Beverage caffeine intake in US consumers and subpopulations of interest: estimates from the Share of Intake Panel survey

Concerns exist about the potential adverse health effects of high consumption of dietary caffeine, especially in children and pregnant women. Recommended caffeine intakes corresponding to no adverse health effects have been suggested recently for healthy adults (400–450 mg/day), for women contemplating pregnancy (300 mg/day), and for young children age 4–6 years (45 mg/day). To determine whether current caffeine intake approaches these levels, intake from major dietary sources (coffee, tea and carbonated soft drinks) were measured in 10,712 caffeinated beverage consumers in the 1999 US Share of Intake Panel, a targeted beverage survey. Mean caffeine intakes in adult caffeinated beverage consumers ranged from 106 to 170 mg/day (90th percentile intake was 227–382 mg/day). In children 1–5 and 6–9 years, mean caffeine intakes were 14 and 22 mg/day, respectively; corresponding 90th percentile intakes were 37 and 45 mg/day. Pregnant women consumed an average of 58 mg/day (157 mg/day at the 90th percentile), and women of reproductive age ingested 91–109 mg/day (229–247 mg/day at the 90th percentile). These data show that while mean caffeine intakes are within recommended safe levels, heavy consumers of certain subpopulations, including young children and women contemplating pregnancy, might benefit from dietary advice.     

Variability in caffeine consumption from coffee and tea: possible significance for epidemiological studies

Five surveys, using a previously developed high-performance liquid chromatography procedure to measure caffeine concentrations, indicated great variations in the concentrations of caffeine in tea and coffee. In the study of beverages prepared at home, data on caffeine concentrations in 58 samples of tea and coffee, volumes of cups, and numbers of cups consumed/day, indicated that the range of caffeine intakes for the women participating was 49-1022 mg/day. There were considerable day-to-day variations in caffeine contents in coffee samples from some commercial coffee shops. When 17 samples of five national brands of instant coffee were made into beverages in the laboratory, variations in caffeine concentrations between lots were small but between brands were significant. A considerable range of caffeine concentrations was also found when 12 samples of coffee prepared at work by different individuals using the same jar of instant coffee were analysed. Analysis of tea samples prepared in the laboratory indicated that steeping time had an important influence on resulting caffeine and theobromine concentrations. People preparing their own beverages were found to drink more liquid than the volume offered commerically. The mean caffeine 'contents' of home-made coffee and of coffee prepared by individuals at work were 79.4 and 81.7 mg/cup respectively, indicating a mean intake of approximately 80 mg caffeine/cup. When this amount (80 mg/cup) was used to estimate daily intakes of caffeine from coffee, on the basis of the number of reported cups/day, and the values obtained were compared with the amounts actually consumed by individuals, the potential for misrepresentation of individual consumption became obvious. For example, for subjects consuming three cups of coffee, only 25% would have been correctly categorized in the expected range for the daily intake of caffeine, 39% would have been overestimated and 36% underestimated for the amount of caffeine consumed. These variations in caffeine concentrations and in the volume of coffee consumed have frequently been ignored in examinations of the possible relationship between coffee consumption and various health problems, and this could perhaps partly explain some conflicting results seen in epidemiological studies.     

Beverage caffeine intakes in the U.S.

Caffeine is one of the most researched food components, with the vast majority of dietary contributions coming from beverage consumption; however, there is little population-level data on caffeine intakes in the U.S. This study estimated the caffeine intakes of the U.S. population using a comprehensive beverage survey, the Kantar Worldpanel Beverage Consumption Panel. A nationally representative sample of 37,602 consumers (aged ⩾ 2 years) of caffeinated beverages completed 7-day diaries which facilitated the development of a detailed database of caffeine values to assess intakes. Results showed that 85% of the U.S. population consumes at least one caffeinated beverage per day. The mean (±SE) daily caffeine intake from all beverages was 165 ± 1 mg for all ages combined. Caffeine intake was highest in consumers aged 50–64 years (226 ± 2 mg/day). The 90th percentile intake was 380 mg/day for all ages combined. Coffee was the primary contributor to caffeine intakes in all age groups. Carbonated soft drinks and tea provided a greater percentage of caffeine in the younger (<18 years) age groups. The percentage of energy drink consumers across all age groups was low (⩽10%). These data provide a current perspective on caffeinated beverage consumption patterns and caffeine intakes in the U.S. population.     

