Tuesday 11 November 2014

Multiple Online Resources to Educate Yourself - FOR FREE




All education is self-education. Period. It doesn’t matter if you’re sitting in a college classroom or a coffee shop. We don’t learn anything we don’t want to learn.

Those people who take the time and initiative to pursue knowledge on their own are the only ones who earn a real education in this world.

Take a look at any widely acclaimed scholar, entrepreneur or historical figure you can think of. Formal education or not, you’ll find that he or she is a product of continuous self-education.

If you’re interested in learning something new, this article is for you. Broken down by subject and/or category, here are several top-notch self-education resources I have bookmarked online over the past few years.

Note that some of the sources overlap between various subjects of education. Therefore, each has been placed under a specific subject based on the majority focus of the source’s content.




MIT OpenCourseWare – MIT OpenCourseWare is a free web-based publication of MIT course materials that reflects almost all the undergraduate and graduate subjects taught at MIT.
Tufts OpenCourseWare – Tufts OpenCourseWare is part of a new educational movement initiated by MIT that provides free access to course content for everyone online. Tufts’ course offerings demonstrate the University’s strength in the life sciences in addition to its multidisciplinary approach, international perspective and underlying ethic of service to its local, national and international communities.
HowStuffWorks Science – More scientific lessons and explanations than you could sort through in an entire year.
Harvard Medical School Open Courseware – The mission of the Harvard Medical School Open Courseware Initiative is to exchange knowledge from the Harvard community of scholars to other academic institutions, prospective students, and the general public.
Khan Academy – Over 1200 videos lessons covering everything from basic arithmetic and algebra to differential equations, physics, chemistry, and biology.
Open Yale Courses – Open Yale Courses provides lectures and other materials from selected Yale College courses to the public free of charge via the internet. The courses span the full range of liberal arts disciplines, including humanities, social sciences, and physical and biological sciences.
webcast.berkeley – Every semester, UC Berkeley webcasts select courses and events for on-demand viewing via the Internet. webcast.berkeley course lectures are provided as a study resource for both students and the public.
UC San Diego Podcast Lectures – UCSD’s podcasting service was established for instructional use to benefit our students. Podcasts are taken down at the end of every quarter (10 weeks Fall-Spring and 5 weeks in the summer). If you’re enjoying a podcast, be sure to subscribe and download the lectures. Once the podcast has been taken offline, faculty rarely approve their reposting.
Johns Hopkins OpenCourseWare – The Johns Hopkins Bloomberg School of Public Health’s OpenCourseWare project provides access to content of the School’s most popular courses. As challenges to the world’s health escalate daily, the School feels a moral imperative to provide equal and open access to information and knowledge about the obstacles to the public’s health and their potential solutions.

Carnegie Mellon Open Learning Initiative – No instructors, no credits, no charge. Use these self-guiding Carnegie Mellon materials and activities to learn at your own pace.
Utah State OpenCourseWare – Utah State OpenCourseWare is a collection of educational material used in our formal campus courses, and seeks to provide people around the world with an opportunity to access high quality learning opportunities.
AMSER – AMSER (the Applied Math and Science Education Repository) is a portal of educational resources and services built specifically for use by those in Community and Technical Colleges but free for anyone to use.
Wolfram Demonstrations Project – Wolfram brings computational exploration to the widest possible audience, open-code resource that uses dynamic computation to illuminate concepts. Free player runs all demos and videos.
The Science Forum – A very active scientific discussion and debate forum.
Free Science and Video Lectures Online! – A nice collection of video lectures and lessons on science and philosophy.
Science.gov – Science.gov searches over 42 databases and over 2000 selected websites from 14 federal agencies, offering 200 million pages of authoritative U.S. government science information including research and development results.
The National Science Digital Library – NSDL is the Nation’s online library for education and research in Science, Technology, Engineering, Mathematics.
EnviroLink Network– A non-profit organization, grassroots online community uniting organizations and volunteers around the world. Up-to-date environmental information and news.
Geology.com – Information about geology and earth science to visitors without charge: Articles, News, Maps, Satellite Images, Dictionary, etc.
Scitable – A free science library and personal learning tool that currently concentrates on genetics, the study of evolution, variation, and the rich complexity of living organisms. The site also expects to expand into other topics of learning and education.
LearningScience.org – A free open learning community for sharing newer and emerging tools to teach science.





