Research shows social capital enhances adherence to dietary guidelines

31 May 2024 --- A new study by researchers from the Yunnan Center for Disease Control and Prevention, The First People’s Hospital of Yunnan Province and Wuhan University, China, about the influence of “social capital” on diet quality found that it enhances adherence to dietary guidelines by improving nutrition knowledge and social support.

Current theoretical frameworks, such as the socio-ecological model, posit that dietary habits are shaped by individuals’ interactions with their social and physical surroundings. Studies have shown that social capital — as resources embedded in social networks — is favorable for healthy eating in various cultural contexts and populations.

The researchers of the current study believe further research on how social capital affects diet intake is crucial to inform policy decisions. Based on their findings published in Nutritional Epidemiology, Frontiers in Nutrition, the researchers propose that nutrition promotion programs should consider including strategies that foster social capital development, particularly in disadvantaged populations.

Last month, the World Health Organization began a process of setting up global guidelines on animal-source foods and plant food alternatives by calling on nutrition and food safety experts to apply to join the multidisciplinary team. This is an effort to address the growing interest in food-based guidance. The new guidelines, which should be finalized in 2027, will complement existing WHO guidance on macronutrient intake.

Salience of social capital
A probability sample of 1,033 people between 47 and 62 years old from two ethnic minority groups in Yunnan Province, China, was used. Bonding and bridging social capital were assessed with the Personal Social Capital Scale, while the dietary data were evaluated with the Chinese Healthy Eating Index (CHEI), a measure of diet quality that reflects adherence to the Chinese Dietary Guidelines. 

Nutrition knowledge and social support were measured with a validated questionnaire and scale. Structural Equation Modeling calculated the direct, indirect and total effects of social capital on CHEI scores. The CHEI comprises 17 components, including total grains, whole grains and mixed beans, tubers, total vegetables, dark vegetables, fruits, dairy, soybeans, fish and seafood, poultry, eggs, seeds and nuts, red meat, cooking oils, salt, added sugars and alcohol. 

Social capital is regarded as an important health determinant attributed to the positive impacts of social support and the information gained from social networks. It is estimated that more than 20% of global adult deaths each year can be attributed to dietary risk factors, such as excessive salt intake and inadequate consumption of vegetables, fruits and whole grains. 

In the current study, the mean score of CHEI was 57.4, give or take 9.8. The score was significantly lower in men and older people. Low adherence to dietary guidelines was observed in the consumption of dairy, beans, nuts, animal-source food vegetables and fruits. 

Social support and lifestyle behavior
Bonding and bridging social capital were positively associated with the CHEI score. Social support and nutrition knowledge mediated 45.9 and 39.5% of the total effect of social capital on the CHEI score.

Another study in China observed that older adults with extensive social networks and active social participation have higher health literacy — the motivation to use information to promote and maintain good health and follow healthier diets. 

Furthermore, social support is important for the adoption of healthy lifestyle behaviors. Several studies have shown that families, friends and peers significantly influence personal dietary intake.

The current study shows that social capital significantly influences adherence to healthier diets through access to nutrition knowledge.

Yunnan province, where the current study population is from, has the largest number of ethnic groups in China, including small ethnic groups like the Bu Lang and Pu Mi. The study sites were selected based on the towns with the highest populations of these ethnicities. 

Subsequently, 150 households were randomly selected from each village using local household registration information. Adults in these households were invited to participate in the study, excluding individuals on prescribed diets or those with serious physical or mental illnesses. Data were collected through a face-to-face interview conducted by trained local health workers.

The mean scores of CHEI among the two ethnic minority groups were 57.4, which is close to the result of a nationwide study conducted in 2011. The results indicate that adherence to dietary guidelines remains low among the Chinese population, encompassing both the Han and minority groups.

Nutrition knowledge predicts diet quality
Essentially, social capital positively predicts the diet quality of the study population, both directly and indirectly. The finding corroborates the conclusion from previous studies that social capital is a protective factor of dietary guidelines adherence.

According to the researchers, nutrition knowledge and social support are crucial factors that 

influence individual dietary intake. As a result, the Healthy China Action (2019–2030) has incorporated improving nutrition knowledge and creating supportive environments as critical steps to achieving and maintaining healthy eating among residents.

However, the study population’s nutrition knowledge and social support levels are lower than those of individuals from developed areas. In their mediation analysis, the scientists discovered that higher social capital was related to increased levels of nutrition knowledge and social support, which were linked to a higher CHIE score.

According to the current research, the consumption of animal-source foods has continued to increase in Chinese adults while the consumption of dairy, vegetables and fruits remained low. 

The findings suggest that factors beyond income significantly affect dietary intake. 

The results demonstrate that social capital promotes dietary guidelines adherence partly by improving nutrition knowledge and social support and suggest a penitential avenue for advancing the process and ultimate goals of the Healthy China Action. 

In other industry developments, researchers at the Harvard T.H. Chan School of Public Health demonstrated that healthy eating patterns advised by the Dietary Guidelines for Americans reduce the risk of dying prematurely. Data were collected over 36 years and included 119,315 participants.

Another scientific article recently published by scientists in Brazil and Mexico similarly emphasized the importance of socioeconomic and environmental factors to nutrition, particularly in relation to the rise in obesity and the consumption of ultra-processed foods in developing low- and middle-income countries.

By Inga de Jong