Download Carbohydrates

Chapter 3
CARBOHYDRATES:
PLANT-DERIVED
ENERGY NUTRIENTS
What Are Carbohydrates?
• Carbohydrates (CHO)
• One of the three macronutrients
• 4 kcal/gram
• A primary energy source, especially for nerve/brain cells
• Composed of carbon, hydrogen, oxygen
• Most come from plant sources
• Grains, fruits, veggies
• Table 3.1, page 69
What Are Carbohydrates?
• The most abundant carbohydrate?
• Glucose
• Produced by plants through
• Photosynthesis
• “non-plant” source of CHO?
• Milk products
(CO2)
(CHO)
(H2O)
CHO
Classification
Simple Sugars
Monosaccharides
Complex CHO
(Polysaccharides)
Glycogen
(Body)
Disaccharides
Glucose
Maltose
Starch
(Diet)
Fructose
Sucrose
Fiber
(Diet)
Galactose
Lactose
What Are Carbohydrates?
• Simple carbohydrates are sugars
• Contain less than 10 sugar molecules
mono = one
• Monosaccharides contain only one molecule
• Glucose
• Fructose
• Galactose
saccharide = sugar
• Disaccharides contain two molecules
• Lactose, maltose, sucrose
di = two
Simple Carbohydrates
Simple Carbohydrates
Is honey healthier
than sucrose
(table sugar)?
Nutritive versus
non-nutritive
sweeteners
What Are Carbohydrates?
• Complex carbohydrates
• Long chains of glucose molecules
poly = many
saccharide = sugar
• Polysaccharides
• Starch (plants)
• Glycogen (animals)
• Liver and muscles
• Dietary Fiber
• Cannot be digested by human enzymes
Complex Carbohydrates
• Starch
• Plants store glucose as starch
• We digest (break down) starch into glucose
• Grains, legumes, and tubers are good sources of starch in our diet
Complex Carbohydrates
• Glycogen
•
•
•
•
Animals store carbohydrate as glycogen
Stored in the liver and muscles
Broken down into glucose quickly
Not found in food and therefore not a source of dietary carbohydrate
Complex Carbohydrates: Fiber
Gives plants their structure
1. Dietary fiber is the non-digestible part of plants
• Found naturally in whole grains, vegetables, seeds, legumes, fruits
2.
Functional fiber is carbohydrate added to food
• Cellulose, guar gum, pectin, psyllium
Total fiber =
dietary +
functional fiber
Sources of Carbohydrate
• AMDR = 45% - 65% of daily calories
• Sugar, bread, pasta, dairy, baked goods, potatoes, legumes
• Hidden sugars!!
• Sugar free ≠ calorie free
• CHO type matters
• What type of CHO should we eat the most of?
TIPS:
 Look for “whole
grain” as the 1st
ingredient
 Use legumes
 Eat peels
Celiac Disease
• CD is an allergic reaction to gluten
• Wheat, rye, barley, (oats)
• Immune response damages
small intestine lining
• 1 in 200 people
• “Gluten sensitive”
• Not necessarily healthier
Key Functions of CHOs
• Energy
• Immediate & Stored
• 4 kcal/gram
• Protein Sparing
• Minimize the use of protein
• Gluconeogenesis
• Break down fats
• Prevent ketosis
• Blood Glucose Regulation
Blood Glucose Regulation
• Liver and pancreas primary organs
• Liver:
Blood Glucose Regulation
• Pancreatic hormones
• Insulin
• Glucagon
Blood Glucose Regulation
Blood Glucose Regulation
• Other hormones that increase blood glucose:
• Cortisol
• “stress hormone”
• Growth hormone
• Epinephrine
• Adrenaline
• Adrenal glands
Glycemic Index
• What is the glycemic
index (GI)?
