Acrylamide
Encyclopedia
Acrylamide is a chemical compound
with the chemical formula
C
3H
5N
O
. Its IUPAC name is prop-2-enamide. It is a white odourless crystalline solid, soluble in water, ethanol
, ether
, and chloroform
. Acrylamide is incompatible with acids, bases, oxidizing agents, iron, and iron salts. It decomposes non-thermally to form ammonia
, and thermal decomposition produces carbon monoxide
, carbon dioxide
, and oxides of nitrogen
.
Acrylamide is prepared on an industrial scale by the hydrolysis of acrylonitrile
by nitrile hydratase
.
Most acrylamide is used to synthesize polyacrylamide
s, which find many uses as water-soluble thickeners. These include use in wastewater
treatment, gel electrophoresis
(SDS-PAGE
), papermaking
, ore
processing, and the manufacture of permanent press
fabrics. Some acrylamide is used in the manufacture of dye
s and the manufacture of other monomers.
Acrylamide also occurs in many cooked starchy foods and is of concern as a possible carcinogen. Acrylamide was accidentally discovered in foods in April 2002 by scientists in Sweden when they found the chemical in starch
y foods, such as potato chip
s, French fries, and bread that had been heated (production of acrylamide in the heating process was shown to be temperature-dependent). It was not found in food that had been boiled or in foods that were not heated.
In February 2009, Health Canada announced that they were assessing whether acrylamide, which occurs naturally during the cooking of French fries, potato chips, and other processed foods, is a hazard to human health and whether any regulatory action needs to be taken. They are currently collecting information on the properties and prevalence of acrylamide in order to make their assessment. In December 2009, after a positive reception from the food industry, Health Canada invited comment from the public on this proposal.
The European Chemical Agency added acrylamide to the list of substances of very high concern
in March 2010.
to separate charged molecules. The technique is widely accepted today, and remains a common protocol
in molecular biology
labs.
Acrylamide has many other uses in molecular biology laboratories, including the use of linear polyacrylamide (LPA) as a carrier, which aids in the precipitation of small amounts of DNA
. Many laboratory supply companies sell LPA for this use.
. In fried
or baked
goods, acrylamide may be produced by the reaction between asparagine
and reducing sugar
s (fructose
, glucose
, etc.) or reactive carbonyl
s at temperatures above 120 °C (248 °F).
A study by the U.S. Food and Drug Administration (FDA) proposed a mechanism that involves asparagine
, which, when heated in the presence of glucose
, forms acrylamide.
Based on current stage of knowledge, acrylamide is a natural byproduct that forms when certain carbohydrate-rich foods are fried, baked, or roasted at temperatures above 120 °C. Acrylamide causes cancer in rats when administered orally in high-dose experiments, increasing tumors in the nervous system, oral cavity, peritoneum, thyroid gland, mammary gland, uterus, and clitoris. There is a margin of 900-fold between the dose that gave cancer to 10% of rats and human exposure to acrylamide in the diet.
range from twenty to forty percent; prune
juice has a high concentration of acrylamide, though adults consume it in far smaller quantities.
Browning
during baking
, frying
or deep-frying will produce acrylamide, and over-cooking foods may produce large amounts of acrylamide. The FDA has analyzed a variety of U.S. food products for levels of acrylamide since 2002. Results of the analysis can be found here.
content rises sharply, so that the acrylamide formation during baking or deep-frying will be higher.
es that produce less or no acrylamide are being bred. Using varieties that are low in sugar such as sweet potatoes and blanching the raw potato before frying or roasting removes some of the sugars, thereby rendering the acrylamide in the end-product. Experiments have also been conducted with oregano extract, which have resulted in a reduction of up to 49% of acrylamide in potatoes.
may lower the acrylamide formation.
When silicone
is used as a foam inhibitor in deep-frying fat
s in the food industry
, the acrylamide content is doubled.
, a naturally-occurring enzyme, can be added to bread or potato mixtures to reduce formation of acrylamide during cooking.
s. Direct exposure to pure acrylamide by inhalation, skin absorption, or eye contact irritates the exposed mucous membranes, e.g., the nose
, and can also cause sweating
, urinary incontinence
, nausea
, myalgia
, speech disorder
s, numbness, paresthesia
, and weakened legs and hands. In addition, the acrylamide monomer is a potent neurotoxin
, causing the disassembly or rearrangement of intermediate filament
s. Ingested acrylamide is metabolised to a chemically reactive epoxide
, glycidamide.
The second study sought to evaluate how much of the acrylamide humans eat is absorbed by the body. The study consisted of six young healthy volunteers consuming a meal containing 0.94 mg of acrylamide, and then providing urine for up to 72 hours thereafter. The study concluded that “most of the acrylamide ingested with food is absorbed in humans.”
Potatoes low in sugar
Best frying temperature
Golden, not brown!
reported on a study conducted between 1991–2000 in Italy and Switzerland that analyzed the risk of cancer of the oral cavity and pharynx, esophagus, larynx, large bowel, breast, and ovaries. It found “reassuring evidence for the lack of an important association between consumption of fried/baked potatoes and cancer risk.”
