Perceived social support and diet quality among ethnic minority groups in Yunnan Province, Southwestern China: a cross-sectional study

Unhealthy eating has become a serious public health problem worldwide [1, 2]. It is estimated that 11 million deaths worldwide (22% of all deaths among adults) were attributable to dietary risk factors such as high intake of sodium, and low intake of whole grains and fruits [3]. Over the past decades, China has also experienced an accelerating nutrition transition characterized by unhealthy changes in dietary patterns and increasing prevalence of diet-related diseases [4, 5]. Nearly half of Chinese adults are facing the problem of double burden of malnutrition, which refers to the coexistence of micronutrient deficiencies along with overweight and obesity within individuals [6].

To promote healthy eating behaviors among the public, some countries have developed dietary guidelines based on scientific evidence and local dietary habits [7, 8]. Dietary indexes such as Healthy Eating Index (HEI) for Americans and Diet Balance Index (DBI) for Chinese, have also been constructed to measure how well individual diets meet recommendations of the guidelines [9, 10]. In addition to dietary assessment, these priori indexes are also used to examine associations between diet quality and health outcomes [11, 12]. Notably, data from the 2010–2012 China Nutrition and Heath Surveillance showed that 73.6% adults were at moderate or high levels of inadequate food intake, while 27.9% were at moderate or high levels of excessive food intake [13]. What’s more, diet imbalance is more likely to be found among people living in rural areas, with lower education level and household income [12]. In recent years, social and interpersonal influences on dietary behaviors have received increasing attention. For example, a study in Canada shows that social deprivation (an indicator reflects deprivation of social networks, from family to community) is associated with lower diet quality [14]. In contrast, another study from Switzerland reported that women who dined more often with healthy eaters were on a higher diet quality and a lower body mass index (BMI) [15]. These findings suggest that social networks may have a shared perception of healthy eating, which would influence individual’s dietary practices. Thus, individual’s social relationships would be an important consideration for healthy eating promotion.

Social support is the emotional, instrumental and informational aid exchanged through social relationships and interpersonal transactions, which can be measured as perceived support or received support [16]. Perceived social support is the mostly measured index for its ease of measurement and strong associations with health outcomes [17, 18]. Although positive and causal relations between social support and health have been well documented, the influence of social support on some key health-related behaviors like diet are still understudied, especially in adults. For single food intakes of individuals, social support often appears a protective effect. For example, two studies from the United States show that social support was correlated with high consumptions of fruits and vegetables, or low consumptions of sugar and processed meat [19, 20]. In contrast, the relations between social support and overall diet quality remain controversial. In one study, social support was positively associated with HEI-2010 among middle-aged and older US men; however, such association was not statistically significant among American minority youths [21, 22]. Moreover, sources of social support may have different effects on eating behaviors. For instance, fruit and vegetable consumption were positively associated with family support, but not with friend or pastor support among African-Americans [23]. In addition, effects of social support on dietary behaviors may also differ in gender, age and ethnicity [24, 25]. Thus, although social support being perceived as one of the best strategies to promote health, the associations of between social support and dietary behaviors need to be further examined in certain contexts.

Yunnan Province is a less developed and multi-ethnic province in Southwest China. Benefited from the National Poverty Alleviation and Development Program, the local economy has been growing at a high speed in the past decades, especially in the ethnic regions. Therefore, we hypothesize that unbalanced dietary consumptions would have emerged among the ethnic minority groups and social support may have a role in this process. In his study, we examined the associations between sources of perceived social support and DBI-16 among adults of six ethnic minority groups in Yunnan Province. The purpose of the study was to evaluate dietary intakes of the ethnic groups and further understand the influential factors.

Table 1 shows the characteristics of the study population. A total of 3564 ethnic adults were included in the final analysis, comprising 1496 men (42%) and 2068 women (58%). Proportions of subjects aged 18–34, 35–44, 45–59, 60 years and older were 20.2, 21.7, 35.6 and 22.5%, respectively. Each of the six ethnic minority groups approximately accounted for 16% of the sample. Most of the participants were farmers and over one third only had primary school or no formal education. Nearly one fourth of the adults had a household income less than 5000 Yuan per year.

Table 2 presents the scores for DBI-16 components and the percentage of people with each score. Over intakes of cereals, meat and oil were common, with the score for about 80 to 90% participants being in the positive range. In contrast, under intakes of dairy, fruits and fish were also common, with over 90% of the ethnic adults having a negative score. Diet variety was very poor in the population, with almost all of them (99.9%) in the negative range.

The distribution of DBI-16 indicators is presented in Table 3. The LBS indicated that 51.2% of the participants had moderate or high levels of inadequate food intake, respectively. The distribution of HBS indicated that 21.3% of people had a moderate or excessive food intake. According to the distribution of the DQD, an indicator used to evaluate the overall unbalance in dietary intake levels, 74% of the ethnic adults had moderate or high levels of unbalanced food intake.

Table 4 shows the median scores for LBS, HBS and DQD by sociodemographic characteristics of the participants. Results of Kruskal-Wallis test indicated that women and people who were younger, had higher education or income were less likely to have inadequate, excessive and unbalanced dietary intakes.

Associations between moderate or high levels of inadequate and excessive food intake and perceived social support are shown in Table 5. Logistic regression models with potential confounders adjustment showed that support from family were negatively associated with inadequate food intake, while support from friends were positively associated with both inadequate and excessive food intake. No significant associations were found between support from significant others and DBI-16 indicators.

