|
|
Fats - III Hallo, me again ! Gosh time is flying!!! So let's start without wasting any more time Let' look at FAT DIGESTION. Fat digestion takes much longer than the digestion of carbohydrates and somewhat longer than the digestion of proteins. A raw salad consisting of non-starchy vegetables can be digested within 2-3 hours. When free fat such as corn, sesame, peanut or other oils are added to the salad, digestion is delayed for another 2 - 3 hours. By adding oil to our foods, the digestive juices are prevented access to those foods until the oil has been digested. Free fats, unlike carbohydrates, require special digestive action before absorption. This is because the end product of all digestion are carried in a water medium ( blood & lymph ) Free fats are not soluble or transportable in these water mediums until they undergo special changes. After fats leave the stomach they enter the duodenum of the small intestine. Their presence causes the stimulation of the gallbladder, which forces bile down into the small intestine. The bile emulsifies all the fats in the intestines. The emulsified fats are then split by enzymes, into fatty acids & glycerol. At this point the fats can be absorbed through the intestinal mucosa. . During the absorption, the fatty acids and glycerol recombine with a small amount of protein to form microscopic particles of fat called chylomicrons. The fats in the form of chylomicrons are now soluble enough to enter lymph circulation. The fatty acids are now converted by the liver to acetate or ketone bodies as an energy source for the cells. The fat which is not used immediately for the body's energy needs, is stored primarily in adipose tissue. Adipose tissue is a special kind of tissue ( found mainly around the stomach, thighs and buttocks ) which contains the necessary enzymes to continually produce and release new fat to meet the body's need. Fat is used in the body in 4 main ways: 1) As a source of heat and energy 2) as padding and insulation for organs and nerves 3) as regulator for the fat soluble vitamins 4) as a source for the essential fatty acids. Fats are converted ton energy by being split into fatty acids and glycerol. Glycerol is then converted to either glucose or glycogen. At this point , the usual processes of carbohydrate metabolism takes over to produce needed energy from the glucose and glycogen. Each gram of fat supplies 9 calories. This is more than twice the amount of energy supplied by a gram of carbohydrates . Even if fat is not eaten, the body can manufacture most of it's fatty acids from fruit and vegetable sugars. There are 3 fatty acids , however , that the body cannot synthesize. These are called the essential fatty acids. They are; Linoleic acid, Arachidonic acid and Linolenic acid. Collectively these fatty acids are sometimes referred to as Vit F. These fats are considered essential for normal glandular activity, especially the adrenal glands. These essential fatty acids promote the availability of calcium and phosphorus to the cells and help form the fat containing portion of every cell's structure. They are also considered a factor in growth and reproduction. A lack of Vit F is said to contribute to to skin disorders, gallstones, loss of hair, impaired growth and reproductive function, kidney and prostate disorders and menstrual disturbance. The following foods contain the shown % of linoleic acid, the major fatty acid. In general, if the intake of linoleic acid in the diet is adequate, then all other fatty acid needs are also well satisfied. FOOD % LINOLEIC ACID Walnuts 40 Sunflower seeds 30 Sesame seeds 22 Pumpkin seeds 20 Brazil nuts 17 Pecans 14 Almonds 11 Pistachio 10 Hazel nuts 10 Cashew nuts 3 Avocados 2 Coconut 1 All fresh fruits contain between 0.5% and 1% unsaturated fats. Some fruits are higher in fat ( particularly avos which contain 155 to 22% fat ) We will conclude the chapter on oils next week by analysing the harmful fats. Until then, The Crazy Nut team