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I am currently working on a Master's Degree in Nutrition and requirements for Registered Dietician R.D. I plan to run my first full marathon in 2009. This blog is about everything I learn, eat, and do along the way. Cheers!

Saturday, September 27, 2008

Metabolism

Metabolism:

  • how macronutrients are absorbned, digested and what happens once they are in the body
  • what comes in what goes out what happens in between
  • occurs every nanosecond of your life
  • understanding metabolism allows us to understand disease
What:
Synthesis: making molecules
Catabolism: break down of molecules
Where:
In cells and tissues of the body

* The highest yield of usable energy per acre is from Grains ( get the most calories per acre)

Photosynthesis
Sun + 6 CO2 + 6 H2 O - --- > Glucose! ( 6 C6 H12 O 6) + 6 CO2 ---> We process the glucose with oxygen -----> We export more CO2 and Water ... process continues

Glucose is essentially a carbon chain with water surrounding it

Stereoisomers ( mirror images) aka enantiomers

  • molecules exist in 2 forms D and L orientations
  • if molecule is in D form, the enantiomer is L
  • Monosaccharides (sugars) have enantiomers (D, L)
  • Human enzymes only recognize D forms
--- D-glucose - our "blood sugar"- --> (clinical significance) the presence of this in urine indicates Diabetes Mellitus (Hyperglycemia)
---D fructose- changed easily in liver to glucose for blood----> (clinical significance) hereditary intolerances (Hypoglycemia )

Disaccharide:
Trehalose
  • is found in mushrooms and insects. Humans have the trehalose enzyme which tells us that primitive people ate insects because we have the enzyme! Ew!

-Inulin
  • is a polymer of fructose and has been showing up more in processed foods.
Bananas have 0.5 g of Inulin per 100g food
Chicory Root has 42 g of Inulin per 100g food !!
Cereal has 2.5 g " "
Dried Garlic, Raw Dandelion Greens, Dried Onions all have approx 13-28 g " " ..

Starches:
1. Cellulose: linear chain of glucose, B 1-4 bonds, aka Fiber
2. Glycogen: (branced) storage form of glucose, Alpha 1-4 Bonds
3. Amylose : linear, has Alpha 1-4 glucosidic linkages, and helical coil structure
4. Amylopectin: branched, has Alpha 1-4 and Alpha 1-6 glucosidic bonds

Glycogen is more branched in its structure than Amylopectin, even though both only have one reducing end in their molecule, this more branched structure helps account for how we (and plants) can store CHO.

Cellulose has :
  • Beta 1-4 bonds
  • Linear Structure
  • Is Digestible by bacterial enzymes but insoluble
Oat, Barley (Beta-Glucan) has:
  • Beta 1-3 or 1-4 bonds
  • Linear Structure
  • Digestible by bacterial enzymes but is dispersable and viscous in water.
Food Groups and Polymers: Vegetable Fruit and Seeds Have these Polymers:
  • Cellulose
  • Pectic Substances
  • Xyloglucans
  • Non-Cellulosic polysaccharides
  • lignin
  • cutin
  • waxes
Food Additives have:
  • gums
  • algal polys
  • alginates
  • cellulose esters
  • modified starches
Cereals have these Polymers:
  • Cellulose
  • arabinoxylans
  • B-D Glucan
  • Noncellulosic polysacchs
  • phenolic esters
  • lignin



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