Saarela Functional Dairy Products

1. Auflage 2007
ISBN: 978-1-84569-310-7
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Englisch, 560 Seiten

Reihe: Woodhead Publishing Series in Food Science, Technology and Nutrition

Dairy products have a prominent position in the development of functional foods. As understanding of the health benefits of dairy products increases and consumer awareness of these health benefits grows, demand for new and improved functional dairy products is likely to rise. Functional dairy products: Volume 2 reviews the latest developments in the field and their industrial applications.Part one outlines the health benefits of functional dairy products and their applications in areas such as weight management, child health and gut health. The second part of the book discusses various ingredients used in functional dairy products such as pro- and prebiotics, hypoallergenic hydrolysates and plant sterols and stanols. The final part of the book considers aspects of product development such as biomarkers and experimental models to investigate health benefits, genomics of probiotic microorganisms and functional dairy product regulation and safety.With its distinguished editor and collection of international authors, Functional dairy products: Volume 2, together with its companion volume, provides professionals and researchers within the field with an invaluable reference. - Outlines the health benefits of functional dairy products, and their applications in areas such as weight management and gut health - Discusses ingredients used in functional dairy products such as pro- and prebiotics - Considers various aspects of product development

Autoren/Hrsg.

Saarela, Maria

Leseproben

1 Dairy components in weight management: a broad perspective
L.S. Ward; E.D. Bastian    Glanbia Research Center, USA 1.1 Introduction
Milk as a nutritional food has recently been the topic of research and discussion related to weight management. In fact, consumption of dairy products has been linked to several health benefits that are the direct antitheses of diseases and complications that arise from overweight and obesity. For example, individuals that consume low-fat dairy products are more likely to have lower weight (Zemel, 2004), lower blood pressure (Moore et al., 2005, Vollmer et al., 2001), and decreased risk of stroke (Abbott et al., 1996), colon cancer (Kampman et al., 2000, Holt, 1999) and osteoporosis (McCabe et al., 2004, Savaiano, 2003). This review is an attempt to put into perspective the advances that have been made connecting milk components to weight management and to show some of our own data that support the concept that milk-derived components can positively impact weight management. For more information about the regulation of food intake and the effects of dairy products on satiety see Chapter 2. 1.2 Components from skimmed milk and weight loss
1.2.1 Calcium and weight loss
It may not seem obvious to discuss blood pressure in relation to weight management, but the link between dairy components and weight management was initially derived from blood pressure studies. Zemel (2002) reported a 4.9 kg reduction in body fat in an African American population that had elevated blood pressure and were being ‘treated’ with dairy products to reduce blood pressure. When the dairy connection to weight management was proposed, Heaney et al. (2002) re-examined calcium-related blood pressure and bone studies and reported a strong relationship between dairy consumption and weight reduction. Two mechanisms have been proposed to explain calcium’s impact on weight and fat loss in the body: (1) reduced absorption of fatty acids and (2) metabolic shifts in adipocytes that reduce lipogenesis and increase lipolysis. Dietary calcium and magnesium have a modest impact on overall energy balance through inhibition of fatty acid absorption via formation of calcium and magnesium soaps (Vaskonen, 2003). A randomized crossover study (Jacobsen et al., 2005) evaluated the short-term effect of dietary calcium on fat absorption. A total of 10 subjects consumed a low calcium and normal protein diet, a high calcium normal protein diet or a high calcium and high protein diet. The high calcium normal protein showed a 2.5-fold increase in fecal fat excretion compared to the other two diets. Another study (Shahkhalili et al., 2001) compared the absorption of cocoa butter with calcium (900 mg/ day) or without calcium in a chocolate supplement. In this randomized, double blind, crossover study 10 men were fed control diets with or without the calcium supplemented chocolate. The results of the study showed a 2fold increase in fecal fat excretion and a 9% decrease in absorbable energy. These two studies (Jacobsen et al., 2005, Shahkhalili et al., 2001) both obtained similar fecal fat values (8.4 g/day and 8.2 g/day) with an increase of calcium per day of 900 mg/day and 1261 mg/day respectively. Decreasing fat absorption results in less available energy to the body. In theory, obese individuals with a stable weight and low calcium consumption could lose 3.5 kg/y by increasing calcium consumption provided they have a consistent weight to begin with and maintain the same energy intake (Jacobsen et al., 2005). The second proposed mechanism by which calcium enhances fat loss is an indirect influence on fat lipolyis or lipogenesis through