More recently, in January, 2008, one of the HEATOX members published a study, stating “So far, epidemiological studies have not shown any association between human cancer risk and dietary exposure to acrylamide. The purpose of this study was to conduct a nested case control study within a prospective cohort study on the association between breast cancer and exposure to acrylamide using biomarkers.” The study found that “[a]fter adjustment for smoking behavior... a positive association was seen between acrylamide-hemoglobin levels and estrogen receptor positive breast cancer... A weak association between glycidamide hemoglobin levels and incidence of estrogen receptor positive breast cancer was also found, this association, however, entirely disappeared when acrylamide and glycidamide hemoglobin levels were mutually adjusted.”
, included 43,404 Swedish women in the Women’s Lifestyle and Health Cohort. The women’s greatest single source of acrylamide was from coffee (54% of intake), fried potatoes (12% of intake), and crisp bread
(9% of intake). The study concluded that “Compared with the lowest quintile of acrylamide intake, there was no significantly increased risk of breast cancer in the higher quintiles and no evidence of a linear dose response. For quintile 5 compared with quintile 1, the relative risk was 1.19 (95% confidence interval, 0.91–1.55). Furthermore, there was no association between breast cancer risk and higher intake of any specific foods including coffee, fried potatoes, and crisp bread.”
(WHO) has set up a clearinghouse
for information about acrylamide that includes a database of researchers/data providers; references for research published elsewhere; information updates about the current status of research efforts; and updates on information relevant to the health risk of acrylamide in food.
One question the site’s FAQ addresses is whether there can be an acceptable level of acrylamide in food. The WHO states that “Acrylamide belongs to the group of chemicals thought to have no reliably identifiable ‘threshold’ of effects, meaning that very low concentrations will also result in very low risks, but not in zero risk: Some risk is always present when the chemical is ingested. However, for these carcinogens, risk is thought to increase with increasing exposure.
Very low risks (even of cancer), such as those that are less than one in one million, are considered to be acceptable to some consumers. To others this is unacceptable. The important pre-requisite for any decision is, however, a clear picture of the nature and level of the risk, as well as the potential for lowering this level. This clear picture does not exist for acrylamide at present.”
On February 18, 2009, the same journal Advance Access published a study by researchers at the Harvard School of Public Health and Brigham and Women’s Hospital in Boston, MA on the relationship between dietary acrylamide intake and premenopausal breast cancer. Similar to the Swedish study, the research revealed no association between dietary acrylamide intake and breast cancer risk. The study examined 90,628 premenopausal women.
Hence, a woman weighing 132 pounds (59.9 kg) could safely consume 30 mg of acrylamide daily without neuropathy; a man weighing 180 pounds (81.6 kg), about 41 mg; a child weighing 40 pounds (18.1 kg), 9 mg.
The WHO and FAO established that the safe limit of 0.5 mg/kg body weight/day pertains only to neuropathy. There has not been an established safe dietary limit of acrylamide as it pertains to causing cancer, since there is limited relative data.
Referring to the chart below for the amount of acrylamide in foods, in a single day, the child can eat 13 kg (28.7 lb) of French fried potatoes, the woman can drink 86 kg (~86 L, or 23 US gal) of prune juice, and the man can eat 29 kg (63.9 lb) of oven-baked potatoes, and each of them will have ingested less than 50 percent of the NOAEL of acrylamide.
(adapted from Table: Top Eight Foods by Acrylamide Per Portion, page 17)
announced that acrylamide can be found in baked and fried starchy food
s, such as potato chips, bread
s, and cookie
s. Concern was raised mainly because of the probable carcinogen
ic effects of acrylamide. This was followed by a strong but short-lived interest from the press. On 2005-08-26, California
attorney general
Bill Lockyer
filed a lawsuit against top makers of french fries
and potato chips to warn consumers of the potential risk from consuming acrylamide. The lawsuit was settled on 2008-08-01, with the food producers agreeing to cut acrylamide levels in half.
In 2007, more than 100 articles were written about acrylamide, according to Nexis and Factiva
, including pieces in the LA Times, the Boston Globe, the Guardian, and the Wall Street Journal, among others. Of these articles, nearly half appeared in November and December, when people were frying potatoes for latkes, and roasting pigs and turkeys.
On August 1, 2008, four food manufacturers - H.J. Heinz Co., Frito-Lay, Kettle Foods Inc., and Lance Inc. - agreed to reduce levels of acrylamide in their products (such as potato chips and French fries) over a three-year period and pay a combined $3 million in fines as a settlement with the California attorney general's office. California had sued these four companies in 2005, alleging they violated a state requirement that companies post warning labels on products with carcinogens.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with the chemical formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
C
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
3H
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
5N
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
O
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
. Its IUPAC name is prop-2-enamide. It is a white odourless crystalline solid, soluble in water, ethanol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
, ether
Diethyl ether
Diethyl ether, also known as ethyl ether, simply ether, or ethoxyethane, is an organic compound in the ether class with the formula . It is a colorless, highly volatile flammable liquid with a characteristic odor...
