Vitamin C (or L-Ascorbic acid, ascorbate) is a water soluble vitamin that is largely stored in the adrenal glands but also found in high levels in the pituitary glands, white blood cells (leukocytes), brain and eye tissues. It is required to form collagen, serotonin, norepinephrine and thyroxine and helps certain enzymes to function. It acts in the body as an antioxidant, or reducing agent, protecting tissues against oxidative stress which is important for disease prevention.
Deficiency in Australia today is uncommon with most children and adults consuming around double their recommended daily intake, though many will have heard of the vitamin C deficient condition of ‘scurvy’. When scurvy occurs, gums bleed easily around the teeth and teeth become loose as cartilage weakens and capillaries under the skin break. Inadequate amounts of collagen synthesis is associated with haemorrhaging and massive internal bleeding can result. Muscles, including the heart degenerate and the skin becomes rough, brown and scaly with poor wound healing. Bone rebuilding slows, causing soft malformed bones, increased likelihood of fractures and deficiency can be associated with hysteria and depression.
Vitamin C is released from the adrenal glands in times of stress. So those with high activity levels or suffering from burns, temperatures, heavy metal toxicity or drugs will require higher levels of vitamin C intake than the general population. Similarly, smoking can significantly raise the requirements for vitamin C and smokers will often have significantly lower vitamin c levels in the body (up to 40% for male smokers). The amount of vitamin C required for optimal health varies throughout the lifespan and is notably higher during pregnancy and lactation.
Though most people can quite efficiently excrete excess vitamin C, some maybe susceptible to it’s accumulation, especially in response to a high dose of supplements taken over a short time. Such excess vitamin C can cause abdominal cramps, urinary tract infections and diarrhoea. It can also cause both false positives and negative results when testing for diabetes and can interfere with anti-clotting medications. Excess vitamin C can also lead to kidney stones in susceptible people and can cause or exacerbate iron overload as it enhances absorption. This is especially relevant to haemochromatosis patients (affecting about 1 in 300 Caucasians) where it could exacerbate iron-induced tissue damage.
For these reasons, it is recommended that generally daily intake should not exceed 1000mg for adults, so if you are taking supplements, it’s worth a check to verify that this is not exceeded. The role of supplementing vitamin C to treat or prevent illness is still controversial and the evidence is far from conclusive. Most of the controlled clinical trials have found no significant effect of supplementation to reduce the frequency or incidence of colds though there is fair evidence to support how supplementation of 1000mg/day or slightly above can alleviate the symptoms and duration of colds. Such supplementation however, should only be taken after careful consideration of the possible adverse or side effects that may affect some as noted above.
Consuming foods rich in Vitamin C with those containing iron, leads to increased absorption of iron which can be valuable for those whose iron intakes may be low.
Vitamin C is easily destroyed in oxygen and heat and the concentration can vary in natural produce based on the season, shelf life and storage method. Ideally, eat your vitamin C-rich fresh fruit and vegetables as soon as they are cut and refrain from reaching for juices or supplements to top up your vitamin C as they are generally unnecessary. Juices can contribute towards weight gain as they are very high in sugar but low in fibre, and generally the vitamin C in bottled juices is often artificially added after processing to replace such losses through manufacture and storage.
If you are concerned about your vitamin C intake or would like to increase it, try adding some more of these particularly vitamin C-rich foods your diet: citrus fruits, capsicum, kiwi, berries, cabbage, cruciferous or dark green vegetables, cantaloupe and tomatoes. Life Nutrition can also help analyse your diet and work with you to improve your vitamin C intake, so please do not hesitate to contact us further.