Capítulo 2: Marco Referencial
2.5.4. Libros, memorias, capítulos de libros y boletines menores
12.3
Regulatory limits for chemicals in food
The approval process for food additives includes consideration of the theoretical intake of the additive assuming that it will be added at the level necessary to achieve its technological purpose in all the foods in which it could be used, taking into account how much of those foods is likely to be eaten. If this exposure assessment indicates that the ADI could be exceeded, then restrictions are placed on the maximum levels or the different food uses, in order to ensure that the intake is below the ADI. These restrictions are specified in international, European Union (EU) and UK regulations.
Whilst contaminants are not subject to an approval process, regulatory limits are applied for some key contaminants to help reduce exposure to below the TDI, where one could be set. The process for establishing regulatory limits for contaminants also takes into account the levels that occur in different types of food, the extent to which it is techno-logically feasible to reduce the levels, and also what can be reliably measured and therefore enforced. Within Europe the regulations are set by the European Commission, with input from representatives of the national food authorities in member states.
Because of the different ways that regulatory limits are set, a food exceeding the regulatory limit for a particular additive or contaminant will not inevitably result in intakes above the ADI or TDI.
12.4
Implications of exceeding the ADI or TDI
When foods are found to exceed regulatory limits for additives or contaminants, or when assessing levels of unregulated contaminants, it is important to first assess the anticipated intake for average and high-level consumers of the foods containing the additive or con-taminant. Consideration of children’s food consumption is generally important because young children have a higher caloric requirement, expressed in relation to body weight. If the estimates of total dietary exposure for different subgroups are below the ADI/TDI, then there is not considered to be a health risk. If, the ADI/TDI is exceeded by some subgroups, then it is necessary to consider if the available toxicological information allows further conclusions to be drawn. The ADI/TDI is not a threshold of toxicity, and for a substance that does not have acute effects, occasionally exceeding the ADI/TDI is unlikely to be harmful. The greater the degree by which it is exceeded, and the longer the period of potential exceedance, the more likely it becomes that adverse effects will occur. In such situations, action may be taken to withdraw the affected food from sale, and if appropriate, specific advice may be given to subgroups at particular risk.
12.5
Recent health concerns related to food additives and contaminants
12.5.1 Aspartame
Aspartame is an intense artificial sweetener that is widely used in beverages and processed foods. Some people have concerns that aspartame could be the cause of a wide range of human illnesses, largely based on unsubstantiated information available on the internet.
In fact, the available evidence on aspartame has been reviewed on many occasions (see EFSA ( 2011 ) for an overview of the evaluations) over the past two to three decades. It is metabolized in the gastrointestinal tract into two amino acids (aspartic acid and phenyla-lanine) and methanol, all of which are present naturally in many foods and in the human body. Ingestion of aspartame at the level of the ADI does not result in elevation of these components within the blood. EFSA ( 2006 ) concluded that intakes of aspartame at the ADI do not lead to toxicologically relevant systemic exposure and confirmed that there was no reason to revise the previously established ADI. Estimates of intakes, even for high-level consumers, are well below the ADI. Since 2006, EFSA has reviewed a number of scientific studies on aspartame and concluded that they did not influence the previous conclusions (EFSA 2011 ).
12.5.2 Sudan dyes
Sudan dyes have never been approved as food colours in the UK. Although not tested to current standards, the available information indicates that they are genotoxic and carci-nogenic. Therefore the expert opinion is that it is not possible to propose a TDI and exposures should be reduced to as low as reasonably practicable. In 2003 it was discov-ered that Sudan dyes were being used illegally to increase the market value of some spices, such as chilli powder, and legislation was introduced to require testing of chilli and chilli products imported into the EU (EC 2003 ). Since then there have been a number of occa-sions in which Sudan dye adulterated foods have been found on the UK market. At the levels detected the cancer risk is likely to be extremely small, but it is an unnecessary risk that can be avoided if action is taken to prevent these dyes from being added to food.
12.5.3 Acrylamide
Acrylamide has been used as an industrial chemical since the mid-1950s, but its presence in food was only discovered in 2002 (FAO/WHO 2006 ). There has been extensive inter-national effort to investigate how acrylamide forms in food and how formation could be reduced, and also to develop and refine risk assessment for dietary exposure to acryla-mide. Acrylamide is known to be neurotoxic in humans as a result of occupational and accidental exposure. Studies in animals have shown that it can cause reproductive effects and that it is genotoxic and carcinogenic. It is not known whether dietary exposure to acry-lamide could cause cancer in humans, but based on the evidence from the animal studies, it is considered possible. Research conducted since 2006 has confirmed the earlier conclu-sion that estimates of dietary exposure to acrylamide indicate a health concern (FAO/
WHO 2011 ). As with the Sudan dyes, the expert opinion is that it is not possible to pro-pose a TDI and intakes should be reduced to as low as reasonably practicable. However, because acrylamide is present in a wide variety of cooked foods, it is not possible to have a healthy balanced diet that avoids acrylamide. It is also likely that it has been in our food for generations.