, and chloroform
Chloroform
Chloroform is an organic compound with formula CHCl3. It is one of the four chloromethanes. The colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered somewhat hazardous...
. Acrylamide is incompatible with acids, bases, oxidizing agents, iron, and iron salts. It decomposes non-thermally to form ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
, and thermal decomposition produces carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
, carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
, and oxides of nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
.
Acrylamide is prepared on an industrial scale by the hydrolysis of acrylonitrile
Acrylonitrile
Acrylonitrile is the chemical compound with the formula C3H3N. This pungent-smelling colorless liquid often appears yellow due to impurities. It is an important monomer for the manufacture of useful plastics. In terms of its molecular structure, it consists of a vinyl group linked to a nitrile...
by nitrile hydratase
Nitrile hydratase
In enzymology, nitrile hydratases are mononuclear iron or non-corrinoid cobalt enzymes that catalyse the hydration of diverse nitriles to their corresponding amidesR-C≡N + H2O → R-CNH2-Metal cofactor:...
.
Most acrylamide is used to synthesize polyacrylamide
Polyacrylamide
Polyacrylamide is a polymer formed from acrylamide subunits. It can be synthesized as a simple linear-chain structure or cross-linked, typically using N,N-methylenebisacrylamide. Polyacrylamide is not toxic...
s, which find many uses as water-soluble thickeners. These include use in wastewater
Wastewater
Wastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations...
treatment, gel electrophoresis
Gel electrophoresis
Gel electrophoresis is a method used in clinical chemistry to separate proteins by charge and or size and in biochemistry and molecular biology to separate a mixed population of DNA and RNA fragments by length, to estimate the size of DNA and RNA fragments or to separate proteins by charge...
(SDS-PAGE
SDS-PAGE
SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis, describes a collection of related techniques widely used in biochemistry, forensics, genetics and molecular biology to separate proteins according to their electrophoretic mobility...
), papermaking
Papermaking
Papermaking is the process of making paper, a substance which is used universally today for writing and packaging.In papermaking a dilute suspension of fibres in water is drained through a screen, so that a mat of randomly interwoven fibres is laid down. Water is removed from this mat of fibres by...
, ore
Ore
An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....
processing, and the manufacture of permanent press
Permanent press
A permanent press is a characteristic of fabric that has been chemically processed to resist wrinkles and hold its shape. Alternative terms include wrinkle resistant, wash and wear, no-iron,durable press, and easy care...
fabrics. Some acrylamide is used in the manufacture of dye
Dye
A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is generally applied in an aqueous solution, and requires a mordant to improve the fastness of the dye on the fiber....
s and the manufacture of other monomers.
Acrylamide also occurs in many cooked starchy foods and is of concern as a possible carcinogen. Acrylamide was accidentally discovered in foods in April 2002 by scientists in Sweden when they found the chemical in starch
Starch
Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...
y foods, such as potato chip
Potato chip
Potato chips are thin slices of potato that are deep fried...
s, French fries, and bread that had been heated (production of acrylamide in the heating process was shown to be temperature-dependent). It was not found in food that had been boiled or in foods that were not heated.
In February 2009, Health Canada announced that they were assessing whether acrylamide, which occurs naturally during the cooking of French fries, potato chips, and other processed foods, is a hazard to human health and whether any regulatory action needs to be taken. They are currently collecting information on the properties and prevalence of acrylamide in order to make their assessment. In December 2009, after a positive reception from the food industry, Health Canada invited comment from the public on this proposal.
The European Chemical Agency added acrylamide to the list of substances of very high concern
Substance of very high concern
A substance of very high concern is a chemical substance for which it has been proposed that the use within the European Union be subject to authorisation under the REACH Regulation...
in March 2010.
Laboratory use
Polyacrylamide was first used in a laboratory setting in the early 1950s. In 1959, the groups of Davis and Ornstein and of Raymond and Weintraub independently published on the use of polyacrylamide gel electrophoresisGel electrophoresis
Gel electrophoresis is a method used in clinical chemistry to separate proteins by charge and or size and in biochemistry and molecular biology to separate a mixed population of DNA and RNA fragments by length, to estimate the size of DNA and RNA fragments or to separate proteins by charge...
to separate charged molecules. The technique is widely accepted today, and remains a common protocol
Protocol (natural sciences)
In the natural sciences a protocol is a predefined written procedural method in the design and implementation of experiments. Protocols are written whenever it is desirable to standardize a laboratory method to ensure successful replication of results by others in the same laboratory or by other...
in molecular biology
Molecular biology
Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...
labs.
Acrylamide has many other uses in molecular biology laboratories, including the use of linear polyacrylamide (LPA) as a carrier, which aids in the precipitation of small amounts of DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
. Many laboratory supply companies sell LPA for this use.
Prepared foods
Acrylamide levels appear to rise as food is heated for longer periods of time. Though researchers are still unsure of the precise mechanisms by which acrylamide forms in foods, many believe it is a byproduct of the Maillard reactionMaillard reaction
The Maillard reaction is a form of nonenzymatic browning similar to caramelization. It results from a chemical reaction between an amino acid and a reducing sugar, usually requiring heat....
