Diet, Immunity and Functional Foods
Functional foods (specific nutrient and/or food components) should beneficially affect one or more target functions in the body. The use of functional foods as a form of preventive medicine has been the subject of much research over the last two decades. It is well known that nutrition plays a vital role in chronic diseases, but it is only recently that data relating to the effects of specific nutrients or foods on the immune system have become available. This chapter aims to summarize the effects of some functional foods (e.g., prebiotics and micronutrients) on the immune system. It should be noted, however, that studies into the role of functional foods with regard to the human immune system are still in their infancy and a great deal of controversy surrounds the health claims attributed to some functional foods. Consequently, thorough studies are required in human and animal systems if we are to move towards developing a functional diet that provides maximal health benefits.
Available from: Sylwia Mildner-Szkudlarz
- "On the other hand, the term " functional foods " has been commonly used in marketing but still lacks a firm regulatory definition (BJelakOvic & Gluud, 2007). HOyles and Vulevic (2008) noticed that studies into the role of functional foods with regard to the human immune system are still in their infancy and a great deal of controversy surrounds the health claims attributed to some functional foods. Therefore, more studies are required in human and animal systems if we are to move towards developing a functional diet that provides maximal health benefits. "
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ABSTRACT: We examined the hypothesis that rye bread enriched with green tea extract (GTE) (at two different doses) can prevent obesity as a component of a hypercaloric diet by decreasing the absorption of energy providing nutrients and regulating lipid metabolism-related hormones, in comparison with normal caloric diet used in the Wistar rats. Adult male Wistar rats were divided into 4 groups: group ND received a normal caloric diet, group HRB received a hypercaloric diet with control rye bread, groups HRB0.8% and HRB1.1% received a hypercaloric diet with rye bread enriched with 0.8% and 1.1% GTE, respectively. Higher food intake in the ND group compared with the other groups of rats was noted; however, there was no statistical difference in the energy intake among any of the groups. Consumption of the hypercaloric diet increased the body weight of the rats (in comparison with ND), but rats from HRB1.1% group showed a tendency towards smaller gains in body weight (∼4.0%) when compared to the HRB group. The addition of 1.1% GTE to rye bread resulted in an increase in the energy content of faeces, compared to both HRB and ND groups. No differences were observed in plasma leptin concentrations between the four groups. The insulin level in rats fed a hypercaloric diet was higher in comparison to rats from the ND group. The consumption of rye bread enriched with 1.1% GTE may increase faeces energy excretion, but without significantly suppressing body weight gain, visceral fat accumulation, or changing biochemical parameters related to lipid metabolism.
Available from: Wils Daniel
- "The authors indicated that this phenomenon could be linked to the decrease of pH of gut content as encountered in our study. Prebiotics are not only nutrients for bacteria, but can also induce environmental changes such as changes in luminal pH, mineral absorption , trophicity, and improvement of the immune system . "
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ABSTRACT: The resistant dextrin NUTRIOSE®, developed from starch, is expected to act as a prebiotic. The aim of this study was to determine the effects of NUTRIOSE® on cecal parameters, short-chain fatty acid (SCFA) concentrations, and fecal excretion in rats. In an initial experiment, twenty-four male Fischer F344 rats were randomly assigned to one of the following four treatments for 14 days: G0 (control diet), G2.5 (control diet + 2.5% of dextrin), G5 (control diet + 5% of dextrin), and G10 (control diet + 10% of dextrin). After 14 days, total cecal weight, cecal content, and cecal wall weight were significantly increased in G5 and G10 compared to G0. At the same time, cecal pH was significantly lower in G10 compared to G0. Total SCFA concentration was significantly higher in G10 than in G5, G2.5, and G0, and significantly higher in G5 than in G0. Acetate, butyrate, and propionate concentrations were significantly increased in G5 and G10 compared to the controls. In a second trial based on a similar design, eighteen male Fischer F344 rats were treated with a control diet supplemented with 5% of dextrin or 5% of fructo-oligosaccharide. The results obtained with NUTRIOSE® were similar to those obtained with the fructo-oligosaccharide. In a third experiment, two groups of 5 Fischer F344 rats were orally treated with 100 and 1,000 mg/kg NUTRIOSE®, respectively, and from 18% to 25% of the dextrin was excreted in the feces. The results of these three studies show that the consumption of NUTRIOSE®, by its effects on total cecal weight, cecal content, cecal wall weight, pH, and SCFA production, could induce healthy benefits since these effects are reported to be prebiotic effects.
Available from: Harry Wichers
- "In particular, vitamins, such as A, C, D and E, and minerals as Zn and Se are focal points for this, next to PUFAs such as docosahexaenoic acid (22:6n-3; DHA) and eicosapentaenoic acid (20:5n-3; EPA). A detailed essay on the immunomodulatory properties of each of these nutrients is beyond the scope of this paper, so the reader is referred to a number of recent reviews and research papers that deal with these matters [21–26], and references therein. For a number of other nutrients and products, research is still in a less advanced stage—at the stage of in vitro or animal models at best—and some research issues in this field will be dealt with below. "
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ABSTRACT: The importance of a properly functioning and well-balanced immune system for maintaining health has become strikingly evident over the past decades. Roughly since World War II, there has been an apparent decrease in the prevalence of "traditional" infectious diseases, with a concomitant increase in immune-related disorders, such as allergies. Causally, a relationship with changes in life-style-related factors such as the increasing use of hygienic practices seems likely. Diet and nutrition can affect the functioning of various immune parameters. This concept can be utilised in attempts to prevent or mitigate allergic reactions via the development of targeted food products or ingredients. This review describes recent findings with respect to food products and ingredients that show potential in this respect, with special emphasis on pro- and prebiotics, beta-glucans and fungal immunomodulatory proteins. What all of these approaches have in common is that they appear to strengthen Th1-mediated immunity, thus possibly restoring defective immune maturation due to overly hygienic living conditions: a little bit of dirt does not seem bad!
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