Research is underway to investigate how acrylamide formation can be reduced without incurring other food risks, but so far this has had limited impact on levels of acrylamide
in food and total dietary exposure. The Food Standards Agency advises that people should not change their diets because of concern about acrylamide, but should follow the healthy eating guidelines that help to protect against some cancers as well other chronic diseases.
12.5.4 Contaminants in fish
Fish is an important source of nutrients, and most people in the UK eat less than is recom-mended for health benefits. However, fish also contain contaminants that can be a health concern. There are two main issues: methylmercury accumulates in large predator fish, regardless of whether they are oily or non-oily, and persistent organic pollutants, such as dioxins, have the potential to accumulate in oily fish. Fish is the major source of exposure to methylmercury. Dioxins and related compounds are widely present in other foods, although levels have decreased significantly over the past three decades.
The Food Standards Agency asked an expert group of nutritionists and toxicologists to advise on the benefits and risks associated with fish consumption (SACN/COT 2004 ) in order to give cohesive advice to consumers. Methylmercury is neurotoxic and the most sensitive effect is impaired neurodevelopmental as a result of pre-natal exposure. Dioxins have a wide range of health effects, the most sensitive of which was considered to be on development of the male reproductive system as a result of pre-natal exposure. The expert group advised that the tolerable intakes set to protect against accumulation of methylmercury and dioxins in a woman’s body to levels that could have adverse effects on the foetus should also be applied to susceptible subgroups.
However, as seen in Figure 12.1 , if the most sensitive effect relates to exposure during pregnancy, the TDI could be over-precautionary for people who are not pregnant.
Therefore the COT set additional guidelines, based on the next most sensitive effect, to be applied for men and for women who were not or would not become pregnant, for the range of fish consumption at which there would be nutritional benefits without undue risks from the contaminants. Combined with information on the levels of contaminants present in different types of fish and other dietary sources of dioxin-like compounds, this opinion forms the basis of Food Standards Agency advice to consumers.
12.6
References
EC. ( 2003 ) Commission decision 2003/460/EC of 20 June 2003 on emergency measures regarding hot chilli and hot chilli products . Official Journal of the European Union . L 154/114 .
EFSA. ( 2006 ) Opinion of the Scientific Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food (AFC) on a request from the Commission related to a new long-term carcinogenicity study on aspartame . Adopted on 3 May 2006 . Available at: http://www.efsa.
europa.eu/EFSA/efsa_locale-1178620753812_1178620765743.htm .
EFSA. ( 2011 ) EFSA Statement on the scientific evaluation of two studies related to the safety of artificial sweeteners . EFSA Journal 9 ( 2 ): 2089 . doi:10.2903/j.efsa.2011.2089. Available at: www.efsa.europa.eu/
efsajournal .
FAO/WHO. ( 2006 ) Safety evaluation of certain food additives . Food Additive Series No 56 . World Health Organization , Geneva . Available at:
http://whqlibdoc.who.int/publica-tions/2006/9241660554_eng.pdf .
FAO/WHO. ( 2011 ) Safety evaluation of certain contaminants in food. Food Additive Series No 63 . World Health Organization , Geneva . Available at: http://whqlibdoc.who.int/
publications/2011/9789241660631_eng.pdf .
SACN/COT. ( 2004 ) Scientific Advisory Committee on Nutrition Reports . Available at: http://www.
sacn.gov.uk/reports/# . Accessed February 2008.
12.7
Further reading
IPCS. ( 2009 ) Environmental Health Criteria 240. Principles and methods for the risk assessment of chemicals in food . http://www.who.int/foodsafety/chem/principles/en/index1.html .
12.8
Useful internet links
COT opinions : http://www.food.gov.uk/science/ouradvisors/toxicity/ . EFSA opinions : http://www.efsa.europa.eu/en/science.html .
Food Standards Agency website : http://www.food.gov.uk .
JECFA procedures and opinions : http://www.who.int/ipcs/food/jecfa/en/and http://www.inchem.org/ . SCF opinions : http://ec.europa.eu/food/fs/sc/scf/outcome_en.html .