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Frequently Asked Questions about 3-monochloropropane-1,2-diol (3-MCPD)

BfR FAQs, 17 December 2007

The substance 3-monochloropropane-1,2-diol (3-MCPD) may be formed when fat-containing foods that also contain salt are exposed to high temperatures during production. It has been detected in numerous heated foods, for instance in dark brown toast. During the production of fats and oils, 3-MCPD fatty acid esters may be formed from 3-monochloropropane-1,2-diol when the fats and oils are heated to high temperatures. Significant amounts of 3-MCPD fatty acid esters have now been detected by food control authorities in numerous edible fats and fat-containing foods, for instance in infant formula and follow-up formula. The Federal Institute for Risk Assessment (BfR) has assessed the detected levels from the health angle and recommended that concerted action be taken to lower the levels of 3-MCPD esters in infant formula and follow-up formula. The Institute recommends that mothers who are unable to breastfeed their infants and give them infant formula should continue to do so. BfR responds to Frequently Asked Questions about 3-MCPD below.

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Questions

What is 3-MCPD, how is it formed and what effect does it have?

3-monochloropropane-1,2-diol (3-MCPD) is a substance which may be formed in fat and salt-containing foods through a chemical reaction when these foods are exposed to high temperatures during the production process. 3-MCPD, also referred to as "free" 3-MCPD, has been detected in numerous foods, amongst others in dark toast, in the crust of bread and in soy sauces. The substance belongs to the group of chloropropanols. In animal experiments it led to an increase in the cell count (hyperplasia) in the renal tubules and higher levels triggered benign tumours. No genotoxic effect was observed. It can, therefore, be assumed that the tumours observed in the animal study only occur above a threshold value. Based on these scientific findings, scientific expert bodies of the EU, the World Health Organisation (WHO) and the Food and Agriculture Organisation (FAO) set a tolerable daily intake (TDI) of 2 micrograms (free) 3-MCPD per kilogram body weight for humans. Based on this TDI concept, the occasional exceeding of the TDI value can be tolerated when the adverse effect concerned is only observed in animal experiments after long-term intake of the substance and there is no concrete danger for the consumer. The ongoing exceeding of this value would, however, be worrying.

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How are 3-MCPD fatty acid esters formed?

During the production of fats and oils, 3-MCPD fatty acid esters may be formed from 3-monochloropropane-1,2-diol when the fats and oils are heated to high temperatures.

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Where have 3-MCPD fatty acid esters been detected and do they have the same effect as 3-MCPD?

Whereas untreated edible fats and oils only contain low levels of 3-MCPD, study results from the official food control authorities show that all refined, i.e. non-native edible oils and fats contain what are in some cases substantial amounts of 3-MCPD fatty acid esters. According to the latest scientific knowledge available, they are formed during oil refining, i.e. during cleaning and processing. Crude oils also contain various accompanying substances which are removed for reasons, amongst other things, of odour and taste. In the course of refining the oils are degummed, deacidified, bleached and steamed at high temperatures. Steaming is also called "deodorisation".

We do not know whether 3-MCPD fatty acid esters have the same toxic properties as free 3-MCPD. No data are available but it cannot be ruled out that free 3-MCPD is formed from most of the fatty acid esters during digestion.

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In which foods have 3-MCPD fatty acid esters been detected?

Fatty acid esters of 3-monochloropropane-1,2-diol have been detected by official food control authorities in all the samples they examined from refined edible oils and edible fats and in foods made from them like for instance infant formula and follow-up formula. Infant formula and follow-up formula contain varying amounts of dried powder and water. The dried powder, in turn, contains fat that infants need. This fat is heated to a high temperature during the cleaning and refining steps of the production process.

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What levels of 3-MCPD fatty acid esters were detected?

The amounts of 3-MCPD fatty acid esters detected in edible oils and fats were in the four to five digit microgram range. The highest level of 11,206 micrograms per kilogram (µg/kg) was found in deep-frying fat. In the infant formula and follow-up formula examined the highest level identified was 4,196 µg/kg in the fat content. For this food it amounts to around 25 percent of the dried powder.

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How do the detected levels of 3-MCPD fatty acid esters relate to the tolerable daily intake?

The tolerable daily intake (TDI) was established for free 3-monochloropropane-1,2-diol. In its health assessment of the detected levels BfR assumes that 3-MCPD fatty acid esters are fully converted into free 3-MCPD. At the present time, it is not possible to give a clear scientific answer to the question as to whether this is really the case. Based on this assumption, men who consume 100 g of vegetable margarine with the highest detected level of 3-MCPD fatty acid esters daily would exceed the TDI five-fold.

Based on the same assumption and the customary intakes of formula and follow-up formula, infants would exceed the TDI three to twenty-fold. In this context it must be borne in mind that in this case the TDI was used as an alternative. Normally, the TDI concept does not apply to the first months of life as we do not know how sensitively infants react at that age. Moreover, too little is known about their metabolism.

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Do the detected levels carry a risk for consumers and, more particularly, infants?

The number of samples examined by the official food control authorities is still small and does not permit a representative overview of the products on the market. Some questions have still to be clarified scientifically. No data are available on the toxicological effect of 3-MCPD fatty acid esters. Nor is it clear whether and, if so, on what scale the fatty acid esters are converted into 3-MCPD and then absorbed. This means that the assessment of the health risk from the detected levels of 3-MCPD fatty acid esters has a certain degree of uncertainty. Furthermore, the most sensitive effect of 3-MCPD in animal experiments, hyperplasia in the renal tubules, is not described as a clinical picture in man. If one, nevertheless, assumes that the toxicological effects are comparable or that there is large scale conversion of 3-MCPD fatty acid esters into 3-monochloropropane-1,2-diol, then the expected long-term exceeding of the TDI is not acceptable in the opinion of BfR particularly as children and adults ingest 3-MCPD from other sources, too. Any short-term exceeding of the TDI value would, by contrast, not present a safety concern.

According to the current level of scientific knowledge, babies in particular may ingest levels of 3-MCPD esters from infant formula and follow-up formula for which, in the worst case scenario, the safety margin to the effects observed in animal experiments would be deemed to be too low. Hence, BfR feels there is a need for action to reduce the levels. BfR does not believe that there is an acute danger.

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Should mothers who have given their babies infant formula and follow-up formula be concerned?

In the assessment of a possible health risk from 3-MCPD fatty acid esters in infant formula and follow-up formula, a number of questions have still to be answered from the scientific angle. In particular it is not clear whether the hyperplastic effect of the substance on the renal tubules occurs at all in man. At the present time, it is not therefore possible to give a definitive answer to the question as to how high the risk is. Mothers should not be unduly concerned: A risk is not the same as a "hazard". The term "risk" merely describes the "probability" that damage will occur. BfR is of the opinion that this probability could increase. Hence, steps must be taken quickly to lower the levels of 3-MCPD fatty acid esters.

According to the current level of scientific knowledge, babies in particular may ingest levels of 3-MCPD esters from infant formula and follow-up formula for which, in the worst case scenario, the safety margin to the effects observed in animal experiments would be deemed to be too low. Hence, BfR feels there is a need for action to reduce the levels. BfR does not believe that there is an acute danger.

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Should mothers refrain from giving their babies infant formula and follow-up formula as a precautionary measure?

Mothers should continue feeding their infants as usual. For infants who are not breastfed there is no alternative to formula and follow-up formula. Mothers should not switch to cow, goat or horse milk either as they do not contain some of the essential nutrients that infants need. As the contamination of products with 3-MCPD fatty acid esters is not restricted to individual types or manufacturers, the problem must be solved rapidly from the technological angle.

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