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The Nutritional Value of Pasta the nutritionist’s opinion. Carlo Cannella, Alessandro Pinto Institute of Food Science and Nutrition “La Sapienza” University, Rome, Italy. Function of carbohydrates.
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The Nutritional Value of Pastathe nutritionist’s opinion Carlo Cannella, Alessandro Pinto Institute of Food Science and Nutrition “La Sapienza” University, Rome, Italy
Function of carbohydrates An adult subject needs about 180 g/die of glucose to meet nervous system and erythrocytes energy requirements Essentiality Necessity Carbohydrates are necessary but not essential nutrients because the human body can produce glucose from aminoacids (gluconeogenesis) In a low carbohydrate diet, when the catabolism of glucose is active, acetyl-CoA from lipids is burned otherwise it accumulates to form ketone bodies/fatty acids
Carbohydrate: classification Simple Complex Available or not available
Starch Starch consists of linked glucose units arranged in either straight or branched chains Amylose straight-chain form of starch based on several hundred glucose residues linked by alpha-glucosidic bonds between carbons 1 and 4 of adjacent glucose molecules Amylopectin branched-chain component of starch based on straight-chain form plus side-branches (by additional bonds between carbons 1 and 6 of two adjacent glucose molecules)
Metabolic Pathway Glucose and other absorbed monosaccharydes (fructose, galactose and mannose) are isomerised and phosphorilated to glucose-6-P Blood glucose Hepatic and muscle glycogen CO2 + H2O + ATP Pentose phosphate Adipose tissue
Blood glucose control Release of Insulin from pancreas glucose uptaken into cells glycogenosynthesis High levels of blood glucose 110 mg/dl blood glucose - normal range 70 mg/dl • breakdown of glycogen • increase of gluconeogenesis Release of Glucagon from pancreas Low level of blood glucose
Glucose Amount from different sources 100 g bread 80 g pasta 60 g sugar They cause different glucaemia increase rates G.I. “glycaemic index”
Glycaemic index It is possible to measure the relative effects of different carbohydrate foods on the blood sugar level. The rise in blood glucose following ingestion of a portion of a test food containing 50 g of available carbohydrate is compared with the effect on blood glucose of a 50 g available carbohydrate portion of a standard such as glucose or white bread. Comparison of the areas under the two glucose curves obtained produces a “glycaemic index” Glycaemic Load = GI x dietary carbohydrate content
Scientific evidences support pasta daily consumption • Its glycaemic index is suitable for achievements of daily quota of carbohydrates (50-60% total energy uptake)Its association with different sauces improves nutritional value of proteins (cheese) and exerts an anticancer activity (tomato and onion)It has a reduced fat content especially of saturated fatty acids and an important source of fiber (affecting other nutrient absorption) …… but remember portion size of 80 g!