

But in recent years, Japanese researchers have been uncovering previously unknown facts.

Nice to meet you.

Pleased to see you.

The mouse experiment was conducted by Ishigami Akihito, a leading vitamin C researcher.

He discovered the amazing power of the life-sustaining nutrient, while studying the mechanism of aging for many years.

Vitamin C is extremely important
for the human body.

A deficiency causes scurvy,
which can lead to death.

This is one of the reasons
vitamin C is essential.

Why does a vitamin C deficiency, why does it lead to brutal bones or, you know, basically, I guess, the early stages of osteoporosis?

When vitamin C is lacking,
we are unable to make collagen.

Collagen makes up 20% of regular bones
and 50 percent of cartilage.

In fact, there have been reports of
vitamin C deficiency affecting the bones.

Ishigami's team bred mice that are incapable of producing vitamin C.

These animals are playing a crucial role in experiments involving the nutrient.

The team published a paper on the special mice in a US science journal in 2006, which caused a sensation.

They have helped accelerate vitamin C research in Japan.

Humans cannot synthesize vitamin C, which is necessary for us to stay alive.

We sustain ourselves by getting vitamin C from food.

But many animals, including mice, dogs and cats, can produce vitamin C internally.

In a world's first, Ishigami discovered an enzyme necessary for producing the nutrient.

He used genetic engineering to develop mice that are unable to synthesize vitamin C.

An experiment by Ishigami has suggested that vitamin C has a major effect on lifespan.

The average lifespan of a mouse is said to be around two years.

In his experiment, Ishigami gave just enough vitamin C to sustain life to 20 mice incapable of producing it.

All of the normal mice survived for at least ten months.

The vitamin-C-deficient mice started to die in less than three months.

Half of the vitamin-C-deficient mice died in about six months.

That's a huge difference.

Pathological analyses found that the dead mice
were nearly free of the diseases that humans get, such as cancer and diabetes.

They died after their bodies deteriorated
due to old age, just like many long-living humans.

This confirmed that a long-term
vitamin C deficiency reduces the lifespan.

Vitamin C also plays an important role in maintaining the muscles.

Muscles make up 30 to 40 percent of body weight.

They're known to contain high levels of vitamin C.

Ishigami divided mice incapable of synthesizing vitamin C into two groups.

He gave one group a diet containing vitamin C, and the other a diet without the nutrient.

He then had them do the same exercise.

Four weeks later, muscle mass in the group not given vitamin C declined 17 to 25 percent.

The animals' grip strength and stamina also decreased.

That's fascinating, that link, because I think people would assume protein is responsible for preserving muscle mass with age.

But I think most people would not think of vitamin C.

What was really interesting was
that when we gave vitamin C to the mice that had been deprived
of it, their muscle mass recovered!

Really!? So you can have a deficiency, then, of vitamin C, add vitamin C, and it preserves the muscle mass?

I believe vitamin C prevents
muscles from deteriorating.

So how much vitamin C do you need daily to get that result?

Japan's health ministry recommends
100 milligrams a day.

You can get that amount by eating one-third of a red bell pepper, or two-thirds of a gold kiwifruit.

Then every aged care facility should be implementing a lot more, adding a lot more vitamin C, fresh vitamin C, through food with their meals.

Yes, then there might be fewer bed-ridden people.

Facilities for the elderly should
serve food high in vitamin C.

Vitamin C is believed to be closely associated, not just with the bones and muscles, but also the brain.

However, little is known about how it spreads through and affects the brain.

Scientists around the world have been studying this mystery for many years.

In January 2022, a Japanese research team published a paper in a US science journal about its discovery of a protein that transports vitamin C to the brain.

Takada Tappei conducted the experiment.

He studies effective drug-delivery mechanisms in the body.

We've found that the brain, lungs and liver
contain a relatively large amount of vitamin C.

Vitamin C is thought to play an
important role in the brain.

Learning how it functions there will help us
find the causes of brain diseases and prevent them.

When vitamin C enters the body, it is first sent to the liver.

It then enters the blood stream and spreads through the body.

Some of the vitamin C reaches the blood-cerebrospinal fluid barrier, at the center of the brain.

