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Vitamin C and Immune Function

In 1970, Linus Pauling announced in Vitamin C and the Common Cold that taking 1,000 mg of vitamin C daily will reduce the incidence of colds by 45% for most people but that some people need much larger amounts (1). The 1976 revision of the book, retitled Vitamin C, the Common Cold and the Flu, suggested even higher dosages (2).

Vitamin C and Immune Function

To test the effect of vitamin C on colds, it is necessary to compare groups which get the vitamin to similar groups which get a placebo. The common cold is a very variable illness so proper tests must involve hundreds of people for significantly long periods of time and a recently published (2013) systematic review of the literature once again concluded the failure of vitamin C supplementation to reduce the incidence of colds in the general population (3). The review did however, conclude that ‘given the consistent effect of vitamin C on the duration and severity of colds in the regular supplementation studies, and the low cost and safety, it may be worthwhile for common cold patients to test on an individual basis whether therapeutic vitamin C is beneficial for them’.

Exhaustive review of the evidence leads EFSA (4) to declare a favourable claim regarding vitamin C and normal function of the immune system for the general population in that vitamin C helps support the body’s immune system. Vitamin C helps protect cells and keeps them healthy. It cannot be stored in the body so is needed every day.

Decent food sources of vitamin C include kiwi fruit, citrus fruit (oranges, lemons etc), blackcurrants, guava, mango, papaya, pepper, Brussels sprouts, broccoli and sweet potato. The recommended intake of vitamin C for adults aged 15 years old and over is 80mg a day and more if you are a smoker.

So we know that vitamin C is a powerful antioxidant that boosts the immune system. Although it can’t prevent you catching the common cold, higher doses may reduce the severity of your symptoms. In addition remember to rest up as much as you can, eat healthily and drink plenty of fluids to replace those lost due to sweating and a runny nose.

  1. Pauling L: Vitamin C and the Common Cold. San Francisco: WH Freeman, 1976
  2. Pauling L: Vitamin C, the Common Cold and the Flu. San Francisco: WH Freeman, 1976
  3. Hemila H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2013 Jan 31: 1:CD000980. doi: 10.1002/14651858.CD000980.pub4
  4. EFSA Journal 2010;8(10):1815

Penny Hunking Registered Dietitian

-Penny Hunking RD, R.SEN, R.Nutr (Public Health)

From fuelling fitness for sports performance to healthy eating and fat loss, Penny Hunking has written, researched and talked to consumers and professionals about virtually every aspect of diet, weight management and exercise. She has also written or contributed to many books on key aspects of food, fat loss, fitness and special diets in a career spanning more than 3 decades.

Penny is a Registered Dietitian, a member of the British Dietetic Association, the Nutrition Society, Nutritionists in Industry, Association of Obesity and Sports Dietitians UK. But life is not all hard work, she is passionate about scuba diving, water skiing, cookery, travel and eating out.

RD – Registered Dietitian
R.SEN – Registered Sport and Exercise Nutritionist
R.Nutr – Registered Nutritionist (with a nutrition specialism in Public Health)