The world of vitamins and minerals can be confusing and intimidating. There are eight forms of vitamin B alone! In the next few weeks, I hope to bring a little more clarity to vitamins and minerals, the reasons we need them, the different forms they come in, and how much we need to take.
We'll start right at the beginning with vitamin A.
The food most commonly associated with vitamin A may be carrots! Carrots contain carotenoids, a group of pigments found in yellow, orange and green fruits and vegetables. Carotenoid-containing fruits and vegetables such as carrots, cantaloupe, apricots, broccoli, sweet potatoes and spinach, as well as dairy products, liver and egg yolks, provide a good source of the fat-soluble vitamin A that is essential to our health.
There are two different forms of vitamin A found in the human diet. One is retinol, also known as preformed vitamin A. It is one of the most usable forms of vitamin A and is found in both plant and animal sources. The other is provitamin A carotenoids. These are darkly colored pigments found in plant foods that can be converted to vitamin A. Common carotenoids found in foods are beta-carotene, alpha-carotene, lutein, zeaxanthin, lycopene and cryptoxanthin. The one that is most efficiently converted to retinol in the body is beta-carotene.
Vitamin A helps you see normally in the dark. In fact, one of the first signs of a deficiency is night blindness, a condition in which the eyes have difficulty adjusting to the dark or to bright lights. If it takes you more than a minute to adjust your eyes in a darkened area, you may have this condition. Although vitamin A deficiency is not common in North America, it still occurs as diets become more and more processed.
Vitamin A is also involved in the formation and maintenance of healthy skin, hair and mucous membranes, which provide a barrier to bacteria and viruses. It may also help lymphocytes, a type of white blood cell, fight infections more effectively. In countries where vitamin A deficiency is common, millions of children die each year from complications of infectious diseases. Vitamin A is necessary for proper bone growth, tooth development, reproduction and cell division.
Some carotenoid compounds, in addition to providing vitamin A, have also been shown to function as antioxidants, which are important for protecting cells from free radicals that are thought to contribute to degenerative diseases such as cancer and heart disease.
Eating a variety of foods that contain vitamin A (and carotenoids) is the best way to get an adequate amount. Healthy individuals who eat a balanced diet, including plenty of yellow and orange fruits, dark green leafy vegetables, and lean meat and eggs, rarely need to supplement with vitamin A. Ideally, we should get a minimum of five daily servings of carotenoid-rich fruits and vegetables.
Since vitamin A can be lost from foods during preparation, cooking or storage, serve fruits and vegetables raw whenever possible. Keep vegetables and fruits covered and refrigerated during storage. Steam vegetables, and braise, bake or broil meats instead of frying.
Although vitamin A is an essential nutrient found in our diets, taking too much vitamin A can be toxic. Vitamin A is a fat-soluble vitamin and is easily stored in the body. Taking large doses for prolonged periods can cause severe problems. These include vomiting, bone and joint pain, dry scaly skin and liver damage. It is important to consult with a health care professional before taking any supplement.
Photo from here, with thanks.