. In fried
Frying
Frying is the cooking of food in oil or another fat, a technique that originated in ancient Egypt around 2500 BC. Chemically, oils and fats are the same, differing only in melting point, but the distinction is only made when needed. In commerce, many fats are called oils by custom, e.g...
or baked
Baking
Baking is the technique of prolonged cooking of food by dry heat acting by convection, and not by radiation, normally in an oven, but also in hot ashes, or on hot stones. It is primarily used for the preparation of bread, cakes, pastries and pies, tarts, quiches, cookies and crackers. Such items...
goods, acrylamide may be produced by the reaction between asparagine
Asparagine
Asparagine is one of the 20 most common natural amino acids on Earth. It has carboxamide as the side-chain's functional group. It is not an essential amino acid...
and reducing sugar
Reducing sugar
A reducing sugar is any sugar that either has an aldehyde group or is capable of forming one in solution through isomerisation. This functional group allows the sugar to act as a reducing agent, for example in the Tollens' test or Benedict's test.-Chemistry:...
s (fructose
Fructose
Fructose, or fruit sugar, is a simple monosaccharide found in many plants. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbed directly into the bloodstream during digestion. Fructose was discovered by French chemist Augustin-Pierre Dubrunfaut in 1847...
, glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
, etc.) or reactive carbonyl
Carbonyl
In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups....
s at temperatures above 120 °C (248 °F).
A study by the U.S. Food and Drug Administration (FDA) proposed a mechanism that involves asparagine
Asparagine
Asparagine is one of the 20 most common natural amino acids on Earth. It has carboxamide as the side-chain's functional group. It is not an essential amino acid...
, which, when heated in the presence of glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
, forms acrylamide.
Based on current stage of knowledge, acrylamide is a natural byproduct that forms when certain carbohydrate-rich foods are fried, baked, or roasted at temperatures above 120 °C. Acrylamide causes cancer in rats when administered orally in high-dose experiments, increasing tumors in the nervous system, oral cavity, peritoneum, thyroid gland, mammary gland, uterus, and clitoris. There is a margin of 900-fold between the dose that gave cancer to 10% of rats and human exposure to acrylamide in the diet.
Uncooked foods
Acrylamide has been found in black olives, prunes, and dried pears.Herbicides
Acrylamide may be a natural decay product of the polyacrylamide used as a thickening agent in some commercial herbicides. Lab tests have shown that heat and light can decompose polyacrylamide into acrylamide.Beverages
Estimates for the proportion of acrylamide in adults’ diet coming from the consumption of coffeeCoffee
Coffee is a brewed beverage with a dark,init brooo acidic flavor prepared from the roasted seeds of the coffee plant, colloquially called coffee beans. The beans are found in coffee cherries, which grow on trees cultivated in over 70 countries, primarily in equatorial Latin America, Southeast Asia,...
range from twenty to forty percent; prune
Plum
A plum or gage is a stone fruit tree in the genus Prunus, subgenus Prunus. The subgenus is distinguished from other subgenera in the shoots having a terminal bud and solitary side buds , the flowers in groups of one to five together on short stems, and the fruit having a groove running down one...
juice has a high concentration of acrylamide, though adults consume it in far smaller quantities.
Cooking methods that affect acrylamide production
Acrylamide cannot be created by boiling, and very few uncooked foods contain any detectable amounts.Browning
Maillard reaction
The Maillard reaction is a form of nonenzymatic browning similar to caramelization. It results from a chemical reaction between an amino acid and a reducing sugar, usually requiring heat....
during baking
Baking
Baking is the technique of prolonged cooking of food by dry heat acting by convection, and not by radiation, normally in an oven, but also in hot ashes, or on hot stones. It is primarily used for the preparation of bread, cakes, pastries and pies, tarts, quiches, cookies and crackers. Such items...
, frying
Frying
Frying is the cooking of food in oil or another fat, a technique that originated in ancient Egypt around 2500 BC. Chemically, oils and fats are the same, differing only in melting point, but the distinction is only made when needed. In commerce, many fats are called oils by custom, e.g...
or deep-frying will produce acrylamide, and over-cooking foods may produce large amounts of acrylamide. The FDA has analyzed a variety of U.S. food products for levels of acrylamide since 2002. Results of the analysis can be found here.
Reduction of acrylamide formation
The Confederation of the Food and Drink Industries in the EU (CIAA) has published a number of brochures to help people reduce the amount of acrylamide formed in their food. They offer a general acrylamide "toolbox" as well as publications specific to reducing the acrylamide in biscuits, crackers & crispbreads, bread products, breakfast cereals potato crisps (chips), and French fries.Storage
In the case of potatoes, for instance, the storage temperature should not drop below 8 °C (46.4 °F). When the temperature is as low as 4 °C (39.2 °F) the reducing sugarReducing sugar
A reducing sugar is any sugar that either has an aldehyde group or is capable of forming one in solution through isomerisation. This functional group allows the sugar to act as a reducing agent, for example in the Tollens' test or Benedict's test.-Chemistry:...
content rises sharply, so that the acrylamide formation during baking or deep-frying will be higher.
