Does vitamin C prevent, shorten, or cure the common cold?
What is the function of vitamin C?
Vitamin C is a water-soluble nutrient that humans cannot make within their own body. Vitamin C has two major functions within the body that are reducing damage caused by oxidative stress and being essential to many enzymatic reactions.
According to the Linus Pauling Institute "Vitamin C even in small amounts, can protect indispensable molecules in the body, such as proteins, lipids, carbohydrates, and DNA & RNA, from damage by free radicals and reactive oxygen species that are generated during normal metabolism, by active immune cells, and through exposure to toxins and pollutants as well as recycle other antioxidants like vitamin E.
Many readers may be interested to know that vitamin C is a cofactor to reactions that create collagen (the major component of connective tissues that make up several body parts, including tendons, ligaments, skin, and muscles) and carnitine (crucial to energy production) in addition to influencing how genes are expressed.
The big question on everyone's mind is can vitamin C prevent the common cold?
According to the Linus Pauling Institute, there are mixed results based on scientific research. However, vitamin C supplementation did reduce the incidence of cold by 50% in individuals under heavy physical stress (think athletes or workers in unforgiving environments). Regular vitamin C supplementation decreased the duration of cold in children and adults with greater benefit to the children. The reductions in duration were 14% and 8% respectively. Most importantly and contrary to popularly held beliefs, vitamin C supplementation at onset of cold (1 to 8 grams per day) showed no significant effect in therapeutic trials.
What are natural dietary sources of vitamin C?
There are many excellent sources of naturally occurring vitamin C. According to Dr. Axe they include (in descending order):
- Black Currant — 1 cup: 203 milligrams (338 percent DV)
- Red Pepper — 1 cup: 190 milligrams (317 percent DV)
- Kiwifruit — 1 cup: 164 milligrams (273 percent DV)
- Guava — 1 fruit: 126 milligrams (209 percent DV)
- Green Bell Pepper — 1 cup: 120 milligrams (200 percent DV)
- Orange — 1 large: 98 milligrams (163 percent DV)
- Strawberries — 1 cup: 89 milligrams (149 percent DV)
- Papaya — 1 cup: 87 milligrams (144 percent DV)
- Broccoli — 1 cup, raw: 81 milligrams (135 percent DV)
- Kale — 1 cup, raw: 80 milligrams (134 percent DV)
- Parsley — 1 cup: 80 milligrams (133 percent DV)
- Pineapple — 1 cup: 79 milligrams (131 percent DV)
- Brussels Sprouts — 1/2 cup, cooked: 48 milligrams (81 percent DV)
- Cauliflower — 1 cup, raw: 46 milligrams (77 percent DV)
- Mango — 1 cup: 46 milligrams (76 percent DV)
- Lemon — 1 fruit: 45 milligrams (74 percent DV)
- Grapefruit — 1/2 fruit: 38 milligrams (64 percent DV)
- Honeydew — 1 cup: 32 milligrams (53 percent DV)
- Peas — 1 cup, cooked: 23 milligrams (38 percent DV)
- Tomatoes — 1 cup, raw: 23 milligrams (38 percent DV)
Should I be wary of synthetic vitamin C?
According to the Linus Pauling Institute, "Natural and synthetic L-ascorbic acid are chemically identical and there are no known differences regarding biological activities or bioavailability."
Is there more?
There is much to learn about vitamin C and we recommend starting with the Linus Pauling Institute's vitamin C page. They have well-cited easy to read content that is balanced and inforamative. See below for link.
Reference:Linus Pauling Institute: https://lpi.oregonstate.edu/mic/vitamins/vitamin-C