Higher dietary species richness is associated with better diet quality in adults: results from the Italian IV-SCAI...

Dietary species richness (DSR) is key to food security and nutrient adequacy, but only recently has attracted research attention in Europe. This is the first analysis to assess food biodiversity through DSR in Italian adults, considering its potential link to diet quality across regions. Data from the nationally representative Italian dietary survey (IV SCAI study 2018-2020) were used, including 726 adults (346 male, 380 female), aged from 18 to 64 years. Dietary assessment was conducted with the use of two non-consecutive 24-h recalls. Total, vegetable and fruit DSR were calculated for both days per individual by summing the total number of unique species consumed. Diet quality was assessed using the global diet quality score (GDQS). Total GDQS was calculated based on 25 food groups (score 0-49), and sub-indices GDQS+ (16 food groups; score 0-32) and GDQS- (9 food groups; score 0-17) were calculated according to the consumption of healthy and unhealthy foods, respectively. Spearman's rho test was used to evaluate potential correlations among the variables. Linear regression was performed to evaluate potential associations between DSR and GDQS and their subcategories, using age, sex, body mass index, vegetable and fruit consumption as covariates. This study showed that higher total, vegetable and fruit DSR were associated with higher total GDQS and GDQS+, while higher meat and meat products consumption was weakly correlated with lower GDQS (ρ = -0.296; p < 0.0001). Further research is needed to develop innovative dietary assessment methods that consider DSR, food healthiness and local biodiversity, particularly in regions like Italy.