Macro #2 & #3: Carbohydrates Flashcards
Carbohydrates basic reccomendations
- RDA 130 g/day for adults
- Our diets should have less than 10% of our diet be added sugars
Main functions of carbohydrates
- Provides energy by pulling from different parts of the body
- Prevents protein catabolism in the body
Red blood cells and carbs
Red blood cells rely on glucose because they do not have mitochondria which means they cannot create ATP or really do anything without glucose going through the anaerobic processes
Skeletal muscle and carbohydrates
Skeletal muscle is a primary energy source for our body, especially during exercise. This is THE ONLY source for high-intensity anaerobic exercise
The brain and carbohydrates
The brain and central nervous system use 60% of our glucose when at rest
Gluconeogenesis
Using things that are not carbohydrates to create glucose such as amino acids/lactate/glycerol
Simple carbohydrates (CHO)
Monosaccharides
Disaccharides (2 monosaccharides)
Complex CHOs
Oligosaccharides (3-9 monosaccharides)
Polysaccharides (10-1,000 monosaccharides)
Monosaccharides
Glucose
Galactose
Fructose
Galactose
Found in milk as part of lactose
Fructose
Found mainly in fruits and vegetables
Disaccharides
Sucrose
Lactose
Maltose
Sucrose
Glucose + fructose
Sugarcane, maple syrup, honey, table sugar
Lactose
Glucose + galactose
Found in milk or dairy
Lactose Intolerance
these people lack the enzyme or have insufficient levels of the enzyme that doesn’t break down the lactose disaccharide into the two monosaccharides (25% of US adults)
Maltose
Glucose + glucose
Polysaccharides
Starch
Glycogen
Fiber
These three are composed of many glucose monosaccharides
Starch
Mostly form amylose starch or amylopectin starch
Storage form of glucose in plants
Glycogen
Storage form of glucose in animals
Fiber
Structural components of plants (stems, cell walls) that are ingestible to humans
Slow Carbs
Enter bloodstream slowly
1. Fructose
2. Galactose
3. Amylose (starch)
Whole grains are complex CHO and slow carbs
Types of Complex CHOs
Whole Grains
Legumes
Starchy Vegetables
Whole grain v refined grains
Whole grains have
1. Endosperm: starchy portion of grain
2. Germ & Bran: fiber, protein, minerals, vitamins etc
Refined grains strip the germ & bran so all thats left is the starch that can do straight into your bloodstream with no nutritional benefit
Legumes
Peas, bens, lentils
Generally high in protein and fiber
Starchy vegetables
Potatoes, yams, beets, carrots, cassava, platanos
Consuming refined and added sugars
Once consumed, fructose is converted to a triglycerides that are stored in the liver
Excessive fructose consumption
Can lead to non-alcoholic fatty liver disease, increased triglycerides in the body, increased visceral fat, and increased cholesterol
Fiber
Non-digestible CHO
Soluble fiber (dissolved in water)
Insoluble fiber (does not dissolve in water)
Five health benefits of fiber
- Slows the breakdown of starch into glucose (prevents rapid increase of glucose in blood)
- Lowers LDL cholesterol
- Prevents the formation of blood clots that can cause heart attacks
- Lowers risks of some cancers
- Promotes healthy gut bacteria
Digestion CHO
- Mouth: Salivary amylase: breaks down starch in mouth
- Pancreas: pancreatic amylase: breaks down starch in small intestine
- Small intestine: maltase: breaks down maltose into two glucose; sucrase: breaks down sucrose into a glucose and a fructose; lactase: breaks down lactose to glucose and galactose
Absorption of CHO
Once CHO are fully digested into monosaccharides they can be absorbed across the intestinal wall through absorptive enterocyte cells (which can only carry monosaccharides through the wall)
the name of the transporter through the enterocyte cells is GLUT2
Portal vein
The vein that monosaccharides travel through to get to the liver from the bloodstream after being brought through the intestinal wall
Fructose and galactose in the liver
Converted into glucose or glycogen
3 Fates of glucose
- Used for fuel
- Stored as glycogen in muscle or liver
- Converted to fatty acids and stored in adipose tissue
How glucose is turned into fatty acids and triglycerides
The liver and skeletal muscle have a limited storage capacity for glycogen. Excess glucose is converted to fatty acids during lipogenesis.
Fatty acids combine with glycerol to form triglycerides that are stored in adipose tissue
Glycemic Index
Measures the increase of blood glucose two hours after consuming 50 g of CHO-containing food (how quickly CHO is converted to blood glucose)
