This study aimed to investigate the most important factors affecting socio-economic status in quality of nutrition of west of Iran. In this study, mean HEI was close to 50 which reflect undesirable nutritional status. Among the three groups HEI, the most significant differences in the quality of nutrition was associated with socioeconomic status. Different studies presented different results. In general, in more reports, the significant effect of SES on the quality of nutrition on individuals is evident(24, 25). The results of a systematic review by Ana-Lucia Mayén on the impact of interventions on reducing social inequalities in quality of nutrition in low-and middle-income countries, including Iran, suggested that intervention improves the nutritional quality but for reducing disparities, interventions need to be carried out with more focus in deprived communities. Although interventions in the entire population results in better quality of nutrition in the whole population, the difference between socio-economic groups is likely to remain unchanged(26). Considering the nutritional status of the participants in this study, intervenetion in all groups with more focus on people with lower SES and villagers was preferred. To change traditional eating habits, it is also necessary to improve nutritional quality through a team including experts from public health and nutrition educators.
As SES improved, HEI score of most components, especially dairy, fatty acids, sodium, total fruits, and whole fruits, increased. Individuals with higher SES earned lower scores only in terms of saturated fatty acids consumption. By more detailed analysis of the relationship between saturated fatty acid and the five socio-economic groups, it can be concluded that people with scores 5 to 8 were more likely to have higher SES, and those with scores 9 to 10 were more concentrated on lower SES.
Another interesting point in this study is that, HEI scores in people with cardiovascular diseases, high blood pressure, and diabetes was favorable compared with healthy people. Given that this was a cross-sectional study, the results might be influenced by the knowledge of patients in selection and proper use of food followed by medical consultation after the diagnosis of their disease. Further studies can be helpful in assessing the health status and nutritional quality among incident cases of such conditions and measure the impact of health education on health eating.
Villagers, with poor SES, had lower quality diet than city dwellers (OR=0.37) even after adjustment for all other important factors, especially in terms of fruits and vegetables. With the expansion of agricultural land and horticulture and livestock in Iran, especially in rural areas, villagers expected to have enough consumption of fruits and vegetables, especially dairy and meat; yet, according to conducted studies in Iran, consumption of these valuable foods has been low in most Iranian adults. Such differeces between people living in rural areas and those in urban areas might be related to the culture and nutritional habits. Although according to other published reports, the most important causes of low consumption of high quality food are weak economic situation, higher price of such foods, and low education levels; nutritional habits are also important(27-30).
The results suggested that, as the level of education improves, the odds for better HEI increases. The positive effect of education on improving the quality of nutrition has been reported in different studies. Although there is a direct relationship between education and knowledge in different fields including nutrition, it is worthwhile to consider the type of individual’s knowledge so as to be able to explain inconsistent studies such as studies in Turkey(31, 32).
In this study, althoug BMI has no relationship with the quality of nutrition, it can be assumed that increased food intake has led to an increase in weight, which in turn increased the HEI score (in 9 components of Adequacy consumtion). Considering that 70% of the study population had BMI>25 and this is a significant risk factor for most chronic diseases, greater efforts is needed to promote and educate the quality of proper nutrition in this society so as to benefit from its outcomes as well as balanced weights.
The main reason for low scores of refined grains and whole grains in the studied population was related to high consumption (more than scoring standards) of white rice and white bread, the staple food of the region which constitutes the first and most important component of their daily food so that even SES had no significant effect on the refined grains. By eliminating this component in the HEI calculations, the subjects’score increase significantly. Following a high-carbohydrate dietary pattern, that is common to the most less developed societies, may be due to lower prices of sources of carbohydrates than protein in these societies (33). A diet containing larger amount of refined grains, fast food, industrial drinks, and less whole grains is consistent with that pattern found in other reports from Iran(34, 35). Also according to research conducted in Poland, people who care more about their health tend to use whole wheat bread and replace it with white bread(36). Although there are some discrpencies among reports, there are often consistent reports on the use of refined grains, especially in less developed societies(24, 37-39). Due to significant weight gain in a large number of the studied subjects, interventions for improving dietary habits such as mandatory use of wheat bran in bakeries, promoting the use of brown rice; and providing a package of whole-grain food instead of refined grains, is very important.
Considering the importance of legumes and its role in preventing a range of chronic diseases, HEI (2015) included it among the four HEI components (total vegetables, greens and beans, total protein foods, seafood and plant proteins)(40). In the present study, all four components were mostly consumed by the rich. Farvid et al. (in 2017) examined 42403 Iranian adults over 11 years and observed that consumption of legumes was in favorable condition and daily intake of 1 unit of beans was an important factor in reducing the risk of death to all causes(17).
In our study, women had better mean HEI than men andthe quality of their nutrition was 1.27 times better than men. According to previous studies, women are more concerned about their health than men. Because of employment, men often spend little time for choosing and serving snacks, especially at work, but women are often housewives and use more healthy snacks (41, 42). However, the results of another study in Iran were indicative of the better status of men than women in terms of quality of nutrition(31).
Reducing disparities should be addressed with regard to the structure of society and vulnerable groups and the quality of nutrition can be promoted by addressing the weaknesses for example through increasing the knowledge and awareness of individuals. Nutrition knowledge is very effective in improving the dietary pattern. In a systematic review by Xiao Zhou et al. (in 2018) showed the effect of nutritional knowledge and awareness on improving the quality of nutrition(43).
Weaknesses and limitations
This research may also be affected by a recall bias. However, all such bias is more likely to be non-differential and therefore it tends to move the point estimate to null. To our knowledge, this is the first report of its type among Kurdish people to investigate the nutritional quality, the socio-economic status, and the other factors in nutritional quality, simultanously. For the purpose of this study, we used a population-based study with large enough sample size and with standard tools for data collection by trained personnel with less than 1% missing information. In addition, we used HEI-2015 method for the first time in Iran.