Evaluation of dietary patterns among Norwegian postmenopausal women using plasma carotenoids as biomarkers.

A number of studies have examined dietary patterns in various populations. However, to study to what extent such patterns capture meaningful differences in consumption of foods is of interest. In the present study, we identified important dietary patterns in Norwegian postmenopausal women (age 50-69 years, n 361), and evaluated these patterns by examining their associations with plasma carotenoids. Diet was assessed by a 253-item FFQ. These 253 food items were categorised into forty-six food groups, and dietary patterns were identified using principal component analysis. We used the partial correlation coefficient (r(adj)) and multiple linear regression analysis to examine the associations between the dietary patterns and the plasma carotenoids α-carotene, β-carotene, β-cryptoxanthin, lutein, lycopene and zeaxanthin. Overall, four dietary patterns were identified: the 'Western'; 'Vegetarian'; 'Continental'; 'High-protein'. The 'Western' dietary pattern scores were significantly inversely correlated with plasma lutein, zeaxanthin, lycopene and total carotenoids (-0·25 ≤ r(adj) ≤ -0·13). The 'Vegetarian' dietary pattern scores were significantly positively correlated with all the plasma carotenoids (0·15 ≤ r(adj) ≤ 0·24). The 'Continental' dietary pattern scores were significantly inversely correlated with plasma lutein and α-carotene (r(adj) = -0·13). No significant association between the 'High-protein' dietary pattern scores and the plasma carotenoids was found. In conclusion, the healthy dietary pattern, the 'Vegetarian' pattern, is associated with a more favourable profile of the plasma carotenoids than our unhealthy dietary patterns, the 'Western' and 'Continental' patterns.