Vitamin C

Vitamin C is probably one of the best known and most talked about vitamins, it’s one of the most widely used supplements and is available in a number of forms. In this blog we are going to take a closer look at vitamin C and its importance in our diet and what you need to know when making your choice of supplement. 

The Biology of Vitamin C

Most vertebrates synthesise vitamin C in the liver from glucose, but humans cannot. It is estimated that around 40 million years ago humans lost the capacity to use the enzyme L- gulonolactone (GULO) which is required for the final step in the synthesis of ascorbate from glucose. Because of this, humans must consume vitamin C in their daily diet.

The human diet contains both vitamin c (ascorbate) and its oxidised form dehydroascorbic acid (DHA), which is the most plentiful.

Ascorbic acid is one of the least stable vitamins and is easily destroyed by cooking, although it can be better retained when steam cooking. It is easily oxidised in air and is sensitive to both heat and light.

Absorption of ascorbic acid occurs in the duodenum, proximal jejunum buccal mucous membrane and usually leaves the blood again around three hours later, which is why it is so important to have regular intakes

Ascorbic acid is a powerful antioxidant and immune booster and has a role in growth mechanisms of all body tissue, especially in the formation of collagen. Vitamin C is also a well-known as a water-soluble reducing agent and antioxidant that quenches free radicals produced by normal metabolism. To function well as an antioxidant, high levels need to be maintained.

There has also been research to support its important role in immunity. Ascorbic acid has been shown to stimulate the immune system by enhancing t-cell proliferation in response to infection.

It has been calculated that if humans were able to synthesise ascorbic acid, they would do so at a rate of around 2-4g per day under normal conditions and up to 15g per day under stress.

 

Using supplements

Supplements of vitamin c are available in many forms, including synthetic ascorbic acid, mineral ascorbates, synthetic ascorbic acid with bioflavonoids and vitamin C presented in a fermented product.

There appears to be no difference in biological activities or bioavailability between natural and synthetic vitamin c. In the ascorbate forms, mineral salts act as a buffer and are therefore less acidic than ascorbic acid and may provide an additional source of minerals such as calcium or magnesium.

Vitamins rarely work in isolation and, since vitamin c is found in nature with bioflavonoids in fruits and vegetables, it makes sense to produce supplements that are as near to food ‘as nature intended’.

Many people are unable to swallow tablets or capsules, therefore liquid forms are ideal. The challenge that the supplement manufacturers have is finding the balance between a supplement that is palatable and contains the correct daily dose of the vitamin.

Traditionally, effervescent vitamin c tablets are flavoured and sweetened with unnatural and potentially harmful synthetic sweetener and flavouring in order to get the required taste.  

Often found in effervescent supplements is sodium lauryl sulphate which is used in numerous hair and personal care products because it is inexpensive and an effective foaming agent so you should be very cautious when looking at effervescent vitamin C.

It is worth being familiar with what is good for you and what isn’t and always, always read the label!