The sweet tooth of infancy: Is sweetness exposure related to sweetness liking in infants up to 12 months of age?

Does sweetness exposure drive 'sweet tooth'?

It is widely believed that exposure to sweetened foods and beverages stimulates the liking and desire for sweetness. Here we provide an updated review of the empirical evidence from human research examining whether exposure to sweet foods or beverages influences subsequent general liking for sweetness (‘sweet tooth’), based on the conclusions of existing systematic reviews and more recent research identified from a structured search of literature. Prior reviews have concluded that the evidence for a relationship between sweet taste exposure and measures of sweet taste liking is equivocal, and more recent primary research generally does not support the view that exposure drives increased liking for sweetness, in adults or children. In intervention trials using a range of designs, acute exposure to sweetness usually has the opposite effect (reducing subsequent liking and desire for sweet taste), while sustained exposures have no significant effects or inconsistent effects. Recent longitudinal observational studies in infants and children also report no significant associations between exposures to sweet foods and beverages with measures of sweet taste preferences. Overall, while it is widely assumed that exposure to sweetness stimulates a greater liking and desire for sweetness, this is not borne out by the balance of empirical evidence. While new research may provide a more robust evidence base, there are also a number of methodological, biological and behavioural considerations that may underpin the apparent absence of a positive relationship between sweetness exposure and liking.

Comparing body composition between the sweet-liking phenotypes: experimental data, systematic review and individual participant data meta-analysis

BACKGROUND

Legislation aimed at reducing sugar intake assumes that sweet-liking drives overconsumption. However, evidence that a greater liking for sweet taste is associated with unhealthier body size is mixed and complicated by relatively small samples, an overreliance on body mass index (BMI) and lack of classification using sweet-liking phenotypes.

METHODS

We first examined body size data in two larger samples with sweet-liking phenotyping: extreme sweet-likers, moderate sweet-likers and sweet-dislikers. Adults (18-34yrs), attended a two-session lab-based experiment involving phenotyping for sweet-liking status and a bioelectrical impedance body composition measurement (Experiment One: N = 200; Experiment Two: N = 314). Secondly, we conducted an individual participant data (IPD) meta-analysis: systematic searches across four databases identified 5736 potential articles. Of these, 53 papers met our search criteria: a taste assessment that measured liking using sucrose (>13.7% w/v), which allowed sweet-liking phenotyping and included either BMI, body fat percentage (BF%), fat-free mass (FFM) or waist-circumference.

RESULTS

A significant effect of sweet-liking phenotype on FFM was found in both Experiment One and Two, with extreme sweet-likers having significantly higher FFM than sweet-dislikers. In Experiment One, sweet-dislikers had a significantly higher BF% than extreme sweet-likers and moderate sweet-likers. However, as these data are from one research group in a young, predominantly westernised population, and the results did not perfectly replicate, we conducted the IPD meta-analyses to further clarify the findings. Robust one-stage IPD meta-analyses of 15 studies controlling for sex revealed no significant differences in BF% (n = 1836) or waist-circumference (n = 706). For BMI (n = 2368), moderate sweet-likers had slightly lower BMI than extreme sweet-likers, who had the highest overall BMI. Most interestingly, for FFM (n = 768), moderate sweet-likers and sweet-dislikers showed significantly lower FFM than extreme sweet-likers.

CONCLUSION

The higher BMI often seen in sweet-likers may be due to a larger FFM and questions the simple model where sweet liking alone is a risk factor for obesity.