The barrier prevents unnecessary substances from entering the brain.

Vitamin C cannot surpass the barrier on its own.

Scientists presumed that there must be a substance that transports it to the cerebrospinal fluid, which is believed to provide the brain with nutrients.

The research team led by Takada managed to identify this transporter, which had been a mystery for many years.

It was a type of protein known as Glut12.

This image shows the brain of a mouse.

The Glut 12 appears red.

It is present in large amounts in the barrier at the center of the brain.

Takada compared vitamin C levels in the cerebrospinal fluid of two groups of mice.

One group consisted of normal mice; the other was made deficient of Glut12 through genetic engineering.

The vitamin C levels in the Glut12-deficient mice were only about 20 percent of those of normal mice.

I was very happy to solve
the long-standing mystery.

Takada also compared the weight of the mice's brains for any changes.

The brains of the Glut12-deficient mice were lighter than those of normal mice.

This seems to indicate that the brains of mice that had less Vitamin C actually got smaller.

And their hippocampuses were smaller than those of the control group.

This part of the brain is closely associated with memory.

Reports have suggested that vitamin C levels in
the blood and cerebrospinal fluid may be linked to the size and functioning of the brain.

Our studies have revealed low vitamin C levels
are related to a smaller brain.

This could lead to research that may help us
better understand the pathology of dementia and find a way to prevent it. We're excited.

Researchers are also studying the possible effects of vitamin C on COVID-19, which is still disrupting our lives.

When infectious diseases, such as COVID-19, worsen, sepsis can occur.

This is a life-threatening condition.

The body's immune system protects against pathogens that cause infectious diseases.

Sepsis occurs when the immune system overreacts, harming the organs and causing widespread inflammation.

A survey in 2017 showed that sepsis kills an estimated 11 million people a year worldwide.

This is more than the number of deaths caused by cancer.

Horio Fumihiko, who has been studying vitamin C for over 35 years, discovered that the nutrient could play a key role in preventing sepsis.

I found that vitamin C deficiency and
inflammation cause very similar conditions.

The conditions are also just like those caused
by sepsis, which is an inflammatory disorder.

Vitamin C curbs inflammation.

We should therefore take vitamin C
to reduce inflammation in the body.

A research team led by Horio conducted an experiment involving three groups of rats incapable of synthesizing vitamin C.

The team gave the first group a diet without vitamin C.

The second group was given a diet containing the daily required amount of vitamin C.

The last group was given a diet containing 10 times that amount of the nutrient.

After being fed for 8 days, all of the rats were given a substance that triggered sepsis.

The researchers then checked their survival rates.

The rats given no vitamin C began to die off.

Over 90 percent died within 20 hours of developing sepsis.

Their survival rate was 5.5 percent.

The survival rate for the rats given the daily necessary amount of vitamin C was about 40 percent.

The figure for the rats fed ten times that amount stood at about 60 percent.

Vitamin C has the potential to prevent
the damage caused by inflammation, as well as inflammatory diseases
such as sepsis if it is taken properly.

I am very hopeful that vitamin C will be used
to help overcome such damage and diseases.

Research is underway around the world on whether vitamin C can prevent severe COVID-19.

Several papers have been published
in the past 3 years or so on the relationship between vitamin C and COVID-19.

Some say vitamin C is effective against
COVID-19, while others say it isn't.

It's still hard to say for sure, but I believe
we'll see more studies that confirm its benefits.

To consume vitamin C efficiently, it's necessary to understand its characteristics.

Vitamin C is water-soluble.

It leaches out when food is boiled.

Soup is a good way to take in the nutrient.

It also tends to break down in heat.

It's best to avoid cooking food on high heat for long periods.

When a large dose of vitamin C is consumed, the excess passes through the body without being absorbed.

It is important to take it in small quantities frequently.

I recommend potatoes as a source of vitamin C.

They are readily available and contain
vitamin C that is resistant to heat.

You can get the nutrient easily and efficiently.

Everyone's going to be so happy to hear that news, because I think everybody loves potatoes.

They're used in foods such as potato chips.
Chips actually retain quite a bit of vitamin C.

Really!? Potato chips!? I would have never thought that before.

Yes, but you must keep in mind
that they contain a lot of oil.

