North-south differences in some indices of Vitamin B6 nutritional status in older British people.

The National Diet and Nutrition Survey, nationally representative for the British population aged 65 years and over, has revealed a north-south geographical gradient, with a decline from south to north of vitamin B6 status indices. The present study further explores the possible explanatory factors (dietary intake of vitamin B6 and riboflavin, alcohol consumption, smoking habits and some other lifestyle determinants) on the difference of vitamin B6 indices--plasma concentrations of pyridoxal phosphate (pPLP) and pyridoxic acid (pPA), between older people living in the north (Scotland, North of England) and the south (Southern England, Wales and Midlands). The results showed that older people living in the northern half of Britain are at greater risk of poor vitamin B6 status, mainly as a result of low intakes of this vitamin, than the people living in the southern half of the country. Riboflavin intake, alcohol consumption, smoking and socio-economic status also correlated with the north-south gradient of pPLP and pPA. Other potential determinants such as use of vitamin B6 supplements, medicines probably affecting vitamin B6 metabolism, were not independent correlates of the north-south gradient in vitamin B6 status indices. This may have important implications for disease-risk geographical gradients in the UK.