Vitamin C – does it cure colds?
Vitamin is also known as ascorbic acid. It’s a water soluble vitamin which means it’s found in the watery compartments of food, and is quickly absorbed into the blood stream when consumed. Water soluble vitamins travel freely throughout the body and are taken up by cells as needed. Excess water soluble vitamins are excreted, generally via the kidneys. This means you need to have a regular intake of foods with water soluble vitamins to keep levels up.
More about Vitamin C
Humans cannot synthesis vitamin C, so it must be obtained through the diet, or supplements if the diet is inadequate. Vitamin C is dose dependent i.e the more you take the less the body takes up the vitamin. So if you choose to supplement with vitamin C, don’t take one or 2 large does, spread the dose out. Better yet, consult a practitioner qualified in nutrition as they will be able to prescribe a dosage regime that will ensure uptake of the vitamin.
The recommended daily allowance of vitamin C is between 75mg and 90mg per day. Smokers need an additional 35mg per day. You’ll find vitamin C in citrus fruits, green leafy vegetable (cabbage etc, lettuce), capsicum, broccoli, strawberries, black currants, rosehips and parsley.
Vitamin C and the Immune System
So, does vitamin C prevent colds and flu? There is no short answer to this question. Vitamin C is an immunomodulator i.e it regulates immune function through enhancing the activity of immune cells. Vitamin C increases immunity a number of ways, e.g influencing T-cells, stimulating the production of interferons (proteins that protect cells against viruses), stimulating production of antibodies, and stimulating production of humoral thymus factor. Vitamin C also improves the function of leucocytes (white blood cells).
Think of Vitamin C as a nutrient that primes the internal army that fights viruses and other pathogens. To achieve this effect you need to take vitamin C beyond the recommended daily intake (RDI). This should only be done under the supervision of a suitably qualified practitioner. Taking vitamins and other supplements in high does can be dangerous, so don’t do it without seeking advice first.
Using Vitamin C to boost your immune system
A maintenance dose of vitamin C, along with specific herbs, is a standard preventative of colds and flu over the winter months. Vitamin C is also useful in the prevention and management of seasonal allergies as is inhibits the release of histamines.
Other functions of Vitamin C
Vitamin C is an antioxidant i.e it mops up excess free radicals produced as part of the metabolic process, and those that make their way into the body in other ways e.g smoking, exposure to pollution. Vitamin C is also needed for the formation of collagen, the matrix which holds tissue, including teeth, together. Collagen holds cell walls together, so is really important for all tissues, particularly blood vessels. When you think about what vitamin C does for collagen production, you can see the link between low vitamin C levels and scurvy, symptoms of which include bleeding gums. Other symptoms of vitamin C deficiency include muscle degeneration, pin-point haemorrhages and skin becomes scaly, dry and rough.
Vitamin C enhances iron absorption.
Bioavailability of Vitamin C
A very important consideration with vitamins sourced from food or supplements, and other nutrients, is bioavailability. While it’s easy to determine how much vitamin is present in a particular food, it’s difficult to say how much of that vitamin is absorbed by the body once the food is consumed. An efficient digestion will break down the food so that the nutrients are readily available for absorption. This will depend on nutritional status, what foods/nutrients are consumed at the same time, how the food is prepared (cooked, processed, raw) and whether the nutrient comes from a natural source or is synthetic. The best way to get vitamin C is from fresh food on a daily basis. Supplement if your diet is low in vitamin C rich foods, but only to the recommended RDA.
Adverse Reactions to Vitamin C
Too much vitamin C (usually taken as a supplement) can lead to symptoms including nausea, abdominal cramps, and diarrhoea.
Excessive doses of vitamin C can adversely effect warfarin and other anti-coagulants, as well as being detrimental to people with iron overload.
Inadequate Vitamin C
British sailors of the later 1700s and early 1800s who were known to have a daily ration of lime juice to prevent scurvy – a classic sign of vitamin C deficiency. However, British navy physicians did know that a daily dose of lime juice prevented scurvy. Scurvy was the scourge of sailors back then. leading to an early death due to vitamin C deficiency, that is if they managed to survive the other risks of taking to the open sea in wooden boats with sails, not to mention pirates etc.
Other symptoms of vitamin C deficiency include fatigue, malaise, chronic stress, weakness, wounds that heal slowly, bruise easily, nosebleeds (weak blood vessels); joint/muscle pain & swelling; weak connective tissue & bone. Extremely low levels of vitamin C can lead to oedema, which is an indication that blood vessels are not reabsorbing fluid correctly.
Vitamin C Supplements
If you feel that you may be at risk of vitamin C deficiency, or you want to use vitamin C supplementation to prevent colds and flu, consult a health care professional trained in human nutrition.
Reference: Herbs & Natural Supplements: An evidence based guide (3rd Edition), by Lesley Braun and Marc Cohen. The Nutrient Bible (6 th Edition), by Henry Osiecki. Understanding Nutrition (11 th Edition) by Ellie Whitney and Sharon Rady Rolfes