Background The prevalence of Huntington Disease (HD) in Europeans are 10 times higher than Asian populations. The domestic per capita tea consumption is higher in Sri Lanka compared to the West. We hypothesise that, the frequency of natural product consumption and environmental factors that are unique to this part of the world may contribute to the disparity in phenoconversion in HD.

Method Sociodemographic data, dietary history, clinical and genotyping of CAG repeats followed by a detailed haplotype analysis was performed in HD patients and controls.

Results Pilot data of HD 16 patients: [Adult onset n = 14 (85%), Juvenile onset n = 2 (15%), Male n = 9(56%), Female n = 7(44%)], age of onset: 16–60yrs (mean = 42.9 ± 14.1). The CAG repeats on normal alleles (n = 11) range: 16–22 (mean =18.3 ± 2), abnormal allele (n = 11) range: 41–66 (mean = 46 ± 7). A significant inverse correlation exists between the age of onset and CAG repeat length (r = 0.897, p < 0.001). The tea consumption and the Mini-Mental State Examination (MMSE) were; tea consumption ≥3 cups/day n = 4, 2 (50%) scored ≥23, the other 2 patients scored 20 and 16 (mean = 21.2 ± 4); 2 cups/day n = 6, 4 (67%) scored ≥ 20 the other 2 patients scored 18 and 17 (mean = 20.8 ± 3); 1 cup/day n = 1 scored 18.

Discussion The data suggest that, regular consumption of black tea was associated with a lower risk of cognitive impairment. We propose future studies with a larger sample size to improve statistical power.