Arsenic levels in cooked food and assessment of adult dietary intake of arsenic in the Region Lagunera, Mexico.

The aim of this paper is to estimate the levels of arsenic (As) ingestion through cooked foods consumed in an arsenic endemic area and the assessment of their dietary intake of As. The study was conducted in two villages: a population chronically exposed to a high concentration of As via drinking water (410+/-35 microg/l) and to a low-exposure group (12+/-4 microg/l). A 24-h dietary recall questionnaire was applied to about 25 adult participants in each community. Samples of cooked food, ready for intake, were collected separately from each family's participants. To obtain the As estimate for each food item consumed, the mean quantity of food ingested in grams (wet weight) was calculated and the concentrations of total arsenic (TAs) in each cooked food were determined. The estimations of TAs intake were based on the sum over mean of As ingested from each food item consumed during the 24-h period for each participant. For the estimation of total daily As intake, we summed the mean obtained from food, plain water and hot beverage intakes. The TAs average intakes calculated for low-As-exposure group were 0.94 and 0.76 microg/kg body weight/day, for both summer and winter exposure scenarios, respectively. These values are 44.7 and 36% of the provisional tolerable daily intake (PTDI) for inorganic arsenic (2.14 microg/kg body weight/day), established by the World Health Organization (WHO) in 1989. The WHO reference value was obtained on a weekly basis intake estimation assuming an average body weight of 68 kg in adults. In contrast, for the high-exposure group the TAs average intakes were 16.6 and 12.3 microg/kg body weight/day for summer and winter, respectively. Ingestion via cooked food represented 32.5 and 43.9% of the total daily As intake in the high-exposure group; for summer and winter, respectively. None the less, the bioavailability of As through food can be different than via drinking water.     

Assessment of beverage consumption by young adults in Saudi Arabia

ObjectiveThe primary objective was to assess beverage consumption pattern and calorie intake among undergraduate students on weekly and daily basis. Secondary objectives were to determine the relationship between demographic variables and beverage intake, assess mean differences in calorie intake between students’ groups and, report the predictors of beverage consumption.MethodsA cross-sectional study was conducted for 3 months (January–March 2019) among currently enrolled undergraduate students studying in 8 colleges of a public sector university in Dammam, Saudi Arabia. The study used the Arabic version of Beverage Frequency Questionnaire (BFQ) and collected data through purposive stratified sampling. Total intake in ml and calories in kcals were calculated. Data was analyzed through SPSS version 23 and the study was approved from ethics committee of the university (IRB‐2019‐05‐021).ResultsA total of 507 students responded to the survey. The average volume of sugar sweetened beverages (SSBs), caffeine containing beverage (CCBs) and carbonated beverages (CarBs) consumed was 4.2 L, 4 L and 1.5 L per week and 650.6 ml, 575.2 ml and 224.6 ml per day, respectively. Average daily calorie intake from SSBs, CCBs and CarBs was 187.6 kcals, 87.6 kcals and 52.5 kcals, respectively. Body mass index (BMI) was significantly related to CCB (ρ = 0.130) and CarBs (ρ = 0.100) intake (mL) (p < 0.05). Mean difference in calorie intake was mostly significant (p < 0.05) when accounted for students’ demographics, gender, BMI, residence, illness and, examination time, in case of SSBs, CCBs, CarBs and, all beverages. Averge % contribution towards total daily energy expenditure (TDEE) for SSBs, CCBs and CarBs were 10.2%, 6.3% and 2.8%, respectively. Year of study, BMI, residence and illness were predictors of SSBs consumption while BMI, residence and examination time were predictors of CCBs consumption. Gender and BMI were predictors of CarBs intake.ConclusionThere was a high consumption of beverages in students that was related to their demographic characteristics. There is a need to create awareness among the students regarding the detrimental effects of chronic consumption of these beverages.     