Raw material
New varieties of potatoPotato
The potato is a starchy, tuberous crop from the perennial Solanum tuberosum of the Solanaceae family . The word potato may refer to the plant itself as well as the edible tuber. In the region of the Andes, there are some other closely related cultivated potato species...
es that produce less or no acrylamide are being bred. Using varieties that are low in sugar such as sweet potatoes and blanching the raw potato before frying or roasting removes some of the sugars, thereby rendering the acrylamide in the end-product. Experiments have also been conducted with oregano extract, which have resulted in a reduction of up to 49% of acrylamide in potatoes.
Production methods
In many cases, it is advisable to lower the maximum temperature during baking. Also, new production methods such as vacuum fryingVacuum fryer
A vacuum fryer is a deep-frying device housed inside a vacuum chamber. It was originally developed for potato chip production.Vacuum fryers are fit to process low-quality potatoes that contain higher sugar levels than normal, as they frequently have to be processed in spring and early summer before...
may lower the acrylamide formation.
When silicone
Silicone
Silicones are inert, synthetic compounds with a variety of forms and uses. Typically heat-resistant and rubber-like, they are used in sealants, adhesives, lubricants, medical applications , cookware, and insulation....
is used as a foam inhibitor in deep-frying fat
Fat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...
s in the food industry
Food industry
The food production is a complex, global collective of diverse businesses that together supply much of the food energy consumed by the world population...
, the acrylamide content is doubled.
Recipe formulation
AsparaginaseAsparaginase
Asparaginase is an enzyme that catalyzes the hydrolysis of asparagine to aspartic acid. Asparaginases are naturally occurring enzymes expressed and produced by microorganisms. Different types of asparaginases can be used for different industrial and pharmaceutical purposes. The most common use of...
, a naturally-occurring enzyme, can be added to bread or potato mixtures to reduce formation of acrylamide during cooking.
Cations
Gökmen and Şenyuva (2007) showed that by dipping French fries into calcium chloride, they were able to reduce acrylamide formation by up to 95%. They reported that the treatment did not affect final product quality either. In similar manner, sodium ions were able to reduce acrylamide formation by as much as 50% in a model asparagine and fructose system.Inhaled, absorbed or ingested acrylamide
There is evidence to suggest that exposure to large doses can cause damage to the male reproductive glandGland
A gland is an organ in an animal's body that synthesizes a substance for release of substances such as hormones or breast milk, often into the bloodstream or into cavities inside the body or its outer surface .- Types :...
s. Direct exposure to pure acrylamide by inhalation, skin absorption, or eye contact irritates the exposed mucous membranes, e.g., the nose
Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...
, and can also cause sweating
Sweating
Perspiration is the production of a fluid consisting primarily of water as well as various dissolved solids , that is excreted by the sweat glands in the skin of mammals...
, urinary incontinence
Urinary incontinence
Urinary incontinence is any involuntary leakage of urine. It is a common and distressing problem, which may have a profound impact on quality of life. Urinary incontinence almost always results from an underlying treatable medical condition but is under-reported to medical practitioners...
, nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...
, myalgia
Myalgia
Myalgia means "muscle pain" and is a symptom of many diseases and disorders. The most common causes are the overuse or over-stretching of a muscle or group of muscles. Myalgia without a traumatic history is often due to viral infections...
, speech disorder
Speech disorder
Speech disorders or speech impediments are a type of communication disorders where 'normal' speech is disrupted. This can mean stuttering, lisps, etc. Someone who is unable to speak due to a speech disorder is considered mute.-Classification:...
s, numbness, paresthesia
Paresthesia
Paresthesia , spelled "paraesthesia" in British English, is a sensation of tingling, burning, pricking, or numbness of a person's skin with no apparent long-term physical effect. It is more generally known as the feeling of "pins and needles" or of a limb "falling asleep"...
, and weakened legs and hands. In addition, the acrylamide monomer is a potent neurotoxin
Neurotoxin
A neurotoxin is a toxin that acts specifically on nerve cells , usually by interacting with membrane proteins such as ion channels. Some sources are more general, and define the effect of neurotoxins as occurring at nerve tissue...
, causing the disassembly or rearrangement of intermediate filament
Intermediate filament
Intermediate filaments are a family of related proteins that share common structural and sequence features. Intermediate filaments have an average diameter of 10 nanometers, which is between that of 7 nm actin , and that of 25 nm microtubules, although they were initially designated...
s. Ingested acrylamide is metabolised to a chemically reactive epoxide
Epoxide
An epoxide is a cyclic ether with three ring atoms. This ring approximately defines an equilateral triangle, which makes it highly strained. The strained ring makes epoxides more reactive than other ethers. Simple epoxides are named from the parent compound ethylene oxide or oxirane, such as in...
, glycidamide.
