Abstract
BACKGROUND:
Yogurt is a food product with intrinsic health properties. Health messaging and promotion has emphasized its nutritional qualities and its role in weight management. Some evidences highlighted that yogurt consumption has been more commonly adopted by people with healthier diet and lifestyle.
OBJECTIVE:
To explore if yogurt intake of Italian adults and older adults is associated with sociodemographic and lifestyle factors.
METHODS:
A cross-sectional survey was carried out on a sample of households randomly selected after geographical stratification of the national territory. 2798 subjects aged 18–97 years were considered for this study. Yogurt intake was assessed using a 3-day dietary record. Sociodemographics, smoking and alcohol habits, physical activity, dieting, out-of-home eating, interest for nutrition information, were obtained from self-administered questionnaires.
RESULTS:
636 subjects (22.7% ) consumed yogurt, with an average intake of 90.4 g/day. Higher intake was reported by subjects with higher levels of education, those who practiced ≥2 hours/week of sporting activities, those with a good knowledge of the food-health relationship and accustomed to reading food labels. Yogurt consumers demonstrated healthier behaviours compared with non-consumers.
CONCLUSIONS:
Further analyses on the dietary and nutritional profile of yogurt consumers are needed in order to examine more in-depth the role of yogurt in the Italian diet.
Introduction
Yogurt is the most commonly consumed fermented milk product, with some intrinsic health properties. It is an excellent source of high quality protein, calcium, phosphorus, magnesium, zinc, vitamin B12, riboflavin and niacin [1].
In Italy and most of the EU member states the national legislation on yogurt is in line with the standard for fermented milks adopted by the FAO/WHO Codex Alimentarius, which allows the terms “yogurts” and “fermented milks” only to products containing live bacteria. Main bacteria used to produce yogurt are probiotic ingredients, with demonstrated health benefits in humans, such as alleviation of lactose intolerance and reduction of the incidence of gastrointestinal infections [2].
Since 1950 s, when the dairy industry begun to produce and commercialize yogurt, this product has been more and more consumed in Europe. The demand for yogurt consumption increased particularly in the period 2004–2008 in all the European Union countries (EU 27), and Italy experienced an even greater increase in those years [3].
Although the per-capita yogurt intake in Italy was well below the one observed in most other European countries, such as France, Spain, Germany, but also Hungary and Poland [4], it showed an increasing trend, from 4.3 g/day for total population in 1980 s (5), to 16.0 g/day (adults) and 10.5 g/day (older adults) in 1990 s (6), up to 22.0 g/day for adults, and 15.6 g/day for older adults seen in the most recent food consumption survey carried out in 2005-06 [7].
Among the reasons for the increase in yogurt consumption in Italy and in other countries, of considerable importance are several product innovations introduced in the last 20 years, aimed at satisfying the needs of different types of consumers. A wide range of products are now available: creamy and flavoured to satisfy hedonistic consumers, low-fat and low-calorie for those who need to control body weight, yogurts for children, drinking yogurts, organic yogurts produced with environmentally friendly processes. Moreover, from late 1980’s to mid 2000’s main yogurt manufacturers operating in Italy have largely invested in the development and marketing of functional yogurts, that is yogurts enriched with probiotic ingredients, vitamins, minerals and fibre, with demonstrated beneficial effects, “in a way that is relevant to either an improved state of health and well-being and/or reduction of risk of disease” [2]. Functional yogurts have been the driving factor of the Italian yogurt market, so as to achieve a considerable market share in 2007 [8]. As maufacturers successfully differentiated the market of conventional yogurts, and successfully focused on functional yogurt segment, the image of yogurt as a healthy product was strengthened by health messaging and promotion.
Many studies have analysed yogurt consumers through different approaches. Consumers’ perceptions of conventional and functional yogurts has been the subject of several researches [9–14], resulting mainly related to health, nutrition, sensory characteristics and pleasure.
Several studies focused on the Italian yogurt market [15–17]. In particular, Bonanno [18] analysed the demand for both conventional and functional yogurts to assess the role of health-related demographic characteristics.
Pala et al. [19] found a healthier lifestyle among yogurt consumers, and Cormierl [20] observed that yogurt consumption is associated with a health-related dietary pattern.
The present study aimed to contribute to a better understanding of the characteristics of yogurt consumers in Italy, respect to non-consumers, in terms of sociodemographic and lifestyle factors, and food-related behaviours, employing yogurt consumption data from the INRAN-SCAI 2005-06 dietary survey.
