A lot of us have heard that eating carrots can improve our vision, especially night vision.
Have you ever wondered if this is true, can eating carrots really help us see better at
night?
To learn more, keep watching.
Hello everyone This is Dr Audrey Tai, I'm a board-certified and fellowship trained Cataract
and refractive surgeon, ophthalmologist and cornea specialist, welcome back to my channel
- eye Channel by eye surgeon.
I am here to bring you the latest information on eye health and medicine.
In today's video, I will cover whether eating carrots can really improve your night vision,
whether eating too many carrots can be harmful, and if you stay with me until the end of this
video, as a bonus, I will review some other nutrient dense foods that can help improve
or maintain healthy vision.
Don’t forget to hit the subscribe button and notification bell so you won’t miss
any of my new videos.
The idea that eating carrots can improve night vision really started to become popular during
the second world war.
In the early 1940s, the British Ministry of food started a propaganda campaign stating
that the key to the British pilots’ success in shooting down the German bombers at night
was due to their superb night vision from the carrot rich diet they ate.
And the ministry encouraged civilians to consume more British grown carrots.
In fact this rumor spread so far across the Pacific Ocean, a news article published in
Time magazine on December 22 1941, entitled “science : rabbit food for owl eyes”,
stated that “the Royal aviation force, may soon be eating Arizona carrots in preference
to all other carrots on earth…
Arizona's 3 to 4000 acres of carrots may be the answer to every aviation command’s problem
of preventing night blindness in its flyers”.
So was this true?
Were the RAF pilots really able to beat their German opponents in the sky because they ate
more carrots?
Most students of history would point out, that the RAF’s success in that era probably
had much more to do with the invention of onboard radar systems than carrots.
In fact, rumor has it that the British Royal Air Force may have pushed the carrots message
as a cover-up for the use of onboard radar technology by telling the public that carrots
were the key to their success.
During war time, blackouts occurred often in London and other areas in the UK, and food
shortages were quite common, but there was a surplus of domestic carrots, and the British
Ministry of food wanted to encourage the consumption of carrots, by advertising them as a healthy
nutritious food source, that would also help improve night vision.
But was the British Ministry of food telling the truth?
Is the notion that eating carrots can help improve night vision fact or fiction?
The answer to this question may surprise you.
Eating carrots can in fact sometimes improve night vision, but only under certain conditions.
Let me explain.
The key nutrient in carrots that is important for maintaining eye health is beta-carotene,
which can be converted into vitamin A in our body.
Vitamin A is the molecule that transmits the signal of stimulation from light in our eyes
to the brain, allowing us to see both during the day and at night.
This important step occurs in the retina, which is the layer of nerve tissue in our
eyes.
There are two types of cells in the retina that contain Vitamin A, Rod cells which are
responsible for vision at night and dim light situations, and Cone cells which are responsible
for vision during the day and well-lit situations.
Vitamin A is also essential for maintaining the health of the cornea, which is the clear
windshield of our eyes.
Our body cannot produce vitamin A on its own, and has to rely on external sources, such
as dietary intake, in order to obtain this essential nutrient.
Dietary sources of vitamin A can be divided into two groups, preformed vitamin A and provitamin
A carotenoids.
Preformed vitamin A is found in foods of animal origin, such as milk, yogurt, liver, and fish
oils; and Provitamin A is found in vegetable sources, such as carrots, pumpkins, sweet
potatoes, and spinach.
Because pro-vitamin A needs to be converted into a biologically usable form of vitamin
A in our body through enzymatic conversion, pro-vitamin A obtained from plant sources
are an inefficient dietary source of vitamin A when compared to preformed vitamin A. Additionally,
Vitamin A is a fat soluble molecule, both digestion and absorption of vitamin A require
lipids or fat, so people who eat diets with critically low fat content, and people with
certain medical conditions such as pancreatic or liver diseases, may have difficulty with
absorption of vitamin A. It is estimated that globally about 30% of children younger than
five years of age are vitamin A deficient.
And vitamin A deficiency is the single most important cause of childhood blindness in
developing countries.
In the US, we are very lucky, as vitamin A deficiency affects less than 1% of the population,
and it mainly affects people with a history of digestive diseases, such as inflammatory
bowel disease, like Crohn's disease, and liver disease, like cirrhosis etc.
Therefore there is no need for most of us in the US to run to the store to buy a large
amount of carrots.
So can eating carrots help improve your night vision or not?
The answer depends on whether or not you are Vitamin A deficient.
In settings where people suffer from vitamin A deficiency, studies have shown that supplements
of vitamin A or beta-carotene actually do improve night vision.
If you are suffering from vitamin A deficiency, exactly how many carrots do you need to eat
to help improve night vision?
Most of the studies have looked into the benefits of beta-carotene from plant sources, which
are the sole source of vitamin A in many developing countries.
A randomized control study published in 2005 in the American Journal of clinical nutrition
studied the benefits of vitamin A supplementation from different food sources in pregnant women
with night blindness.
That study concluded that daily consumption of 4.5 ounces of cooked carrots for six weeks
improved night vision in the pregnant women studied.
As I mentioned before, if you live in the US or other developed countries, eating more
carrots is unlikely to improve your night vision, unless you suffer from vitamin A deficiency
due to various digestive diseases or dietary restrictions.
That being said, carrots are very healthy and they are high in antioxidants, so if you
want to go ahead and eat more carrots, that should be fine for most people.
If you do need a multivitamin supplement, I’ve listed some recommendations in the
description, you can check them out.
One thing to mention about Vitamin A, as a fat soluble vitamin, it is possible to have
too much vitamin A in your body.
This is known as vitamin A toxicity.
However, it is very unlikely for you to develop vitamin A toxicity solely from eating carrots.
The conversion of beta-carotene from carrots, to active vitamin A in our body is quite inefficient,
the ratio is estimated to be 12:1 by weight, meaning it takes 12 times more beta-carotene
to make the equivalent amount of bioavailable vitamin A. Which means eating extra carrots
is very unlikely to cause vitamin A toxicity.
Most cases of vitamin A toxicity are actually due to supplements.
Some people have even experienced their skin turning orange after taking large amount of
beta-carotene supplements, it’s a real condition called carotenemia.
Please also be careful when taking large amounts of vitamin A supplements in preformed vitamin
A form, for example vitamin A supplements which come in capsule form with lipid carriers.
Taking too much of those vitamin A supplements can cause toxicity, and symptoms such as abdominal
pain, nausea, skin rash, increased intracranial pressure, and increased risk of fractures.
As I promised earlier, here is a bonus list of foods that are important for maintaining
eye health: dark leafy greens such as kale and spinach, contain important xanthophylls,
such as lutein and zeoxanthan, they are important to maintain the health of the retina; fruits
and vegetables high in vitamin C and other antioxidants, such as oranges and broccoli,
are important for combating oxidative stress in our eyes and body; foods high in omega
3 oil, such as wild caught fish and sea weed, are important for preventing dry eyes.
To learn more about cataract prevention and oxidative stress in the eyes, you can check
out this video – 5 tips to prevent cataracts.
Let me know in the comments below if you would like me to make more videos in the future
to learn more about natural foods that can improve your eye health.
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