MIT Sloan School of Management – MIT Sloan is a world-class business school long renowned for thought leadership and the ability to successfully partner theory and practice. This is a subsection of the larger MIT OpenCourseWare site.
Investopedia Financial Investing Tutorials – A plethora of detailed lessons on money management and investing.
U.S. Small Business Administration Training Network – The Small Business Administration has one of the best selections of business courses on the web. Topics include everything from starting a business and business management to government contracting and international trade. Most courses take only 30 minutes to complete.
VideoLectures.NET (Business) – A free and open access educational video lectures repository. The lectures are given by distinguished scholars and scientists at the most important and prominent events like conferences, summer schools, workshops and science promotional events from many fields of Science.
UC Irvine OpenCourseWare (Business) – Rapidly with the addition of nearly 10 new courses every month. Many of our OCW offerings are directed at working adults seeking continuing education, with the option to enroll in instructor-led, for-credit courses, related to the OCW content.
Kutztown University of Pennsylvania – The Kutztown University of Pennsylvania’s Small Business Development Center offers more than 80 free business courses online. Kutztown’s courses are individualized and self-paced. Many of the courses feature high-end graphics, interactive case studies and audio streams.
Boston College Front Row (Business) – Boston College Front Row is a Web site that offers free access through streaming media to tapes of cultural and scholarly events at Boston College.
Financial Management Training Center – The Financial Management Training Center provides several free downloadable business courses for people who need to learn the finer points of financial management. All courses offered can be taken online; courses include full exams as well as evaluation forms for people seeking Continuing Professional Education (CPE) credits.
The Free Nonprofit Micro-eMBA – Free Management Library’s Free Nonprofit Micro-eMBA Program is an especially great resource for students wishing to learn more about nonprofit management, but most of the lessons also apply to general business management. Completion of this program will not result in an MBA degree, but enrollment is free and the material is well structured.
Bookboon Free Business e-books – Hundreds of free business books online in PDF format.
TheStreet University – If you’re just starting out as a stock and bond investor or need a refresher’s course, this is the place to learn what you need to know.




University of Washington’s OpenUW – Explore a variety of learning in several free history-centric online courses from the University of Washington.
Notre Dame OpenCourseWare – Notre Dame OCW is a free and open educational resource for faculty, students, and self-learners throughout the world.
Bio’s Best – Biography.com’s most popular biographies on notable historical figures.
UC Irvine OpenCourseWare (Social Science) – Rapidly with the addition of nearly 10 new courses every month. Many of our OCW offerings are directed at working adults seeking continuing education, with the option to enroll in instructor-led, for-credit courses, related to the OCW content.
Boston College Front Row (History) – Boston College Front Row is a Web site that offers free access through streaming media to tapes of cultural and scholarly events at Boston College.
MIT OpenCourseWare (History) – The MIT History Faculty offers about 70 subjects in the areas of Ancient, North American, European, East Asian, and Middle Eastern history.
Wikiversity School of Social Sciences – Wikiversity is a Wikimedia Foundation project devoted to learning resources, learning projects, and research for use in all levels, types, and styles of education from pre-school to university, including professional training and informal learning.
OpenLearn (Arts and Humanities) – The OpenLearn website gives free access to Open University course materials.
A Biography of America – A Biography of America presents history not simply as a series of irrefutable facts to be memorized, but as a living narrative of America’s story.
Have Fun with History – A resource for students, educators and all lovers of American History.
The USGenWeb Project – Free genealogy and family history resources online.
MacroHistory and World Report – Tell without illusions or ideological restraints the story of our ancestors, our parents and us.
World History HyperHistory – Navigates through 3000 years of World History with links to important persons and events of world historical importance.
American Digital History – Online American history textbook. An interactive, multimedia history of the United States from the Revolution to the present.




Duke Law Center for the Public Domain – Duke University is counted amongst the best schools in the South. If you’re interested in law, Duke’s open courseware in that subject area can go a long way towards helping you learn more about the justice system.
Intute Law – Provides free access to high quality resources on the Internet. Each resource has been evaluated and categorised by subject specialists based at UK universities.
Boston College Front Row (Law) – Boston College Front Row is a Web site that offers free access through streaming media to tapes of cultural and scholarly events at Boston College.
American University – Offers a selection of podcasts on a number of different law-related subjects. There is even a very interesting podcast on debt relief and the law.
Case Western Reserve University School of Law – Offers a number of interesting lectures on different law subjects. These lectures are both podcasts and Web casts. You can look ahead to the coming school year, which already has a number of interesting subjects lined up.
Harvard Law School – Provides a number of Web casts of law lectures, symposia, panels and conferences. A great collection of relevant information and insights on how the law interacts with current events.
Stanford Law – Provides open courseware via iTunes on a variety of law subjects, including the theory of justice, mobile content distribution, gay marriage, judicial review and privacy protection. The tracks are available for free, but you’ll need iTunes. Put the lectures on your iPod or iPhone and listen them anywhere.
MoneyInstructor Business Law – From MoneyInstructor.com provides a look at a number of basics in business law. Learn how to define crimes under business law. Worksheets and curriculums are available for teachers. Ordinary folks will find them useful as well.