Effects of concurrent saccharin availability and buprenorphine pretreatment on demand for smoked cocaine base in rhesus monkeys

The effects of saccharin and the opioid partial agonist buprenorphine on cocaine base smoking were evaluated in five male rhesus monkeys. Monkeys completed a sequence of responding consisting of lever-press responses maintained under a fixed-ratio (FR) schedule followed by inhalation responses (FR5) on a smoking spout to gain access to a single delivery of volatilized cocaine base (1.0 mg/kg per delivery). Monkeys could receive a maximum of ten smoke deliveries per session. In the first experiment, either saccharin (0.03% wt/vol) or water was concurrently available under an FR1 schedule through a lip-operated drinking device. As lever FR values increased from 128 to 256, 512, 1024 and 2048, the number of cocaine smoke deliveries decreased. Cocaine intake was not statistically different when water versus saccharin was concurrently available. However, as cocaine consumption decreased, saccharin intake increased demonstrating that under these conditions, saccharin was substituting for cocaine as a reinforcer. On the first day that lidocaine replaced cocaine, all of the monkeys received the maximum number of smoke deliveries (ten) and saccharin intake increased. Lever-press responding gradually extinguished over days when lidocaine (1.0 mg/kg per delivery) was available with concurrent saccharin. In the second experiment, water was concurrently available with cocaine and buprenorphine (0.01 or 0.1 mg/kg) was administered intramuscularly (IM) 30 min before the start of the session. Although pretreatment with the lower dose of buprenorphine (0.01 mg/kg) had little effect on cocaine intake overall, individual differences in cocaine intake occurred. The higher dose of buprenorphine (0.1 mg/kg) decreased the amount of cocaine consumed at all lever FR values tested.     

Predicting caffeine plasma concentrations resulting from consumption of food or beverages: a simple method and its origin

Multiple dosage regimens for therapeutic agents are commonly comprised of a constant dosing interval and a constant dose size. This is not true for the ingestion of a pharmacologically active agent that is a component in a dietary source. Caffeine is contained in foods and beverages that are regular components of the diet for many people. Because daily intake is unsystematic, a computer program was written to simulate caffeine plasma concentration-time courses following ingestion of variable amounts on irregular schedules. Literature values for caffeine pharmacokinetics, for the caffeine content in various foods and beverages, and for consumer habits were employed to simulate various caffeine plasma concentration-time courses. By searching for predictable traits in a wide variety of plasma concentration-time courses representing normal adults, a simple noncomputer method was developed to allow individuals to estimate caffeine plasma concentrations based on personal intake habits. Changes in the time courses due to smoking, oral contraceptive use, and liver disease, all of which alter caffeine pharmacokinetics, were also examined.     

Are energy Drinks Scapegoats? Decomposing Teenagers' Caffeine intake from Energy Drinks and Soda Beverages

Background: Energy drinks have been repeatedly blamed for contributing to caffeine intake among teenagers. Objectives: This study aimed to estimate and compare the caffeine intake of US teenagers from soda drinks versus energy drinks and shots. Methods: Data were taken from a 2015 nationally representative survey (Monitoring the Future) of 8th and 10th graders in the US (47.2% 8th grade; 51.1% female). Participants reported their numbers of consumed sodas, diet sodas, energy drinks, and energy shots per day. These were converted into mg caffeine/day and were contrasted with common guidelines for healthy caffeine intake, stratified by age group and sex. Error-bar charts, ANOVA and ROC curves were used for contrasting caffeine intake from soda drinks and energy drinks, as well as their contribution to exceeding recommended caffeine intake cutoffs. Results: First, in both sexes and grades the intake from soda drinks was significantly higher than the intake from energy drinks. The soda and energy drink intake for males was higher than the intake for females; intake for 8th graders was higher than this of 10th graders. Second, caffeine intake from soda drinks was significantly higher even in those who exceeded the recommended maximum caffeine intake. Third, caffeine intakes from soda and energy drinks were efficacious in explaining the exceeding of the recommended threshold for daily caffeine intake, but the explanatory power of soda drinks was larger. Conclusions: From a caffeine consumption standpoint, health professionals should emphasize reduction in both soda and energy drinks.     

Estimation of cytochrome P-450 CYP1A2 activity in 863 healthy Caucasians using a saliva-based caffeine test.

