Association between intake of total vs added sugar on diet quality: a systematic review

Given its potential effect on nutrient and energy density, the sugar content of the diet is a subject of controversy.

The aim of this review was to examine the cross-sectional or prospective evidence for associations between the intake of total sugar or added sugar (high vs low intakes) and diet quality or nutrient intakes in the general population.

The following databases were searched for English-language articles published between 1972 and 2012: CINAHL Plus, EBM Reviews, ERIC, MEDLINE, PREMEDLINE, PsycINFO, PubMed, and ScienceDirect.

The search identified studies that examined the association between intake of total sugar and/or added sugar and diet quality (n = 22) or nutrient intakes (n = 30).

The following data were extracted: sample size and population, dietary assessment method, source of added sugar data, source of funding, comparator, association between total sugar or added sugar and diet quality, and the direction and magnitude of the association.

Of 22 studies, all except 1 found a higher intake of added sugar to be associated with poorer diet quality, and the exceptional study did not adjust for total energy intake. Twenty-one of 30 studies found a negative association between added sugar and micronutrient intakes. The same association was not found for total sugar intake.

Any negative association between dietary sugar and diet quality is better exposed by referring to added sugar rather than total sugar. There was substantial variation in features of study quality, including sample size, so the magnitude of the observed effect was generally small and may not be of clinical significance. Furthermore, the positive influence that core foods such as fruit and milk exert on total sugar values may bias the association between total sugar and diet quality.