Dietary and nutritional aspects of fatty acid binding proteins

Information on cytosolic fatty acid binding proteins (FABP) related to dietary and pharmacological manipulations is discussed in terms of FABP function. FABP present in liver, heart, intestinal mucosa and omental fat responds to different diets. A parallel change occurs in tissue levels of FABP and metabolism of fatty acids. It seems FABP might play a role in lipid metabolism by interacting with membrane bound enzymes. The available data also support the argument in favor of FABP involvement in intracellular transport, compartmentalization and channeling of fatty acids.     

Dietary carbohydrate effects on some plasma organic acids and aspects of glucose metabolism in turkey poults

The effects on newly-hatched turkey poults of feeding diets with varying levels of carbohydrate and of oral gavage with suspensions of corn starch were studied. Feeding lowered hepatic glucose-6-phosphatase activity and raised blood glucose and hepatic glycogen concentrations. In Nicholas strain turkeys, increases of dietary levels of carbohydrate enhanced hepatic glycogen stores without affecting blood glucose concentration or glucose-6-phosphatase activity. Oral gavage of poults with suspensions of corn starch in water raised blood glucose and hepatic glycogen concentrations and lowered glucose-6-phosphatase activity in dose- and time-dependent manners. Changes were noted at 1 hr post-gavage. Oral gavage with starch lowered lactate concentrations in muscle and plasma and lowered plasma concentrations of β-hydroxybutyrate and urate. Plasma concentrations of pyruvate appeared to decline with post-hatch holding without feed. Thus, the apparent effect of starch gavage on plasma pyruvate (high concentration) is dependent upon the length of the holding period for the controls. The data show that poults can alter their metabolism (decrease lipid oxidation and gluconeogenesis and increase carbohydrate stores) almost immediately (1 hr) after oral administration of carbohydrate.     

Dietary fiber

Dietary fiber is plant-derived material that is resistant to digestion by human alimentary enzymes. Fiber may be divided into two broad chemical classes: 1) non-alpha-glucan polysaccharides (cellulose, hemicelluloses, and pectins) and 2) lignins. Dietary fiber behaves within the gastrointestinal tract as a polymer matrix with variable physicochemical properties including susceptibility to bacterial fermentation, water-holding capacity, cation-exchange, and adsorptive functions. These properties determine physiological actions of fiber and are dependent on the physical and chemical composition of the fiber. Fiber undergoes compositional changes as a consequence of bacterial enzymatic action in the colon. Dietary fiber is of clinical significance in certain disorders of colonic function and in glucose and lipid metabolism. Dietary fiber increases stool bulk by acting as a vehicle for fecal water and by increasing fecal bacterial volume. Use of fiber in the treatment of constipation and uncomplicated diverticular disease is well established. By increasing stool bulk, fiber also reduces the fecal concentration of bile acids and other substances. Certain types of fiber decrease the rate of glucose absorption and attenuate postprandial rises in blood glucose and insulin. Plasma cholesterol levels are reduced by mucilaginous forms of fiber. This effect appears to be mediated in part by an increase in fecal acidic sterol excretion.     

Dietary chromium intake

Chromium content of 22 daily diets, designed by nutritionists to be well-balanced, ranged from 8.4 to 23.7 μg/1000 cal with a mean ±SEM chromium content of 13.4±1.1 μg/1000 cal. Most dairy products are low in chromium and provide <0.6μg/serving. Meats, poultry, and fish are also low in chromium, providing 2 μg of chromium or less per serving. Chromium contents of grain products, fruits, and vegetables vary widely, with some foods providing >20 μg/serving. In summary, chromium content of individual foods varies, and is dependent upon chromium introduced in the growing, transport, processing, and fortification of the food. Even well-balanced diets may contain suboptimal levels of dietary chromium.     

Dietary fats and cancer

The present review addresses the evidence for a possible link between dietary fat and cancer. International comparisons suggest that a high-fat diet may increase cancer risk, and this hypothesis is supported by animal experiments. However, epidemiological studies within populations show little or inconsistent associations. Taken together, the available evidence for a relation between dietary fat and cancer is weak.