Osteomalacia is a disease in adults that results from vitamin D deficiency. Characteristics of this disease are softening of the bones, leading to bending of the spine, bowing of the legs, proximal muscle weakness, bone fragility, and increased risk for fractures.
https://en.wikipedia.org/wiki/Vitamin-D
Quick Answer. The term vitamin E describes a group of eight fat-soluble antioxidants, all of which are naturally present in certain types of foods, according to The World's Healthiest Foods. Foods that are rich in vitamin E include sunflower seeds, spinach, peanuts, asparagus and mustard greens, among others, according to Healthaliciousness.com. Keep Learning.
https://www.reference.com/health/vitamin-e-come-a932538b3027de73
“Vitamin A” is the blanket term for retinoids, biologically active compounds that occur naturally in both plant and animal tissues. The vitamin A that comes from animal sources is fat-soluble, and in the form of retinoic acid, retinal and retinol. Because these retinoids are very bioavailable and stored in our tissues, too much animal-derived vitamin A can build up in the body and become toxic.
https://www.drweil.com/vitamins-supplements-herbs/vitamins/facts-about-vitamin-a/
Vitamin D refers to a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, iron, magnesium, phosphate, and zinc. In humans, the most important compounds in this group are vitamin D3 (also known as cholecalciferol) and vitamin D2 (ergocalciferol).
https://en.wikipedia.org/wiki/Vitamin-D
Vitamin A is necessary for eye health and vision. Vitamin A, a fat-soluble vitamin found as either preformed vitamin A or provitamin A carotenoids in the diet, plays an important role in the growth and development of several systems in the body. According to the Office of Dietary Supplements, preformed vitamin A commonly comes from animal sources, especially liver. Beta-carotene is the most common form of provitamin A carotenoid and is present in many dark orange fruits and vegetables.
http://healthyeating.sfgate.com/vitamin-do-5262.html
What foods might naturally contain B12? Animal foods, including meat, milk, and eggs, contain B12 and are essentially the exclusive source of the vitamin in the American food supply (not counting supplements or fortification).
http://nutritionstudies.org/12-questions-answered-regarding-vitamin-b12/
What you’ll learn is that B12 certainly need not cause anxiety once you have a little bit of understanding about the vitamin and what you should do to get enough. Here is a conversation covering the basics. This is my interpretation of the evidence for general knowledge and should not be taken as medical advice.
http://nutritionstudies.org/12-questions-answered-regarding-vitamin-b12/
Vitamin K: What Is It and Where Does It Come From? Vitamin K is a fat soluble vitamin found in a variety of food sources. Vitamin K refers to a family of compounds (Figure 1), the most common consumed form being phylloquinone (vitamin K1) which is found in plants. Figure 1.
http://www.thedoctorwillseeyounow.com/content/nutrition/art2043.html
Vitamin B12 is one of the most common topics I get asked about for those interested in a plant-based diet. I think we have a natural tendency to make sure we are getting enough of everything, and vitamin B12 is a legitimate concern for exclusively plant-based eaters, so it causes a fair amount of anxiety.
http://nutritionstudies.org/12-questions-answered-regarding-vitamin-b12/
Vitamin A is a fat-soluble vitamin that comes from two sources: preformed retinoids and provitamin carotenoids. Retinoids, such as retinal and retinoic acid, are found in animal sources such as liver, kidney, eggs, and dairy products. Carotenoids, such as beta-carotene (which has the highest vitamin A activity), are found in plants such as dark or yellow vegetables and carrots.
http://www.mayoclinic.org/drugs-supplements/vitamin-a/background/HRB-20060201
what does vitamin a come from
Vitamin A is coming from animal sources and in the form of retinoic acid, retinal and retinol.