A pronounced variability limits the usefulness of CYP1A2 phenotyping for drug therapy, for evaluating liver function, and for assessing the role of this enzyme in carcinogenesis. To identify and quantify sources of this variation, we estimated CYP1A2 activity in 863 healthy Caucasians using caffeine clearance derived from saliva concentrations before and 5-7 h after a caffeine test dose. Data from 786 individuals were eligible for evaluation (mean age 39 years, 415 women including 94 taking oral contraceptives, 401 non-smokers). Overall geometric mean (geometric SD) caffeine clearance was 1.34 ml min(-1) kg b.w.(-1) (1.65). The effect of the following covariates was evaluated by analysis of covariance: age, sex, oral contraceptives, body height, body weight, body mass index, number of cigarettes smoked, tar exposure from smoking, several indices of dietary caffeine consumption, intake of sauerkraut, and country of residence (Germany, Bulgaria or Slovakia). Estimated changes relative to arbitrarily defined basal caffeine clearance (male, non-smoking, German resident) exerted by significant (P < 0.05) covariates were: coffee, 1.45-fold per litre of coffee drunk daily; body mass index, 0.99-fold per kg m(-2); smoking, 1.22-fold, 1.47-fold, 1.66-fold, and 1.72-fold for 1-5, 6-10, 11-20, and > 20 cigarettes smoked per day, respectively; oral contraceptives, 0.72-fold; country of residence, 0.81-fold and 0.74-fold for Bulgaria and Slovakia, respectively; female, 0.90-fold. These covariates explained 37% of overall variation. The 95% confidence interval of individual clearance was 0.46-2.20 times the predicted value. No relevant polymorphism was found for CYP1A2 activity when adjusted for covariate effects.     

Evidence for a relationship between daily caffeine consumption and accuracy of time estimation

The present study examined the relationship between regular caffeine consumption and time estimation. Sixty participants (aged 18-57 years, mean 24 years) completed a 47 s time estimation exercise and questionnaires related to daily caffeine consumption and perceptions of time. We hypothesized that the effects of caffeine on time estimation would follow a U-shaped pattern such that individuals who reported moderate amounts of daily caffeine would be more accurate in their perceptions of time than would those who reported high amounts of caffeine intake or no daily caffeine consumption. Timing accuracy was computed by dividing participant-reported time by actual time (47 s). Timing accuracy followed a U-shaped curve such that those respondents who reported 'low' daily caffeine consumption (< or = 135 mg/day, n = 24) were the most accurate in their time estimates (mean= 44.2 s). Individuals who reported no caffeine (mean= 69.3 s; n= 7) or 'high' daily caffeine consumption (mean=56.2 s; >135 mg/day, n = 28) were less accurate in their time estimates [F(2, 56)= 3.34, p< 0.05]. Findings suggest that 'low' daily caffeine consumption may enhance time estimation accuracy above that of 'high' or no daily caffeine consumption.     

The NMDA receptor channel blocker memantine and opioid receptor antagonist naltrexone inhibit the saccharin deprivation effect in rats

Several drugs, such as N-methyl-D-aspartate (NMDA) receptor channel blockers (memantine), naltrexone (but not naloxone) and acamprosate, have previously been reported to attenuate the expression of the alcohol deprivation effect, a phenomenon seen as an increase in post-deprivation alcohol consumption. The present study aimed to evaluate the effects of these drugs on the development and expression of the saccharin deprivation effect in adult male Wistar rats. Memantine (13 mg/kg per day) and naltrexone (5 mg/kg, twice daily), but not naloxone (24 mg/kg per day) or acamprosate (200 mg/kg, twice daily), prevented the increase in the consumption of saccharin after a 1-week deprivation from free-choice, unlimited access to saccharin (0.1%, w/v). Taken together with the results of previous studies, these results suggest that naltrexone and memantine attenuate the expression of both the alcohol and saccharin deprivation effects.     

Estimated intake levels for Finnish children of methylmercury from fish

Methylmercury (MeHg) is a well-known neurotoxic agent, and consumption of contaminated fish is the principal environmental source of MeHg exposure in humans. Children are more susceptible to adverse effects than adults. No previous specific data exist for intake by Finnish children of methylmercury from fish. We estimated fish consumption and MeHg intakes from species most commonly consumed by Finnish children aged 1–6 years. The total mercury concentrations were determined in fish species consumed, and age-specific methylmercury intakes were derived. We also examined safety margins and the proportion of children exceeding the tolerable daily intakes set by international expert bodies. The daily intake of MeHg ranged from 0 to 0.33 μg/kg bw. The strictest reference value 0.1 μg/kg bw/day for MeHg, proposed by USEPA, was exceeded by 1–15% of the study population, and FAO/WHO JECFA provisional tolerable weekly intake of 1.6 μg/kg bw was exceeded by 1% of boys and 2.5% of girls aged 6 years. Intakes of 1-year old girls were higher than of boys, whereas for 3-year olds they were the opposite. The highest intakes were observed for 6-year-old boys and girls. There was great variation in the estimated MeHg intakes among Finnish children.     

