CVD is a major health concern among African Americans. Dietary carotenoids have been implicated in decreased risk for CVD. The purpose of this study was to assess the intake and serum concentrations of α- and β-carotene, β-cryptoxanthin, lutein plus zeaxanthin, and lycopene among participants of the JHS-DPASS using three dietary assessment tools (two regional FFQs and the average of four 24 h recalls) and to assess associations between intake measures and serum concentrations. In addition, we identified the relative contributions of foods to carotenoid intakes in this population.
Despite reports of low fruit and vegetable intake in this region(24
), the carotenoid intakes of the JHS-DPASS participants were within the 50th–90th percentile values from the Third National Health and Nutrition Examination Survey (NHANES III) for similar age and sex groups for all carotenoids except lycopene, where the intakes were within the 50th–75th percentile range(25
). In general, the biochemical status of the carotenoids was also within the 50th–75th percentile range for African American participants of the NHANES III examination(26
) and similar to those reported for other populations(26
). Serum lycopene concentrations appeared higher than other published values. This did not appear to be due to a higher intake of dietary lycopene, but rather could be attributed to the inclusion of both cis
isomers of lycopene in our estimation of serum lycopene concentrations. Generally, the cis
isomers are not included in lycopene estimations(32
). When we included only trans
-lycopene in the assessment, the age-adjusted serum trans
-lycopene concentrations were 0.50 (standard error of the mean (SEM) 0.02) μmol/l for men and 0.45 (SEM 0.01) μmol/l for women, which were closer to values reported by others.
The FFQs used in this study were specifically developed for use with a southern US population. Correlations comparing intake measured with other assessment tools including the Block or Harvard FFQ and biochemical measures of carotenoids have demonstrated correlation coefficients ranging from 0.09 to 0.45 for various carotenoids(28
), similar to our range of 0.12 to 0.35. Some of the lowest correlations seen were for lutein plus zeaxanthin. Lutein and zeaxanthin, unlike nutrients such as β-cryptoxanthin, are present in a wider variety of foods. This could make its estimation using FFQs with a limited number of food items difficult(38
The mean lycopene intakes obtained from both FFQs in general were higher than those from the recalls. This has also been previously reported by other researchers(39
). Relatively weak correlations were also seen for lycopene with the long and the short FFQ compared with the average of the 24 h recalls. It is possible that the recalls capture processing techniques that may reflect availability of lycopene from tomato-containing products better than the FFQs, which make assumptions about the tomato content in foods such as pasta with meat dishes(40
). Besides this, researchers have suggested that the lack of correlation between intake and serum measures may be affected by several other factors including recent lycopene intake, age and genetics, as well as individual absorption capacity(40
The design of the DPASS included administration of the short FFQ at the time of the clinic visit. If the participant met the criteria for the diet sub-study, he or she was asked to join, and if the participant agreed, the first DPASS visit with administration of the first 24 h recall took place on average a month or two after the clinic visit. The next three 24 h recalls were scheduled to be administered approximately one month apart, and a week after the last recall, the participant was administered the long FFQ. As recruitment to the JHS was on a rolling basis, participants enrolled into the DPASS on a rolling basis as well. Because the short FFQ was administered on the day of the blood draw (date of clinic visit), it could be expected that the correlations between carotenoid intake and bio-chemical status may be artefactually higher than for the FFQ administered later; however this was not the case. Correlations for β-carotene and lutein plus zeaxanthin were higher for the long FFQ than for the short, despite the greater distance in time between measures.
In this population of African Americans, orange vegetables were the top contributors to α-carotene intake and greens and sweet potato were the top contributors to β-carotene intake. In a study conducted in the LMD region(20
), we previously reported that sweet potatoes were the top contributor to vitamin A intakes in the African American subgroup. Citrus fruit juices were the main contributors of β-cryptoxanthin intakes in this population. This has been reported in several diverse study populations(31
). Dark green leafy vegetables were the main source of lutein plus zeaxanthin. Nebeling et al
) reported similar findings in the African American subgroup of a national survey. In our study, tomato and tomato products were the top contributors of lycopene intake. This is in agreement with other studies conducted in the USA, where most of the lycopene is accounted for by tomato and tomato-containing products(44
Contrary to our expectation, carotenoid intakes and status did not appear to be lower in this population of southern African American adults than in the general US population. The deattenuated adjusted correlations obtained using the 24 h recalls were higher than those obtained from either FFQ. This could indicate that multiple recalls may be a better way to capture carotenoid intake. However, the range of correlations seen with these FFQs is similar to those published from validation studies of carotenoids with other FFQs. This, taken with the advantages of single administration and lower cost, suggests that FFQs provide relatively valid and useful measures of carotenoid intake in this population.