Common Cold Prevention: Vitamin C

In the 1970s, a scientist named Linus Pauling stated that consuming at least 1,000 mg of vitamin C every day could prevent the common cold. Since that time, various studies have shown that vitamin C cannot actually prevent the onset of the common cold, but it can shorten the duration and severity of symptoms once you have a cold.

Vitamin C and Colds

Vitamin C can help shorten the duration and severity of a cold in two ways. The vitamin helps boost your immune system by enabling the body to produce adequate amounts of healthy white blood cells. White blood cells are an important aspect in the fight against infections. According to "Nutrition and You," vitamin C also has an antihistamine effect, which can block the action of the chemical histamine, which causes many of the symptoms associated with a cold.

Recommended Daily Intakes

The Food and Nutrition Board, a subgroup of the Institute of Medicine, provides recommendations for daily intake of vitamin C based on age and sex. Children between the ages of 1 and 3 should consume 15 mg of vitamin C per day, whereas children between 4 and 8 should consume 25 mg daily. Female and male children between the ages of 9 and 13 should consume 45 mg of vitamin C every day. Males between the ages of 14 and 18 should consume 75 mg per day, and females of the same age should consume 65 mg per day. Adult males over the age of 18 should aim for 90 mg of vitamin C every day, and adult females over the age of 18 should consume 75 mg daily.

Food Sources of Vitamin C

According to "Nutrition and You," Americans meet approximately 90 percent of their vitamin C needs through the consumption of fruits and vegetables. Oranges and orange juice are the most popular food sources. Other excellent sources of vitamin C include tomatoes, cantaloupe, peppers, potatoes and broccoli.

Considerations

Vitamin C is a water-soluble vitamin, meaning it immediately dissolves in water upon entering the body and is deposited directly into the bloodstream. Because it circulates in water, however, excess amounts of a water-soluble vitamin are excreted in the urine, rather than stored in the body. Because of this it is important to make sure that you are consuming recommended amounts of vitamin C every day.

Upper Intake Level

Although high amounts of vitamin C aren't known to be toxic to humans, consuming too much vitamin C can cause nausea, abdominal cramps and diarrhea. Because of this, you should take care when using any supplements or eating foods fortified with vitamin C. The upper limit for vitamin C has been set at 2,000 mg per day for adults.