Risk Assessment of "Other Substances" – Taurine

ABSTRACT

The Norwegian Scientific Committee for Food Safety (Vitenskapskomiteen for mattrygghet, VKM) has, at the request of the Norwegian Food Safety Authority (Mattilsynet; NFSA), assessed the risk of "other substances" in food supplements and energy drinks sold in Norway. VKM has assessed the risk of doses in food supplements and concentrations in energy drinks given by NFSA. These risk assessments will provide NFSA with the scientific basis while regulating the addition of “other substances” to food supplements and other foods. "Other substances" are described in the food supplement directive 2002/46/EC as s ubstances other than vitamins or minerals that have a nutritional and/or physiological effect . It is added mainly to food supplements, but also to energy drinks and other foods. VKM has not in this series of risk assessments of "other substances" evaluated any claimed beneficial effects from these substances, only possible adverse effects. The present report is a risk assessment of taurine, and it is based on previous risk assessments and articles retrieved from a literature search. According to information from NFSA, taurine is an ingredient in food supplements and energy drinks sold in Norway. NFSA has requested a risk assessment of 750, 800, 900, 1000 and 2000 mg/day of taurine in food supplements, and of 300, 350 and 400 mg/100 ml of taurine in energy drinks. Drinking patterns reflecting a high acute intake, a mean chronic intake and a high chronic intake were assessed. For food supplements, the intake of taurine was estimated for the age groups children (10 to <14 years), adolescents (14 to <18 years) and adults (>18 years), whereas for energy drinks the age group children (3 to <10 years) was also included. Other sources of taurine, such as foods and cosmetics, have not been included in the present risk assessment. Taurine (CAS No. 107-35-7) is synthesised endogenously (average 50-125 mg per day), and participates in the formation of bile salts and is involved in a number of crucial physiological processes, including modulation of calcium flux and neuronal excitability, osmoregulation and membrane stabilisation. Taurine occurs naturally in food, especially in meat and seafood. The mean daily intake of taurine from the diet has been estimated to vary between 40 and 400 mg/day. There are indications that taurine may have cardiovascular and neurological effects in humans. However, based on the human studies, an intake of approximately 21 mg/kg bw per day is considered unlikely to cause adverse health effects. Based on a 13-week neurotoxicity study in rats, a no observed adverse effect level (NOAEL) of 1000 mg/kg bw per day for pathological changes was set in 2009 by the European Food Safety Authority (EFSA). In the present risk assessment, VKM has used this NOAEL of 1000 mg/kg bw per day from rats. The human studies available were not of sufficient quality (due to low number of participants, non-healthy populations, short duration) to be used as the sole basis for the risk characterisation. The risk characterisation is based on the margin of exposure (MOE) approach; the ratio of the NOAEL to the exposure. An acceptable MOE value for a NOAELbased assessment of taurine based on an animal study is ≥100, which includes a factor 10 for extrapolation from animals to humans and a factor 10 for interindividual human variation. However, since the NOAEL set by EFSA was based on the highest tested dose and there is a possibility that the actual NOAEL is higher than 1000 mg/kg bw per day, the intake that was considered unlikely to cause adverse health effects based on human studies (21 mg/kg bw per day) was also taken into consideration in the risk characterisation. Food supplements For children (10 to <14 years), the estimated daily intakes of taurine were 17.3, 18.4, 20.7, 23.0 and 46.1 mg/kg bw per day from daily doses of 750, 800, 900, 1000 and 2000 mg taurine, respectively, from food supplements. The margin of exposure (MOE) values was in the range of 22-58 for the various taurine doses, i.e. all below 100. However, from a daily intake of 750, 800 or 900 mg taurine from food supplements, the estimated intakes were below 21 mg/kg bw per day (the intake considered unlikely to cause adverse health effects based on human studies). VKM therefore concludes that it is unlikely that a daily intake of 750, 800 or 900 mg taurine from food supplements causes adverse health effects in children (10 to <14 years). The estimated exposure from a daily intake of 1000 or 2000 mg taurine was above 21 mg/kg bw per day. Thus, VKM concludes that a daily intake of 1000 or 2000 mg taurine from food supplements may represent a health risk in children (10 to <14 years). For adolescents (14 to <18 years), the estimated daily intakes were 12.2, 13.1, 14.7, 16.3 and 32.6 mg/kg bw per day from daily doses of 750, 800, 900, 1000 and 2000 