British Journal of Cancer
One study reanalysed a population-based Swedish case-control study encompassing cases with cancer of the large bowel, bladder, and kidney, and 538 healthy controls. Researchers assessed the impact of dietary acrylamide “by linking extensive food frequency data with acrylamide levels in certain food items recorded by the Swedish National Food Administration. Unconditional logistic regression was used to estimate odds ratios, adjusting for potential confounders.” They “found consistently a lack of an excess risk, or any convincing trend, of cancer of the bowel, bladder, or kidney in high consumers of 14 different food items with a high (range 300–1200 µg/kg) or moderate (range 30–299 µg/kg) acrylamide content.” Also, “Unexpectedly, an inverse trend was found for large bowel cancer (P for trend 0.01) with a 40% reduced risk in the highest compared to lowest quartile.” The article concludes “We found reassuring evidence that dietary exposure to acrylamide in amounts typically ingested by Swedish adults in certain foods has no measurable impact on risk of three major types of cancer. It should be noted, however, that relation of risk to the acrylamide content of all foods could not be studied.”Cancer, epidemiology, biomarkers, and prevention
A number of studies pertaining to acrylamide have appeared in various issues of Cancer, Epidemiology, Biomarkers & Prevention. The first study included 62,573 women, aged 55–69 years. The acrylamide intake of subcohort members and cases was assessed with a food frequency questionnaire and was based on chemical analysis of all relevant Dutch foods. Subgroup analyses were done for never-smokers to eliminate the influence of smoking, an important source of acrylamide. After 11.3 years of follow-up, the researchers observed 327, 300, and 1,835 cases of endometrial, ovarian, and breast cancer, respectively. They concluded that their subjects faced “increased risks of postmenopausal endometrial and ovarian cancer with increasing dietary acrylamide intake, in particular, among never-smokers. Risk of breast cancer was not associated with acrylamide intake.”The second study sought to evaluate how much of the acrylamide humans eat is absorbed by the body. The study consisted of six young healthy volunteers consuming a meal containing 0.94 mg of acrylamide, and then providing urine for up to 72 hours thereafter. The study concluded that “most of the acrylamide ingested with food is absorbed in humans.”
Heat-generated food toxicants (HEATOX)
The Heat-generated Food Toxicants (HEATOX) Project was a “multidisciplinary research project involving 24 partners in 14 countries.” It ran from late 2003 to early 2007. Its objectives were to “estimate health risks that may be associated with hazardous compounds in heat-treated food [, and] find cooking/processing methods that minimise the amounts of these compounds, thereby providing safe, nutritious, and high-quality food-stuffs.” It found that "the evidence of acrylamide posing a cancer risk for humans has been strengthened," and that "compared with many regulated food carcinogens, the exposure to acrylamide poses a higher estimated risk to European consumers." HEATOX sought also to provide consumers with advice on how to lower their intake of acrylamide, specifically pointing out that home-cooked food tends to contribute far less to overall acrylamide levels than food that was industrially prepared, and that avoiding overcooking is one of the best ways to minimize exposure at home. The report also recommended that national authorities highlight the following:Potatoes low in sugar
- Low-sugar potato varieties
- Maintenance of suitable storage temperature during the supply chain
- Low sugar levels in prefabricated potato products for domestic frying.
Best frying temperature
- Frying temperature in the range 145 to 170 °C (293 to 338 F) for deep-frying potatoes
- Clear and accurate cooking instruction on the package of pre-fried products
- Clear and accurate instruction for fryers for domestic use.
Golden, not brown!
- French fries and roasted potatoes cooked to a golden-yellow rather than golden-brown colour
- Bread toasted to the lightest colour acceptable.
International Journal of Cancer
In March, 2003, the International Journal of CancerInternational Journal of Cancer
International Journal of Cancer publishes articles about experimental and clinical cancer research. It publishes original research articles, mini reviews, short reports, and letters to the editor. The journal appears 24 times a year.-External links:* *...
reported on a study conducted between 1991–2000 in Italy and Switzerland that analyzed the risk of cancer of the oral cavity and pharynx, esophagus, larynx, large bowel, breast, and ovaries. It found “reassuring evidence for the lack of an important association between consumption of fried/baked potatoes and cancer risk.”
More recently, in January, 2008, one of the HEATOX members published a study, stating “So far, epidemiological studies have not shown any association between human cancer risk and dietary exposure to acrylamide. The purpose of this study was to conduct a nested case control study within a prospective cohort study on the association between breast cancer and exposure to acrylamide using biomarkers.” The study found that “[a]fter adjustment for smoking behavior... a positive association was seen between acrylamide-hemoglobin levels and estrogen receptor positive breast cancer... A weak association between glycidamide hemoglobin levels and incidence of estrogen receptor positive breast cancer was also found, this association, however, entirely disappeared when acrylamide and glycidamide hemoglobin levels were mutually adjusted.”