The effects of caffeine and nicotine consumption on mood and somatic variables in a penitentiary inmate population.

A sample of 144 inmates from a maximum security penitentiary responded to a request for information regarding their average daily intake of nicotine and caffeine. They also rated the quality of their appetite and sleep, their level of concentration, their mood and specific feelings of anger, anxiety, frustration, and irritability. Factor analysis generated a two-factor solution of these variables, namely general mood state (mood, anxiety, anger, frustration, and irritability) and a somatic state (appetite, concentration, and sleep). Analysis of variance showed an interaction between level of smoking (nonsmokers, low and high cigarette smokers) and caffeine use (moderate vs. high) on the general mood factor. Nonsmokers who consumed high levels of caffeine experienced poorer general mood than any other group. There was a main effect of cigarette smoking status on the somatic factor, such that greater dissatisfaction was associated with greater consumption. Caffeine consumption was generally high, averaging 800 mg of caffeine per day, per inmate, well above the amount considered to be potentially damaging to health.     

Methods for estimating heterocyclic amine concentrations in cooked meats in the US diet.

Heterocyclic amines (HAs) are formed in numerous cooked foods commonly consumed in the diet. A method was developed to estimate dietary HA levels using HA concentrations in experimentally cooked meats reported in the literature and meat consumption data obtained from a national dietary survey. Cooking variables (meat internal temperature and weight loss, surface temperature and time) were used to develop relationships for estimating total HA concentrations in six meat types. Concentrations of five individual HAs were estimated for specific meat type/cooking method combinations based on linear regression of total and individual HA values obtained from the literature. Using these relationships, total and individual HA concentrations were estimated for 21 meat type/cooking method combinations at four meat doneness levels. Reported consumption of the 21 meat type/cooking method combinations was obtained from a national dietary survey and the age-specific daily HA intake calculated using the estimated HA concentrations (ng/g) and reported meat intakes. Estimated mean daily total HA intakes for children (to age 15 years) and adults (30+ years) were 11 and 7.0 ng/kg/day, respectively, with 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) estimated to comprise approximately 65% of each intake. Pan-fried meats were the largest source of HA in the diet and chicken the largest source of HAs among the different meat types.     

Dietary exposure to essential and toxic trace elements from a Total diet study in an adult Lebanese urban population

This study assesses, by the Total diet study approach, the adequacy of micronutrient intake (Co, Cu, Fe, Mn, Ni, Zn) and the dietary exposure of a Lebanese adult urban population to two toxic elements (Cd, Pb). The foods that made up the average ‘total diet’ were derived from a previous individual consumption survey. A total of 1215 individual foods were collected, prepared and cooked prior to analysis. Analytical quantification was performed using inductively coupled plasma mass spectrometry. Average daily intakes of Co (11.4 μg/day), Cu (1104.19 μg/day), Fe (13.00 mg/day), Mn (2.04 mg/day), Ni (126.27 μg/day) and Zn (10.97 mg/day) were below toxicological reference values and were found to satisfy nutritional recommendations, except for manganese in men and iron in women. Average dietary exposure to Pb and Cd represented 3.2% and 21.7% of the respective provisional tolerable weekly intakes. Estimates of dietary intakes of iron appeared to be inadequate for 63% of adult women. These findings should constitute a current measure of assessing the adequacy and safety of foods consumed in Lebanon and may be a basis for future monitoring studies.     

Nicotine-induced taste aversion: characterization and preexposure effects in rats

Rats were trained to drink their 24 hr water intake during a single daily 30 min period. After stabilization, rats were presented with 0.1% (w/v) of sodium saccharin for 30 min. Immediately after removal of the saccharin solution, the animals were injected with saline, mecamylamine hydrochloride or hexamethonium hydrobromide; thirty minutes later, saline or nicotine, 0.05, 0.16, or 0.50 mg/kg were administered. Twenty-four hr later, rats were allowed access to both water and saccharin. Nicotine caused a dose-related decrease in the proportion of fluid consumed as saccharin solution during the 30 min testing situation. Neither mecamylamine nor hexamethonium alone decreased saccharin preference; however, 3 mg/kg of mecamylamine blocked the decrease of saccharin preference induced by nicotine. Preexposure of drug-naive rats to 0.5 mg/kg of nicotine for 2 or 4 days abolished the nicotine-induced taste aversions to saccharin when tested one day, or one week, after conditioning.     

