Health compromising components in French fries and fried chicken available in the markets of Dhaka city, Bangladesh

ABSTRACT French fries (FF) and fried chicken (FC) are known contributors to overweight and obesity among adolescents worldwide. Top selling five brands for both FF and FC were analyzed to determine their health compromising contents, which were sampled from the markets of Dhaka, Bangladesh. Sodium (Na) was determined by flame photometry, trans fatty acids (TFAs) by gas chromatography and heavy metals like arsenic (As), lead (Pb), cadmium and chromium by graphite furnace atomic absorption spectrophotometry. The median concentration of Na, TFA, As and Pb in FF was 0.45 gm/100 gm, 0.11 gm/100 gm, 0.93 mg/kg and 0.03 mg/kg, respectively. Similarly, in FC the median concentration of Na, TFA, As and Pb was 0.46 gm/100 gm, 0.13 gm/100 gm, 0.053 mg/kg and 0.06 mg/kg, respectively. The study findings suggests that consuming FF and FC impose a health risk among the exposed population.


Introduction
Fast food consumption has increased worldwide over the past few decades (Majabadi et al., 2016) leading to significant rise in obesity (Afolabi et al., 2013;Shori et al., 2017) and a poorer quality of diet (Dias et al., 2015).Often these fast foods contains high level of sodium (Na), trans fatty acids (TFA) and heavy metals like arsenic (As), lead (Pb), cadmium (Cd) and chromium (Cr), which are potentially toxic, and known risk factors for hypertension, cardiovascular diseases, diabetes, depression, stroke, and multiple cancers (Chavasit et al., 2019;Harvard, 2020;Stender et al., 2007).Among the varieties of fast food available, French fries (FF) and fried chicken (FC) are the most popular items consumed by people worldwide (Leffler, 2017).Fast foods have become an important part of the dietary menu for urban children and adolescents because of its easy availability, as it is accessible from most restaurants, cafes, food carts and markets situated around schools and colleges, quick preparation time of the food items and it's low price (Haque et al., 2019).For this reason, fast foods have been determined as a risk factor for overweight and obesity among the adolescents in Bangladesh (Alam et al., 2021).Fast food ingredients are often high in salt, sugar, processed chemicals, and toxic heavy metals, which have been linked to health problems such as obesity, diabetes, heart disease, and even cancer (Bhaskar, 2012).As the deleterious effects of the fast foods become apparent only after prolonged consumption, it is imperative to assess the levels of salt, fat and heavy metals, to raise public awareness against the health risk of these foods.Therefore, the objective of this study was to determine the health compromising components present in the top-selling brands of FF and FC available from various fast food shops inside the markets of Dhaka city, Bangladesh.

Sampling and sample collection
A descriptive cross-sectional study was conducted, where five top selling brands of FF and FC available from various fast food shops inside the markets of Dhaka, Bangladesh were sampled for the study.Two stage stratified sampling was done for selecting the brands of FF and FC from various fast food shops.Among the two city corporations of Dhaka, Dhaka South City Corporation was randomly selected by lottery for sample collection, from which a zone (Dhanmondi) for sample collection was chosen purposively.Then eight popular fast food shops were identified from the selected zone.The fast food shops for sample collection were located at indoor markets within the selected zone.A questionnaire was used to conduct short interviews of the salespersons from the selected eight fast food shops to identify the volume of daily sales of FF (packets and weight) and FC (pieces and weight), an approach which is mentioned elsewhere (AHM et al., 2021).Based on the maximum sell approach (Pehrsson et al., 2013), a ranking technique was implemented to identify the top selling fast food shops.For FF, the total number of packets (by weight in grams) sold daily was considered and ranked as I to VIII following the order of the values.Rank I was allocated for the fast food shop with the highest number of FF packets sold, II to VIII were given for to the next order of shops selling the most to least number of packets of FF, respectively.Then, the top selling five shops for FF were identified.For FC, the total weight of the daily sold pieces of each shop was converted into grams then the highest to lowest values were ranked as I to VIII and the top selling five FC shops were identified.For anonymity, the samples were coded using capital letters (A-E) to identify the brand names.French fry samples were coded as FF (A-E) and fried chickens as FC (A-E).This coding process was conducted and kept confidential by the researchers.The collected samples were analyzed in Bangladesh Council of Scientific & Industrial Research (BCSIR), Dhaka, Bangladesh.The ethical permission for this study was received from the Institutional Review Board of Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh (Ref No. BSMMU/2017/7388).

