FLUORIDE CONTENT AND HAZARD QUOTIENT FOR BEVERAGES MARKETED IN IRAN

Abstract

Beverages are one of the main sources of fluoride (F) entry to the body, especially in some countries located in the tropical regions. The aim of this study was to determine, for various beverages available in markets in Iran, the F concentration, the estimated daily intake, and the hazard quotient value (HQ), a measure of non-carcinogenic risk. The beverages studied were: doogh (a popular dairy-based drink in the Middle East produced from fermented milk made from mixing yoghurt, water, herbs, and salt), carbonated soft drinks, non-alcoholic beers, and energy drinks. The F contents of 105 beverage samples were analyzed by using an ion-selective electrode. The range and mean values (mg L^-1) of the F concentrations found in the various beverages were: doogh: 0.058-0.86, 0.21; carbonated soft drinks: 0.012-1.10, 0.23; non-alcoholic beers: 0.006-0.58, 0.11; and energy drinks: 0.076-1.60, 0.37. The results indicated that there was a statistically significant difference between the F levels of the energy drinks and the other beverages. The HQ values for all the age groups showed that no significant risk of fluoride toxicity for consumers was present due to beverage consumption. However, it should be noted that other F sources such as drinking water, food, toothpaste and other beverages, such as different types of tea, may contribute to a higher intake of F in body and consequently, increase the risk of adverse health effects from high F exposure.

Headnote

ABSTRACT: Beverages are one of the main sources of fluoride (F) entry to the body, especially in some countries located in the tropical regions. The aim of this study was to determine, for various beverages available in markets in Iran, the F concentration, the estimated daily intake, and the hazard quotient value (HQ), a measure of non-carcinogenic risk. The beverages studied were: doogh (a popular dairy-based drink in the Middle East produced from fermented milk made from mixing yoghurt, water, herbs, and salt), carbonated soft drinks, non-alcoholic beers, and energy drinks. The F contents of 105 beverage samples were analyzed by using an ion-selective electrode. The range and mean values (mg L^-1) of the F concentrations found in the various beverages were: doogh: 0.058-0.86, 0.21; carbonated soft drinks: 0.012-1.10, 0.23; non-alcoholic beers: 0.006-0.58, 0.11; and energy drinks: 0.076-1.60, 0.37. The results indicated that there was a statistically significant difference between the F levels of the energy drinks and the other beverages. The HQ values for all the age groups showed that no significant risk of fluoride toxicity for consumers was present due to beverage consumption. However, it should be noted that other F sources such as drinking water, food, toothpaste and other beverages, such as different types of tea, may contribute to a higher intake of F in body and consequently, increase the risk of adverse health effects from high F exposure.

Keywords: Beverages; Daily intake; Fluoride; Hazard quotient; Risk assessment.

(ProQuest: ... denotes formulae omitted.)

INTRODUCTION

Fluoride (F) is widely distributed in the environment and due to its detrimental adverse health effects is of special concern. It causes a wide range of adverse health effects. Dental, skeletal, and non-skeletal fluorosis, including genetic mutations, disorders of weight and height in infants, neurological effects, and renal and hepatic impairment, are some of adverse health effects of excess F intake.1-4 F can enter the environment in many different ways including natural activities and human activities, such as with marine aerosols and the burning of fluoride-rich coal.5 Also F can enter the human body via different sources such as drinking water, beverages, foods, toothpaste containing F, and breathing. In this regard, many studies have monitored the concentration levels of F in drinking water, sea water, foods, toothpaste, and biota samples, such as fish,6-11 as well as F removal by adsorption.12-15 Some studies showed that fluorosis may be associated with beverage consumption and beverages can change the risk factors for dental fluorosis in young children.16

