We are now deep in the heart of winter, and you have probably already spent a good deal of the season trying to keep cold and flu viruses away by frequently washing your hands, getting lots of rest, and eating plenty of fruits and vegetables to keep your immune system in top shape. One nutrient that is important for battling infections is vitamin A.
This nutrient is based on chemical substances called retinoids and carotenoids. Each performs a number of vital functions in the body.
Immune System
When it comes to viruses and bacteria, vitamin A boosts the strength of mucous to fight these organisms and prevent them from entering the body. Vitamin A is also key in the development of lymphocytes - white blood cells that spur your immune system into action and kill infected cells.
Blood Health
As well as influencing white blood cells, vitamin A plays a role in the development of oxygen carried by red blood cells. Sufficient amounts of this vitamin can also help increase the supplementation is often used to treat iron-deficiency anemia.
Vision
Vitamin A is crucial for eye health, as it helps your vision adjust to darkness and protects many parts of the eye from damage. We are fortunate in North America because vitamin A deficiency is rare compared to developing countries, where this nutrient deficiency is the leading cause of blindness.
Cancer
Vitamin A may play a positive role in cancer by preventing the creation of cancerous cells. But more research needs to be conducted as some of the results from the cancer studies are mixed.
In one study, researchers were surprised to find that vitamin A may actually increase the risk of lung cancer in smokers. The research recruited 9,000 smokers and gave each of them 25,000 international units of retinol and 30 milligrams of betacarotene (both vitamin A precursors) daily for four years. At the end of the research period, the incidence of lung cancer was 28% higher in the supplement group compared to the placebo group. However, a study undertaken in China revealed participants who took a daily supplement containing betacarotene, selenium and vitamin E for five years saw a 13% reduction in esophageal and gastric cancers.
An interesting report published in the Archives of Internal Medicine showed that high blood levels of alpha-carotene (converted to vitamin A in the body) were linked to a lower overall risk of death from disease over a 14-year period. Alpha-carotene also seemed to reduce the chances of dying from cancer and cardiovascular disease. The researchers noted that alpha-carotene may be more powerful at blocking cancerous tumors than its chemically similar cousin beta-carotene.
Best Dietary Sources of Vitamin A
How much vitamin A should you get daily? The answer will depend on your age, gender and current state of health. Daily guidelines suggest 900ug (micrograms) for men and 700ug for women (19 years or older). Amounts for infants and children vary by age. Talk to your chiropractor for the amount that is right for you and your loved ones.
The best supplies of vitamin A can be found in yellow, orange and dark green vegetables, such as carrots, sweet potatoes, spinach, asparagus and yellow squash. Whole eggs, fish liver oil and fortified dairy products are also good sources.
Too Much of a Good Thing
Large doses of vitamin A supplements can be toxic, and depending on the chemical formulation, may increase the risk of birth defects. You should not take supplements without first discussing them with a qualified healthcare professional.
Make an appointment with your chiropractor to review your nutritional habits and discover the ways to eat for optimal health.
Disclaimer: Information contained in this Wellness Express™ newsletter is for educational and general purposes only and is designed to assist you in making informed decisions about your health. Any information contained herein is not intended to substitute advice from your physician or other healthcare professional. Copyright © Wellness Express™
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