bio 28: nutrition instructor: paul nagami laney college jan. 30, 2014 carbohydrates, pt. 2

Bio 28: NutritionInstructor: Paul Nagami

Laney College

Jan. 30, 2014

Carbohydrates, pt. 2

Today’s Agenda• Reminders + Administrative Details• Review• More on chemistry, to help prepare

you for next chapter.• Benefits of Carbohydrates• Blood Glucose• Diabetes• Tooth Decay• Pick up work

(Review and Chemistry Chalk Talk here)

If you missed this class, you may want to pay close attention to the opening parts of chapter 4 and ask me to clarify any confusing details at office hours!

You should know how atoms make molecules (what a chemical bond is) and what the difference is between a single and a double bond.

Why Carbohydrates?Many diets (Atkins, etc) emphasize reducing non-fiber carbohydrates. What useful roles do carbohydrates serve in our body?

Energy source: How many kcal of energy are there in a gram of carbs?

Protein sparing: The body needs glucose to run its cells! Without carbohydrates, it will get glucose from other sources, such as proteins, via gluconeogenesis.

Preventing ketosis: Without carbs, the body turns fats into acidic ketone bodies, which can potentially lower blood pH, hurt the kidneys, and have other ill effects. (Though it may help epileptics.)

Glycemic IndexCarbohydrates raise your blood sugar, but not all of them raise it equally quickly. For diabetics, it’s important to avoid sudden spikes in blood sugar!

Food (50 grams

taken on an empty stomach)

Glycemic index

(relative to

glucose)

Glucose 100

Boiled potato 85

Soda 72

Table sugar 64

Baked beans 44

Apple 38

Glycemic index is a measure of how quickly food causes blood sugar to rise – in theory, anyway.

Use as a weight-loss tool remains controversial. A low glycemic index food can still have plenty of calories!

Mobilizing Blood Sugar

Balancing Blood Sugar

Diabetes mellitus occurs when the body can’t control blood sugar levels. Fat is incompletely broken down, creating acidic ketones.The loss of water through the urine (to get rid of excess sugar) causes dehydration.Blood vessels can get narrow, leading to the death of tissue.

Diabetic Retinopathy

Types of DiabetesType I Diabetes (Juvenile-onset, usually): Pancreas doesn’t make insulin. Beta cell damage. 10% of all diabetes patients.Type II Diabetes (adult-onset, usually): Body makes insulin but doesn’t respond to it! (Insulin resistance)

U. S. Diabetes cases per year, in thousands, from 1980 to 2011. Source: Centers for Disease Control

Gestational diabetes: Pregnant women are at higher risk of insulin resistance. Untreated, this can harm the fetus.

Risk Factors for Diabetes

Obesity: A huge risk factor for Type 2 Diabetes. In one study of nurses aged 30-55, severe obesity raised the risk of diabetes 49 times over!

Age: As people approach middle age, the risk of diabetes rises.Genetics: Inherited differences in metabolism can play a role.

Race/Ethnicity: African-American, Native American, and Hispanic patients, especially women, are more likely to develop diabetes than men.

Estimated 24 million Americans with diabetes.

Managing DiabetesConsidering the differences between Type I and Type II diabetes…

How much would you expect insulin shots to help someone with Type I diabetes?

How much would you expect insulin shots to help someone with Type II diabetes?

How could Type II diabetes be managed?

Tooth Decay

Sugary foods increase the risk of tooth decay, since they stick to the teeth, forming a film that bacteria can consume and live in.The bacteria convert the sugar into lactic acid, which eats away at the enamel of teeth!