Beverages containing high F levels are one of the most important sources of F entry to the human body, especially in the countries located in the tropical and warm regions. Iran is located in the Middle East and the most popular drinks available in the market in Iran include doogh (ayran, dhallě, tan; a dairy based drink produced from fermented milk made from mixing yoghurt, water, herbs, and salt), carbonated soft drinks, non-alcoholic beers, and energy drinks. As well as in Iran, these beverages are common drinks in the world but to date only a few studies have focused on the F concentration levels of these drinks and the risk assessment of the F in the beverages on human health. To the best of our knowledge, there has been no report yet on the F content of energy drinks and or on a risk assessment of energy drinks. In the present study we aimed to determine the content of F in the beverages doogh, carbonated soft drinks, non-alcoholic beers, and energy drinks. In addition, we assessed the estimated daily F intake from these beverages, and the hazard quotient value (HQ), a measure of the non-carcinogenic risk of the F in these beverages for consumers aged 4-65 years.

MATERIAL AND METHOD

The F concentration levels were determined in four types of drinks, available in the Iran market: doogh, carbonated soft drinks, non-alcoholic beers, and energy drinks. Samples from 13 brands of doogh, 11 brands of soft drinks, 7 brands of non-alcoholic beers, and 4 brands of energy drinks were bought from supermarkets (total samples=105). From each brand, 3 samples were collected in three different areas of Bushehr port during November 2018 to February 2019. All samples were transferred to the laboratory and the information on the labels was recorded. Samples were kept in a dark place in the original closed plastic, glass, or can containers until analysis. Doogh samples were stored at 4°C temperature and the other samples were stored at room temperature. The basic ingredients of doogh are water and yoghurt. The values of pH were determined by a pH meter (744 pH meter, Metrohm, Switzerland). Before the analyses, the carbonated beverages were degassed by heating and the doogh samples were brought to 25°C temperature. For the F concentration measurement, the beverage samples were mixed 1:1 with TISAB II. Then, after calibration, the F concentration was measured directly by an ion-selective electrode (model 781 pH/Ion meter, Metrohm, Switzerland). The F concentration of each sample was measured in triplicate and the mean values are reported here.

The health risk was evaluated after assessing the estimated daily intake (EDI) of F due to beverage consumption by using Equation 1:

... Equation 1

Where: EDI = Estimated daily intake of fluoride (mg kg-1 bw day-1)

Cf = Concentration of fluoride in the sample (mg L-1)

Cd = Average daily beverage consumption (L day-1)

BW = Average body weight (kg)

The hazard quotient (HQ) was used to determine the non-carcinogenic risk of F based on Equation 2 as follows:

... Equation 2

Where: HQ Hazard quotient

EDI Estimated daily intake of fluoride (mg kg-1 bw day-1)

RfD Oral reference dose of F (0.06 mg kg-1 day-1)

The oral reference dose (RfD) of F of 0.06 mg kg-1 day-1 was determined based on a database of the Integrated Risk Information system, USEPA.17 The acceptable level of the HQ is <1 and when the value of HQ is >1, it shows a probability of adverse health effects on a population.

The EDI and HQ values were evaluated for five different age groups with different daily average intakes of beverages, based on available references with a little modification,18-21 as well as the body weight as presented in Table 1.21,31

RESULTS AND DISCUSSION

The mean F concentration (± SD), the range of the F concentration, and the pH values of the different drinks are shown in Table 2. The pH values of the samples ranged from 3.82-5.39. The brand F of non-alcoholic beer had the highest pH level (5.39) and brand I of carbonated soft drink had the lowest pH value (3.82) of all samples. The F contents of the different beverages in the studies reported in the literature are presented in Table 3.

The F concentration of doogh samples ranged from 0.058-0.86 mg L-1 with a mean concentration level of 0.21 mg L-1. The highest mean concentration level of F was observed in brand E of doogh and the lowest was observed in carbonated doogh brand C.