Determination of sodium
Sodium (Na) content was determined by flame photometry using a JENWAY PEP7 Flame Photometer, made in United Kingdom.Flame photometry was carried out according to AOAC method 990.23z (AOAC, 1980).This method has the advantage of following the direct determination of the Na ion.As reagent, standard Na solution was used, where 2.542 g of sodium chloride crystals was dissolved in water and diluted the solution to a volume of 1000 ml.This solution contained 1000 ppm of Na.Measurement of Na was done by comparing the emission with the standards made from distilled water containing 0.5, 10 and 20 ppm of Na.

Determination of trans fatty acids
Trans Fatty Acids (TFAs) were analyzed with Shimadzu GC-14B (Japan) series gas chromatograph equipped with flame ionization detector and fused silica capillary column (FAMEWAX, Crossbond ® polyethylene glycol, 15 m × 0.25 mm × 0.25 µm film thickness, Restek; Pennsylvania, U.S.A.).In the laboratory the food samples were cut into small pieces of about 1 cm 2 , from which 400 g of the samples were placed in a conical flask, and 500 ml of petroleum ether (Merck, sourced from Mumbai, India) was added into the flask, shaken well for proper mixing, and then it was kept overnight for oil extraction.The solvent with the oil was then filtered through a filter paper, evaporated in the water bath, and the extracted oils were kept in sample bottle for analysis.In this method, a few drops of extracted fat were dissolved in petroleum ether in a test tube and methylated by using sodium methoxide (Merck, sourced from Germany) in presence of flame.The solution was then diluted with distilled water and allowed to settle for a few minutes, until a clear portion was visible in the upper part of the tube.The upper layer of fatty acid methyl ester was then collected and used for gas chromatograph analysis.

Determination of heavy metals (arsenic, lead, cadmium, and chromium)
Heavy metals were determined by using graphite furnace atomic absorption spectrophotometry (GF-AAS).Collected food samples were taken in a similar amount using an electric balance and cut into small pieces with a sharp stainless steel knife for further analysis.Samples were then weighed in equal amounts and stored for acid digestion.Then, 5.0 g of each sample was taken and placed in a hot plate on the Barnstead fume hood.Concentrated 2.0 ml of nitric acid was added to the sample and heated until the sample turned into black color.The sample was then placed in the furnace for at least eight hours.After that, the sample was placed in the fume hood and 5.0 ml of hydrochloric acid was added to complete the acid digestion.The digested sample was then water boiled and filtered to remove the debris.Then, the sample's final volume was made up to 100 ml in a volumetric flask and stored in the fridge until analyzed by the GF-AAS.

Statistical analysis
All the statistical analyses were performed using Microsoft Excel (version 2013).Levels of Na and TFAs are reported as g/ 100 g and heavy metals are reported as mg/kg.The average value was achieved by calculating the median.Estimation of the heavy metal content was done for every 100 g of FF and 100 g of FC.The estimated concentration was then compared to the maximum allowable daily exposure level (MADL) of heavy metals and how much it contributed to the MADL.Data is presented in table and in text, following descriptive analysis.

Results
Among the samples of FF analyzed, the median concentration of Na was 0.45 g/100 g, and was found highest in FF A (0.54 g/100 g) (Table 1).The median of the Cd content was 1.31 × 10 −3 mg/kg, which was highest in FF C (5.78 x 10 −3 mg/kg).For total As in FF, the median was 0.93 mg/kg and was found to be highest in FF D (1.35 mg/kg).In the analyzed samples of FC (Table 2), the median Na content was 0.46 g/100 g and the highest concentration was found in FC C (0.60 g/100 g).The median concentration of Cd and total As in FC was 2.17 × 10 −4 mg/kg and 0.053 mg/kg, respectively.Highest level of Cd was determined in FC D (6.06 × 10 −3 mg/kg), where total As was found highest in FC C (0.144 mg/kg).
Considering the intake of 100 g of FF and FC for an adult, since the MADL for As is 0.22 mg (Huq et al., 2006), 100 g of FF will contribute to 42.57% of his daily allowable limit of As (Table 3).Similarly, the intake of 100 g of FC will fulfil 2.41% of the daily allowable limit of As.For Pb, the MADL is 0.25 mg/day (Sharma et al., 2005), therefore eating 100 g of FF will contribute to 1.20%, and 100 g of FC will fulfil 2.40% of the daily allowable limit of Pb.

