BIO 105-03

Bio 105 Lecture 3 Notes

A. Disease of Day: Diabetes Mellitus

  • identified thousands of years ago by Greeks and Egyptians
  • “diabetes” = Greek derived
    • related to a siphon – excessive urination symptom
  • “Mellitus” – Latin for “honey”
    • related to excess sugar in urine
    • historical diagnosis by flies or ants attracted to urine sample, tasting urine sample
  • cells don’t take up glucose -> excess glucose in blood, urine -> starve body

Diabetes and insulin

  • Type I diabetes:
    • very little to no insulin produced
  • Type II diabetes
    • problem is at insulin receptors
    • over time, may stop producing insulin
  • either way, little to no sugar leaving blood and entering cells

1. Diabetes and Insulin

  • Type I diabetes:
    • very little to no insulin produced
  • Type II diabetes
    • problem is at insulin receptors
    • over time, may stop producing insulin
  • either way, little to no sugar leaving blood and entering cells

2. Diabetes Types

a. Type I

  • “Juvenile” diabetes (5-10% of diabetics)
  • autoimmune – own body attacks cells that make insulin
    • need insulin supplied through shots, pump
    • need to monitor blood sugar throughout day
  • sudden onset
  • cure – need to replace insulin-producing cells
    • pancreas(and kidney) transplant)
    • researching stem cells

b. Type II

  • “adult-onset” diabetes (90-95% of diabetics)
  • insulin made but cells are resistant to it
    • usually controlled with diet
    • possible for cells to stop making insulin due to “exhaustion:” will need medication and/or insulin to compensate
  • gradual onset
    • often goes undiagnosed for some time due to different individuals’ symptoms
  • strongly correlated with obesity
  • often found in ethnic minorities (Hispanic, Native American, African-American, Asian)
  • No cure, but some good correlation found with gastric bypass

c. Other

  • gestational diabetes
    • during pregnancy (2-5% of pregnancies) similar to Type II
    • may improve or disappear after birth
    • approx. 20-25% of women develop Type II later in life
  • Prediabetes
    • “Impaired glucose tolerance”
    • excess glucose in blood, but not as much as in true diabetes
    • must be more closely monitored for diabetes symptoms

2. Diabetes Symptoms

  • frequent and voluminous urination
    • 10-15 quarts per day, waking up in middle of night
  • unquenchable thirst
  • craving for sugar and other carbs
  • weight loss, weakness

3. Diabetes Complications

  • high blood glucose over short-term (days)
    • ketoacidosis
      • so many ketone bodies and glucose with dehydration
      • blood becomes acidic
    • acid impairs basic functions -> coma, death
    • usually seen in Type I diabetics


4. Diabetes Management

  • Insulin
    • Type I –  absolute necessity, need to monitor blood glucose
    • Type II – not necessary unless pancreas stops making insulin
  • diet

B. Sugar Substitutes

  • as sweet or sweeter than sugar, but contain fewer calories
    • “calories” are dictated by body’s ability to digest
  • must be approved by FDA
  • don’t promote tooth decay “sugar free”
  • example: polyols, saccharin, aspartame, sucralose

1. Polyols

  • sugar alcohols – sugar molecule with alcohol unit
    • used gram for gram like sucrose
    • not as sweet as sucrose (appx 50-70%)
  • synthetic and natural (in plants)
  • slowly broken down by body and incompletely absorbed
    • good for diabetics
    • too much leads to diarrhea  (except erythritol – “Truvia”)
    • sugar-free b/c no tooth decay
  • sorbitol, xylitol, etc

2. Saccharin

  • 1st sugar substitute 1879
  • 200-700 sweeter than sucrose
  • no calories b/c not broken down by body
  • 1977-2000 saccharin products had warning label
    • after later research, now considered safe

3. Aspartame

  • not a carb – actualy a very small 2-pt protein
    • individuals with PKU (a type of protein sensitivity) need to watch intake
    • is broken down in body as protein
      • so is 4 cal/gram
    • avg man (70kg) eats 0.14g/day
  • 200% sweeter than sucrose
  • neotame is similar but can not be broken down by body, so safe for PKU individuals

4. Sucralose

  • modified sugar molecule
  • 600% sweeter than sucrose
  • body can not break down – no calories
    • excreted in urine
  • can use for some baking b/c it is heat-stable

C. Fats, Oils and Other Lipids

  • lipids: category of compounds containing carbon (organic), hydrogen and oxygen that are hydrophobic (insoluble in water)
  • performs a variety of function in foods
    • give flaky texture to baked goods
    • make meats tender
    • provide flavor and aroma
    • contribute to satiety

1. Lipids Basics

a. Facts

b. Functions

  • energy storage
  • insulation
  • transport of proteins in blood
  • cell membrane structure
  • help body absorb vitamin A D E K

2. Triglycerides: Dietary Fat

  • 3 fatty acids connected to glycerol backbone
    • most common lipid found in foods and body
    • functions
      • energy
      • insulates, cushions, protects internal organs
    • referred to as fats
      • saturated fats – have mostly saturated fatty acids
      • unsaturated fats – mostly unsaturated fatty acids
  1. Structure of a Triglyceride/Fatty acids (graphic)

      • over 20 different fatty acids
      • can vary by
        • length of chain
        • whether carbons have double or single bonds
        • total # of double bonds
    • chain of carbon and hydrogen atoms with acid group (-COOH at one end)
  1. Saturated fats

  1. Unsaturated fats

    • Monounsaturated fats

    • Polyunsaturated fats

d. Hydrogenated Fats/Trans Fats

  1. Essential Fatty Acids

– Omega-3 FA

– Omega-6 FA

3. Phospholipids

4. Sterols

Clicker Questions

Which hormone is responsible for the removal of glucose from the blood?

  1. Insulin

  1. Glucagon

  1. Glycogen

Which one of the following foods is most likely to cause the greatest rise in blood glucose level?

  1. Apple

  1. Peanuts

  1. Bagel, plain

  1. Carrots

Which of these sugar substitutes has the highest relative sweetness?

  1. Aspartame

  1. Saccharin

  1. Sucralose

  1. Sorbitol

According to the Acceptable Macronutrient distribution range, the percent of your daily calories that should come from fat is:

  1. 5-10%

  1. 15-25%

  1. 25-35%

  1. 30-40%

Which of the following is not high in saturated fat?

  1. Butter

  1. Coconut oil

  1. Margarine

  1. Olive oil

Healthy individuals over the age of 2 are advised to limit their average daily cholesterol intake to under:

  1. 300 mg

  1. 500 mg

  1. 1,000 mg

  1. 1,500 mg

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