mg taurine, respectively, from food supplements. For adults (≥18 years), the estimated intakes were 10.7, 11.4, 12.9, 14.3 and 28.6 mg/kg bw per day from a daily intake of 750, 800, 900, 1000 and 2000 mg taurine, respectively, from food supplements. For adolescents (14 to <18 years) and adults (≥18 years), the MOE values were in the range of 31-82 and 35-93, respectively, i.e. all below 100. However, from a daily intake of 750, 800, 900 or 1000 mg taurine from food supplements the estimated intakes were below 21 mg/kg bw per day (the intake considered unlikely to cause adverse health effects based on human studies) for both age groups. Thus, VKM concludes that it is unlikely that a daily intake of 750, 800, 900 or 1000 mg of taurine causes adverse health effects in adolescents (14 to <18 years) and adults (≥18 years). For adolescents (14 to <18 years) and adults (≥18 years) the estimated MOE values were 31 and 35, respectively, i.e. below 100, after a daily intake of 2000 mg taurine from food supplements. In addition, the estimated intakes were above the intake level of 21 mg/kg bw per day (the intake considered unlikely to cause adverse health effects based on human studies) for both age groups. Thus, VKM concludes that a daily intake of 2000 mg of taurine may represent a risk of adverse health effects in adolescents (14 to <18 years) and adults (≥18 years). Energy drinks High acute drinking pattern, all age groups For the high acute drinking pattern, the estimated consumption of energy drinks was 1000, 1500, 2000 and 2000 ml/day for children (3 to <10 years), children (10 to <14 years), adolescents (14 to <18 years) and adults (≥18 years), respectively. For the concentrations of 300, 350 and 400 mg taurine/100 ml energy drink, the intake levels of taurine after a high acute consumption of energy drinks (in mg/kg bw per day) were 130, 152 and 173; 104, 121 and 138; 97.9, 114 and 131; and 85.7, 100 and 114, for children (3 to <10 years), children (10 to <14 years), adolescents (14 to <18 years) and adults (≥18 years), respectively. Due to lack of an acute reference dose or other data for acute toxicity of taurine, it was not possible to characterise the risk related to an acute intake of taurine for any of the age groups. Mean chronic drinking pattern, all age groups For the mean chronic drinking pattern, the estimated consumption of energy drinks was 58, 65, 64 and 71 ml/day for children (3 to <10 years), children (10 to <14 years), adolescents (14 to <18 years) and adults (≥18 years), respectively. For the concentrations of 300, 350 and 400 mg taurine/100 ml energy drink, the intake levels of taurine after a mean chronic drinking pattern (in mg/kg bw per day) were 7.5, 8.8 and 10.0; 4.5, 5.2 and 6.0; 3.1, 3.7 and 4.2; and 3.0, 3.6 and 4.1, for children (3 to <10 years), children (10 to <14 years), adolescents (14 to <18 years) and adults (≥18 years), respectively. In all age groups, the estimated MOE values were 100-333, i.e. 100 or above, for all three taurine concentrations. In addition, the estimated intakes were all below 21 mg/kg bw per day (the intake considered unlikely to cause adverse health effects based on human studies) for all age groups. Thus, VKM concludes that it is unlikely that the mean chronic intake of all three concentrations of taurine causes adverse health effects in children (3 to <10 years), children (10 to <14 years), adolescents (14 to <18 years) and adults (≥18 years). High chronic drinking pattern, all age groups For the high chronic drinking pattern, the estimated consumption of energy drinks was 163, 180, 211 and 320 ml/day for children (3 to <10 years), children (10 to <14 years), adolescents (14 to <18 years) and adults (≥18 years), respectively. For the concentrations of 300, 350 and 400 mg taurine/100 ml energy drink, the intake levels of taurine after a high chronic drinking pattern (in mg/kg bw per day) were 21.2, 24.7 and 28.2; 12.4, 14.5 and 16.6; 10.3, 12.0 and 13.8; and 13.7, 16.0 and 18.3 mg/kg bw per day for children (3 to <10 years), children (10 to <14 years), adolescents (14 to <18 years) and adults (≥18 years), respectively. For children (3 to <10 years), the estimated MOE values were 47, 40 and 35, for the three taurine concentrations of 300, 350 and 400 mg/ml, respectively, i.e. all below 100. In addition, the estimated intakes were all above 21 mg/kg bw per day (the intake considered unlikely to cause adverse health effects based on human studies) for all three taurine concentrations. Thus, VKM concludes that a high chronic intake of all three concentrations of taurine from energy drinks may represent a health risk in children (3 to <10 years). For children (10 to <14 years), adolescents (14 to <18 years) and adults (≥18 years), the estimated MOE values were in the range of 55-97, i.e. all below 100 for all three taurine concentrations. However, the estimated intakes were all below the intake level of 21 mg/kg bw