Vitamin A plays an important role in the proper health and nutrition of men. It helps vision, bone growth, regulates the immune system and prevents infection. However, when it comes to taking vitamin A supplements, getting too much of a good thing is possible. Since vitamin A is a fat-soluble vitamin, it is stored in the body and is not flushed away like water-soluble vitamins. If you are a man taking vitamin A supplements, take care not to consume too much.
Types of Vitamin A
Two categories of vitamin A exist. Foods that come from animals that contain vitamin A is called preformed vitamin A, while foods that come from plants that contain vitamin A are called provitamin A carotenoid. Your body generally can absorb and use vitamin A that comes from animal-based foods better than vitamin A that comes from plant-based foods, according to the Office of Dietary Supplements. Although it is unlikely that you will consume too much vitamin A through food alone, whether it is preformed vitamin A or provitamin A carotenoid, it is possible to consume too much if you take vitamin supplements.
Recommended Daily Allowance
The recommended daily allowance of vitamin A is listed as micrograms of retinol activity equivalents. They are published in this way so that the differences in biological activity of the two types of vitamin A can be accounted for. Most males older than the age of 13 should consume about 900 mcg RAE each day. Most vitamin supplements will display the amount of vitamin A in IUs, however. The RDA for males older than the age of 13 is equivalent to 3,000 IU. However, your specific recommended daily amount of vitamin A may vary, depending on your lifestyle and medical situation. If you believe you may have a special life circumstance that may require more or less of this vitamin, contact your doctor.
Tolerable Upper Intake Levels
While you can usually consume slightly more vitamin A than the recommended daily allowance, exceeding the tolerable upper intake levels increases your risk of experiencing unpleasant or even dangerous side effects. In 2011, the tolerable upper intake level for retinol vitamin A was 2,800 mcg for boys 14 to 18 and 3,000 mcg for men older than the age of 18. This is the equivalent to 9,240 IU and 10,000 IU respectively. However, some men who have a vitamin A deficiency or other medical condition may require more than these amounts. Always talk to your doctor if you are unsure of how much vitamin A to take.
Hypervitaminosis A
Hypervitaminosis A is a condition that occurs when a person stores too much vitamin A in the body. Although it is possible to exceed these amounts through food alone, it is unlikely. It most often occurs as a result of taking excessive amounts of vitamin supplements. Hypervitaminosis A can lead to liver abnormalities, central nervous system disorders and reduced bone mineral density in men. Symptoms of this condition include nausea, vomiting, dizziness, headache, blurred vision and lack of coordination.
Considerations
Vitamin A supplements in the form of beta-carotene may also pose health risks when taken in excess. Although research was ongoing as of April 2011, some studies have indicated that beta-carotene supplements may increase the incidence of lung cancer and death among smokers. Others studies have not found this to be true. While there are not established tolerable upper levels for beta-carotene supplements, the Institute of Medicine recommends that men should avoid taking these supplements unless specifically instructed by a doctor to do so.
References
- Office of Dietary Supplements: Vitamin A and Carotenoids
- Colorado State University Extension; Fat-Soluble Vitamins; J. Anderson et al; 2008
- Institute of Medicine of the National Academies: Dietary Reference Intakes: Recommended Dietary Allowances and Adequate Intakes, Vitamins
- Institute of Medicine of the National Academies: Dietary Reference Intakes: Tolerable Upper Intake Levels, Vitamins
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