Protein fructosylation: fructose and the Maillard reaction

Abstract

Fructose, as is the case for other reducing sugars, undergoes the Maillard reaction with proteins and amino acids. The first stage of the reaction results in one or more substituted amino sugars. These products in turn enter the advanced and final stages of the Maillard reaction, which involve the formation of reactive intermediates, cross-linking of proteins, and the formation of brown and fluorescent polymeric materials. It would appear that the initial stages of the reaction occur more rapidly with fructose than with glucose. The Maillard reaction with any sugar, including fructose, results in a decrease in protein quality due to the loss of amino acid residues and decreased protein digestibility. Maillard products can inhibit the uptake and metabolism of free amino acids and of other nutrients such as zinc and some advanced Maillard products have mutagenic and/or anticarcinogenic properties. In vivo the Maillard reactions between proteins and fructose, glucose, and other reducing sugars may play a role in aging and in some of the clinical complications of diabetes.

Fructose Malabsorption is Associated with Decreased Plasma Tryptophan

“…This chemical interaction according to the so-called Maillard reaction (26) could provide an explanation for the possible association between fructose malabsorption and disturbed tryptophan metabolism. Maillard products can also inhibit the uptake and metabolism of other free amino acids such as Ltryptophan and of other nutrients such as zinc (26).…”

Recommendations for the nutritional management of patients with diabetes mellitus

“…There may be gastrointestinal disturbance with large doses (Dills, 1993) and concerns about the possible role of dietary fructose on cataractogenesis and neuropathy exist (Grigoresco et al, 1988). On the available data however, there is no concern about diabetic people consuming foods that contain fructose naturally, for example, fruits (Woraich et al, 1994), but fructose does not offer proven advantages over sucrose as a sweetener.…”

A new look at dietary carbohydrate: chemistry, physiology and health

“…This is clearly important for diabetes and has led to major changes in dietary recommendations for diabetics. The importance of maintaining lower blood glucose pro®les in healthy humans has been questioned, but recent studies suggest that this is a signi®cant determinant of protein glycosylation (Brownlee et al, 1988;Dills, 1993;McDonald, 1995). Because of the physical nature of starch it has been assumed that it is hydrolysed and absorbed more slowly than sugars.…”

“…Because of the physical structure of the cell wall carbohydrates they affect satiety (Blundell et al, 1994;Haber et al, 1977) and the rate and extent of starch digestion, which is a major factor controlling blood glucose and insulin (Crapo et al, 1976;Hermansen, 1994;Jenkins et al, 1981;Wolever & Miller, 1995). The concentrations of glucose and fructose in blood are also important in determining protein glycosylation and possibly the process of ageing (Brownlee et al, 1988;Dills, 1993;McDonald, 1995). Some starches affect large bowl function (Cummings et al, 1996;Munster et al, 1994;Phillips et al, 1995) and the concept of resistant starch (RS) has been developed (Englyst et al, 1992).…”