The role of fat replacers in reducing cardiovascular disease

There is a general consensus that a high-fat diet is linked with the development of obesity, high serum cholesterol level, and cardiovascular disease. In addition, there is evidence that high fat intake may increase the incidence of breast, colon, and prostate cancers (National Cancer Institute 1984). The relationship between dietary fat and the development of cardiovascular disease has been well documented. Latta (1990) reported that reduction of fat consumption lowered the risk of heart disease by 10 per cent, and the risk of cardiovascular disease by 20 per cent in people who were overweight by losing their weight and altering their diet. Hooper et al. (2001) reported that the reduction of dietary fat resulted in the decrease in cardiovascular events by 24 per cent in participants after a period of 2 years. Recent research indicates that the amount and the type of fat in diet are also associated with the prevention of cardiovascular and coronary heart disease.

Diets rich in polyunsaturated or monounsaturated fatty acids tend to reduce the risk of cardiovascular and coronary heart disease. Conversely, diets rich in saturated fatty acids increase the risk of cardiovascular and coronary heart disease (Dyerberg et al. 1978; Grundy 1994). Therefore, restriction of fatty foods in diet is an effective way of reducing the risk of chronic diseases such as cardiovascular and coronary heart disease. Reducing fat and calories in the everyday diet has become a number one concern for most health-conscious individuals in the US.

Many health-related authorities including the US Dept. of Health and Human Services, US Surgeon General, American Heart Association, American Diabetes Association, American Dietetic Association, American Cancer Society and National Institutes of Health have recommended dietary energy from fat should be reduced to 30 per cent with saturated fat intake to less than 10 per cent. Fat intake has been generally decreased since the 1970s. A national food consumption survey showed that total fat intake has decreased from 36 per cent in 1978 to 34 per cent in 1990 (Carroll et al. 1983; Lenfant and Ernst 1994), but the proportion of energy obtained from fat is still higher than the recommended level (Frazao 1996). The main sources of dietary fat in the US are meat, poultry, fish, baked goods, fats and oils, and dairy products, which accounts for about 90 per cent of total fat intake (Mattes 1998). The decrease in energy and fat consumption may be due to the awareness of health issues and increased availability of low- and reduced-fat products. A national survey in 2000 (Calorie Control Council 2001) showed that 163 million adult Americans (79 per cent of the adult US population) consume low-fat or reduced-fat foods and beverages. The rapid increase in reduced and low-calorie food products has resulted in confusion about labeling standards. Therefore, food labels bearing information on a reduction in fat or calories are important to consumers and food manufacturers. The US nutrition labeling regulations provide claims for the use of reduced fat- and calorie-related terms as shown in Table above (US Food and Drug Administration 1999). Food manufacturers have developed a number of fat replacers and more than 5000 reduced-fat, nonfat or low-calorie food products have been introduced to the market (Wylie-Rosett 2002). Fat replacers have opened the door for a new age of reduced-fat or fat-free options in variety of foods.

There are some studies in the literature that show that fat replacers provide health benefits to the public, such as weight loss, reduction in cholesterol, and lower incidence of cardiovascular disease. Most of the health benefit studies of fat replacers have been concentrated on one fat replacer, olestra. Patterson et al. (2000) reported that subjects consuming olestra had significantly reduced total serum cholesterol levels compared with subjects without consuming olestra. Other studies have shown that olestra has potential to lower total and low-density lipoprotein (LDL) cholesterol levels in both normal and hyper­cholesterolemic individuals (Fallat et al. 1976; Glueck et al. 1979, 1983; Jandacek et al. 1990). Olestra also may be a promising tool for weight reduction.

Roy et al. (2002) reported that a significant weight loss was observed in men and women who replaced one third of dietary fat with olestra during the study period. One study involving obese patients with and without diabetes mellitus was conducted by Grundy et al. (1986). He reported that there was a decrease in total and LDL-cholesterol level in people without diabetes and a marked decrease in plasma triglycerides but no uniform change in LDL-cholesterol in people with diabetes when a low-calorie diet with or without olestra was supplied. Considering the report that the annual incidence of cardiovascular disease is increased more than two times in people with diabetes (American Diabetes Association 1996), consumption of foods containing olestra would be advantageous in reducing total and LDL-cholesterol.

Nutrient content claims, indicating reduced fat and calorie food*.Less than 0.5 g of fat/serving25% or less fat than a reference product/serving40 or fewer calories than regular product /serving25% or fewer calories than regular product/serv ing1/3 fewer calories or 50% of the fat in a reference foodA large number of fat replacers have been developed and are being used in partial or complete replacements for fat in foods. Each fat replacer has unique characteristics and uses. Some of fat replacers have been already approved by the Food and Drug Administration (FDA), while others are under review, and still others are in the developmental stage. Fat replacers represent a diverse chemical structure, functional and sensory properties and food applications.

The term fat replacer is a general term to encompass any ingredients used to replace fat. Generally, fat replacers are categorized into two groups ± fat mimetics and fat substitutes. Fat mimetics are substances that imitate organoleptic or physical properties of triacylglycerol (triglycerides, conventional fats, and oils) but that cannot replace fat on a 1:1 weight basis (Shand 1997; McClements and Demetriades 1998; Akoh 2002). Fat mimetics have different chemical structures from triacylglycerols and protein- or carbohydrate-based fat replacers belong to this category. The caloric value of fat mimetics ranges from 1 to 4 kcal/g. Fat mimetics entrap a substantial amount of water and denature or caramelize at high temperatures, so they are not suitable for frying. Fat mimetics carry water-soluble flavors but not lipid-soluble flavor compounds and are generally less flavorful than fat (Akoh 2002). Fat substitutes are ingredients that resemble triacyglycerols chemically and physically. They can replace fat on a 1:1 weight basis and contribute either fewer calories than fat or no calories. Lipid-based fat replacers belong to this category. They are stable to cooking and frying temperatures. The terms fat replacer and fat substitute have been differentiated (Miraglio 1995; Shand 1997; Akoh 2002), but they are used interchangeably to cause confusion and misunderstanding. An ideal fat replacer should be safe with a significant caloric and fat reduction while maintaining the functional and organoleptic properties of a conventional fat (Warshaw and Franz 1996). Since no single ingredient is an ideal fat replacer, several fat replacers are often used in combination as part of a functional blend in one food system. Therefore, the search for an ideal fat replacer continues.

Fat replacers represent a variety of chemical types with diverse physicochemical and sensory properties, so it is not easy to provide a simple classification. Fat replacers may be classified as carbohydrate-based, protein-based, or lipid-based replacers, depending on chemical composition of the ingredients (Hassel 1993; Warshaw and Franz 1996).