Table 6 show the correlation coefficients between DBI-16 component scores and perceived social support. Support from family were positively associated with intakes of fruits, dairy, fish, egg and diet variety, while negatively associated with vegetable and meat consumption. Support from friends were positively associated with intakes of dairy, beans, fish, egg, sugar and diet variety, while negatively associated with cereals, vegetable and meat consumptions. Support from significant others were positively associated with intakes of dairy, beans, fish, egg, sugar and diet variety, while negatively associated with cereals, vegetable and meat consumptions.

The cross-sectional study examined the associations between diet quality and perceived social support among adults of six ethnic minority groups in Yunnan Province, Southwest China.. Dietary assessment with DBI-16 indicated that dietary imbalance is common among the population, especially among men and those who are older, had lower education or income levels. Notably, support from family, friends and significant others showed different effects on healthy eating. To our best knowledge, this was the first study to explore interpersonal factors of dietary behaviors among ethnic minorities in less developed areas of China.

There are 15 ethnic minority groups native to Yunnan Province. Historically, these groups live in remote, poor areas. A study conducted in Yunnan among preschool-aged children 10 years ago showed that the prevalence of stunting, underweight and wasting were significantly higher in ethnic minority groups than in Han ethnicity [33]. Benefited from the poverty alleviation work in recent years, these areas have achieved impressive economic developments. In the former case, changes in lifestyle and diet often come with rapid economic developments [34, 35]. A longitudinal study in China showed that between 1995 and 2014 stunting, thinness continued to reduce in school-aged children and adolescents while the prevalence of obesity markedly increased [36]. In this study, Engel’s coefficient is 0.4, suggesting that living standard of the ethnic minority groups is just at a crucial stage of nutrition transition. Besides, most of the ethnic adults are low educated and have poor health awareness, which would make them difficult to develop or keep a healthy dietary habit in the nutrition transition. A recent study showed that although the prevalence of non-communicable chronic diseases in adults of Nu ethnicity was still lower than in Han Chinese, excessive intakes of meat and cereals were more prevalent in the former [37, 38]. For developing and implementing targeted intervention programs, it is of significance to evaluate diet quality and influential factors of the population.

Our findings indicate that 51.2% of the ethnic minority groups had moderate or high levels of inadequate food intake; 23.3% had moderate or high levels of excessive food intake; and 74.0% had moderate or high levels of unbalanced food intake. In contrast to a recent Chinese national representative study, diet quality of the study population already exceeded than the rural residents but was still inferior to the urban residents (LBS: 56.9–91.0%; HBS: 22.3–33.7%; DQD: 58.6–89.1%) [31]. Diet quality is usually better among urban residents due to higher income and more diversified food supply [39]. This study reflects the effect of rapid urbanization on dietary patterns among the population. Our results that there were socioeconomic disparities in diet quality are consistent with previous studies, highlight the necessity of paying more attention on people with low socioeconomic status [10, 40]. One interesting finding of our study is that only 10% of the study population consumed adequate vegetables and fruits, which is lower than people in Shanghai (about 20%) [39]. But actually, vegetables and fruits are fairly cheap and widely available in the ethnic areas. In contrast, over 80% of the subjects had excessive intake of meat, which was even higher than urban residents in Shanghai (about 60%) [39]. These findings suggest that the ethnic minority groups would not have formed a correct perception of what constitutes a healthy diet. Thus, more research is required to understand the influential factors in addition to economic development and personal income.

In the literature, social support has been proposed as a social psychological mechanism that social ties affect bodily and emotional well-being [41]. People can obtain both normative and behavioral guidance through comparisons with others, for example, norms about healthy eating. Besides, facts or recommendations from others may enable subsequent behavioral changes that make everyday tasks more efficient, economical or successful. Thus, social support is recognized as a promising strategy to promote health and has been used in clinical and adolescent nutrition interventions [42, 43]. In this study, social support from different sources showed different effects on healthy eating. Family support had a protective effect for inadequate food intake, whereas the support from friends was a risk factor for both inadequate and excessive food intake. And no significant associations were found between diet quality and the support from significant others. These results suggest that the influences of social relationships on dietary behaviors in the ethnic population are mainly from family and friends. In terms of individual food intakes, effect directions of the three sources of social support are generally consistent. This finding may imply that the perception of healthy eating across the three types of people are homogenous. In addition, the effects of perceived social support on individual food consumption are not completely consistent with recommendations of the Dietary Guidelines. For example, social support is positively associated with diet variety and dairy consumption but also negatively associated with vegetable intakes. This result may reflect the fact that nutrition knowledge among the ethnic minority groups are fragmental and inaccurate. In the current “Healthy China Action”, supportive environment construction (including infrastructure and relationships) is particularly emphasized [44, 45]. Thus, future studies may wish to focus on how to incorporate social support in healthy eating promotions of the public.

There are several limitations to this study. First, the cross-sectional design of the study restricts casual inference between dietary intakes and perceived social support. Second, although a FFQ could prevent seasonal variations in dietary intakes, the self-report food intake within a year might be subject to recall bias. Third, although socioeconomic factors are adjusted in the regression models, potential factors at contextual levels for both diets and social support are not fully considered, for example cultural differences in the ethnic minority groups. Last but not least, we only calculated the individual intake of condiments and sugar based on consumption at home and exclude the intakes outside the home. Thus, the consumption of oil, salt and sugar might be underestimated.

In conclusion, unbalanced dietary consumption is common among the ethnic minority groups in Yunnan Province. Perception of support from family, friends and significant others has an effect on overall diet quality, and should be taken into account when designing and implementing intervention programs.