VideoLectures.NET (Computer Science) – A free and open access educational video lectures repository. The lectures are given by distinguished scholars and scientists at the most important and prominent events like conferences, summer schools, workshops and science promotional events from many fields of Science.
Wikiversity School of Computer Science and Technology – Wikiversity is a Wikimedia Foundation project devoted to learning resources, learning projects, and research for use in all levels, types, and styles of education from pre-school to university, including professional training and informal learning.
New York State University (US), Computer Science – Hundreds of lectures, tutorials and links to educational material.
Dream.In.Code Tutorials – Lots of computer programming tutorials.
MIT OpenCourseWare (Engineering and Computer Science) – MIT OpenCourseWare is a free web-based publication of MIT course materials that reflects almost all the undergraduate and graduate subjects taught at MIT.
Maine University (US), Fogler Guide to Computer Science – An insanely detailed list of computer science resources.
FreeComputerBooks.com – Free computer, mathematics, technical books and lecture notes.
Collection of Computer Science Bibliographies – A massive collection of bibliographies of scientific literature in computer science, updated weekly from original locations, more than 3 millions of references (mostly to journal articles, conference papers and technical reports), clustered in about 2000 bibliographies.
W3Schools – Web-building tutorials, from basic HTML and XHTML to advanced XML, SQL, Database, Multimedia and WAP.
FreeTechBooks.com – This site lists free online computer science, engineering and programming books, textbooks and lecture notes, all of which are legally and freely available over the Internet.
Free computer Tutorials – Free computer courses and tutorials site. All the courses are aimed at complete beginners, so you don’t need experience to get started.
Programmer 101: Teach Yourself How to Code – Several helpful resources for computer programming beginners.
Google Code University – Provides sample course content and tutorials for Computer Science (CS) students and educators on current computing technologies and paradigms.































Mass Boston Mathematics – Various online mathematics classes provided free by UMass Boston.
VideoLectures.NET (Mathematics) – A free and open access educational video lectures repository. The lectures are given by distinguished scholars and scientists at the most important and prominent events like conferences, summer schools, workshops and science promotional events from many fields of Science.
Wikiversity School of Mathematics – Wikiversity is a Wikimedia Foundation project devoted to learning resources, learning projects, and research for use in all levels, types, and styles of education from pre-school to university, including professional training and informal learning.
AMSER Mathematics – AMSER (the Applied Math and Science Education Repository) is a portal of educational resources and services built specifically for use by those in Community and Technical Colleges but free for anyone to use.
Math.com – Math.com is dedicated to providing revolutionary ways for students, parents, teachers, and everyone to learn math.
Intute Mathematics – Provides free access to high quality resources on the Internet. Each resource has been evaluated and categorized by subject specialists based at UK universities.
Free-Ed College Mathematics – Offers a wide range of free online math courses and study programs.




Open Yale Courses (English) – Open Yale Courses provides lectures and other materials from selected Yale College courses to the public free of charge via the internet.
Writing Guidelines for Engineering and Science Students – These guidelines for engineering writing and scientific writing are designed to help students communicate their technical work.
MIT Writing and Humanistic Studies – The MIT Program in Writing and Humanistic Studies gives students the opportunity to learn the techniques, forms, and traditions of several kinds of writing, from basic expository prose to more advanced forms of non-fictional prose, fiction and poetry, science writing, scientific and technical communication and digital media.
Merriam-Webster Online – In this digital age, your ability to communicate with written English is paramount skill. And M-W.com is the perfect resource to improve your English now.
National Novel Writing Month – Valuing enthusiasm and perseverance over painstaking craft, NaNoWriMo is a novel-writing program for everyone who has thought fleetingly about writing a novel but has been scared away by the time and effort involved.
Lifewriting – A complete text of the 9-week writing class a professor taught for years at UCLA.
Guide to Grammar and Writing – Grammar and writing techniques, lessons and quizzes.
Purdue Online Writing Lab – Over 200 free resources including lessons on: writing, research, grammar, and style guides.



FOREIGN AND SIGN LANGUAGES

BBC Languages – Teach yourself a new spoken language online.
American Sign Language Browser – Teach yourself sign language online.
Livemocha – Start learning a new language online for free.
Learn10 – Gives you a language learning habit that’s hard to kick. 10 new words; everywhere, every day.
One Minute Languages – Learn a new language via podcasts that are updated regularly.
Mango Languages – Over 100 lessons, shown to you in PowerPoint style with interstitial quizzes, to move you through any language without cracking a book.