Sweet and sour sips: No effect of repeated exposure to sweet or sour-tasting sugary drinks on children's sweetness preference and liking

Health agencies advocate reducing children's sweetness exposure to lower sweetness preference or liking to ultimately lower sugar intake. However, the relationship between sweetness exposure, preference, and liking remains unclear. This work investigated the influence of exposure to a sucrose-containing sweet or sour-tasting drink on sweetness preference and liking for sweet and sour products in 4-7-year-old children (n = 65). The children were randomized into three groups with one daily exposure to either the sweet drink, sour drink, or water (control group) for 14 days. Sweetness preference was assessed at baseline (t1), day 15 (t2), and two months after the intervention (t3), using a forced-choice, paired comparison test with five beverages varying in sweetness intensity. Hedonic liking for the intervention drinks, a sweet and sour yogurt, and a sweet and sour candy was evaluated using a 5-point pictorial scale. Linear mixed models revealed a significant increase in sweetness preference from t1 to t3 (F(2) = 7.46, p < 0.001). However, ANCOVA analysis indicated that this effect was not caused by the intervention. Based on linear mixed models, we observed that children's hedonic liking for sweet and sour products remained stable from t1 to t3 and was not influenced by the intervention. These findings suggest that 14 exposures to a sucrose-containing sweet or sour-tasting drink did not affect sweetness preference or liking in 4-7-year-old children.

Understanding the Determinants of Sweet Liking in the African and East Asian Ancestry Groups in the U.S. - A Study Protocol

Background

The liking for sweet taste is a powerful driver for consuming added sugars, and therefore, understanding how sweet liking is formed is a critical step in devising strategies to lower added sugars consumption. However, current research on the influence of genetic and environmental factors on sweet liking is mostly based on research conducted with individuals of European ancestry. Whether these results can be generalized to people of other ancestry groups warrants investigation.

Methods

We will determine the differences in allele frequencies in sweet-related genetic variants and their effects on sweet liking in 426 adults of either African or East Asian ancestry, who have the highest and lowest average added sugars intake, respectively, among ancestry groups in the U.S. We will collect information on participants' sweet-liking phenotype, added sugars intake (sweetness exposure), anthropometric measures, place-of-birth, and for immigrants, duration of time living in the U.S. and age when immigrated. Ancestry-specific polygenic scores of sweet liking will be computed based on the effect sizes of the sweet-related genetic variants on the sweet-liking phenotype for each ancestry group. The predictive validity of the polygenic scores will be tested using individuals of African and East Asian ancestry from the UK Biobank. We will also compare sweet liking between U.S.-born individuals and immigrants within each ancestry group to test whether differences in environmental sweetness exposure during childhood affect sweet liking in adulthood.

Discussion

Expanding genetic research on taste to individuals from ancestry groups traditionally underrepresented in such research is consistent with equity goals in sensory and nutrition science. Findings from this study will help in the development of a more personalized nutrition approach for diverse populations.

Trial registration

This protocol has been preregistered with the Center for Open Science (https://doi.org/10.17605/OSF.IO/WPR9E) and is approved by the City University of New York Human Research Protection Program (IRB#: 2023-0064-Brooklyn).

Oh So Sweet: A Comparative Investigation of Retail Market Composition of Sweetened and Flavoured Beverages in Singapore and Australia

The consumption of sugar and non-nutritive sweeteners has been associated with poor health outcomes. The aim of this paper was to provide a comparison of the range of sweetened or flavoured beverages between two high-income countries in the Asia-Pacific region: Australia and Singapore. Following the FoodTrackTM methodology, nutrition, labelling, and price data were collected from major Australian and Singaporean supermarket chains and convenience stores. The nutrient profiles of products were tested for differences using Kruskal−Wallis and Mann−Whitney U tests. The greatest number of products collected in Australia were from the ‘carbonated beverages’ category (n = 215, 40%), and in Singapore the greatest number of products were from the ‘tea and coffee ready-to-drink’ category (n = 182, 35%). There were more calorically sweetened beverages in Singapore compared with Australia (n = 462/517 vs. n = 374/531, p < 0.001). For calorically sweetened products, the median energy of Singaporean products was significantly higher than Australian products (134 kJ vs. 120 kJ per 100 mL, p = 0.009). In Australia, 52% of sweetened or flavoured beverages displayed a front-of-pack nutrient signposting logo, compared with 34% of sweetened or flavoured beverages in Singapore. These findings also indicate that the consumption of just one serving of calorically sweetened carbonated beverages or energy drinks would exceed the WHO maximum daily free sugar recommendations.