Carbohydrate nutrient density

The response to a diet may change when the proportions of energy supplied as carbohydrates and fat are varied. For example, an animal may increase its consumption of food when carbohydrates are substituted in place of an equal weight of fat. This increase is due to the animaTs desire to satisfy its energy requirement. The increase in food consumption results in increases in the intake of protein, vitamins, and minerals, and thus their possible oversupply. A solution to the problem of comparing physiological responses to diets of different carbohydrate/fat ratios is available. The equivalent of 1 kj of carbohydrate can be omitted from the diet and replaced by 1 kJ of fat plus nonnutritive fiber, where the weights of the carbohydrate and fat -i- fiber are identical. This type of substitution maintains the nutrient density of all the other nutrients (Harper, 1986). 

An experimental nm had been conducted to study the effect of airflow rate in the 3 litres aeration wastewater treatment tank. Nutrients were added in the treatment tank to ensure sufficient bacterial growth. In each experiment, the cell optical density, COD and die concentration of chemicals equivalent to carbohydrates were monitored for the duration of aeration. 

Lipid metabolism in the liver is closely linked to the carbohydrate and amino acid metabolism. When there is a good supply of nutrients in the resorptive (wellfed) state (see p. 308), the liver converts glucose via acetyl CoA into fatty acids. The liver can also take up fatty acids from chylomicrons, which are supplied by the intestine, or from fatty acid-albumin complexes (see p. 162). Fatty acids from both sources are converted into fats and phospholipids. Together with apoproteins, they are packed into very-low-density lipoproteins (VLDLs see p.278) and then released into the blood by exocytosis. The VLDLs supply extrahepatic tissue, particularly adipose tissue and muscle. 

Despite the fact that a plethora of dietary factors could, and will, affect the absorption characteristics of phytochemicals, this area has not been systematically explored. One reason might be the complexity of dietary factors and their interactions that could affect absorption. A nonexhaustive list would include the volume and composition of the food consumed, pH, caloric density, viscosity, nutrients (carbohydrates, protein, fat, fibers), alcohol, caffeine, and the presence of other phytochemicals. Such dietary factors affect the functional status, motility, and acidity of the gastrointestinal tract in a complex manner and modify the physicochemical properties, formulation, and dissolution characteristics of the compound of interest. Calcium in dairy products, for example, has the potential to chelate tetracyclines and fluoroquinolones and, thereby, reduce their bioavailability and biological activity [31]. 

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