The ancient Egyptians had a cure for "night blindness". They fed the patient lots and lots of liver. Perhaps they thought they were appeasing the Gods of sight. In 1930, the first fat-soluble vitamin was discovered - vitamin A - which, it turns out, does indeed appease the Gods of sight.

Vitamin A is best known for improving eyesight, particularly at night, which is one of two reasons we call it the glow-in-the-dark vitamin. But the eyes are not the only part of your body grateful for your generous consumption of vitamin A.

Your skin also benefits. And your hair. And mucous membranes. And nails. In fact, almost any surface lining your body can find.

Your immune system benefits, too, giving you added resources to ward off infections. Bones and teeth are strengthened with proper amounts of vitamin A, and even the risk of some cancers can be reduced with vitamin A.

And there are more confirmed and suspected benefits.

The other reason we call Vitamin A the glow-in-the-dark vitamin is because it is best known as the bright orange color in so many foods we enjoy. Like pumpkins, pumpkin pie and my favorite: pumpkin cheesecake ( see my recipe at http://www.thehappyguy.com/pumpkin-cheesecake-recipe.html ). And, of course, carrots, squash, peaches, apricots, cantaloupe, mangoes, sweet potatoes and the rest of the orange-spangled veggie gang.

But again, vitamin A is much more than meets the eye, because it is not actually vitamin A that turns the fruit and vegetables orange, but a precursor to vitamin A called beta carotene. Beta carotene does not become vitamin A until your body processes it.

And vitamin A is just as likely, if not more so, to come from protein sources such as most dairy products, egg yolks and some fish. And the queen of all vitamin A sources is liver, that ancient Egyptian God of sight. Calves liver. Chicken liver. Pork liver. Any liver you can sink your teeth into.

The vitamin A in protein sources is real vitamin A, no processing required.

Other great sources of vitamin A are dark green vegetables, such as Swiss chard, broccoli, spinach and beet greens.

As important as it is to glow with vitamin A, don't glow too brightly. An overdose can be harmful to bones and skin, causing weakness and brittleness, even leading to fatigue and vomiting.

It is advisable not to take a vitamin A supplement except under the supervision of a physician. In most cases, it is much better to take a liquid multivitamin such as Essential Nectar in recommended daily doses. There is very little chance of getting an overdose that way.

Also, increase your intake of beta carotene sources to avoid an overdose. Whereas your body absorbs all the vitamin A it takes in directly, it converts only the beta carotene it needs (talk about customization!).

So get glowing and get the vitamin A you need.

David Leonhardt

David Leonhardt is a website marketing specialist and an SEO consultant. He also publishes A Daily Dose of Happiness and is author of Climb Your Stairway to Heaven: The 9 Habits of Maximum Happiness. Prior to his online career, he was one of the best-known consumer advocates in Canada.