ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

The health benefits of Vitamin A

Updated on May 15, 2012

Vitamins can be defined as essential organic compounds required in very small amounts that are involved in fundamental functions of the body, such as growth, maintenance of health, and metabolism. All vitamins are generally classified as water soluble and fat soluble vitamins. Vitamin A is a member of four fat soluble vitamins, A, E, D, and K. Vitamin A is actually a family of fat-soluble vitamins such as retinol, which is considered the most active form of vitamin A.

The vitamin A of origin from animal products is referred to as preformed vitamin A and is found in foods such as liver, egg yolk, butter, whole milk products, and fish liver oils.

The vitamin A of origin from plants is called provitamin A. Carotenoids, the red, orange, and yellow pigments are synthesized by a wide variety of plants including carrots and other vegetables including: Raw spinach, cantaloupe, tomatoes, sweet potatoes, papayas, apricots, romaine lettuce. Vitamin A is involved in many important body functions in addition to helping with vision.

Health benefit to vision

Vitamin A is required in the production of rhodopsin, the visual pigment used in low light levels. Vitamin A improves our vision and prevents night blindness.

Maintaining epithelial cell's structure and function

Vitamin A affects gene expression and thus controlling cell development. Epithelial cells of the lungs, trachea, skin, and gastrointestinal tract need vitamin A to maintain their normal structure and functions. Vitamin A directs the differentiation of keratinocytes (immature skin cells) into mature epidermal cells. Vitamin A also directs the synthesis of keratins, with genes for small keratin molecules transcribed and translated.

Functions in growth

Vitamin A promotes growth through stimulating the growth of epithelial cells and other possible mechanism such as increasing the synthesis of cell surface components. One important member of these components is glycoprotein which is needed for important cell-to-cell connections. Vitamin A can modify cell surfaces through increasing glycoprotein synthesis at the gene level or by improving attachment of glycoproteins to cell surfaces to induce cell adhesion.

Participating in cell surface functions

One of vitamin A's cell surface functions is mediated through glycoprotein. Glycoprotein is a principal cell surface component involved in many cell surface functions such as cell communication, cell recognition, cell adhesion, and cell aggregation.

Acting as antioxidants

Carotenoids are powerful antioxidants that protect the body's cells from damage caused by pollution, aging and other factors. They also prevent cardiovascular diseases by protecting low-density lipoproteins from oxidation sand protecting eye health.

Other functions

Vitamin A makes immune system healthy and strong. It is needed for T-lymphocyte function and for antibody response to viral parasitic, and bacterial infections. Natural killer cell activity and phagocytosis are also impaired with vitamin A deficiency. Bone development and maintenance also needs vitamin A. Vitamin A deficiency results in excessive deposition of bone.

Deficiency symptoms

Vitamin A deficiency is less common in the United States than in developing countries where inadequate is common in children under 5 years old. Deficiency symptoms include anorexia, retarded growth, increased susceptibility to infections, obstruction and enlargement of hair follicles, and keratinization of epithelial (mucous)cells of the skin with failure of normal differentiation, night blindness, and abnormal changes in conjunctiva and cornea of the eyes. Some conditions and populations may need more vitamin A. For example, people who have absorptive disorders such as those with steatorrhea, pancreatic liver, or gallbladder diseases. People who have chronic nephritis, acute protein deficiency, intestinal parasites, or acute infections may also need more vitamin A intake.

As discussed above, vitamin A is needed to maintain many important body functions. Although deficiency is not very common in the United States, under some special health conditions or with different populations, we need to pay attention to these people's requirement for vitamin A.

Comments

    0 of 8192 characters used
    Post Comment

    No comments yet.

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://hubpages.com/privacy-policy#gdpr

    Show Details
    Necessary
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Marketing
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Statistics
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)