Chemistry, Biochemistry, and Safety of Acrylamide. A Review

Abstract

Acrylamide (CH2=CH-CONH2), an industrially produced alpha,beta-unsaturated (conjugated) reactive molecule, is used worldwide to synthesize polyacrylamide. Polyacrylamide has found numerous applications as a soil conditioner, in wastewater treatment, in the cosmetic, paper, and textile industries, and in the laboratory as a solid support for the separation of proteins by electrophoresis. Because of the potential of exposure to acrylamide, effects of acrylamide in cells, tissues, animals, and humans have been extensively studied. Reports that acrylamide is present in foods formed during their processing under conditions that also induce the formation of Maillard browning products heightened interest in the chemistry, biochemistry, and safety of this vinyl compound. Because exposure of humans to acrylamide can come from both external sources and the diet, a need exists to develop a better understanding of its formation and distribution in food and its role in human health. To contribute to this effort, this integrated review presents data on the chemistry, analysis, metabolism, pharmacology, and toxicology of acrylamide. Specifically covered are the following aspects: nonfood and food sources; exposure from the environment and the diet; mechanism of formation in food from asparagine and glucose; asparagine-asparaginase relationships; Maillard browning-acrylamide relationships; quenching of protein fluorescence; biological alkylation of amino acids, peptides, proteins, and DNA by acrylamide and its epoxide metabolite glycidamide; risk assessment; neurotoxicity, reproductive toxicity, and carcinogenicity; protection against adverse effects; and possible approaches to reducing levels in food. Further research needs in each of these areas are suggested. Neurotoxicity appears to be the only documented effect of acrylamide in human epidemiological studies; reproductive toxicity, genotoxicity/clastogenicity, and carcinogenicity are potential human health risks on the basis of only animal studies. A better understanding of the chemistry and biology of pure acrylamide in general and its impact in a food matrix in particular can lead to the development of improved food processes to decrease the acrylamide content of the diet.

Prospective study of dietary acrylamide and risk of colorectal cancer among women

“…There exists variation in acrylamide levels within and between foods, 6 which could lead to nondifferential misclassification of exposure. While it appears that we can appropriately rank individuals with respect to acrylamide intake, 14 we cannot rule out this bias, which would in general bias estimates to the null.…”

“…17 Adding to the complexity, the mode of exposure between animals and humans differs, and we currently do not know about the bioavailability of acrylamide in foods. While evidence from animal 11,19 and risk assessment models 6,28 suggests a small increase in risk in humans, risk assessment models have generally assumed a linear dose-response relation at low levels of exposure, 29 but this is not known for certain. The level of uncertainty in these models is indeed substantial, being an 8-to 9-fold difference in potential risk due to a range from a relative risk of Incidence rate per 100,000 person-years.-2 Data adjusted for age at screening.-3 Data adjusted for age at screening, body mass index, education, alcohol intake, energy intake, saturated fat intake and fiber intake.- 4 Reference category.…”

“…Since that time, elevated levels of acrylamide have been confirmed in several foods including cereals, crisp and soft breads, fried and baked potato products, chocolate and coffee. [5][6][7] Acrylamide formation occurs as a result of a chemical reaction, a Maillard process, between sugars and specific amino acids (e.g., asparagine) within foods upon exposure to high heat. 8,9 In this way, acrylamide occurs as a natural product of cooking, rather than as a food contaminant.…”

Fontes vegetais naturais de antioxidantes

“…100 Nestes estudos, é frequente a estimativa de produtos de Maillard, 101 que são decorrentes da reação de Schiff e posterior isomerização -portanto, não enzimática -entre açúcares redutores (aldoses) e resíduos de aminoácidos básicos (lisina, arginina) de proteínas em alimentos, após processo de aquecimento em altas temperaturas. 102 Estes produtos de condensação entre aldeídos derivados de produtos de oxidação avançada de lipídios, açúcares e bases de DNA têm sido utilizados como marcadores de doenças e envelhecimento. [103][104][105] São denominados, respectivamente, de AGES (Advanced Glycation End-products) e ALES (Advanced Lipoperoxidation Products).…”

Differences in hemoglobin adduct levels of acrylamide in the general population with respect to dietary intake, smoking habits and gender

“…Both compounds are reactive towards biomacromolecules [6], however, AA being much less reactive than GA towards DNA [7][8][9]. This fact, together with the genotoxicity of GA, has led to the assumption that GA is the genotoxic agent and probably also the cancer-risk increasing factor in AA exposure (e.g.…”