The mean content of F in the doogh samples in the present study (0.21 mg L-1) was lower than that found by Zohouri et al. (0.321 mg L-1),22 although the maximum value of F in this study was higher (0.86 mg L-1) (Table 2A). Unfortunately there is no similar study on the F content of doogh to compare our results with but a study on the F contents of other dairy products found the mean F concentration of milk, yoghurt, and cheese were 0.02-0.18, 0.06-0.19, and 0.02-0.19 mg L-1, respectively, and did not differ significantly from one another.23

A study from the UK24 reported a lower F content of cow's milk with a range of 0.013-0.025 mg L-1.

These dairy products are common worldwide but doogh is a popular drink in the Middle East and therefore, it can be one of the main sources of F in people living in that region.

The F content of carbonated soft drinks ranged from 0.012-1.1 mg L-1 with a mean value of 0.23 mg L-1 (Table 2B). The A and I brands of carbonated soft drink, with mean F concentration levels of 0.57 and 0.025 mg L-1, respectively, had the highest and the lowest mean F concentrations.

In a study, Jiménez-Farfán et al. determined the F concentration of cola drinks in Mexico.25 They have reported a range of 0.10-1.62 mg L-1 with a mean value of 0.49 mg L-1. They found higher concentration levels of F compared to our study (mean 0.23 mg L-1). In another study, the F concentration in 15 brands of soft drinks was reported in the range of 0.05-0.16 mg L-1 with a mean value of 0.06 mg L-1 that was lower than in the present study (mean 0.23 mg L-1)26

Another study reported a mean F concentration level of soft drink of 0.72 mg L-127

The F concentration in the non-alcoholic beers ranged from 0.006-0.58 mg L-1 with a mean concentration level of 0.11 mg L-1 (Table 2C). The A and F brands of non-alcoholic beers, with mean concentration levels of 0.32 and 0.029 mg L-1, respectively, had the highest and the lowest F concentration levels of F of all the nonalcoholic beers examined.

The range of F in the energy drinks was from 0.076-1.6 mg L-1 with a mean concentration level of 0.37 mg L-1 (Table 2D). Unfortunately, to date there is no similar study on the F concentration level of energy drinks to compare our results with. It should be noted that, even though the consumption of energy drinks is high worldwide, there is a scientific gap for studies on the chemical contents of these popular drinks, such as of the F content, and further studies are highly recommended.

Energy drink samples had the highest mean F concentration between all the studied beverages with a mean value of 0.37 mg L-1 and non-alcoholic beer samples had the lowest mean F concentration with a mean value of 0.11 mg L-1 (Tables 2C and 2D). So a high and daily consumption of energy drinks, compared to the other beverages in this study, could be of special concern due to the adverse health effects of F. The type of bottle (container), the water source, and the geographical conditions25, 27 are the main factors that influence the F content of beverages. In a study by Murrell at al.,28 the F concentration in beverages from the UK had higher values than beverages from the USA and the range of F concentration in the different beverages in the UK and USA was higher than that found in the present study.

As seen in Figure 1, the results indicated that there was no significant difference between the F concentration level of the doogh and carbonated soft drink samples but the F content of the non-alcoholic beers was significantly lower than the other beverages and the F content of the energy drinks was significantly higher than the other beverages. The higher mean concentration levels of energy drinks compared to other beverages was mainly due to the high F content of brand D.

The contents of F in the different brands of the mentioned beverages are presented in Figures 2A-2D. As seen in Figure 2A, the level of F in the C (carbonated) and F brands of doogh were significantly lower compared to other doogh brands. Also as shown in Figure 2B, there were statistically significant differences between the F concentration levels of some of the carbonated soft drink brands examined. The A brand of non-alcoholic beer significantly contained a higher F level compared to the other brands while the F brand had a significantly lower F content compared to other brands (Figure 2C). In the case of the energy drinks, there was a significant difference between the F concentrations of D brand and the other brands (Figure 2D).

The EDI and the HQ for the different age groups consuming the studied beverages are shown in Tables 4A and 4B. The ranges of the EDI values (pg kg-1 bw day-1) for the four beverage groups were: doogh: 0.47-0.52, carbonated soft drink: 0.23-1.5, non-alcoholic beer: 0.12-0.47, and energy drink: 0.0096-0.065 pg kg-1 bw day-1.