OpenLearn – The OpenLearn website gives free access to Open University course materials. Multiple subjects are covered.
Capilano University OpenCourseWare – The Capilano University OpenCourseWare site is a free and open educational resource for faculty, students, and self-learners throughout the world.
University of Southern Queensland’s OpenCourseWare – Provides access to free and open educational resources for faculty members, students, and self-learners throughout the world.
YouTube EDU – Educational videos on YouTube organized by subject matter.
LearnHub Test Prep – Raise your test scores with free practice tests & counseling on various subjects.
iTunes U – Hundreds of universities — including Stanford, Yale and MIT — distribute lectures, slide shows, PDFs, films, exhibit tours and audio books through iTunes U. The Science section alone contains content on topics including agriculture, astronomy, biology, chemistry, physics, ecology and geography.
United Nations University OpenCourseWare – Showcases the training and educational programs implemented by the University in a wide range of areas relevant to the work of the United Nations.
Brigham Young Independent Study – BYU Independent Study now offers free courses in different areas of study. These areas include Family History, Family Life, and Religious Scripture Study, Personal Dev elopement, etc. Use these courses as a starting point for your personal studies or just to add insight to an area of interest.
United States Nation Archives – The National Archives and Records Administration (NARA) is the nation’s record keeper. Valuable records are preserved and are available to you, whether you want to see if they contain clues about your family’s history, need to prove a veteran’s military service, or are researching an historical topic that interests you.
Wikiversity – Wikiversity is a Wikimedia Foundation project devoted to learning resources, learning projects, and research for use in all levels, types, and styles of education from pre-school to university, including professional training and informal learning.
UMass Boston OpenCourseWare – Various online classes provided free by UMass Boston.
About U – A collection of free online educational courses from About.com.
Academic Earth – Online degrees and video courses from leading universities.
Free-Ed – Clusters of courses that support your preparation for today’s fastest-growing careers and critical academic disciplines.
Connexions – A place to view and share educational material made of small knowledge chunks called modules that can be organized as courses, books, reports, etc. Anyone may view or contribute.
TED – Motivational and educational lectures from noteworthy professionals around the world.
Intute – Provides free access to high quality resources on the Internet. Each resource has been evaluated and categorised by subject specialists based at UK universities.
Boston College Front Row – Boston College Front Row is a Web site that offers free access through streaming media to tapes of cultural and scholarly events at Boston College.




LibraryThing – LibraryThing connects you to other people who are reading what you’re reading and allows you to see which books are popular in various categories of reading.
Textbook Revolution – Links to free online textbooks and other educational materials.
Book TV – This is the companion site to Book TV on C-Span2. The site holds some current interviews with authors, many past interviews, opinions, reviews, and featured programs through online video.
Bookboon – Bookboon provides online textbooks for students in PDF format. The free ebooks can be downloaded without registration. Our books are legal and written exclusively for Bookboon. They are financed by a few in-book ads.
Scribd – Scribd, the online document sharing site which supports Word, Excel, PowerPoint, PDF and other popular formats. You can download a document or embed it in your blog or web page.
BookYards – BookYards is a web portal in which books, education materials, information, and content will be freely to anyone who has an internet connection.
Planet eBook – Free classic literature to download and share.
E-Books Directory – Thousands of ebooks on various subjects to download and share.
Read Print Library – Free online books library for students, teachers, and the classic enthusiast.

GoodReads – Get great book recommendations and keep track of what you want to read.
The Online Books Page – University of Pennsylvania database with over 30,000 books.
Public Literature – Thousands of familiar classics, children’s books, plays and poems, as well as books by new authors.
Full Books – Thousands of full-text nonfiction and fiction books.
Many Books – Free fiction and nonfiction ebooks for your PDA, iPod or ebook reader.
Get Free Books – Thousands of free ebooks to download.
Project Gutenberg – More than 20,000 free books from the first producer of free e-books.
Bibliomania – Thousands of classic books, poems, short stories and plays.
Classic Reader – Large collection of free classic books, plays, and short stories from more than 300 authors.
Bartleby Fiction – Classic anthologies and volumes.
The Personal MBA Recommended Reading List – MBA programs don’t have a monopoly on advanced business knowledge: you can teach yourself everything you need to know to succeed in life and at work. The Personal MBA features the very best business books available, based on thousands of hours of research.
Books Should Be Free – Free audio books from the public domain.




BBC Learning – Online learning, support, and advice. This site offers internal and offsite links to a vast amount of materials.
Biography – The site holds videos to past interviews and biographies on people in topics that range from Black history to women’s history.
Book TV – This is the companion site to Book TV on C-Span2. The site holds some current interviews with authors, many past interviews, opinions, reviews, and featured programs through online video.
CBC Archives — Relive Canadian history through thousands of available radio and television clips.
History Channel – Visit the Video Gallery for a selection on historical topics. Like the Discovery Channel, this network provides many opportunities for you to gain access to information and reference materials.
NOVA — Watch current science shows or browse by category. PBS sponsors this channel.
Research Channel — Speakers, researchers and professors present revolutionary thoughts and discoveries. Use their Webstreams and an extensive video-on-demand library for research.
Weather Channel – You can learn about weather all over the world, but the Weather Channel also offers dynamic content based upon seasons and special conditions and a special multimedia and education section.