Discussion
This current study is a first of its kind in Bangladesh, to evaluate the levels of health compromising ingredients in the most commonly consumed fast foods like FF and FC.Both of these mentioned foods are known contributors to obesity among children and adolescents (Das, 2016).

Content of Na in French fries and fried chicken
This study determined the median Na content in FF and FC was 0.45 g/100 g and 0.46 g/100 g, respectively.Few studies previously had determined the mean content of Na in FF, where it was 0.28 g/100 g in New Zealand (Prentice et al., 2016), 0.21 g/100 g in U.S.A. (Ahuja et al., 2015), and 0.59 g/ 100 g in Argentina (Calliope & Samman, 2020).Similarly, the mean Na content in FC revealed in other studies includes 0.68 g/100 g in U.S.A., 0.75 g/100 g in Korea, and 0.61 g/100 g in New Zealand (Ahuja et al., 2015;Lee et al., 2020;Prentice et al., 2016).The variation in the findings of the mean content of Na might be due to the salt applied as a surface seasoning before or after frying.Another possible contributor to Na in the FC, possibly because of the chicken preparation procedure, where many chicken manufacturers soak or inject chicken meat with salt water (brine), to keep it juicy (Lehman, 2020).The World Health Organization (WHO) recommends, for an adult, the recommended consumption of Na be limited to 2 g/day (WHO, 2012).Therefore, based on the current findings, for an adult, consuming 100 g of FF or FC will fulfil almost one quarter of the daily recommended limit of Na.This pattern of high salt consumption is a public health concern since high Na consumption leads to high blood pressure and increases the risk of heart disease, particularly stroke (Polonia et al., 2016).In Bangladesh, noncommunicable diseases account for 61% of the total disease burden, with hypertension being the most prevalent (IEDCR, 2018).Therefore, the findings of this study, in conjunction with other evidence can be used to address the reduction of salt consumption, through advocating and educating people to limit their salt intake, along with creating an enabling environment for healthy eating through policy interventions and the promotion of healthy food (WHO, 2012).

Content of TFAs in French fries and fried chicken
The TFA content determined by the current study in FF ranged from non-detectable to 0.17 g/100 g and the median was 0.11 g/100 g.The TFA content in takeaway FF sampled in six leading fast food outlets in Australia ranged from 0.2 to 1.5 g/100 g (Wijesundera et al., 2007), and in Denmark, only 3 out of 43 samples of FF had TFA below 1.0 g/100 g (Stender et al., 2006).These reported content of TFA were quite high compared to the current study findings.Correspondingly, the TFA determined in FC in this present study ranged between non-detectable to 0.57 g/100 g, median was 0.13 g/100 g.Other studies stated the TFA content in FC from fast food joint was 0.08-0.14g/100 g (Soonpan et al., 2011), 0.159 mg/100 g (Ahmed & El-Sisy, 2021) and 0.16-1.96g/ 100 g (Akmar et al., 2013).The likely cause for the differences in TFA content might be due to the type of oil/fat used for frying the food (Davies et al., 2016), making use of different brands of fats and oils (Soonpan et al., 2011), and differences in cooking methods, since deep frying and cooking at high temperatures commonly lead to the increase in TFA (Hénon et al., 1999).It is also worth mentioning that samples from one brand of fast food denoted as C (FF C and FC C) did not have detectable levels of TFAs.This non-detectable levels of TFAs may be due to the fact that the oil may not have been used more than once in frying food in that particular shop.
Even though this study determined low levels of TFA, it should be noted that the serving size of these fast foods were usually more than 100 g and is commonly accompanied with other food items such as breads, fizzy drinks and desserts which can lead to the intake of more than 5.0 g TFA/ portion when these meals are consumed.The cutoff criteria to avoid potential health risks based on the FAO/WHO Guideline on Diet, Nutrition and the Prevention of Chronic Diseases, mentioned limiting the intake of TFAs to less than 2.2 g/day (FAO/ WHO, 2003).The concern about the intake of foods containing high TFA amounts has grown in the recent years, as TFA is a main contributor to the imbalance of plasma lipoproteins in the body, which is considered to be an important indicator for the risk of the development of cardiovascular diseases (Lichtenstein et al., 2001;Soonpan et al., 2011).Thus, the data indicated in this study warrant Acceptable level of chromium in food (Rahman, 2014).
more investigation into TFA contents of commonly consumed fast food items, along with changes in food serving size.