Journal of the American Medical Association
A 2005 study, published in JAMAJournal of the American Medical Association
The Journal of the American Medical Association is a weekly, peer-reviewed, medical journal, published by the American Medical Association. Beginning in July 2011, the editor in chief will be Howard C. Bauchner, vice chairman of pediatrics at Boston University’s School of Medicine, replacing ...
, included 43,404 Swedish women in the Women’s Lifestyle and Health Cohort. The women’s greatest single source of acrylamide was from coffee (54% of intake), fried potatoes (12% of intake), and crisp bread
Crisp bread
Crisp bread or hard bread is a flat and dry type of bread or cracker, containing mostly rye flour...
(9% of intake). The study concluded that “Compared with the lowest quintile of acrylamide intake, there was no significantly increased risk of breast cancer in the higher quintiles and no evidence of a linear dose response. For quintile 5 compared with quintile 1, the relative risk was 1.19 (95% confidence interval, 0.91–1.55). Furthermore, there was no association between breast cancer risk and higher intake of any specific foods including coffee, fried potatoes, and crisp bread.”
World Health Organization
The World Health OrganizationWorld Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
(WHO) has set up a clearinghouse
Clearinghouse (GIS)
A clearinghouse in GIS is a repository structure, physical or virtual, that collects, stores, and disseminates information, metadata, and data. A clearinghouse provides widespread access to information and is generally thought of as reaching or existing outside organizational boundaries....
for information about acrylamide that includes a database of researchers/data providers; references for research published elsewhere; information updates about the current status of research efforts; and updates on information relevant to the health risk of acrylamide in food.
One question the site’s FAQ addresses is whether there can be an acceptable level of acrylamide in food. The WHO states that “Acrylamide belongs to the group of chemicals thought to have no reliably identifiable ‘threshold’ of effects, meaning that very low concentrations will also result in very low risks, but not in zero risk: Some risk is always present when the chemical is ingested. However, for these carcinogens, risk is thought to increase with increasing exposure.
Very low risks (even of cancer), such as those that are less than one in one million, are considered to be acceptable to some consumers. To others this is unacceptable. The important pre-requisite for any decision is, however, a clear picture of the nature and level of the risk, as well as the potential for lowering this level. This clear picture does not exist for acrylamide at present.”
American Journal of Epidemiology
The December 1, 2009, issue of the American Journal of Epidemiology included a study conducted at the Karolinska Institute in Stockholm concerning the relationship between dietary intake of acrylamide and breast cancer. Researchers found no statistically significant association between long-term dietary acrylamide intake and breast cancer. The study examined 61,433 Swedish women who were cancerfree and completed a food frequency questionnaire in 1987–1990 and again in 1997.On February 18, 2009, the same journal Advance Access published a study by researchers at the Harvard School of Public Health and Brigham and Women’s Hospital in Boston, MA on the relationship between dietary acrylamide intake and premenopausal breast cancer. Similar to the Swedish study, the research revealed no association between dietary acrylamide intake and breast cancer risk. The study examined 90,628 premenopausal women.
European Journal of Cancer
The March 2009 issue of the European Journal of Cancer published a study examining the relationship between dietary intake of acrylamide and colorectal cancer. Conducted by Swedish researchers at the Karolinska Institute, this study of 45,306 men found no evidence of a link between dietary intake of acrylamide and risk for colorectal cancer.Safe levels of acrylamide in relation to neuropathy
In June 2002, the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) issued a report about the health implications of acrylamide in food. After study, the Consultation concluded that the "no observed adverse effect level" (NOAEL) for acrylamide neuropathy is 0.5 mg/kg body weight/day and the NOAEL for fertility changes is four times higher than for peripheral neuropathy. The study continued, “On the basis of current knowledge, controlling for peripheral neuropathy is expected to control for effects on fertility. The estimated average chronic human dietary intake is in the order of 1 μg/kg body weight/day. This provides a margin between exposure and the NOAEL of 500.”Hence, a woman weighing 132 pounds (59.9 kg) could safely consume 30 mg of acrylamide daily without neuropathy; a man weighing 180 pounds (81.6 kg), about 41 mg; a child weighing 40 pounds (18.1 kg), 9 mg.
The WHO and FAO established that the safe limit of 0.5 mg/kg body weight/day pertains only to neuropathy. There has not been an established safe dietary limit of acrylamide as it pertains to causing cancer, since there is limited relative data.
Referring to the chart below for the amount of acrylamide in foods, in a single day, the child can eat 13 kg (28.7 lb) of French fried potatoes, the woman can drink 86 kg (~86 L, or 23 US gal) of prune juice, and the man can eat 29 kg (63.9 lb) of oven-baked potatoes, and each of them will have ingested less than 50 percent of the NOAEL of acrylamide.