ONLINE ARCHIVES

American Memory – The Library of Congress provides extensive multimedia offerings on various topics through their American Memory Collection, including their outstanding Built in America project that showcases historical buildings through photographs.
Fathom – This archive, provided by Columbia University, offers access to the complete range of free content developed for Fathom by its member institutions. The archives include online learning resources including lectures, articles, interviews, exhibits and seminars.
Internet Archive Open Educational Resources – A digital library of Internet sites and other cultural artifacts in digital form.
National Archives – Provides primary source materials from NARA along with lesson plans for teaching with those sources.
National Climatic Data Center – The NCDC, a division of NOAA, maintains climatic archives, including lists of storms in given counties, and records about global extremes, etc.
The Rosetta Project – A global collaboration of language specialists and native speakers building a publicly accessible online archive of all documented human languages.
September 11 Digital Archive – This site uses electronic media to collect, preserve, and present the history of the 9/11 attacks.
U.S. Census Bureau – If you think the Census Bureau is all about numbers, you might be surprised to learn about their archived photographs, daily radio features, and more available through their Newsroom.


DIRECTORIES OF OPEN EDUCATION

Google Scholar – Provides a simple way to broadly search for scholarly literature. From one place, you can search across many disciplines and sources: articles, theses, books, abstracts and court opinions, from academic publishers, professional societies, online repositories, universities and other web sites.
OpenCourseWare Consortium – This site provides a portal to search through hundreds of free courses or to add new courses you know about to the database.
iBerry – Check out this site for a huge directory of open courseware organized by school and subject matter that can point you in the right direction for any type of learning.
Self Made Scholar Directory – Free online directory of web-based classes and courses.




Please add to the resource list via the comments section if you know of a valuable site we left off the list.

source : worldtruth.tv
              The Souljaspirit.blogspot.com

Monday 10 November 2014

How to Improve Vision Naturally




Contrary to popular belief, your vision doesn’t have to decline over time. With regular exercise of the muscles that control your eye movements and visual acuity, you can reduce eyestrain and maintain or even improve your vision. Utilization of a few acupressure points can also help your vision by encouraging healthy blood flow to your eyes.

The six muscles that control your eye movements are as follows:

Lateral rectus – Primarily moves your eye outward, away from your nose.

Medial rectus – Primarily moves your eye inward, toward your nose.

Superior rectus – Primarily moves your eye upward.

Inferior rectus – Primarily moves your eye downward.

Superior oblique – Primarily rotates the top of your eye toward your nose.

Inferior oblique – Primarily rotates the top of your eye away from your nose.

Perhaps the single greatest reason why people in today’s society suffer from chronic eyestrain and deteriorating vision is the amount of time that is spent staring at computer monitors and television screens.

Your eyes are designed to move regularly. Frequent movement of your eyes is what promotes optimal blood flow and nerve tone to your eyes and the six muscles that control your eye movements.

What follows are several simple eye exercises that you can do on a regular basis to keep your eyes and vision as healthy as possible:

1. Look as far to your right as possible for 3-5 seconds, then as far to your left as possible for 3-5 seconds. Rest for a few seconds, then repeat this sequence several times.

2. Look as far up as possible for 3-5 seconds, then look as far down as possible for 3-5 seconds. Rest for a few seconds, then repeat this sequence several times.

3. Slowly roll your eyes in a circle, first clockwise, then counter-clockwise. Rest for a few seconds, then repeat this sequence several times. Be sure to roll slowly – it should take at least 3 seconds for you to roll your eyes in a full circle.

4. Hold a pen in front of you, about an arm’s length away. Focus your vision on the tip of your pen for 3-5 seconds, then shift the focus of your vision to an object that is farther away for 3-5 seconds. The greater the distance between your pen and the distant object, the better. If you are indoors, look out a window to find a distant object to focus your vision on. Repeat this sequence of going back and forth between your pen and a distant object several times.

Just for interest’s sake, this exercise is used by some professional baseball players to optimize visual acuity, which is essential for the hand-eye coordination that is needed to play pro ball.

Please note that all of these exercises should be done with your eyes, not your head and neck. With this in mind, keep your head and neck still while you take your eyes through the movements described above.

If you would like more comprehensive guidance on how to improve and protect your vision as you age, I highly recommend that you read:

Relearning to See: Improve Your Eyesight – Naturally!

This is an outstanding book that offers a comprehensive array of exercises and information that can help you support your vision. And if you wear eyeglasses or contacts, following the guidance provided in this book may actually help you do away with your prescription eye wear or at the very least, help prevent deterioration of your visual acuity as you age.