When you're deficient in vitamin C, it's also possible to get the nutrient from supplements or drinks.

Is there any issues if you take too much vitamin C?

There have been almost no reports of
negative effects from excessive intake.

But there are occasional reports that say
taking about 10g of vitamin C at once resulted in diarrhea.

But just because this happened to some people,
it doesn't mean it will happen to everyone.

Vitamin C is a very safe nutrient.

Japan's health ministry has set 2000 milligrams as the daily upper limit of vitamin C for an adult.

It's best to get it from food, which also provides other nutrients that your body needs.

Are there any goals that you have for research in vitamin C?

Vitamin C is present throughout the body. We've
discussed the muscles and brain, but little is known about its effects on other parts of the
body. I believe it's my mission to find that out.

Thank you so much for your time today, sensei.

Thank you.

Today, we share some easy recipes for dishes high in vitamin C.

Nice to meet you.

Joining us today is culinary researcher Tanishima Seiko.

Wow! So this is where all of the action happens.

How incredible!

Tanishima is a grandmother of four.

She developes recipes for seniors who live alone.

I understand you're 75 years old.

75, yes.

And I can't quite believe it.

Look, I have more muscle than a man.

You have amazing muscle mass... amazing!

Cooking meals for just yourself can feel like too much effort.

That can lead to not eating properly.

Tanishima is known for her nutrient-dense recipes, that are easy for seniors to prepare.

Today, she will explain how to make marinated bell peppers, which are rich in vitamin C.

They can be added to other dishes, making frequent consumption of the nutrient easy.

They go well with any dish.
They will also help you gain more muscle.

First, cut bell peppers into thin strips, so they cook quickly.

Stir-fry onion and garlic thoroughly in olive oil.

Add bell peppers and stir-fry for three minutes.

Use medium heat to avoid destroying the vitamin C.

When everything is coated with
the olive oil, it's ready.

Add lemon juice, salt and pepper.

Cover the pan and let it cook over residual heat.

This should prevent overcooking.

This lasts for one to two weeks in the fridge, so it's good to use as a pre-prepared ingredient to add to other dishes.

They are the vibrant, you know, and the color stays so vibrant that it smells amazing.

I can't wait to try it.

We'll now introduce three dishes made using the marinated bell peppers.

The first is a Spanish omelet with potatoes, which are rich in vitamin C.

Stir-fry potatoes in olive oil, and add garlic, salt and pepper.

Once the potatoes are tender, add beaten eggs, and cook on both sides.

Garnish the omelet with the marinated bell peppers, and it's ready.

This dish is very nutrient-dense.

It's so delicious with the crunch of the bell pepper on top.

Texture is a component of flavor.

So this, with the addition of both the bell peppers and the potatoes, incredibly vitamin C rich.

Next is sauteed chicken breast.

Dust chicken breast with flour, salt pepper and saute it.

Add a generous amount of the marinated bell peppers.

Cover the pan and steam the chicken.

Once the chicken is thoroughly cooked, it's ready.

This is a good way to get protein, which people tend to lack.

It's also low in calories, and good for people watching their weight.

The bell peppers go well
with meat, don't you think?

I think this would go so well with grilled fish.

You could do it with meat.

You could even do it with tofu as well, for vegans and vegetarians.

That's a great idea.

The last dish is cold soup, which can be prepared in the blink of an eye.

Add water to the bell peppers and blend them.

Use a smaller amount of water if you prefer a thick soup.

Add yogurt and sprinkle black pepper on top, and it's ready.

You can blend it more to make the soup smoother.
Today, I've left it a bit chunky.

The lovely flavors of the bell pepper, and the onion, and...

Onions become very sweet when stir-fried.

And it's incredibly sweet.

I think particularly with bell peppers, a lot of people get so lazy and they just put them in a salad.

They don't know what else to do with them.

But I'm so inspired, and I'm sure that all of you are going to be so inspired to make these recipes, that are so easy, but so delicious.

It's difficult to eat a whole bell pepper raw.

I added sweetness with onions and coated it
in olive oil, to make it healthy and delicious.

Thank you very much.

I'm glad that you liked the dishes.

I will cook them when I get home.