calcitrophic hormone regulation. Calcitrophic hormones respond to dietary levels of calcium. Particularly, 1, 25 dihydroxy-vitamin D is up-regulated when dietary calcium is low and down-regulated when dietary calcium is high. Increased levels of dihydroxy-vitamin D, in response to low calcium intake, cause calcium to be channeled into adipocytes. Conversely, when dietary calcium is high, calcium levels in adipocytes decline. Intracellular adipoctye calcium levels have a regulatory role on lipogenesis and lipolysis. When intracellular calcium levels increase, lipogenesis is up-regulated and lipolysis is down-regulated. When intracellular calcium levels are low, the situation is reversed. Thus, low dietary calcium intake results in high intracellular calcium, lipogenesis and reduced lipolysis; but high dietary calcium decreases lipogenesis and increases lipolysis (Zemel, 2002, 2003b, 2004, Zemel et al., 2004, 2005). A recent study (Zemel, 2002) showed that increasing dietary calcium, via a serving of yogurt, resulted in a larger decrease in body fat, body weight, waist circumference and trunk fat when compared to a non-dairy control. Trunk fat loss was 81% greater than the control samples and also resulted in a significant decrease in waist circumference (- 0.58 versus - 3.99 cm). Other researchers have specifically focused on calcium and implications in weight loss (Zemel, 2001, 2003a, 2003c, 2004, Zemel and Miller, 2004, Schrager, 2005). 1.2.2 Protein and weight loss
Protein plays a satiety, thermogenic and lean muscle preservation role during weight loss. Skov et al. (1999) compared a control group to two treatment groups that consumed either a high carbohydrate and low protein (12% energy) diet or a high protein (25% energy) and low carbohydrate diet. Both groups were on reduced fat diets and obtained 30% of their energy from fat. Foods that had the desirable protein, carbohydrate and fat levels were designated for each group. Each group consumed the various food products ‘ad libitum’. After a six-month time period the high protein group lost more (8.7 kg) than the high carbohydrate group (5.0 kg). Part of the difference was attributed to a protein satiety effect. The high protein group consumed less food energy (9.3 MJ/day) compared to the high carbohydrate group (11.2 MJ/day). It was also pointed out that the thermogenic effect of protein is much higher than carbohydrate (30% versus 4–8%) resulting in more calories being ‘burned’ when protein is consumed in place of carbohydrates. Weight loss also was partitioned differently between the two groups. The intra-abdominal adipose tissue decreased by 16.8 cm2 in the high carbohydrate group compared to 33.0 cm2 in the high protein group. Layman et al. (2003) conducted a study looking at protein to carbohydrate ratios. A high protein group (carbohydrate to protein ratio of 1.4) was compared to a high carbohydrate group (carbohydrate to protein ratio of 3.5). This study controlled for caloric intake and both groups received isoenergetic diets over a 10-week period of time. Results showed that both groups lost significant weight. The high protein group lost 7.53 kg compared to 6.96 kg for the high carbohydrate group. This difference was not significant. However, when looking at body composition, the high protein diet showed a greater sparing of lean muscle tissue loss compared to the high carbohydrate diet. The high carbohydrate diet resulted in a lean muscle loss of 1.21 kg compared to the high protein group that lost 0.88 kg. Some dairy proteins may offer added benefit for muscle sparing because of a high content of the branch chain amino acids, leucine, isoleucine and valine. The role of leucine in weight management has recently been published (Layman, 2003, Layman and Baum, 2004a). Leucine plays a regulatory role in signaling protein synthesis. Increasing intracellular levels of leucine by dietary consumption of protein promotes protein synthesis. When intracellular leucine concentration increases, it stimulates the activity of a kinase (mTOR). mTOR increases protein synthesis via phosphorylation of the 4E-BP1 binding protein or activation of p70S6 kinase. Both reactions stimulate subsequent reactions that lead to protein synthesis. Leucine content in milk proteins is higher than other food protein sources. Skim milk contains both casein (~80% of the total protein) and whey proteins (20% of the total protein). Caseins are divided in the four main classes of as1-casein, as2-casein, ß-casein and ?-casein. The occurrence of branch chain amino acids (number of BCAA/total number of AA × 100) found in each casein is approximately 20%, 13%, 19% and 24%. The major whey proteins include ß-lactoglobulin and a-lactalbumin. The occurrence of branch chain amino acids for these proteins is 26% and 22% respectively. In comparison many other food proteins only contain 15–18% BCAA. Though BCAA content is important, another aspect of milk proteins is the release (during digestion of skim milk) or the occurrence in many whey products of glycomacropeptide (GMP). GMP is a small (64 amino acid bioactive peptide) that stimulates the release of cholecystokinin. Cholecystokinin (CCK) is a peptide/hormone that is released from intestinal cells into the blood stream following the consumption of food. CCK acts on the stomach to slow gastric emptying and help maintain a feeling of satiety....