Writing in the journal Diabetologia, lead researcher Paul Thornalley from the University of Warwick reports that thiamine concentration in blood plasma was decreased by about 75 per cent in both type 1 and 2 diabetics. "The deficiency of thiamine in clinical diabetes may increase the fragility of vascular cells to the adverse effects of hyperglycaemia and thereby increase the risk of developing microvascular complications," wrote Thornalley. "Correction of the low plasma thiamine concentration with thiamine supplements may decrease the risk of microvascular complications in diabetes," he added. An estimated 19 million people are affected by diabetes in the EU 25, equal to four per cent of the total population. This figure is projected to increase to 26 million by 2030.
In the US, there are over 20 million people with diabetes, equal to seven per cent of the population. The total costs are thought to be as much as $132 billion, with $92 billion being direct costs from medication, according to 2002 American Diabetes Association figures. The new research, funded by British charity Diabetes UK, investigated thiamine and related phosphorylated metabolite levels in the plasma, erythrocytes and urine of 74 diabetic patients (26 type 1 and 48 type 2) and 20 healthy controls. Thornalley and co-workers report that the thiamine concentration in blood plasma was decreased 76 per cent in type 1 diabetic patients and 75 per cent in type-2 diabetic patients. This is reportedly the first time that thiamine deficiency has been identified in diabetics, with the researchers indicating that the previous studies used the conventional way of assessing levels of thiamine status was to measure the activity of an enzyme called transketolase in red blood cells - this measure masked deficiency by assuming normal levels of thiamine when in fact the normal enzyme activity was due to increased amounts of two proteins THTR-1 and RFC-1 that help transport thiamine into red blood cells. The increased levels of these proteins were a direct response to there being a deficiency of thiamine in the body.
The decreased availability of thiamine in the vascular cells would reduce the protection of cells against the effects of high glucose levels, and would reflect problems in endothelial cells (endothelial cells line the body's entire circulatory system) and increased risk of atherosclerosis (chronic inflammatuion in the artery walls). The researchers confirmed that trials are now being carried out to see if supplementing diet with thiamine could correct low plasma thiamine concentration in diabetes, and prevent vascular complications. Commenting on the study, Diabetes UK's Matt Hunt said the study could potentially have very exciting outcomes, but called for more research. "Around 80% of people with diabetes die of cardiovascular disease and diabetes is the leading cause of blindness in the UK's working age population," Hunt is quoted as saying by the BBC.
"Therefore, any research that could help must be looked at seriously." Source: Diabetologia Published on-line ahead of print, doi: 10.1007/s00125-007-0771-4 "High prevalence of low plasma thiamine concentration in diabetes linked to a marker of vascular disease"
P.J. Thornalley, R. Babaei-Jadidi, H. Al Ali, N. Rabbani, A. Antonysunil, J. Larkin, A. Ahmed, G. Rayman and C.W. Bodmer