A predominantly plant-based diet reduces the risk for development of several chronic diseases. It is often assumed that antioxidants contribute to this protection, but results from intervention trials with single antioxidants administered as supplements quite consistently do not support any benefit. Because dietary plants contain several hundred different antioxidants, it would be useful to know the total concentration of electron-donating antioxidants (i.e., reductants) in individual items. Such data might be useful in the identification of the most beneficial dietary plants. We have assessed systematically total antioxidants in a variety of dietary plants used worldwide, including various fruits, berries, vegetables, cereals, nuts and pulses. When possible, we analyzed three or more samples of dietary plants from three different geographic regions in the world. Total antioxidants was assessed by the reduction of Fe(3+) to Fe(2+) (i.e., the FRAP assay), which occurred rapidly with all reductants with half-reaction reduction potentials above that of Fe(3+)/Fe(2+). The values, therefore, expressed the corresponding concentration of electron-donating antioxidants. Our results demonstrated that there is more than a 1000-fold difference among total antioxidants in various dietary plants. Plants that contain most antioxidants included members of several families, such as Rosaceae (dog rose, sour cherry, blackberry, strawberry, raspberry), Empetraceae (crowberry), Ericaceae (blueberry), Grossulariaceae (black currant), Juglandaceae (walnut), Asteraceae (sunflower seed), Punicaceae (pomegranate) and Zingiberaceae (ginger). In a Norwegian diet, fruits, berries and cereals contributed 43.6%, 27.1% and 11.7%, respectively, of the total intake of plant antioxidants. Vegetables contributed only 8.9%. The systematic analysis presented here will facilitate research into the nutritional role of the combined effect of antioxidants in dietary plants.

BackgroundA plant-based diet protects against chronic oxidative stress-related diseases. Dietary plants contain variable chemical families and amounts of antioxidants. It has been hypothesized that plant antioxidants may contribute to the beneficial health effects of dietary plants. Our objective was to develop a comprehensive food database consisting of the total antioxidant content of typical foods as well as other dietary items such as traditional medicine plants, herbs and spices and dietary supplements. This database is intended for use in a wide range of nutritional research, from in vitro and cell and animal studies, to clinical trials and nutritional epidemiological studies.MethodsWe procured samples from countries worldwide and assayed the samples for their total antioxidant content using a modified version of the FRAP assay. Results and sample information (such as country of origin, product and/or brand name) were registered for each individual food sample and constitute the Antioxidant Food Table.ResultsThe results demonstrate that there are several thousand-fold differences in antioxidant content of foods. Spices, herbs and supplements include the most antioxidant rich products in our study, some exceptionally high. Berries, fruits, nuts, chocolate, vegetables and products thereof constitute common foods and beverages with high antioxidant values.ConclusionsThis database is to our best knowledge the most comprehensive Antioxidant Food Database published and it shows that plant-based foods introduce significantly more antioxidants into human diet than non-plant foods. Because of the large variations observed between otherwise comparable food samples the study emphasizes the importance of using a comprehensive database combined with a detailed system for food registration in clinical and epidemiological studies. The present antioxidant database is therefore an essential research tool to further elucidate the potential health effects of phytochemical antioxidants in diet.

Objective: To examine the association between nutrient adequacy and dietary diversity, and to assess and compare the determinants for the two constructs in an adult population in rural Mali. Design: Cross-sectional study assessing food intake by a validated 7-day quantitative food frequency questionnaire. Two different dietary diversity indexes were created: food variety score (FVS), a simple count of food items, and diet diversity score (DDS) a count of food groups. Mean adequacy ratio, the mean ratio of intake to recommended intake (each truncated at one) of energy and nine nutrients, was calculated as an indicator of nutrient adequacy. Information on household and individual characteristics, including demography, socioeconomic conditions and food production strategies was obtained using precoded questionnaires. Setting: Bafoulabé district, Kayes region, Western Mali. Subjects: In total, 502 subjects (55% women) aged 15-45 y from 319 different households. Results: Both FVS and DDS had a positive correlation with mean adequacy ratio (MAR). Multivariate analysis (linear regression)showed that the most important factors explaining MAR was the number of milk products, vegetables and green leaves consumed, as well as sex and the number of crops produced in the household. Dietary diversity was associated with socioeconomic status, residence and age. Conclusion: Dietary diversity is useful as an indicator of nutrient adequacy. It is important to examine how various food groups contribute to the nutrient adequacy of the diet in an area. Sponsorship: The Norwegian Research Council and The Strmme Foundation funded the project.

Objective: To assess the validity of two diet quality indexesFfood variety score (FVS) and diet diversity score (DDS) in Western Mali. Design: In two separate studies (A and B), FVS and DDS were derived from a food frequency questionnaire (FFQ) and were compared with the same scores and with measures of nutrient adequacy derived from 2-day weighed records (WR). Setting: Two rural, adjacent villages in Mali, West Africa. Subjects: In study A (1996), 48 women and 27 men (15-59 y) participated. Study B (1999) included 34 women and 36 men (15-45 y). Results: Spearman's correlation coefficients between FVS from the FFQ and WR for men were 0.5 in study A and 0.4 in study B. The corresponding correlations for DDS were 0.2 and 0.4, respectively. Correlations for women were lower, especially in study B. Classification into quartiles was also best for men. Correlations for the two diet variety scores from the FFQ with nutrient adequacy from the WR in study A were about 0.3 for men, but lower for women. In study B, these correlations were around 0.5 for men, whereas for women there was no association. Conclusion: FVS and DDS can be assessed by our FFQ. The two diet variety scores reflect diet quality and are simple tools that can be used for monitoring. The validation study gave better results for men than for women, which has implications for further use of these instruments. Sponsorship: The Norwegian Research Council and The Stromme Foundation funded the project.

Objective: The purpose of this study was to validate a quantitative food-frequency questionnaire (QFFQ) created for assessing the usual intake of foods and nutrients in the prevailing season in Western Mali. Design: Intake of foods and nutrients over the week preceding the interview was measured with a 69-item QFFQ. Intakes were compared with intakes as measured with 2-day combined weighed and recalled diet records. Setting: A rural village in Western Mali, West Africa. Subjects: Twenty-seven men and 48 women (15±59 years of age) representing 18 households. Results: Spearman rank correlations between intake of food groups from the QFFQ and the diet record ranged from 0.09 (meat/fish) to 0.58 (tea/coffee). Median coefficient was 0.37. Median Spearman correlation coefficient for nutrient intake was 0.40. Men had higher median correlation coefficients than did women. The proportion of subjects being classified into the same quartile of food intake was on median 33%, while a median of 7% was misclassified into extreme quartiles. Correct classification into the same quartile for intake of nutrients was on median 34% while a median of 4% was grossly misclassified. Intakes of most food groups and nutrients as measured by the QFFQ were higher than those measured by the diet records. However, while men had higher estimated intakes for foods eaten inbetween meals, women in general had higher intake of foods eaten in the main meals. Conclusion: This QFFQ can be used for comparing the intake of foods and nutrients between groups within this study population. It therefore represents a useful tool in the surveillance of food intake in the population, both in identifying vulnerable groups and for tracking food intake over time. The differences between men and women in overestimating food intake need to be taken into account when using the method.