Voluntary self-administration of both morphine and cocaine by rats

Voluntary self-administration of cocaine and/or morphine was studied in rats. Male rats were offered water bottles or bottles containing either cocaine or morphine, both cocaine and morphine (combination) or cocaine and morphine as a mixture. Alternating the three drug-containing bottles had no effect on drug choice. When offered alone, rats consumed about 12 +/- 8 mg/kg/day of cocaine or 0.3 +/- 0.3 mg/kg/day of morphine. When both drugs were offered in combination, they consumed a higher amount of cocaine (22 +/- 7), but the same amount of morphine (0.4 +/- 0.3). Availability of cocaine/morphine mixture kept morphine consumption constant (0.3 +/- 0.1), but markedly decreased cocaine intake (0.3 +/- 0.2). Addition of saccharin to the drug solutions only slightly increased consumption of both drugs, whereas saccharin added as a competitor or distracter to the drug solution reduced cocaine but not morphine self-administration. Animals showed wide interindividual variations but surprisingly small intraindividual variations in self-administration of cocaine or morphine under all conditions. No correlation between cocaine and morphine intake was apparent in the combination situation. Forcing animals first with cocaine had no effect on subsequent intake of cocaine or morphine presented in combination. However, forcing animals first with morphine subsequently increased morphine and reduced cocaine intake. In conclusion, morphine intake was the same if offered alone, in combination or as a mixture, whereas cocaine intake increased during a combination but decreased in the mixture situation. Cocaine pre-exposure had no effect on subsequent voluntary morphine or cocaine choice, whereas morphine pre-exposure increased subsequent voluntary morphine but decreased cocaine intake. These results suggest the possibility of two reward centers, one for each drug, the morphine center exerting a dominant influence over the cocaine center.     

Intake assessment for benzoates in different subgroups of the Flemish population.

An exposure assessment was performed to estimate the daily intake of benzoates for the Flemish population. Three age groups were considered: preschool children (n=697; age 2-6; 3-day estimated dietary record), adolescents (n=341; age 14-18; 7-day estimated dietary record) and women (n=641; age 18-40; 2-day estimated dietary record). In a first step in the risk evaluation process as proposed by the European Union, the individual food consumption data were multiplied with the maximum permitted use levels for benzoates per food group. The median (interquartile range) estimated daily intake is, respectively, 2.0 (1.0-3.2) mg/kg bw, 1.7 (1.1-2.7) mg/kg bw and 1.92 (1.3-3.0) mg/kg bw for preschool children, adolescents and adult women. In all age groups, the greatest potential contributor to the total estimated benzoate intake was the group of non-alcoholic flavoured drinks. At respectively the 92nd percentile (children), the 97th percentile (adolescents) and the 94th percentile (women), the accepted daily intake (ADI) of 5mg/kg bw/day is exceeded slightly. However, this approach, in which the maximum permitted use levels are used is known to overestimate the intake, since not all food items in which benzoates are allowed, contain (the maximum permitted use level of) benzoates. A more precise estimation, using actual levels, is recommended.     

Caffeine content of energy drinks, carbonated sodas, and other beverages

The caffeine content of 10 energy drinks, 19 carbonated sodas, and 7 other beverages was determined. In addition, the variability of the caffeine content of Coca-Cola fountain soda was evaluated. Caffeine was isolated from the samples by liquid-liquid extraction and analyzed by gas chromatography with nitrogen-phosphorus detection. The caffeine concentration of the caffeinated energy drinks ranged from none detected to 141.1 mg/serving. The caffeine content of the carbonated sodas ranged from none detected to 48.2 mg/serving, and the content of the other beverages ranged from < 2.7 to 105.7 mg/serving. The intra-assay mean, standard deviation, and % coefficient of variation for the Coca-Cola fountain samples were 44.5, 2.95, and 6.64 mg/serving, respectively.