• A food's ability to
raise blood glucose
levels
• Low GI = ≤55
• Moderate GI = 56-69
• High GI = ≥70
Glycemic Index
• Foods with a high GI cause a spike in glucose
• Triggers insulin release
• Sudden drop in blood glucose
• Foods with low GI cause low to moderate glucose fluctuations
• Lower insulin response
Glycemic Load
• Glycemic load = amount of CHO grams x glycemic index value÷ 100
• Watermelon: GI of 72, but a GL of 4
• 5 g CHO x 72 ÷ 100 = 3.6
• Foods with a low glycemic load:
• cause low or moderate changes in blood
glucose
• are better for people with diabetes
• are generally higher in fiber
• may reduce the risk of heart disease and
colon cancer
http://www.health.harvard.edu/newsweek/Glycemic_index_and_glycemic_load_for_1
00_foods.htm
Diabetes
• Diabetes
• Blood glucose levels remain high after meals
• Hyperglycemia
acidosis
• Caused by inadequate or ineffective insulin (IR)
• Normal blood glucose range
• 70 to 100 mg/dL
• Treatment: diet, activity, oral drugs, insulin injections
Diabetes
• Type 1 diabetes
•
•
•
•
•
Accounts for 5-10% of all cases
Patients do not produce enough insulin
Causes hyperglycemia – high blood sugar (glucose)
Requires insulin injections
May be an autoimmune disease
Diabetes
• Type 2 diabetes
•
•
•
•
Most diabetics have type 2 diabetes (90-95%)
Body cells are resistant or less responsive to insulin
Excess insulin is often produced
Causes hyperglycemia because cells cannot take in the glucose from the
blood
• Generally associated with obesity
Symptoms of Diabetes
© 2013 Pearson Education, Inc.
Type 1 and Type 2 Comparison
Type 1 DM
Type 2 DM
Basic Problem
Not enough glucose to get
into cells
Enough glucose can’t get into
cells
Underlying Problem
Pancreas stops producing
insulin
Insulin resistance – cells don’t
respond to insulin
Theory of Cause
Autoimmune disease kills
beta cells of pancreas
Obesity alters cell proteins;
heredity
Treatment
Insulin, diet, exercise
Weight loss, diet, exercise,
oral drugs, insulin
Incidence
5% – 10%
90% - 95%
Untreated Diabetes
Fiber Types
• Soluble
• Dissolves in water
• Viscous
• Gut bacteria digest
• Citrus, oats, beans, berries
• Helps bind bile
• Insoluble
• Do not dissolve in water
• Non-viscous
• Not digested in colon
• Whole grains, veggies, seeds
• Promote healthy BMs, reduces diverticulosis
Fiber Functions
① Insoluble Fiber
• GI Health
• Colon Cancer
② Soluble Fiber
• Diabetes
• Improves blood sugar
• Hemorrhoids
• Weight Control
• Diverticulosis
• Fullness/satiety
• Binds Fat
•
• Heart Disease
• Lowers blood cholesterol
**Not all complex
carbs are high fiber**
Fiber Recommendations
• The Adequate Intake (AI) of fiber is:
• 25 – 38 grams/day
• 14 grams/1,000 kcals consumed
• Drink plenty of water!
• Most Americans eat only half the recommended amount of fiber.
• Perhaps keep to less than 50 grams/day
• Resistant starches
•
•
•
•
Seeds, legumes, whole grains, oatmeal, cooked then cooked spuds
Enhance satiety
Improved glucose tolerance
Promote healthy gut bacteria
Adding Fiber
High- Sugar Diets
• Diets high in added simple sugars:
•
•
•
•
can cause dental problems such as cavities and gum disease
are associated with increased levels of "bad cholesterol"
are associated with decreased levels of "good cholesterol"
may contribute to obesity
• Added sugar should be less than 10% of total energy intake per day
Where’s The Sugar?
Lactose Intolerance
• Lactose intolerance
• Insufficient lactase production causes an inability to digest lactose found in
dairy products
• Symptoms include intestinal gas, bloating, nausea, cramping, diarrhea
• Lactose-intolerant people may need to find alternate sources of calcium
• Almonds, almond butter, fortified plant milks, kale, broccoli, sesame seeds, tahini
• May tolerate yogurt, cheese, Lactaid