| Food | AA concentration (μg/kg) |
Portion size (g) |
AA per portion (µg) |
|---|---|---|---|
| French fries (OB) | 698 | 70 | 48.8 |
| Prune juice | 174 | 140 | 24.4 |
| French fries (RF) | 334 | 70 | 23.3 |
| Postum | 93 | 240 | 22.3 |
| Potato chips | 546 | 30 | 16.4 |
| Canned black olives | 550 | 15 | 8.2 |
| Breakfast cereal | 131 | 55 | 7.3 |
| Brewed coffee | 8.5 | 240 | 3.2 |
(adapted from Table: Top Eight Foods by Acrylamide Per Portion, page 17)
Public awareness
On April 24, 2002, the Swedish National Food AdministrationSwedish National Food Administration
The National Food Administration is a Swedish government agency that answers to the Ministry of Agriculture, Food and Consumer Affairs. The agency is located in Uppsala.It is the central supervisory authority for matters relating to food and drinking water...
announced that acrylamide can be found in baked and fried starchy food
Food
Food is any substance consumed to provide nutritional support for the body. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals...
s, such as potato chips, bread
Bread
Bread is a staple food prepared by cooking a dough of flour and water and often additional ingredients. Doughs are usually baked, but in some cuisines breads are steamed , fried , or baked on an unoiled frying pan . It may be leavened or unleavened...
s, and cookie
Cookie
In the United States and Canada, a cookie is a small, flat, baked treat, usually containing fat, flour, eggs and sugar. In most English-speaking countries outside North America, the most common word for this is biscuit; in many regions both terms are used, while in others the two words have...
s. Concern was raised mainly because of the probable carcinogen
Carcinogen
A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...
ic effects of acrylamide. This was followed by a strong but short-lived interest from the press. On 2005-08-26, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
attorney general
Attorney General
In most common law jurisdictions, the attorney general, or attorney-general, is the main legal advisor to the government, and in some jurisdictions he or she may also have executive responsibility for law enforcement or responsibility for public prosecutions.The term is used to refer to any person...
Bill Lockyer
Bill Lockyer
William Westwood "Bill" Lockyer is an American politician. He is the current 32nd State Treasurer of California, elected in 2006 and re-elected in 2010. He has also served as California Attorney General and President Pro Tempore of the California State Senate...
filed a lawsuit against top makers of french fries
French fries
French fries , chips, fries, or French-fried potatoes are strips of deep-fried potato. North Americans tend to refer to any pieces of deep-fried potatoes as fries or French fries, while in the United Kingdom, Australia, Ireland and New Zealand, long, thinly cut slices of deep-fried potatoes are...
and potato chips to warn consumers of the potential risk from consuming acrylamide. The lawsuit was settled on 2008-08-01, with the food producers agreeing to cut acrylamide levels in half.
In 2007, more than 100 articles were written about acrylamide, according to Nexis and Factiva
Factiva
Factiva is a business information and research tool owned by Dow Jones & Company. Factiva aggregates content from both licensed and free sources, and provides organizations with search, alerting, dissemination, and other information management capabilities...
, including pieces in the LA Times, the Boston Globe, the Guardian, and the Wall Street Journal, among others. Of these articles, nearly half appeared in November and December, when people were frying potatoes for latkes, and roasting pigs and turkeys.
On August 1, 2008, four food manufacturers - H.J. Heinz Co., Frito-Lay, Kettle Foods Inc., and Lance Inc. - agreed to reduce levels of acrylamide in their products (such as potato chips and French fries) over a three-year period and pay a combined $3 million in fines as a settlement with the California attorney general's office. California had sued these four companies in 2005, alleging they violated a state requirement that companies post warning labels on products with carcinogens.
See also
- AcryditeAcryditeAcrydite is a phosphoramidite that allows the synthesis of oligonucleotides with a methacryl group at the 5' end . Acryl oligonucleotides have been tested, but the acryl group is not stable to storage...
: research on this compound casts light on acrylamide - Deep-frying
- Deep fryer
- Vacuum fryerVacuum fryerA vacuum fryer is a deep-frying device housed inside a vacuum chamber. It was originally developed for potato chip production.Vacuum fryers are fit to process low-quality potatoes that contain higher sugar levels than normal, as they frequently have to be processed in spring and early summer before...
- Substance of very high concernSubstance of very high concernA substance of very high concern is a chemical substance for which it has been proposed that the use within the European Union be subject to authorisation under the REACH Regulation...
External links
- Acrylamide Infonet
- Acrylamide Facts
- California Wants to Serve a Warning With Fries
- Center for Food Safety and Nutrition (cfsan.fda.gov) FAQ
- Court case about a suspected acrylamide poisoning
- Environmental Protection Agency Acrylamide and Food
- EPA releases a Toxicological Review of Acrylamide (External Review Draft) for public comment - 01/2008
- Girls who eat chips more likely to get breast cancer
- Harvard School of Public Health press release; baked and fried food does not increase risk of certain cancers in humans
- Harvard School of Public Health press release; no breast cancer risks from acrylamide via food
- IARCInternational Agency for Research on CancerThe International Agency for Research on Cancer is an intergovernmental agency forming part of the World Health Organisation of the United Nations....
Monograph "Acrylamide." - Information about Acrylamide from www.foodrisk.org
- National Pollutant Inventory - Acrylamide
- Prospective study of dietary acrylamide and risk of colorectal cancer among women
- Report about acrylamide in food and cancer risks
- World Health Organization