Beyond doing the exercises described above on a regular basis, another way to reduce eyestrain and promote your best vision is to use your fingers to apply gentle pressure to three acupressure points that can help promote healthy blood flow to your eyes and the muscles that surround your eyes.

The best such acupressure points are as follows:


Bladder-2 (BL-2)

BL-2 is located under the innermost section of each of your eyebrows, in the top-inner region of each of your orbital sockets. When pressing on this point, you should feel direct contact with the bony surface of your orbital socket.



Additional pictures of this point and how to apply pressure to it can be found on pages 90 and 91 of Acupressure’s Potent Points: a Guide to Self-Care for Common Ailments

For those with knowledge of human anatomy: Application of pressure to BL-2 is meant to stimulate optimal blood flow and nerve function to the tendon of the superior oblique muscle, a number of smaller muscles that surround the orbital cavity, branches of the frontal branch of the trigeminal nerve, and branches of the supratrochlear and supraorbital arteries.


Stomach-2 and Stomach-3 (St-2, St-3)

St-2 and St-3 are located under the mid-line of each of your eyes. St-2 is about one finger-width under each eye, while St-3 is located at the bottom of each of your cheekbones. These points are described together because it is quite simple to apply pressure to both of them at the same time on both sides of your face by using your index and middle fingers.



For those with knowledge of human anatomy: Application of pressure to these points is meant to stimulate optimal blood flow and nerve function to the infraorbital nerve, branches of the facial nerve, and branches of the facial and infraorbital arteries and a number of muscles below and within the orbital sockets.

Please note: before self-administering acupressure, it is always best to consult with your doctor to make sure that there are no contraindications to doing so.

Source:

drbenkim.com
Worldtruth.com

Vitamin A deficiency by Larry E. Johnson, MD, PhD




World Distribution of Vitamin A Deficiency




Vitamin A (retinol) is required for the formation of rhodopsin, a photoreceptor pigment in the retina. Vitamin A helps maintain epithelial tissues. Normally, the liver stores 80 to 90% of the body's vitamin A. To use vitamin A, the body releases it into the circulation bound to prealbumin (transthyretin) and retinol-binding protein. β-Carotene and other provitamin carotenoids, contained in green leafy and yellow vegetables and deep- or bright-colored fruits, are converted to vitamin A. Carotenoids are absorbed better from vegetables when they are cooked or homogenized and served with some fats or oils.

Retinol activity equivalents (RAE) were developed because provitamin A carotenoids have less vitamin A activity than preformed vitamin A; 1 µg retinol = 3.33 IU.

Synthetic vitamin analogs (retinoids) are being used increasingly in dermatology. The possible protective role of β-carotene, retinol, and retinoids against some epithelial cancers is under study. However, risk of certain cancers may be increased after β-carotene supplementation.

VITAMIN A DEFICIENCY

Vitamin A Deficiencies


Vitamin A deficiency can result from inadequate intake, fat malabsorption, or liver disorders. Deficiency impairs immunity and hematopoiesis and causes rashes and typical ocular effects (eg, xerophthalmia, night blindness). Diagnosis is based on typical ocular findings and low vitamin A levels. Treatment consists of vitamin A given orally or, if symptoms are severe or malabsorption is the cause, parenterally.

Vitamin A deficiency occurs with protein-energy malnutrition (marasmus or kwashiorkor) for the reason that of dietary deficiency (but vitamin A storage and transport will also be impaired). This happens there are problems in converting carotene to vitamin A, or reduced absorption, storage, or transport of vitamin A. This happens in coeliac disease, tropical sprue, giardiasis, cystic fibrosis, other pancreatic disease, cirrhosis, duodenal bypass surgery, and bile duct obstruction.


Bone and teeth development and regeneration. 

Vitamin A plays an indispensable aspect in the strengthening of bones and the development of the skeletal structure in humans, right from birth to old age. Absence of vitamin A can lead to weaker bones, making them brittle and excess of a typical same can create the bone vulnerable to dangerous diseases like cancer, osteoporosis while others. Vitamin A is likewise designed to prevent tooth and gum problems.

Vision and sight improvement

Vitamin A compound retinol made use of from the eye retina under the reception of sunshine and transfer of images to the brain. Sufficient quantities of Vitamin A are involved to ensure clearer visibility and sharper eyesight. Deficiency could cause night blindness and other eye disorders similar to cataracts, etc.

Smooth disease-free skin

Vitamin A is beneficial for coping with the several skin problems like acne, pimples, sunburns, pigmentation, etc. This holds true both for the external skin surface as well as the lining of many internal organs. Vitamin A’s function in cell formation and regeneration enables person to maintain the skin free of any ailments. Healing of wounds, deficiency of wrinkles, removal of acne, all is by way of the credit rating of Vitamin A.

