4.1. Peanut Consumption in Korea
To the best of our knowledge, this is the first study reporting the sociodemographic and dietary patterns associated with peanut consumption in Korean. We found that 59.8% of Koreans rarely intake peanuts and only 1.9% of the study participants had daily peanut consumption. There was a significant increasing trend in peanut non-intake by year. Overall nutrients including energy, protein, fat, vitamin, and fiber in the diets of the frequent peanut intake group were significantly higher than those in the peanut non-intake group. Interestingly, older age, male, higher education level, and prudent dietary pattern were significantly associated with daily peanut consumption. There was little evidence that peanut consumption was associated with a history of CVD or DM.
In the present study, high education level and prudent dietary pattern rather than household income or occupation were associated with frequent peanut consumption. Peanuts are known to have cardio-protective, anti-inflammatory, and antioxidant properties that may influence blood lipid level, endothelial function, and inflammatory biomarker [6
]. Therefore, peanuts are a key food component in healthy dietary patterns, such as the Dietary Approaches to Stop Hypertension (DASH) diet or the Mediterranean diet [40
]. In addition, a number of studies have demonstrated that peanut consumption was associated with decreased overall [41
] and CVD-specific mortality [8
]. Liu et al. found that those consuming peanuts seven or more times per week had a 20% lower mortality [36
]. Because Koreans consume peanuts as snacks rather than as main foods [44
], the frequency of peanut consumption may depend on health-related information that can be easier to obtain for better-educated populations. Moreover, the highest prudent dietary pattern scores were increased with high frequency of peanut consumption in our results. This finding is consistent with previous studies that showed a positive correlation between healthy dietary patterns and high levels of education [46
]. Finger et al. [46
] showed that adults with a low level of education were more likely to consume energy-dense foods and diets low in fruits and vegetables. An Australian study reported that higher education levels and favorable lifestyle characteristics could predict an increase in healthy dietary patterns over four years [48
]. In addition, current smokers did not significantly consume peanuts in this study. Health-promoting behavior may be associated with frequent peanut consumption for highly educated household members in Korea.
Frequent peanut consumption was also associated with high energy, macronutrients, fiber, and vitamins intake in our study. These results are consistent with previous studies which aimed to compare diet quality between peanut consumers and non-consumers [50
]. A USA study showed that peanut consumers had higher intakes of protein, total fat, polyunsaturated fat, monounsaturated fat, fiber, vitamin A, and iron [50
]. A New Zealand study found that whole nut consumers had higher intakes of dietary fiber, vitamins, and unsaturated fats than those not consuming nuts [51
One concern associated with frequent peanut consumption is weight gain due to high protein and oil contents. In our study, the frequent peanut intake group had higher energy, carbohydrate, protein, and total fat intake. However, our findings showed that overweight or obese individuals were not associated with frequent peanut consumption when controlling for confounders. Moreover, previous trials found that increased peanut intake was associated with a low risk of obesity [53
] and decreased weight gain [55
Our results showed that 59.8% of Koreans, the proportion of which continues to increase, were included in the peanut non-intake group. We propose several hypotheses for this finding. First, response bias may have influenced our results because the assessment of peanut consumption was based on self-reports that only asked for “peanut consumption.” This information did not include peanut consumption from peanut butter, peanut flour, peanut cooking oil, and confectionary peanut products. Therefore, peanut consumption may have been underestimated in our study. Second, responders may not have differentiated between tree nuts and peanuts, which may be perceived by the general population to be “nuts”. The peanut is technically categorized as a pea and belongs to the family (fabaceae
) of beans/legumes [3
]. Most previous studies based on surveys investigated peanuts and tree nuts as one item [57
] because these provide similar nutrition components and are similarly consumed as a processed type of food or as a garnish. Studies for peanut and nut consumption in Koreans are rare. A Korean case–control study for evaluating the association between nut consumption (including peanuts) and colorectal cancer showed that 34.7% of participants were in the nut non-intake group and only 10.5% of participants consumed more than 3 nuts servings per week [59
]. However, study participants herein were patients with cancer for whom a healthy dietary pattern was prescribed. Further investigation is needed to evaluate peanut and tree nut consumption status separately in Korean populations.
4.2. Perspectives for Peanut Allergy
Recent studies suggested that environmental factors in early life may be important key risk factors for peanut allergy development [60
]. An Australian study showed that Australian-born Asians had a higher prevalence of nut (including peanut) allergies than Asians who had postnatally migrate from Asia [62
]. In addition, high education level was associated with peanut and nut allergy [63
]. On the other hand, Fox et al. [36
] found that household peanut consumption (quantified as the combined peanut consumption of all household members) during the first year of life increased the risk of peanut allergy in atopic children. Brough et al. [65
] found that household peanut consumption showed positive correlation with peanut protein presence in both bedroom and living room dust and kitchen surfaces. Trendelenburg et al. [66
] showed a positive correlation between household peanut consumption and peanut level in the eating domain. If household members intake peanuts frequently, hands and saliva may be potential sources for direct or indirect contact with an infant’s disrupted skin barrier (due to eczema, filaggrin mutation, or increased transepidermal water loss) [67
]. As mentioned earlier, peanuts are not frequently used in traditional introduction of foods in Korean infants. However, especially with infants who live with a household member who consume peanuts frequently, efforts to reduce peanut contact via a skin route or to apply active moisturizer or control skin inflammation may be needed to prevent peanut allergy. Our findings provide information on frequency of peanut consumption in Koreans. Further prospective studies are needed to confirm whether frequent household peanut consumption in household members is correlated with prevalence of peanut allergy in Korean children.