According to the available studies, there is no study on health risk assessment in doogh consumers, but the health risk assessment of milk in dairy products has been calculated.29 Murrell et al.29 examined the health risk from F in children (1-3 years) consuming different kinds of milk, including cow's, camel's, sheep, and goat's milk, and found the range of F concentrations (mg L-1) in the milk samples to be: sheep: 1.72-2.43, goat: 1.40-2.03, cow: 0.835-1.41, and camel: 0.425-0.897 mg L-1. The F level in the milk samples of the smaller animals (sheep and goats) was higher compared to other animals (cow and camel). The EDI values calculated by Murrell et al. for the children who used sheep milk and for the children aged more than 3 years old were higher than in the other groups.29 The observed values of the EDI found by Murrell et al. for F intake from milk consumption were in the range of 0.0132-0.052 mg kg-1 bw day-1 which was higher than that found for doogh consumption in the present study (0.00047-0.00052 mg kg-1 bw day-1).

In the present study, based on the results, the F exposure levels and hazard quotients for the maximum amounts of F in the different beverages were evaluated. The noncarcinogenic risks due to the highest F levels in the carbonated soft drink, nonalcoholic beer, doogh, and energy drink in the different age groups were as: 4-9 years (0.076), 4-9 years (0.040), 30-49 years (0.037), and 10-17 years (0.005), respectively. The HQ values obtained, even in the worse scenarios when considering the highest F levels, were less than unity (<1) in all the groups. Therefore it can be concluded that these beverages do not appear to be a significant source of F intake and none of the consumers were exposed to a significant health risk.

The highest values of the EDI and HQ were in the age group of 10-17 years old in carbonated soft drink consumers (1.5 pg kg-1 bw day-1, 0.042, respectively). This age group was more exposed to F and they were the age group most at risk of adverse health effects from F due to beverage drinking. The lowest values of the EDI and HQ were in the age group of 30-49 years in energy drink consumers (0.0096 pg kg-1 bw day-1, 0.00016, respectively) and this was mainly is due to a lower daily average consumption of energy drinks compared to other beverages.

Erdal and Buchanan30 studied the non-carcinogenic risks of F in two exposed populations (<1 year old and 3-5 years old) that consumed different beverages. The results showed that the HQ values were lower than 1 and the age group of 3-5 years old had a higher HQ value compared to the other group. In the present study, the HQ values in all the age groups were also less than 1 and were at an acceptable level. Although the F concentration levels of the studied beverages were low and the values of HQ were not significant, F may have an adverse effect on health if there is a high daily intake of F from other sources, e.g., other beverages, such as tea, food, drinking water.

CONCLUSIONS

Drinks are one of the common sources of F that can increase the F intake in humans, especially in tropical areas such as Iran and other Middle East countries. In the present study, the concentration levels of F in dairy drink (doogh), carbonated soft drink, non-alcoholic beer, and energy drink were determined and the risk assessment of F toxicity from the consumption of these beverages were evaluated. Based on the results, the mean concentration of F in energy drinks was more than in the other beverages, mainly was due to high F level in brand D of energy drink. The highest values for the EDI and HQ were in the age group of 10-17 years in carbonated soft drink consumers. Since the HQ values in all the age groups were less than 1, the health risk analysis showed that the non-carcinogenic risk of F toxicity in the different age groups consuming these beverages was acceptable. However, it should be noted that other F sources such as drinking water, food, toothpaste and other beverages, such as different types of tea, may contribute to a higher intake of F in body and consequently, increase the risk of adverse health effects from high F exposure.

ACKNOWLEDGMENTS

The authors are grateful to the National Institute for Medical Research Development for their financial support (Grant No: 977120) and the Bushehr University of Medical Science for their technical support for the present study, as well as to the laboratory staff of the Systems Environmental Health and Energy Research Center for their cooperation.

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