Reproduction

The presence of sufficient Vitamin A is crucial for the sperm growth. It helps equip smooth pregnancy, trouble free menstrual cycles, etc. Vitamin A is also utilized by women who are pregnant to address the danger of transmitting HIV for their unborn child.

Strengthening immunity

Vitamin A is required of the daily functioning of many immune system. It plays a central aspect in causing the white blood cells, that applied in fighting infections thus preventing diseases and illnesses. Red blood cell formation is also increased due to Vitamin A in the body.

Cell development, formation, regeneration

Every second, every minute, hundreds and many thousands of cells are destroyed and created in the body. Vitamin A consists of a major role to act like under the development of new cells, repair of injured or sick cells.


Etiology
Primary vitamin A deficiency is usually caused by prolonged dietary deprivation. It is endemic in areas such as southern and eastern Asia, where rice, devoid of β-carotene, is the staple food. Xerophthalmia due to primary deficiency is a common cause of blindness among young children in developing countries.

Secondary vitamin A deficiency may be due to decreased bioavailability of provitamin A carotenoids or to interference with absorption, storage, or transport of vitamin A. Interference with absorption or storage is likely in celiac disease, cystic fibrosis, pancreatic insufficiency, duodenal bypass, chronic diarrhea, bile duct obstruction, giardiasis, and cirrhosis. Vitamin A deficiency is common in prolonged protein-energy undernutrition not only because the diet is deficient but also because vitamin A storage and transport is defective. In children with complicated measles, vitamin A can shorten the duration of the disorder and reduce the severity of symptoms and risk of death.
Symptoms and Signs - Impaired dark adaptation of the eyes, which can lead to night blindness, is an early symptom.

Xerophthalmia

Keratoconjunctivitis sicca (KCS) - also called keratitis sicca, xerophthalmia or dry eye syndrome (DES) is an eye disease caused by eye dryness, which, in turn, is caused by either decreased tear production or increased tear film evaporation

Keratinization of the skin and of the mucous membranes in the respiratory, GI, and urinary tracts can occur. Drying, scaling, and follicular thickening of the skin and respiratory infections can result. Immunity is generally impaired.

The younger the patient, the more severe are the effects of vitamin A deficiency. Growth retardation and infections are common among children. Mortality rate can exceed 50% in children with severe vitamin A deficiency. 

Diagnosis - Serum retinol levels, clinical evaluation, and response to vitamin A.

Ocular findings suggest the diagnosis. Dark adaptation can be impaired in other disorders (eg, zinc deficiency, retinitis pigmentosa, severe refractive errors, cataracts, diabetic retinopathy). If dark adaptation is impaired, rod scotometry and electroretinography are done to determine whether vitamin A deficiency is the cause.

Serum levels of retinol are measured. Normal range is 28 to 86 μg/dL (1 to 3 µmol/L). However, levels decrease only after the deficiency is advanced because the liver contains large stores of vitamin A. Also, decreased levels may result from acute infection, which causes retinol-binding protein and transthyretin (also called prealbumin) levels to decrease transiently. A therapeutic trial of vitamin A may help confirm the diagnosis.


Prevention

The diet should include dark green leafy vegetables, deep- or bright-colored fruits (eg, papayas, oranges), carrots, and yellow vegetables (eg, squash, pumpkin). Vitamin A–fortified milk and cereals, liver, egg yolks, and fish liver oils are helpful. Carotenoids are absorbed better when consumed with some dietary fat. If milk allergy is suspected in infants, they should be given adequate vitamin A in formula feedings.

In developing countries, prophylactic supplements of vitamin A palmitate in oil 60,000 RAE (200,000 IU) po every 6 mo are advised for all children between 1 and 5 yr of age; infants < 6 mo can be given a one-time dose of 15,000 RAE (50,000 IU), and those aged 6 to 12 mo can be given a one-time dose of 30,000 RAE (100,000 IU).

Treatment

Vitamin A palmitate

Dietary deficiency is traditionally treated with vitamin A palmitate in oil 60,000 IU po once/day for 2 days, followed by 4500 IU po once/day. If vomiting or malabsorption is present or xerophthalmia is probable, a dose of 50,000 IU for infants < 6 mo, 100,000 IU for infants 6 to 12 mo, or 200,000 IU for children > 12 mo and adults should be given for 2 days, with a third dose at least 2 wk later. The same doses are recommended for infants and children with complicated measles. Infants born of HIV-positive mothers should receive 50,000 IU (15,000 RAE) within 48 h of birth. Prolonged daily administration of large doses, especially to infants, must be avoided because toxicity may result.

