Another day and another opportunity to learn something. You have to expose your mind to new information every day and read about new things to stay sharp. When it comes to dementia, help yourself in advance by regularly reading, solving crosswords, sudoku puzzles, and learning learning learning. Today, I will offer my assistance and present you with educational material about carrots. Why carrots? Well, you are just going to read the post to find out :)
"Let food be thy medicine and medicine be thy food."
–attributed to Hippocrates
I wrote "attributed" on purpose because that line is nowhere to be found in more than 60 texts of Corpus Hippocraticum. There are many misquotes on the internet and I always try to be certain when quoting people who are dead and can not defend their views, it is only respectful. Anyway, you can read the paper about that being a misquote here: Let not thy food be confused with thy medicine: The Hippocratic misquotation by Diana Cardenas. But to get back to my point, I am more concern with the statement itself then by who actually said it first.
The truth is, humans need food for obvious reasons and you being hungry is not the reason. Hunger is our bodies mechanism to alert us that we need nourishment. The human body needs vitamins, minerals, fats, proteins etc. in order to function properly. We all need energy and that energy comes from chemical processes that go on inside our bodies, processes that need chemicals from food. Deficiency in vitamins, minerals and other chemicals may lead to serious illness and while it may not make you a superhero and exclusively keep you healthy, having a balanced diet, with all nutritarians that your body needs, will aid your body in proper functioning. Want to have bigger odds of staying healthy? Eat healthy food (and hope that your genetics do not screw you over).
Interested in how that story about carrots being good for eyesight started? During the World War II, the British Royal Air Force managed to gun down German aircraft. A rumor started how carrots gave their fighter pilots sharp vision and accuracy. Why? The radar was responsible for their success against the Luftwaffe but the British obviously wanted to keep that a secret from their enemies. Some sources say that the Air Force did not start the rumor but did not mind it either and provided no opposition to it until years later. The question, however, still remains, are carrots truly able to improve eyesight?
There is still a matter of fact over fiction. The fact is, yes, carrots are good for eyesight but not exclusively and not all the time. They are good because of their help in the production of vitamin A (retinol) which is important for many things including growth and differentiation of target tissues, proper functioning of the reproductive organs, modulation of immune function, and proper functioning of the retina.
What role does beta-carotene play?
Vitamin A helps the eye convert light into a signal that can be transmitted to the brain. This allows people to see under conditions of very low light. The problem arises when the body does not get enough vitamin A which can lead to cornea almost disappearing. It is estimated that between 250,000 to 500,000 children become blind as a result of vitamin A deficiency and those from Nepal and India are affected the most. Supplements of the vitamin or beta-carotene have been shown to improve night vision and help with sight problems but what is vitamin A, anyway? It is a fat-soluble vitamin necessary for health. Its deficiency can cause disorders of vision, skin, bone, and immunity. The recommended daily allowance for it is 300 to 700 μg for children and approximately 700 to 900 μg for adults. Higher doses can be toxic, leading to a constellation of signs and symptoms as well as liver injury, jaundice, enlargement of the liver and spleen, portal hypertension and cirrhosis.
β-carotene is the precursor of vitamin A in the human diet. It is not only responsible for giving carrots, sweet potatoes, squash, and other yellow or orange vegetables their color but it also structurally related to vitamin A. Two molecules of vitamin A are formed from one molecule of beta-carotene and the process happens in our liver while the breakdown of beta-carotene occurs in the walls of the small intestine.
Structural formula and space-filling model of the β-carotene, public domain images from Wikipedia 1 and 2
The efficiency of conversion of beta-carotene to retinol depends on the level in the diet. If you eat more beta-carotene, less is converted. Once we have enough beta-carotene in our bodies it will no longer convert to vitamin A but be stored in fat reserves in the body. Too much beta-carotene can make you turn yellow, but it is a harmless symptom that is not a health concern. There is no specific amount of carrots you should eat because our bodies are different so the amount that I need to eat does not have to be the same for you. Just keep in mind that most eye problems come from vision-impairment caused by genetics, aging or diabetes and cannot be fixed with an infusion of beta-carotene.
Do not rely on carrots alone. Instead, eat leafy greens too for improvement of your eyesight. Spinach, kale or collard greens are full of lutein and zeaxanthin that will help protect your eyes by filtering high-energy wavelengths of visible light that can damage the retina. They will also help to protect against age-related macular degeneration which is the major cause of blindness in the elderly. Orange vegetables? Sure. Green vegetables? Even better. Combining orange and green? The best solution.
