Wellcome Image of the Week: Vitamin C
This colourful image is reminiscent of computer-generated fractal pattern, but is in fact vitamin C crystals seen under a light microscope. Vitamin C is the left-handed (levo) form of ascorbic acid (the right-handed form exists but does not work as a vitamin). The image was taken by Spike Walker by making a weak solution of levo ascorbic acid (bought as a powder in Boots) and spreading it on a microscope slide. The crystals formed as the water in the solution evaporated.
Individual vitamin C crystals are fine needles, radiating from their point of origin, which is likely to be a speck of dust. Spike breathed on the preparation at intervals to make the crystals temporarily grow faster as they acquired ‘water of crystallization’ (the water present inside crystals) and this made them even finer. He then used a contrast enhancement technique he invented, (which he calls ‘Spikeberg’ illumination due to its similarity to Rheinberg illumination) which rendered the fast and slow-growing areas in different colours.
Vitamin C is a necessary nutrient for many animals and while most animals can make their own, humans and some other animals (including more advanced primates and bats) need to get it from their diet. Vitamin C is needed for many processes in our bodies. For example, it is necessary for collagen to form, the most common protein in mammals that makes up fibrous tissues like tendon, ligament and skin. Vitamin C is also an antioxidant and is most abundant in citrus fruits, tomatoes and cabbages.
A lack of the vitamin leads to scurvy in humans and though scurvy is rarely a problem in the western world nowadays, it is still prevalent where there is malnutrition. The Wellcome Trust helps support global nutrition as part of its research challenge five: connecting environment, nutrition and health.