European paradoxes of coronary heart disease : developing new markers of vitamin E status
This thesis explored the paradoxes of CHD and diet in Europe. A correlational study which examined the relationship between mortality from CHD in men below 65 years with national food and cigarette consumption in 19 western European countries showed that cross-sectionally, wine, vegetables and vegetable oils were the most strongly related with CHD death rates during 1985-87 (r = -0.80, -0.65 and -0.62 respectively). When the data on foods were converted to nutrients, the antioxidant α-tocopherol was the most strongly related to CHD across western Europe (r = -0.78). The major determinant of α-tocopherol supply was usually sunflowerseed oil. The cross sectional finding on α-tocopherol is important because it explains more than 60% of the variability of heart disease in western Europe and also the French and other European paradoxes of CHD. Longitudinal correlations of CHD deaths and α-tocopherol supplies during 1970 to 1987 within most of the countries studied supported the cross-sectional negative relationship. The rest of this thesis focused on the development and validation of two vitamin E indices which could be useful markers of vitamin E status. The first assay investigated whether binding of α-tocopherol to RBC reflected the longer-term intake of vitamin E and possibly also of vitamin E status if bone marrow metabolism reflects the body's demands for free radical scavenging and catabolism of α-tocopherol. The second marker of vitamin E status was the α-tocopherol concentration of the RBC. α-Tocopherol measurements predicted normal individual vitamin E intakes, assessed by a food frequency questionnaire, with good degree of accuracy (r = 0.9, p<0.05). This assay was also sensitive to an increase in intake of 30 mg α-tocopherol daily for 18 weeks, demonstrated by the significantly higher concentration of α-tocopherol in the RBC of the supplemented subjects compared with the controls.