Several previous studies have shown that a diet score based on the Japanese food guide Spinning Top (the original score) is associated with both favourable and unfavourable dietary intake patterns. We developed a food-based diet quality score (the modified score) and examined associations with nutrient intakes. Subjects were 3963 young (all aged 18 years), 3800 middle-aged (mean age 47·7 (sd 3·9) years) and 2211 older (mean age 74·4 (sd 5·2) years) Japanese women. Dietary intakes were assessed using comprehensive (for the young and middle-aged) and brief-type (for the older) diet history questionnaires. The original score was calculated based on intakes of grains, vegetables, fish/meat, milk, fruits, and snacks/alcoholic beverages. The modified score was similarly calculated, but included Na from seasonings and without applying the upper cut-off values for dietary components where increased consumption is advocated for Japanese women (grains, vegetables, fish/meat, milk, and fruits). The original score was positively associated with intakes of carbohydrate, dietary fibre, and all the vitamins and minerals examined including Na and inversely with intakes of fats and alcohol in young and middle-aged women. In older women, the original score was inversely associated with intakes of all nutrients except for carbohydrate and vitamin C. However, the modified score was associated positively with intakes of protein, carbohydrate, dietary fibre, K, Ca, Mg, Fe, vitamins A, C and E, and folate and inversely with intakes of fats, alcohol and Na in all generations. In conclusion, the modified diet score was positively associated with favourable nutrient intake patterns in Japanese women.

A mother’s diet during pregnancy has the potential to influence both her own and her child’s short- and long-term health. This paper reports the effects of a randomized controlled diet intervention during pregnancy on dietary behavior post-intervention as reported in late pregnancy. The diet intervention was part of a lifestyle intervention targeting both diet and physical activity behaviors among nulliparous women participating in the randomized controlled Norwegian Fit for Delivery study (NFFD). Eligible women were enrolled in early pregnancy from eight healthcare clinics in southern Norway between 2009 and 2013. The diet intervention was based on 10 dietary recommendations that were conveyed during two counseling sessions by phone and in a pamphlet describing the recommendations and their simplified rationale. A diet score was constructed from a 43-item food frequency questionnaire (FFQ) and used to assess intervention effect on dietary behavior (score range 0–10). Between-group dietary differences post-intervention were estimated with analysis of covariance, with adjustment for baseline diet. A total of 508 women completed the FFQ both at baseline and post-intervention. There were no between-group differences in diet score and subscales at baseline. Post-intervention, the intervention group had higher overall diet score (control: 4.61, intervention: 5.04, P=0.013) and favorable dietary behavior in seven of the 10 dietary domains: ‘consumption of water relative to total beverage consumption’ (P=0.002), ‘having vegetables with dinner’ (P=0.027), ‘choosing fruits and vegetables for between-meal snacks’ (P=0.023), ‘buying small portion sizes of unhealthy foods’ (P=0.010), ‘limiting sugar intake’ (P=0.005), ‘avoiding eating beyond satiety’ (P=0.009) and ‘reading food labels’ (P=0.011). The NFFD diet intervention improved dietary behavior. Potential long-term clinical influence in mother and child will be investigated in further studies.

Socio-economic gradients in diet quality are well established. However, the influence of material socio-economic conditions particularly in childhood, and the use of multiple disaggregated socio-economic measures on diet quality have been little studied in the elderly. In the present study, we examined childhood and adult socio-economic measures, and social relationships, as determinants of diet quality cross-sectionally in 4252 older British men (aged 60–79 years). A FFQ provided data on daily fruit and vegetable consumption and the Elderly Dietary Index (EDI), with higher scores indicating better diet quality. Adult and childhood socio-economic measures included occupation/father's occupation, education and household amenities, which combined to create composite scores. Social relationships included social contact, living arrangements and marital status. Both childhood and adult socio-economic factors were independently associated with diet quality. Compared with non-manual social class, men of childhood manual social class were less likely to consume fruit and vegetables daily (OR 0·80, 95 % CI 0·66, 0·97), as were men of adult manual social class (OR 0·65, 95 % CI 0·54, 0·79), and less likely to be in the top EDI quartile (OR 0·73, 95 % CI 0·61, 0·88), similar to men of adult manual social class (OR 0·66, 95 % CI 0·55, 0·79). Diet quality decreased with increasing adverse adult socio-economic scores; however, the association with adverse childhood socio-economic scores diminished with adult social class adjustment. A combined adverse childhood and adulthood socio-economic score was associated with poor diet quality. Diet quality was most favourable in married men and those not living alone, but was not associated with social contact. Diet quality in older men is influenced by childhood and adulthood socio-economic factors, marital status and living arrangements.

The literature on predefined indexes of overall diet quality is reviewed. Their association with nutrient adequacy and health outcome is considered, but our primary interest is in the make-up of the scores. In total, twenty different indexes have been reviewed, four of which have gained most attention, and many others were based on those four. The various scores differ in many respects, such as the items included, the cut-off values used, and the exact method of scoring, indicating that many arbitrary choices have been made. Correlations in intake between dietary components may not be adequately addressed. In general, diet quality scores show an association with mortality or disease risk, but these relations are generally modest. Existing indexes do not predict morbidity or mortality significantly better than individual dietary factors. Although conclusions from the review may provide guidance in the construction of a diet quality score, it is questionable whether a dietary score can be obtained that is a much better predictor of health outcome.