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The Macronutrients

The Macronutrients. Chapter 1. Macronutrients. Carbohydrates Lipids Proteins Provide energy Maintain structure. Atoms and Molecules. Atoms 103 elements discovered Human body Nitrogen – 3% Hydrogen – 10% Carbon – 17% Oxygen – 65% Two or more atoms Molecules. Sodium Chloride.

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The Macronutrients

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  1. The Macronutrients Chapter 1

  2. Macronutrients • Carbohydrates • Lipids • Proteins • Provide energy • Maintain structure

  3. Atoms and Molecules • Atoms • 103 elements discovered • Human body • Nitrogen – 3% • Hydrogen – 10% • Carbon – 17% • Oxygen – 65% • Two or more atoms • Molecules

  4. Sodium Chloride

  5. Carbon • Organic compounds • Component of all nutrients • Exception – water, minerals • Bonds with hydrogen, oxygen: • CHO, lipids • And nitrogen: • Proteins • Vitamins also carbon based

  6. Carbohydrates • Monosaccharides • Basic unit • Glucose, fructose and galactose • Disaccharides • Sucrose, lactose and maltose • Oligosaccharides • Short chains of monosaccharides (3-9) • Mostly in legumes (peas, beans and lentils) • Polysaccharides • Long chains of primarily glucose

  7. Monosaccharides • Glucose • Blood sugar, all other CHOs are converted to glucose by the liver • Used by cells for energy • Stored in muscle and liver as glycogen • Converted to fat and stored • Fructose • Fruits and honey • Galactose • Component of milk sugar (lactose)

  8. Disaccharides • Each disaccharide includes glucose as a principle component. • Sucrose = Glucose + Fructose • Found in most CHO containing foods • Sugar, maple syrup, honey • Lactose = Glucose + Galactose • Found in milk • Many are intolerant due to lack of Lactase • Maltose = Glucose + Glucose • Beer, cereals, seeds

  9. Polysaccharides • Polysaccharides • 10-to-thousands of monosaccharides linked together • Two forms: Plant and animal • Plant • Starch: Storage form of CHO in plants • Found in most complex CHOs • Pasta, potatoes, corn, grains, breads, cereals, rice • Animal • Glycogen: Storage form of CHO in animals • Why don’t we derive CHO from meat?

  10. Glycogen Starch (amylopectin) Starch (amylose) A glycogen molecule contains hundreds of glucose units in highly branched chains. Each new glycogen molecule needs a special protein for the attachment of the first glucose (shown here in red). A starch molecule contains hundreds of glucose molecules in either occasionally branched chains (amylopectin; more easily digested) or unbranched chains (amylose).

  11. Fiber • Non-starch polysaccharide • Cellulose (most abundant organic molecule on earth) • Resist digestion • Help digestive process forming • Gels (cellulose, gums, pectin) • Absorb water • Gives “bulk” to stool • Shortens transit time through GI tract • Binding or diluting harmful chemicals • Scraping action on cells of gut

  12. Fiber • Increased fiber intake • May have certain health benefits • Reduce serum cholesterol • Fiber is fermented in large intestine • “feeds” bacteria in the colon, keeping it healthy • May reduce blood sugar in type II diabetics • Types • Water soluble: dissolve in water and form gels • Water insoluble: do not dissolve in water, provide a sort of structure • Sources • Oats, barley, brown rice, peas, carrots, whole wheat, cabbage, beets, cauliflower, apple skin

  13. Glycogen • Most CHO energy stored as glycogen • Vast majority stored in muscle • This amount varies based on training status • Still, small amount of energy • Only enough for ~2hrs of activity

  14. Glycogen • Glycogen is synthesized from glucose • Enzymatic process • Occurs following feeding • Particularly strong following exercise

  15. CHO containing foods

  16. Glycogen Dynamics • Hormones help to regulate blood sugar levels. • Insulin Signals cells to take glucose out of the blood and into the cell for use or storage • Glucagon stimulates the liver to break down glycogen (glycogenolysis) and form glucose from other compounds (gluconeogenesis) to raise blood glucose concentration.

  17. Diabetes • Type 1: Autoimmune disease • Pancreas cannot make insulin • Blood glucose rises to very high levels • Dangerous to small blood vessels and nerves • Can result in death if not controlled • Diabetic coma • How does this happen? • Type 2: Insulin resistance • Caused by obesity • Cell fails to respond to insulin • Blood sugar rises • Easily treated

  18. Diabetes

  19. Type 2 diabetes • Risk factors • >45 yrs of age • Overweight/obese (*) • Family history • Elevated blood pressure (>140/90) • Elevated blood triglycerides (>250 mg/dL) • Physical inactivity

  20. Role of CHO in obesity • Excessive CHO intake • Elevated insulin • Rebound hypoglycemia • Makes you feel hungry • Over eat • Excess CHO • Stored as fat • Limited ability to store CHO as glycogen

  21. Roles of CHO • Energy source • Primary fuel source for most types of activity • Spares protein for structural purposes • Low CHO diets cause proteins to be broken down to Amino acids • Liver converts these amino acids to glucose • Potential strain on kidney • Prevents ketosis • Low CHO prevents “normal” fat metabolism • Fat is still mobilized from reserves • Converted to ketone bodies for energy • Fuel for central nervous system

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