Taking Vitamin A supplements must be handled by a physician. Tests must be taken to prove deficiencies and dosages must be regulated. Too much Vitamin A causes brittle fingernails, hair loss, low blood pressure, pain, nausea and diarrhea, mouth ulcers, immune deficiencies, blood in the lungs, thyroid malfunctions, brain swelling, seizures, heart disease, liver inflammation, comas and in some cases even death.
Beta carotene is a red-orange pigment found in many fruits and vegetables and the body converts this substance into retinol. It is easy to eat enough beta carotene produce, including some green produce to provide the body with all the Vitamin A, it needs. Good sources of beta carotene are carrots, beets, green peas, pumpkin, sweet potatoes, all peppers sweet and hot, soy, broccoli, spinach and other greens including turnip, mustard, Swiss chard and collards, radishes, Brussels sprouts, green beans, all lettuce, kale, asparagus, avocado, cabbage, cucumbers, tomatoes, apricots, peaches, all berries, all melons, all citrus fruit, mangoes, papayas, pumpkin pie spice, apple pie spice, cayenne, basil, turmeric, dill, garlic, parsley, cloves, linoleic acid found in most vegetable oils, and alfalfa tablets. For a treat have a glass of lemonade or limeade.
As reported in the University of Wisconsin-Madison publication, On Wisconsin magazine, March 2013 "The Birth of Vitamin A" by Kate Prengaman as cited below.. In the late 1800's and early 1900's many men and women were researching dietary and nutritional needs in both humans and animals. Elmer McCollum nearly died from malnutrition as a child and spent years of his adult life trying to separate elements in everything from milk to grasses and plant leaves. In essence he was isolating proteins, fats and carbohydrates. He was hunting growth promoting nutrients. His hope was to keep other children from suffering from malnutrition with easily made dietary adjustments.He found what he called a "fat soluble factor." In 1913 he published a book relating his research and calling his find "factor A."
In 1912 Casimir Funk went public with his "Vitamine hypothesis" and after reading McCollum's published work he coined the term Vitamin A and even though McCollum said that his factor was not an amine, Funk's name stuck.