For pregnant or breastfeeding women, prophylactic or therapeutic doses should not exceed 10,000 IU (3000 RAE)/day to avoid possible damage to the fetus or infant.

Key Points

Vitamin A deficiency usually results from dietary deficiency, as occurs in areas where rice, devoid of β-carotene, is the staple food, but it may result from disorders that interfere with the absorption, storage, or transport of vitamin A.
Ocular findings include impaired night vision (early), conjunctival deposits, and keratomalacia.
In children with severe deficiency, growth is slowed and risk of infection is increased.
Diagnose based on ocular findings and serum retinol levels. Treat with vitamin A palmitate.


VITAMIN A TOXICITY

Vitamin A toxicity can be acute (usually due to accidental ingestion by children) or chronic. Both types usually cause headache and increased intracranial pressure. Acute toxicity causes nausea and vomiting. Chronic toxicity causes changes in skin, hair, and nails; abnormal liver test results; and, in a fetus, birth defects. Diagnosis is usually clinical. Unless birth defects are present, adjusting the dose almost always leads to complete recovery.

Acute vitamin A toxicity in children may result from taking large doses (> 300,000 IU [> 100,000 RAE]), usually accidentally. In adults, acute toxicity has occurred when arctic explorers ingested polar bear or seal livers, which contain several million units of vitamin A.

Chronic toxicity in older children and adults usually develops after doses of > 30,000 RAE (> 100,000 IU)/day have been taken for months. Megavitamin therapy is a possible cause, as are massive daily doses (50,000 to 120,000 RAE [150,000 to 350,000 IU]) of vitamin A or its metabolites, which are sometimes given for nodular acne or other skin disorders. Adults who consume > 1500 RAE (> 4500 IU)/day of vitamin A may develop osteoporosis. Infants who are given excessive doses (6,000 to 20,000 RAE [18,000 to 60,000 IU]/day) of water-miscible vitamin A may develop toxicity within a few weeks. Birth defects occur in children of women receiving isotretinoin (which is related to vitamin A) for acne treatment during pregnancy.

Although carotene is converted to vitamin A in the body, excessive ingestion of carotene causes carotenemia, not vitamin A toxicity. Carotenemia is usually asymptomatic but may lead to carotenosis, in which the skin becomes yellow. When taken as a supplement, β-carotene has been associated with increased cancer risk; risk does not seem to increase when carotenoids are consumed in fruits and vegetables.


Symptoms and Signs

Although symptoms may vary, headache and rash usually develop during acute or chronic toxicity. Acute toxicity causes increased intracranial pressure. Drowsiness, irritability, abdominal pain, nausea, and vomiting are common. Sometimes the skin subsequently peels.

Early symptoms of chronic toxicity are sparsely distributed, coarse hair; alopecia of the eyebrows; dry, rough skin; dry eyes; and cracked lips. Later, severe headache, pseudotumor cerebri, and generalized weakness develop. Cortical hyperostosis of bone and arthralgia may occur, especially in children. Fractures may occur easily, especially in the elderly. In children, toxicity can cause pruritus, anorexia, and failure to thrive. Hepatomegaly and splenomegaly may occur.

In carotenosis, the skin (but not the sclera) becomes deep yellow, especially on the palms and soles.
Diagnosis


Clinical evaluation

Diagnosis is clinical. Blood vitamin levels correlate poorly with toxicity. However, if clinical diagnosis is equivocal, laboratory testing may help. In vitamin A toxicity, fasting serum retinol levels may increase from normal (28 to 86 μg/dL [1 to 3 µmol/L]) to > 100 μg/dL (> 3.49 µmol/L), sometimes to > 2000 μg/dL (> 69.8 µmol/L). Hypercalcemia is common.

Differentiating vitamin A toxicity from other disorders may be difficult. Carotenosis may also occur in severe hypothyroidism and anorexia nervosa, possibly because carotene is converted to vitamin A more slowly.
Prognosis

Complete recovery usually occurs if vitamin A ingestion stops. Symptoms and signs of chronic toxicity usually disappear within 1 to 4 wk. However, birth defects in the fetus of a mother who has taken megadoses of vitamin A are not reversible. recommended treatment is to stop Vitamin A administeration.

Key Points

Vitamin A toxicity can be caused by ingesting high doses of vitamin A—acutely (usually accidentally by children) or chronically (eg, as megavitamin therapy or treatment for skin disorders).
Acute toxicity causes rash, abdominal pain, increased intracranial pressure, and vomiting.
Chronic toxicity causes rash, increased intracranial pressure, sparse and coarse hair, dry and rough skin, and arthralgia; risk of fractures is increased, especially in the elderly.
Diagnose based on clinical findings.
When vitamin A is stopped, symptoms (except birth defects) usually resolve within 1 to 4 wk.

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