According to Moniruzzaman et al. (1997) and Karhumaa et al. (2007) there is an accumulation of xylitol and this is due to an imbalance of cofactor (NAD+ and NADPH) which is required for the enzyme (XR) compared to enzyme Xylitol Dehedrogenase (XDH) (Fig. 1 and Fig. 2). They also assessed that the insertion of oxygen shocks (pulses) which inhibits the enzyme XR and thus prevents the accumulation of xylitol.