Methods
Dietary and lifestyle assessment
The study is focused on the most recent yogurt consumption data extracted from the national survey carried out from October 2005 to December 2006 (INRAN-SCAI 2005-06) in Italy. Detailed information about this study can be found elsewhere [7]. Briefly, a total of 3323 individuals participated in the food survey, carried out by a team of thirty trained field workers. Data were collected using a 3-day dietary record. All foods and drinks consumed were recorded by each participant on a semi-structured diary using household measures and estimated portion sizes. Each item consumed, for each meal occasion, was expressed in grams (g) of net raw ingredients and food items were classified in 15 food categories and 51 subcategories [7, 21]. Overall, the analysed records represent 9969 days, weekdays represented 78% of all survey days, and survey days were proportionally distributed among seasons. The present analyses focused on items belonging to the food subgroup “Yogurt and fermented milk”, referred to as “yogurt” in the following text. This included all type of yogurt: skimmed, partially skimmed, whole, flavoured, containing other ingredients (fruit, cereals, nuts, chocolate, etc.), fortified types and also drinkable yogurt. A subsample of 2798 subjects, aged 18 to 97 years, was selected for the present study. Overall, 636 subjects were considered as yogurt consumers, as they consumed at least one average serving (125 g) of yogurt over the 3-day survey period (equivalent of ≥41.7 g/day). Consumers were further split into two groups, “low consumers” defined as those consuming “≥125 g/ <250g” of yogurt over the 3-day survey period, and “moderate consumers” defined as those consuming “≥250g” over the 3-day survey period. Weight and height were self-reported. Overweight was defined as Body Mass Index (BMI expressed as kg/m2) between 25 and 30, and obesity as BMI≥30. A self-administered questionnaire was used to collect information on marital status, education and type of employment, smoking and alcohol habits, dieting, out-of-home eating, time spent for physical activity, interest in nutritional information and knowledge on food-health relationship.
Statistical analysis
Analyses of consumers vs. non consumers, and low vs. moderate consumers, across the selected characteristics were performed using contingency tables and Chi-square test. Differences in the mean servings of yogurt consumed per day between the various sociodemographic and lifestyle groups, for total, low and moderate consumers, were analysed and tests for comparison between means were performed using the Kruskal-Wallis test. Finally, in order to take into account potential confounders in the analysis, descriptive factors were used as independent variables in a logistic regression model, backward stepwise method (using p < 0.05 as the threshold for removing a variable from the models), with yogurt consumption (consumers vs. non-consumers) as the dependent variable.
Analyses were performed using SAS software version 9.2 (SAS Institute Inc., Cary, NC, USA). For all the tests a p value <0.05 was considered to be statistically significant.
Results
Yogurt consumers vs. non-consumers
Overall, 22.7% (n = 636) of the subjects were yogurt consumers according to the definition specified, and reported an average daily intake of 90.4 g/day, with some significant differences across the subgroups (Table 1). Subjects with a high level of education reported a higher intake (102.2 g/day) compared to those with lower levels. Those practicing ≥2 hours/week of sporting activities ate more yogurt (98.9 g/day) than those who practiced <2 hours/week (80.9 g/day) or no sport at all (87.2 g/day). Subjects having a good (perceived) knowledge on food-health relationship consumed more yogurt (97.6 g/day) than those with a sufficient (86.8 g/day) or poor (79.8 g/day) knowledge. Subjects accustomed to reading food labels presented a higher intake (96.5 g/day) than those who were not (81.3 g/day) (Table 1).
The distribution of yogurt consumers across most of the selected demographic and lifestyle factors significantly differed respect to non-consumers. The percentages of females, adults aged 18–64 years, and people from Northern regions were higher among consumers (Table 2). Higher rates of subjects with BMI <25, non-smokers, following a reduced intake diet, and practicing ≥2 hours/week of sport activities were found among yogurt consumers. Among consumers there were higher rates of people expressing interest in receiving nutritional information, using TV/radio programmes, books and magazines as sources of information on nutrition and health, and accustomed to reading food labels (Table 2).
Table 3 presents the results of the logistic regression analysis. Only those factors retained after backward elimination were reported. After adjusting for potential confounding factors, we observed that females were twice as likely to consume yogurt as males, and 18–64-year-olds were 55% more likely to consume yogurt than those aged 65 and over. The likelihood of consumption strongly increased in people in Northern and Central regions of Italy, compared with the South and Islands.
Those who did not practice physical activity, and those who practiced physical activity for <2 h/week were 40% and 35% respectively less likely to consume yogurt than those who practiced ≥2 h/week. Smokers were 30% less likely to consume yogurt than non-smokers. Those subjects who did not eat out regularly at coffee shops or fast food restaurants were 83% more likely to consume yogurt than those who reported to eat out on a regular basis. Subjects interested in receiving nutritional information were 71% more likely to consume yogurt than those not interested.
