The prevalence of overweight and obesity has increased dramatically worldwide over the last decades, regardless of geographical boundaries and cultural differences. Making the desirable and appropriate food choices is important in preventing weight gain and obesity. Food choices are to a great extent guided by the taste of food.
The overall aim of this thesis was to assess the role of taste in energy intake in young children and adults, and to investigate how taste relates to nutrients and adherence to dietary recommendations.
In Chapter 2 we studied the relationship between taste intensity, energy and nutrient content in individual foods. We found associations between sweetness and mono- and disaccharide content, and between saltiness and sodium, protein, and fat content. Saltiness, but not sweetness, was associated with energy content. We found no modifying effect of food form, i.e. liquids, semi-solids and solids, on the relationship between taste intensity and nutrient content.
In Chapters 3-6 we combined our taste database with dietary intake data to investigate dietary taste patterns. First, we evaluated dietary taste patterns based on FFQ against 3-d 24hR and biomarkers of exposure in an adult study population (Chapter 3). We found that the FFQ’s reliability against 24hR was acceptable to good for ranking of adults’ dietary taste patterns. Moreover, associations between dietary taste patterns and urinary Na and N were similar for FFQ and 24hR. These findings suggest that both FFQ and 24hR can be used to investigate dietary taste patterns.
In Chapter 4 we investigated the development of dietary taste patterns during early childhood in a large population-based cohort. In children aged one year the majority of energy intake was obtained from ‘neutral’ (64%) tasting foods, which was substantially higher than in children aged two years (42%). Energy intake from ‘sweet & fat’, ‘fat’ and ‘salt, umami & fat’ tasting foods was higher in two year olds than in one year olds. Higher child BMI Z-scores were associated with relatively more energy from ‘salt, umami & fat’ tasting foods. Furthermore, higher maternal educational level was associated with relatively more energy from ‘neutral’ tasting foods and less from ‘sweet & fat’, ‘ fat’ and ‘ salt, umami & fat’ tasting foods.
Subsequently, dietary taste patterns were investigated in adults in two study populations (Chapter 5). In both study populations we found that men consumed relatively more energy from ‘salt, umami & fat’ and ‘bitter’ tasting foods, whereas women consumed relatively more energy from ‘sweet & fat’ and ‘sweet & sour’ tasting foods. In addition, we found that obese individuals consumed relatively more energy from ‘salt, umami & fat’ tasting foods and relatively less from ‘sweet & fat’ tasting foods than lean individuals.
In our last study, we compared dietary taste patterns of healthy and popular dietary scenarios with Dutch dietary taste patterns in women from the DNFCS 2007-2010 (Chapter 6). In addition, we investigated associations between the extent of adherence to food-based dietary guidelines, as a measure of diet quality, and dietary taste patterns in these women. We found that healthy diets may be lower in taste intensity compared with current Dutch dietary taste patterns in women. Popular diets, such as a Paleo diet, were more similar in taste intensity to the current diet.
Diets lower in sugar, salt, and saturated fat content may be lower in taste intensity and this could be a key explanatory factor for poor adherence to dietary guidelines. However, healthy diets can be made more appealing by adding flavour, such as herbs & spices. One of the strategies that may be used to lower dietary salt, sugar and saturated fat intake is the gradual reduction of these nutrients in food. Another promising but challenging strategy could be that foods are reformulated to reduce levels of salt, sugar and saturated fat without affecting taste and palatability. However, successful application of these techniques requires substantial research and development for each product individually.
Studying dietary intake from a taste perspective has provided new insights that may give new input for the development of randomized controlled trials. These trials are needed to investigate whether high or low sweet and salty taste exposure affects long-term perceived intensity and preferences for sweetness and saltiness and dietary taste patterns. Given the current dietary guidelines to reduce dietary salt, sugar and saturated fat intake, further research on the feasibility of these guidelines, from a taste perspective, is clearly needed.