How Does Socioeconomic Status Affect Nutrient Intakes, and Why Is This Important for Public Health?
Unfortunately, health gradients exist that relate to socioeconomic status. People of lower socioeconomic status tend to have poorer health outcomes than those with higher socioeconomic status. While this may be partly related to a lack of access to health care and other resources due to lower income, other factors such as education level, supportive familial and social networks and personal factors are clearly involved. Health education and promotion activities aimed at improving health outcomes in the general population may actually exacerbate health inequalities between low and high socioeconomic status groups due to greater uptake of the intervention in the high socioeconomic status group. This reduces the power of interventions to change the health of the population, as the people in greatest need of the health promotion activity are less likely to change their behavior based on the intervention.
This issue was explored recently in the context of nutrition by Zarnowiecki, Parletta and Dollman. The authors looked at how contributors to socioeconomic status – family income, parental education, parental occupation and parental employment status – contributed to intakes of fruit and vegetables in children aged 9 to 13. The authors also explored whether family environment for health eating, and children’s own self-efficacy for health eating, affected the relationship.
Other authors have already found that nutrient intakes are affected by socio-economic factors. For example, the Micronutrient Calculator, based on representative nutrient intake data from the US, shows that for many age groups, household income affects the intakes of micronutrients. For example, there is a gradient of increasing intakes by household income for adults in the 31-50 year old category for all nutrients except carbohydrates. For calcium, folate, magnesium, iron, vitamin B1, vitamin A, vitamin B6, vitamin C, vitamin E and vitamin K, there was a difference greater than 10% in the number of people meeting the nutrient requirement between the lowest and highest income categories. Here are other recent examples of articles showing how nutrient intakes are affected by socioeconomic status:
- Wong and co-workers found that New Zealand teenagers of higher socioeconomic status had greater intakes of dietary fiber, polyunsaturated fatty acids, protein and most micronutrients, and lower intakes of sucrose.
- Higher maternal education level, a marker of socio-economic status, was associated with better diets in Dutch preschoolers in a study by Wijtzes et al.
- While dietary quality was reduced in people of lower socio-economic status in Western Australia, this was accounted for by individuals’ attitudes to healthy eating, according to Aggarwal and associates.
- Longitudinal data from the US suggests that both household income and education level independently contribute to differences in nutrient intake patterns between low- and high-socioeconomic status households, from Kant and Graubard.
- Han and Powell report that people living in low socio-economic households in the US were more likely to consume extra calories from sweetened beverages.
The article by Zarnowiecki, Parletta and Dollman found that measures of healthy eating intentions, child self-efficacy and a household environment that supported fruit and vegetable consumption were all associated with higher intakes of fruit and vegetables. In some cases, parental occupation or household income modified the relationship. The authors concluded that targeting parents may help change the household environment to encourage greater fruit and vegetable consumption may be the most effective approach in low socio-economic status households.
Although this may be a good approach for non-urgent nutritional problems, it relies on behavioral change from a sector of the population that is somewhat resistant to behavioral change interventions. A population-level approach may be more effective for preventing nutrient deficiencies. TalkingNutrition reported in 2011 on a move to fortify tortillas produced in the US with folate, as Latino populations were not being reached by the current folic acid fortification program. Mallard and Houghton write that the use of iodine supplements in pregnancy is lower in women of lower socio-economic status, which could have long term effects on the cognitive development of their offspring. Dasgupta and associates also report that the voluntary salt iodization program in the US has meant that most salt consumed in foods prepared away from home is not fortified; this may result in socio-economic disparities in iodine status. For these acute nutrition problems, carefully planned food fortification programs that take into account differences in intakes of particular foods in sectors of the population at greater risk of deficiency may be more effective.
Dorota M. Zarnowiecki, Natalie Parletta and James Dollman. The role of socio-economic position as a moderator of children's healthy food intake. British Journal of Nutrition. doi:10.1017/S0007114514001354.
Aggarwal A, Monsivais P, Cook AJ, Drewnowski A. Positive attitude toward healthy eating predicts higher diet quality at all cost levels of supermarkets. J Acad Nutr Diet. 2014 Feb;114(2):266-72. doi: 10.1016/j.jand.2013.06.006. Epub 2013 Aug 2. http://www.ncbi.nlm.nih.gov/pubmed/23916974
Bandura, A. (1994). Self-efficacy. In V. S. Ramachaudran (Ed.), Encyclopedia of human behavior (Vol. 4, pp. 71-81). New York: Academic Press. (Reprinted in H. Friedman [Ed.], Encyclopedia of mental health. San Diego: Academic Press, 1998). Text accessible via http://www.uky.edu/~eushe2/Bandura/BanEncy.html
Dasgupta PK, Liu Y, Dyke JV. Iodine nutrition: iodine content of iodized salt in the United States. Environ Sci Technol. 2008 Feb 15;42(4):1315-23. http://www.ncbi.nlm.nih.gov/pubmed/18351111
Dow WH, Schoeni RF, Adler NE, Stewart J. Evaluating the evidence base: policies and interventions to address socioeconomic status gradients in health. Ann N Y Acad Sci. 2010 Feb;1186:240-51. doi: 10.1111/j.1749-6632.2009.05386.x. http://www.ncbi.nlm.nih.gov/pubmed/20201876
Han E, Powell LM. Consumption patterns of sugar-sweetened beverages in the United States. J Acad Nutr Diet. 2013 Jan;113(1):43-53. doi: 10.1016/j.jand.2012.09.016. http://www.ncbi.nlm.nih.gov/pubmed/23260723
Kant AK, Graubard BI. Family income and education were related with 30-year time trends in dietary and meal behaviors of American children and adolescents. J Nutr. 2013 May;143(5):690-700. doi: 10.3945/jn.112.165258. Epub 2013 Mar 20. http://www.ncbi.nlm.nih.gov/pubmed/23514763
Mallard SR, Houghton LA. Public health policy to redress iodine insufficiency in pregnant women may widen sociodemographic disparities. Public Health Nutr. 2014 Jun;17(6):1421-9. doi: 10.1017/S1368980013001626. Epub 2013 Jun 19. http://www.ncbi.nlm.nih.gov/pubmed/23777645
Wijtzes AI, Jansen W, Jansen PW, Jaddoe VW, Hofman A, Raat H. Maternal educational level and preschool children's consumption of high-calorie snacks and sugar-containing beverages: mediation by the family food environment. Prev Med. 2013 Nov;57(5):607-12. doi: 10.1016/j.ypmed.2013.08.014. Epub 2013 Aug 27. http://www.ncbi.nlm.nih.gov/pubmed/23988496
Wong JE, Skidmore PM, Williams SM, Parnell WR. Healthy dietary habits score as an indicator of diet quality in new zealand adolescents. J Nutr. 2014 Jun;144(6):937-42. doi: 10.3945/jn.113.188375. Epub 2014 Apr 17. http://www.ncbi.nlm.nih.gov/pubmed/24744308