Vitamin C is a powerful antioxidant and a popular supplement. How valid are the claims behind it?
Lockdown has been a very strange experience for us all. Those movies about parallel dystopian futures where humanity is hanging on by its fingertips after the collapse of civilisation due to a global pandemic suddenly have the tiniest hint of reality. I remember Steven Soderbergh’s film ‘Contagion’ about a fictional disease spreading across the planet. Unfortunately, he made the unforgivable mistake of allowing Gwyneth Paltrow to die rather unpleasantly very early in the movie which is unthinkable (you cannot just kill Gwyneth like that!).
During lockdown there has been some interesting phenomena. I like many people have been giving my full attention to growing vegetables as I embrace the ‘Good Life’ (I am old to enough remember that wonderful BBC sitcom). Fruit and vegetable seed sales are apparently up by 1800 percent generating lengthy lead times and online congestion with retailers. Obviously, many people, like me, would aspire to be completely self-sufficient although this is unlikely. How realistic is this?
Potatoes are a Rich Source of Vitamin C
It might just about be realistic if you have an allotment. According to the Agriculture and Horticulture Development Board, spuds produce more than three times the calories of wheat. An average man consumes 2,500 calories day and women 2000. Assuming an average of 2,250 calories for both sexes this equates to about 820,00 calories per year. Potatoes yield a nutrient dense crop and even a medium sized potato is about 160 calories. A good harvest will produce about 4 kg potatoes per m2.
Doing the maths, you would therefore an area of 266 m2 to feed yourself for an entire year. The average household, according to Foxton’s the estate agent, has 3.7 m2 which would yield enough spuds and calories for only 5 days which would not be good in the setting of a dystopian future when Morrison’s was shut.
However, the estimated average allotment size meanwhile is apparently 250m2. For the lucky few self-sufficiency is plausible but only for one person in the family! The International Potato Centre in Peru suggest that you can survive on little else but potatoes for a year if required such is their nutrient profile (not that you would want to).
Potatoes are essentially a good nutritional source of vitamin C and B6, manganese, phosphorus, niacin and pantothenic acid. Vitamin C particularly as we all know, among other things, is seen as beneficial to our immune system. Obviously, you may think vitamin C status could be relevant to the current circumstances we now face. Healthspan and Superdrug for instance both saw huge spikes in vitamin C sales at the onset of COVID-19 in the UK. This has been widely reported in the media.
A Brief History of Vitamin C
Many animals, unlike humans, can synthesise their own vitamin C. Unfortunately, historically this has been an issue. It was estimated that in the age of discovery, when the famous explorers such as Cook and Magellan conquered the oceans of the world, that two million seafarers died due to vitamin C deficiency.
Clearly crossing the Atlantic Ocean, the Indian Ocean, and the Pacific, meant months at sea. The average sailor consumed 3,000 calories each day. Their rations consisted of 1lb of salted beef or pork per day and if rations were low, they were then served flour mixed with fat instead. They also had 1 lb of biscuits (or ‘hardtack’) daily which were subject to infestations of weevils and 1 gallon of ale or wine or liquor. An unfortunate mix of a salty diet combined with the diuretic effect of alcohol. In preserved food there are no vitamins, so a variety of nutritional diseases would be likely: lack of vitamin B1 would cause beriberi; no vitamin B3 would cause pellagra; and vitamin C, of course, caused scurvy. Pellagra, if you did not know, is a disease caused by a lack of the vitamin niacin which potatoes are, as we know, a particularly good source of.
As a footnote to this, what is remarkable is that for centuries native North American First Nations people had serendipitously already been drinking tea made from pine needles in order to combat a range of conditions including scurvy.
The effects of scurvy are quite distressing as it leads to disintegration of the body as it can longer manufacture collagen. Happily, a solution was found in 1795 by Gilbert Blane, who is regarded as the Father of Naval Medical Science. He organised the distribution of citrus fruits (oranges and limes) to seaman during the Napoleonic Wars. British sailors meanwhile became known as ‘limeys.
Scurvy unfortunately also occurred on land. It was an unfortunate affliction that occurred because of the ‘great potato famine’ in Ireland in 1845. It would take many more years for science to work out exactly what was responsible for maintaining the body’s connective tissues. This was eventually solved by meticulous work of a Hungarian-born researcher named Albert Szent-Györgyi. He isolated and identified vitamin C in 1930 and was recognised with a Nobel Prize in Physiology or Medicine in 1937.
How Effective are vitamin C Supplements?
Vitamin C is a powerful antioxidant and it is a popular supplement. How valid are the claims behind it?
The common cold is the most extensively studied infection regarding the effects of vitamin C. There is some limited evidence although this is generally regarded as a bit of a myth. This comes from a review done in 2013 of 29 randomised trials involving more than 11,000 participants. Researchers found that for exceptionally active people—by this we mean marathon runners, skiers, and Army troops doing heavy exercise in subarctic conditions—taking at least 200 mg of vitamin C every day appeared to cut the risk of getting a cold by 50%. Unfortunately, this did not to apply to the rest of us in the general population.
The review undertaken by Cochrane – an organisation renowned for its unbiased research and seen as gold standard– concluded that for the general public at least “trials of high doses of vitamin C administered therapeutically, starting after the onset of symptoms, showed no consistent effect on the duration or severity of common cold symptoms”.
However, an interesting study in 2017 from the University of Helsinki, Finland did conflict with this opinion; but it is one of the few studies to do so. The benefits in this case appeared to be dose dependent. This study administered 3 g/day vitamin C to two study groups, 6 g/day to a third group, and the fourth group was administered a placebo. Compared with the placebo group the 6 g/day dose shortened colds by 17%, twice as much as the 3 g/day doses did. The second trial administered 4 g/day and 8 g/day vitamin C, and placebo to different groups, but only on the first day of the cold. Compared with the placebo group, the 8 g/day dose shortened colds by 19%, twice as much as the 4 g/day dose did. Both studies revealed a significant dose-response relationship between the vitamin C dosage and the duration of the common cold. It is important however to remember that large amounts of vitamin C can cause diarrhoea, vomiting, cramps and headaches!
The case for vitamin C supplementation remains scientifically contentious and somewhat of a ‘hot potato’ (no irony intended) but there may be a possible slight benefit for limiting illness duration for the common cold although not all studies support this view. While we on the subject off illness duration it is worth mentioning that the anti-viral drug Remdesivir originally designed to treat Ebola has been repurposed to treat COVID-19. Although details have yet to be published early indications suggest that it may cut the duration of symptoms from 15 days down to 11 in clinical trials so far undertaken at hospitals around the world. The trial was run by the US National Institute of Allergy and Infectious Diseases (NIAID) and 1,063 people took part. Some patients were given the drug while others received a placebo (dummy) treatment.
