Introduction: Vitamin E, mainly α- and γ-tocopherol, is known for its antioxidant potential and plays an important role in reducing oxidative stress levels. Research also indicates a more effective antioxidant effect of tocotrienols compared to tocopherols.
Aim: Development of a food frequency questionnaire (FFQ) for evaluation of tocotrienols intake and comparison with data obtained from a 24-hour dietary record in a group of adults.
Methods: This study used a cross-sectional online survey to collect data using the FFQ method and a single 24-hour dietary record. This survey was open to all Poland residents aged 18 -65 years. The final data set included data from 202 participants. Data on age, sex, education level, place of residence, physical activity, as well as height and body mass weight were collected. FFQ includes 15 food categories (e.g. vegetable, fruit, oils, nuts and seeds, fish, eggs, drinks, snacks). Data from the USDA database were used to calculate the content of tocotrienol isoforms.
Results: The study involved 73% of women and 27% of men. Most of the respondents were aged 18-25 (77% of the total) and lived in cities with more than 100,000. The most of the respondents described their physical activity as moderate or high. Over 60% of the respondents had a normal weight. The mean consumption of tocotrienols for all subjects was: 2.165 ± 2,157 mg/day according to the data for the 24-hour dietary record method and 2.236 ± 2,160 mg/day for the FFQ questionnaire. It was found that the tocotrienols in the diet of the respondents met 25% of the Adequate Intake value for vitamin E (as milligrams equivalent of α-tocopherol). Among all forms of tocotrienols, the highest content was β-tocotrienol, and the lowest was δ-tocotrienol. The main dietary sources of tocotrienols were whole grain pasta and bread, brown rice, and carrot juices. Significantly lower intake of α- and δ-tocotrienol and the sum of total tocotrienols were found in women than in men, based on the data obtained from the 24-hour dietary records. The results of the content of tocotrienols obtained by both methods were consistent. Our results are similar to those obtained in the Japanese population, where the mean consumption of tocotrienols was 1.9-2.1 mg / day.
Conclusion: To our knowledge, there is a lack of research results on the share of tocotrienols in the diet, most studies include vitamin E or α-tocopherol. Taking into account the role of tocotrienols as bioactive compounds, it is important to conduct further research to develop a tool to assess their dietary content. Due to the low proportion of tocotrienols in the diet, it seems beneficial to popularize knowledge about their impact on health and food sources.
