Its officially Autumn in Australia now.. and Winter is coming. Its been confusing here in Sydney as its quite warm and humid, yet overcast and rainy. It feels like a non congruent fashion trend, mixing two patterns, which has everyone confused! But thats our weather right now. I’ve been kept busy at work and went to Melbourne last week for an Oncology study day at Peter MacCallam Cancer Centre, my visit there got me thinking more about nutrition and the basics as I often get asked about these things on a daily basis by patients going through their treatments. One big question I have had a lot lately is around vitamin supplements. Can they help or are they just expensive placebos?
I am going to discuss a series of Vitamins starting today with VITAMIN C.
Vitamin C or L-ascorbic acid is a water soluble vitamin present in fruit and vegetables and it was previously associated with Scurvy, or sailors disease. Without access to any fresh fruit or vegetables – the human body cannot synthesise vitamin C by itself because it lacks an enzyme called L-3 gulonolactone oxidase to do so. In Australia around 40% of vitamin C we eat comes from vegetables, 20% from fruit, and around 30% from fruit juices. The body generally has stores to last 4 weeks before it shows early signs of deficiency. These can be very subtle and often be mistaken for feeling under the weather or being tired so often people do not check in with the doctor until much later. In Australia for adults aged 19-70 the Recommended Dietary Intake is 45mg of Vitamin C per day and any excess is usually excreted through the urine. There are different recommendations for children and pregnant women. (Reference: Nutrient Reference Values for Australia and New Zealand )
Vitamin C deficiency can take awhile to develop but it can be diagnosed by blood test with your GP. High risk groups for this are the elderly, people on restricted diets without access to much fresh food, or those who use drugs or alcohol regularly. Vitamin C is important for keeping your skin healthy and has a role in wound healing, keeping connective tissue and bone healthy, and assisting in the absorption of iron from food. It has also been found to have a role in cold and flu prevention.
A Cochrane review exploring the role of daily supplementation of 0.2g/day (or 200mg/day) or more published in 2013 on Vitamin C for prevention and treatment of the common cold showed:
- regular supplementation had no effect on common cold incidence in the normal population (based on 29 trial comparisons involving 11,306 participants);
- regular supplementation had a modest but consistent effect in reducing the duration of the cold symptoms (based on 31 trial comparisons involving 9,745 participants); and
- in 5 trials involving 598 participants exposed to short periods of extreme stress (including marathon runners) – the incidence of the common cold was halved.
Other research into high dose vitamin C supplementation has shown that taking 1000mg/day for the first few days of a cold can reduce the duration by about half a day – but not stop you from developing one. Long term high dose vitamin C supplementation above this amount may also be dangerous to your health and should be discussed with your Dr as it may affect other minerals stored in the body like iron. Absorption of vitamin C is also dependant on the dose – a 250mg dose four times daily is more likely to be better absorbed than 1000mg once a day. So its always best to talk to your Doctor before you start any new supplement routine. (Reference: Nutrient Reference Values for Australia and New Zealand )
Finally, there are insufficient studies into high dose supplementation for people undergoing specialised treatments such as chemotherapy at this stage.
Vitamin C can be found in:
- tropical fruit (pineapple, mango, kiwi, papaya)
- citrus fruit (oranges, lemons)
- berries (strawberries, raspberries)
- vegetables (capsicum, brussel sprouts, broccoli, kale, cauliflower and other brassica cruciferous veggies)
Read more about these veggies in a fun article written by Stephanie Eckelkamp here via Prevention Magazine. Having a plant based diet aiming for 2 fruit and 5 vegetables per day is sufficient to obtain suitable Vitamin C levels over taking a supplement. These fruit and vegetables also contain other vitamins and antioxidants which can be positive for your cardiovascular system, and fibre for your digestive tract. But many people know they are not eating enough nutrient rich foods so take a supplement as they work on their diet. Vitamin C supplement are fairly inexpensive compared to other supplements, however there is much more to be gained from sourcing and cooking something fresh for you and your family.
So as always, a healthy, diet with plenty of fruit and vegetables will help to keep the system functioning well even when its getting cold outside!!