Health and Fitness Hints

Vitamin A is also called retinol is another  member of the fat-soluble nutrients such as vitamin D and K that occurs naturally in two different forms; pro-vitamin A or carotene and the preformed vitamin A found only in certain tissue of animal products.

Carotene is an orange pigment found in many foods. It splits by specialized enzymes in the body to become two active units of vitamin A.

Carotene is abundant in carrots, from which the name is derived, but it is present in higher concentrations in some green and leafy vegetables such as broccoli, beet greens and spinach. One of the richest sources of preformed A is fish liver oil. Animal products such as butter and cream are also good sources of vitamin A and may contain both forms.

Vitamin A plays essential roles in

• Vision; it is important for maintenance of good vision.
• Growth, development and maintenance of healthy skin; it aids the growth and repair of body tissues and helps to maintain smooth, soft and disease free skin.
• Mucous membranes; it protects the mucus membranes of the mouth, nose, throat and lungs and helps reducing susceptibility from infections and air pollution..
• Immune functions; administration of vitamin A has helped shorten the duration of measles, scarlet fever, infections of the eye, ear, intestines, uterus and externally in treating acne and boils.
• Reproduction; Normal levels of vitamin A are required for sperm production and normal reproductive cycles in females.

The upper intestinal tract is the area where primarily vitamin A absorption takes place. Here special enzymes convert carotene into preformed vitamin A. However, the conversion is not 100 percent complete; about one third of carotene in food converts into preformed A.

Several factors that interfere with absorption of vitamin A and carotene are: excessive alcohol, excessive consumption of iron, polyunsaturated fatty acids taken together with carotene; results in rapid destruction of carotene unless antioxidants are also present. Low weather temperatures can hinder transport and metabolism of both preformed A and carotene. Diabetics have great difficulty converting carotene into preformed A type.

Both deficiency and excess intake of vitamin A are well known causes of health issues. In contrast, excessive intake of Carotenoids is not known to cause any health problems. Excess intake (magadoses) of preformed Vitamin A for long periods of time can become toxic. Toxicity symptoms include nausea, vomiting, diarrhea, dry skin, headaches, flaky itchy skin, enlargement of liver and bone fragility.

If toxicity occurs symptoms disappear in a few days once the vitamin is withdrawn. Vitamin C helps with vitamin A toxicity. Shortly before or during pregnancy the daily amount of pre-formed and/or supplemental A intake must limited to 3,300 IU as retinol or 5,000 IU of vitamin A obtained from their diet as it is known higher amounts could cause congenital defects.

Vitamin A deficiency takes place when not sufficient dietary supply exists; when the body is not able to absorb and/or store the vitamin because of conditions such as cirrhosis of the liver, bile duct obstruction, ulcerative colitis; when health ailments interferes with conversion of carotene such as diabetes and hypothyroidism; and in cases of rapid loss of the vitamin such as in case of pneumonia, chronic nephritis and scarlet fever.

Deficiency due to malnutrition or malabsorption can cause; blindness because of inability of the body to synthesize sufficient rhodopsion; increased risk of mortality from infectious disorders - substantially reduce mortality from diseases such as gastrointestinal infections and measles; compromised and abnormal function of epithelia cells- dry skin conditions; compromised mucosal secretions; decreased thyroid hormones and abnormal bone growth.

visit my other sites

Health and Fitness

Health and Fitness Best an online Health Choice Destination.

If you're new here, you may want to subscribe to my RSS feed. Thanks for visiting!