Low vs. moderate yogurt consumers
Low consumers registered an intake of 57.0 g/day, whereas moderate consumers had an intake of 150.2 g/day, with little variation across the subgroups (Table 1).
Some significant differences were found between low and moderate yogurt consumers, according to the selected descriptive factors. Among moderate consumers there was a higher rate of subjects from the Centre of Italy (24.1% vs. 16.9% ), a lower rate from the South (13.2% vs. 21.6% ), and a reduced proportion with low education level (28.4% vs. 38.9% ) (Table 2).
Yogurt was prevalently consumed at home, during breakfast for moderate consumers (71.8 g/day), and theafternoon snack for low consumers (18.6 g/day) (Table 4).
Discussion
This work explored if an association existed between yogurt intake and sociodemographic and health-related lifestyle factors, in those years when the yogurt sector in Italy experienced a great expansion. The present results show that higher yogurt intake was reported by subjects with higher level of education, by those who practiced two or more hours of sporting activities per week, and by subjects with a good knowledge of the food-health relationship and accustomed to reading food labels. Moreover, yogurt consumers in Italy demonstrated healthier behaviours compared with non-consumers. Non-smokers, those who spent more time doing physical activity, and those interested in nutritional information were more likely to consume yogurt.
A research on the Italian yogurt market [8] reported that in 2006 the trend was moving towards further segmentation to target specific consumer groups, such as children, women, traditional consumers, and health-conscious consumers, who take care of their diet and who have modern lifestyles. It also reported an increase in purchase volume of yogurt in 2006 compared to the previous decade, albeit lower than in other European countries [8], partially confirming the present results. The study of Pala et al. [19] found, in addition to other principal results, a healthier lifestyle among yogurt consumers: subjects in the highest tertile of yogurt consumption were significantly less likely to be overweight or obese, did significantly more sporting activities, and were significantly less likely to be current smokers, while the category of subjects in the lowest yogurt consumption tertile contained the highest proportions of people with low education and consistent alcohol drinking habits. Other studies have examined the relationship between health beliefs and dietary practices. Larson et al. [22] found that among American female adolescents, health attitudes were significantly and positively related to milk intake. Allen and Goddard [23] examined individual preferences for milk and yogurt, and found that general nutrition knowledge can predict purchasing and consumption intentions for milk and yogurt products.
According to many researches conducted in recent years, there is some interesting evidence that yogurt might be related to certain health benefits. Regular consumption of yogurt might help to meet the dietary recommendations for some key nutrients [1], reduce the risk of cardiovascular disease and type II diabetes [24–26], lower risk of incident hypertension, smaller long-term increment of systolic blood pressure and smaller long-term gain in weight and waist circumference [27–29], and might be protective against colorectal cancer [19]. Anyway, scientists are cautious in stating that yogurt produces these desirable effects, and agree that further research is needed to determine if the observed associations are causal.
The consumption data used in the present analysis have some known limitations, related to methodological issues that have been already discussed in detail by Leclercq et al. [7] and Sette et al. [30]. Food and nutrient intakes assessed using a 3-day dietary record has been demonstrated to be a reliable and valid method for estimating population food and nutrient intake [31]. Food consumption data are often used to characterize average and high levels of consumption within the population. In the case of food categories with a large number of non-consumers, as was the case in the present analysis, the median (P50) is likely to be zero and the mean values can be very low over the total sample. In these cases ‘consumers only’ mean values can be very different from the total ones.
The low participation rate in this study could have affected the representativeness of the study sample as participants may be more motivated than subjects who are not interested in participating. However, the study was designed with the aim of representativeness of the total population at a national level and in the four main geographical areas in Italy, taking energy intake as the referring parameter [7].
A further limitation of the study is the self-reported nature of the information on lifestyle and the level of interest and knowledge on nutrition and food-health relationship. It is possible that this self-reported information did not reflect the actual behaviours of the selected sample, although we considered it as a rough indicator.
Studies suggest that BMI based on self-reported weight and height is not accurate for individual BMI assessment [32, 33]. However, in this study BMI was used for the purpose of better understanding the lifestyle of respondents, and not to infer specific health risks that might be under/overestimated by self-reporting.
Conclusion
Although yogurt did not belong to the traditional Italian dietary pattern, the consumption of this product has tended to increase in recent decades in Italy, and the results provided here represent a rough indication that its consumption might be linked to the attention of people towards healthy lifestyle and behaviours.
A more in-depth analysis on the dietary and nutritional profile of yogurt consumers is needed in order to complete the analysis presented here and extend our understanding on the role and place of yogurt in the Italian diet.
Footnotes
Acknowledgments
The present work was independently leaded by CRA-NUT and granted by Danone Nutricia Research.