Newly developed dietary assessment tools for lutein and zeaxanthin are correlated with 24-hour diet recalls, but are not a valid measure of intake in Australian and United Kingdom adults

•Baby spinach contributed most to Australian lutein and zeaxanthin (L/Z) intake.•Broccoli contributed highly to United Kingdom dietary L/Z intake.•Correlational statistics overestimated L/Z dietary screener tool validity.•Bland-Altman plot analysis is key to deducing dietary L/Z screener tool validity.•Validity of diet L/Z intake from prior research should be interpreted with caution. Habitual dietary intake measurement of carotenoids lutein and zeaxanthin (L/Z) has often been omitted or attempted with tools of unknown validity in past research. It was hypothesized that the dietary assessment tool, the L/Z screener, developed as part of this study, would be valid with agreement within 0.25 mg/day when compared against multiple 24-hour diet recalls in healthy Australian and United Kingdom adults. Two screeners with 91 food items were developed, 1 with a recall timeframe of a month and the other a week. Over 4 weeks, 56 Australian and 47 United Kingdom participants completed 4 weekly screeners, 2 monthly screeners, and eight 24-hour diet recalls. Validity was assessed through Bland-Altman plot analysis. L/Z intake measured by all tools was significantly correlated, with correlation coefficients from 0.58 to 0.83. Despite these correlations, the screeners were not valid, with poor Bland-Altman plot agreement when compared with the diet recalls. The Australian weekly screener performed best, demonstrating a mean difference of 0.51 mg/day and 95% limits of agreement between –1.46 mg/day and 2.49 mg/day of L/Z intake. Baby spinach, broccoli, and pumpkin provided the greatest proportion of L/Z intake. The low validity may be explained by high rates of misestimation or missed capture of moderate to high L/Z containing foods such as baby spinach. Prior research reliant on correlational statistics for L/Z tool validity should be interpreted with caution, and future screener development should prioritize accurate capture of high contribution foods. A 91-item L/Z diet screener was developed with 2 recall timeframes: a month or a week. Screener L/Z intake compared with 24-hour diet recalls by Bland-Altman plot analysis and correlational statistics in 103 adults resulted in significant correlations. However, agreement was poor (95% limits of agreement ≥0.25 mg/day) because of memory recall bias and missed capture; therefore, the screeners were deemed not valid. Abbreviations: AU, Australia; L/Z, lutein and zeaxanthin; UK, United Kingdom. Created with BioRender.com. [Dis