I suggest that you take a look at some of the articles from sciencedirect.com about beta-carotene here: Beta Carotene and if you are interested in all the things that will keep your eyes healthy, there is a great paper about it that talks about vitamins C, E, β-carotene, Zinc, Omega-3 fatty acids, lutein, and zeaxanthin. It is available here:
Nutrients for the aging eye by Helen M Rasmussen and Elizabeth J Johnson
A team of scientists (led by Philipp Simon from the University of Wisconsin-Madison) has sequenced the carrot genome which provided insight into the vegetables evolutionary origin, its nutrition, and, of course, its vibrant orange color. It is considered to be one of the most complete vegetable genome assemblies known. By comparing genetic sequences of carrots to different plants, they determined that carrots diverged from potatoes and tomatoes around 90.5 million years ago. The carrot genome doubled the amount of DNA somewhere around the time the dinosaurs went extinct (between the Cretaceous and Paleogene periods). The first cultivated carrots were traced to the Middle East and Central Asia, around 1,100 years ago and those domesticated carrots were mainly yellow and purple, not orange. Read that line again... Purple! They were purple!
What was the biggest find?
ORANGE COLOR
They found a gene that controls levels of carotenoids that are associated with color and nutrition. Enhanced breeding has led to more intense orange color and more nutritious crops and carrots we have today contain 50% more carotene than they did back in the 1970s. Why is this important? Since vitamin A deficiency is still a global health issue, it may be possible to insert that gene into other staple root vegetables such as cassava that is widely grown in Africa and in that way help solve the problem.
What exactly did they discover?
The team sequenced the DNA of 35 different carrots in the Daucus genus (both wild and cultivated specimens). Of the 32,113 genes in the genome, 10,530 of them are unique to carrots. Two genes have been identified as responsible for the accumulation of pigments in the roots of carrots. The previously described gene called Y is responsible for the difference between white carrots and ones that are yellow or orange, and there is a new candidate gene called DCAR_032551 that is linked to the unusually high beta-carotene accumulation in the root. The interesting thing is that the carotenoid buildup was actually a defect in the metabolic pathway related to light-sensing. We all know how plants make their own food through photosynthesis. That includes light. Roots are not exposed to light so what gives? These genes were probably selected for domestication by early farmers simply by chance.
"We found that the Y-gene accounts for the accumulation of orange and yellow carotenoid pigments in carrot roots. It is one of two genes responsible for converting ancestral wild-type white carrots to orange ones...We expect the immediate users of the whole genome sequence will be public and private plant breeders who will use it for carrot disease resistance and seed production traits."
-Professor Phillip Simon
You can read the full article, published in the Nature Genetics, here:
A high-quality carrot genome assembly provides new insights into carotenoid accumulation and asterid genome evolution
by Massimo Iorizzo, Shelby Ellison, Douglas Senalik, Peng Zeng, Pimchanok Satapoomin, Jiaying Huang, Megan Bowman, Marina Iovene, Walter Sanseverino, Pablo Cavagnaro, Mehtap Yildiz, Alicja Macko-Podgórni, Emilia Moranska, Ewa Grzebelus, Dariusz Grzebelus, Hamid Ashrafi, Zhijun Zheng, Shifeng Cheng, David Spooner, Allen Van Deynze & Philipp Simon
Of course! Carrots are full of nutrients your body needs. Eat them as much as you like... If your skin turns orange, you should probably stop but hey, if it does not bother you, keep on eating them even then. You can eat them raw or thermally processed, put them in your salads, main dishes, drinks, and even deserts.
To read more about this topic, check out these REFERENCES:
Seeing Through the Carrot Myth from mcgill.ca
Fact or Fiction? Carrots Improve Your Vision from scientificamerican.com
Vitamin A: β-Carotene from chem.libretexts.org
Retinol from pubchem.ncbi.nlm.nih.gov
Meet Your Carrot from thescienceexplorer.com
Scientists Have Discovered Why Carrots Are Orange from iflscience.com
Carrot genome reveals the roots of its orange colour and high nutrition from ABC science
Until next time,
KEEP YOUR SMILE ON!
