Vitamin D, vitamin C, calcium, iron, folic acid … when you start breaking food down into its component parts, it's hard to keep the building blocks of a healthy diet straight. The good news: Vitamin A isn't one of the nutrients you need to worry about, because almost everyone in the developed world already gets a sufficient amount through their diet (with the exception of some pre-term infants and people with cystic fibrosis).
"Vitamin A is abundant in fruits, vegetables, milk, eggs, meats (especially liver), and seafood," Mascha Davis, a registered dietitian nutritionist in Culver City, California says. In fact, it's so unlikely that people in countries like United States will face vitamin A issues that the World Health Organization (WHO) doesn't recommend supplementation to anyone, except pregnant women who live in places that are vitamin A deficient.
But even if you don't have to worry about getting enough vitamin A in your diet, it's still important to know what it does in the body — here's what we know about it.
It helps keep your eyesight healthy.
Vitamin A is probably most well known for it's eyesight benefits, particularly in regards to developing countries. There's an ongoing debate about genetically modifying rice to contain more vitamin A in order to prevent vision issues in lower-income countries, because it's a key player in creating the protein rhodopsin, according to Summer Yule, a registered dietician in Connecticut.
Rhodopsin is a protein that absorbs light in the retina. Without vitamin A, the creation of this protein is inhibited and could lead to things like night blindness — which is an early sign of vitamin A deficiency. If deficiency of this nutrient lasts long enough, it can result in ulceration of the cornea.
According to the National Institutes of Health Office of Dietary Supplements, vitamin A also shows promise for preventing age-related macular degeneration (AMD), which is one of the most common causes of vision problems as people age.
But it is possible to have too much Vitamin A (25,000 IU/kg a day). Instead of giving you X-ray vision, excessive amountsf can result in blurred vision, along with dizziness and nausea, Davis says.
It'll give you glowing skin.
Ever heard of retinoids? That's vitamin A. Retinoids applied topically can be helpful in treating acne, photo-damaged skin, smoothing rough skin, and reducing the appearance of wrinkles, according to the Linus Paul Institute at Oregon State University. But they can also cause irritation if the dose is too high, so apply carefully.
In addition to helping skin on the surface, there's evidence that vitamin A deficiency lead to problems with epithelial tissues — the tissue that lines our organs — in laboratory rats (specifically, tissue that lined the rat's mucous membranes, trachea, and bronchi).
It keeps your immune system in tip-top shape.
Vitamin A (along with vitamin D) is a real MVP when it comes to keeping your immune system functioning. It's involved in creating T-cells, which go after cells infected with germs, as well as cancer cells. Not to mention, it helps keep your gut working well — malnourished children who are suffering from diarrhea often improve faster with vitamin A supplementation.
It could reduce your cancer risk — maybe.
Vitamin A, along with beta-carotene and lycopene, might help reduce the risk of pancreatic cancer according to a 2016 analysis of qualified studies published in the journal Nature. It's also been associated with decreased occurrences of cervical cancer and bladder cancer.
But these studies looked at dietary vitamin A, not supplementation. One study in the New England Journal of Medicine found an increase in lung cancer and cardiovascular disease in 18,314 smokers and asbestos-exposed workers who supplemented with vitamin A and beta-carotene.
It helps children recover from measles.
In a country where the majority of children are vaccinated against measles, this isn't typically an issue. But if a child were to contract this infection, those who are already vitamin A deficient fare worse. Adding a supplement might help reduce death from measles, according to the Mayo Clinic.
The bottom line: The next time you crunch into a vegetable or slurp up a fruit smoothie, give a little shout out to hard-working and plentiful vitamin A. You'd be lost without it.
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