Content of heavy metals in French fries and fried chicken
In this present study, the median total As content of FF and FC was 0.93 mg/kg and 0.053 mg/kg, respectively.Thus, by consuming 100 g of FF contributes to almost half of the daily allowable limit of As.Even though, very little literature was found on the arsenic levels in FF and FC, but plenty were available regarding the alarming levels of arsenic in potatoes and chicken (Anawar et al., 2012;Nachman et al., 2013;Rahaman et al., 2013;Upadhyay et al., 2019;Wallinga, 2006).As usually enters the food chain, when As contaminated water is used for irrigating crops or in feed additives for poultry (Bencko & Foong, 2013), consequently entering into commercial food products prepared from As contaminated raw materials.This study also identified low levels of Pb in the analyzed samples of fast foods.Contrarily, Haque et al. (2019) reported that among different fast foods, chicken burgers had the highest concentrations (1.14 mg/ kg) of Pb, as the poultry farms used poultry feeds high in Pb (1.40-6.59mg/kg), which was consequently passed down the food chain (Haque et al., 2019).The environment in Bangladesh also contributes to the daily exposure to Pb.Thus, frequent consumption of fast foods will possibly add up to exceeding the maximum allowable limit of daily exposure to Pb, posing a high risk for Pb toxicity (Naranjo et al., 2020), especially among the children, because of a high intake of Pb per unit body weight (Sharma et al., 2005).These aforementioned heavy metals usually have a long biological half-lives, are non-biodegradable, and have the potential to accumulate in different body organs, leading to heavy metal toxicity (Wang & Shi, 2001).The accumulation of heavy metals in the agricultural soils and water in Bangladesh is becoming a grave concern due to its potential entry into the human food chain and the consequent health risks.But interestingly, the heavy metals intake via ingestion depends on the food habits of the consumers, which is highly centered towards fast foods in the urban areas (Haque et al., 2019).In such circumstances, the findings of this current study demands to investigate the level of heavy metals in fast foods, their source of origin, transfer to the human food chain, and formulate policies and legislations by the concerning bodies to reduce and resolve heavy metal contamination in the environment (Proshad et al., 2018).
There are some limitations that warrant consideration before concluding the present study.Only branded fast food shops in one city were chosen for sample collection, which limits the generalizability of the study findings.Furthermore, the study did not take into account whether the potatoes or chicken used to make FF and FC were bought from local markets or imported, which might help in tracing the heavy metal content.Finally, estimating only the total As level restricted the current study to explore the organic and inorganic properties of the As present in the analyzed fast foods.However, the findings of this study give an indication towards the need for the concerning authorities to initiate a radical change in the food market and food production industry including availability of wholesome foods and slowly eliminating the regularity of unhealthy fast food intake (Abdullah et al., 2015).It is highly recommended to use this information to create awareness among the consumers for making appropriate food choices, with special consideration to mothers who play a vital role in fostering healthy food habits in children.Another useful approach might be providing the nutritional information of the fast food with its menu so that consumers are aware of the contents (Habib et al., 2011).It is also imperative to investigate the long-term health effects of unhealthy fast food consumption to enable the development of a better evidence-based intervention at preventing non-communicable diseases.Nevertheless, the research findings may also guide the fast food manufacturers to develop strategies for quality control and food reformulation, with the goal of developing healthier food products.Correspondingly, the government regulatory bodies can utilize the study results as an evidence to develop legislator guidelines for regulating the harmful contents in fast foods and make them more nutritionally balanced.

Conclusions
The current study findings suggest that the level of Na, TFA, and As present in FF and FC available in the markets of Dhaka may lead to detrimental health consequences.Awareness among the consumers for making appropriate food choices and strict monitoring by the regulatory authorities of Bangladesh can play an important role in the reduction of the negative impact of fast foods on health.

Table 1 .
Health compromising components in French fries.

Table 2 .
Health compromising components in fried chicken.

Table 3 .
Consumption of heavy metals from French fries and fried chicken. b