Special diets in modern America: Analysis of the 2012 National Health Interview Survey data.

BACKGROUND: Special diets are frequently used by the public but reasons for use and characteristics of users remain unclear.

AIM: To determine prevalence of the use of special diets, the individual characteristics associated with their use and reasons for use.

METHODS: The secondary analysis used data from the 2012 National Health Interview Survey (NHIS), a cross-sectional household interview survey of a nationally representative sample of non-hospitalized US adult populations ( n = 34,525). The dependent variables in this secondary analysis were the use of a special diet (vegetarian, macrobiotic, Atkins, Pritikin, and Ornish) ever and during the past 12 months. Independent variables included sociodemographic, clinical and behavioral variables. Prevalence of special diet use and reasons for use were analyzed descriptively. Associations between independent and dependent variables were analyzed using Chi-square tests and logistic regression. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.

RESULTS: Lifetime and 12-month prevalence of using special diets were 7.5% (weighted n = 17.7 million) and 2.9% (weighted n = 6.9 million), respectively. Individuals using special diets in the past 12 months were more likely female (OR = 1.45; 95% CI = 1.21-1.74), not married (OR = 0.76; 95% CI = 0.63-0.91), college-educated (OR = 1.98; 95% CI = 1.25-3.11) and depressed (OR = 1.50; 95% CI = 1.14-1.98). They more likely also used herbal products (OR = 2.35; 95%CI = 1.84-2.99), non-vitamin (OR = 1.82; 95% CI = 1.45-2.27) and vitamin supplements (OR = 1.57; 95% CI = 1.24-1.99). Diets were mainly used to improve overall health (76.7%) or for general wellness/prevention (70.4%).

CONCLUSIONS: Special diets are mainly used for unspecific health reasons by those who are females, have a college degree or with depression, and commonly used in conjunction with herbs and dietary supplements.