Macronutrients I Flashcards
Are carbohydrates an essential nutrient?
Technically no
The most efficient form of energy because they are the easiest to metabolize
Carbohydrates
Increase fecal excretion of bile acids, thus stimulating the liver to divert more cholesterol into bile acid synthesis
Fiber (a carb)
In the small intestine, fiber slows the rate of
Lipid absorption
Bind cholesterol and make it unabsorbable
Resin medications
Found on the exterior surface of cells where they are bound either to proteins (forming glycoproteins) or lipids (forming glycolipids)
Carbohydrates
Provide ribose for the synthesis of DNA and RNA
Carbohydrates
Carbohydrates are important components of whole grains, fruits, and vegetables, which supply
Essential Nutrients
Monosaccharides and disaccharides are classified as
Simple carbohydrates
Oligosaccharides (3-10 sugars) and polysaccharides (>10 sugars) are classified as
Complex carbohydrates
Monosaccharides have a carbon, hydrogen, and oxygen ratio of
1:2:1
Hexose sugars with differing sweetness
Monosaccharides
An essential energy source that is part of every disaccharide
-essential energy source
Glucose
Mostly comes form lactose in dairy
-only in a few foods in free form
Galactose
The sweetest of the sugars
-comes from food sources
Fructose
A pentose sugar
Fructose
Sucrose consists of
Glucose bound to fructose
Consists of glucose bonded to glucose
Maltose
Consists of glucose bonded to galactose
-found in milk
Lactose
What are three disaccharides
Sucrose, maltose, lactose
The storage form of energy in the body
Glycogen
Comprised of glucose molecules linked together in highly branched chains
Glycogen
Glycogen is a highly branched arrangement of
Glucose
Storage form of energy in plants
Starches
Glucose molecules linked together in branched or unbranched chains
Starches
Starch made up of a linear glucose chain
-digested slower
Amylose
Starch made up of a highly branched arrangement of glucose
-digested faster
Amylopectin
Group of plant polysaccharides that are not digested or absorbed in the human small intestine
Fiber
Makes up the structural parts of plants
Fiber
The bonds in fiber that are resistant to digestive enzymes
β-glycosidic bonds
How do starches and fiber differ?
Starches have β-glycosidic bonds
Dissolves or swells in water
-fermentable
Soluble fiber
What are three examples of soluble fiber?
Pectin, gums, beta-glycans
Does not dissolve in water and is not fermentable
Insoluble fiber
What are some examples of insoluble fiber
Cellulose and hemicellulose
Added to foods to provide beneficial physiological effect
Functional Fiber
Examples of functional fiber that are used as bulking agents and sugar substitutes in food
Polydextrose and polyols
The processing of grains removes the germ and bran portions which contain the majority of the
Vitamins and minerals
What are the three key ingredients in whole grains?
-provide 5g of fiber per serving
Bran, endosperm, germ
Promotes healthy bowel function by softening fecal matter, reducing strain, and making elimination easier
Soluble fibers
Fiber reduces blood cholesterol by binding to
Bile acids in the gut
-reduces enterohepatic circulation of bile acids
Soluble fibers delay
-promotes satiety and lowers blood lgucose levels
Gastric emptying
Short chain fatty acids synthesized from fiber bacteria reduce
Cholesterol synthesis
Soluble fiber also helps to prevent
Colon cancer
Increases fecal weight and volume and promotes healthy bowel function
Insoluble fiber
Can help prevent and alleviate constipation
Insoluble fiber
Which type of diseases do insoluble fibers help to prevent?
Diverticular diseases (also colon cancer)
Present in foods that are abundant in fiber, where they bind to important dietary constituents and prevent their efficient absorption
Phytates
Reasonable intake of high fiber foods does not compromise
Mineral balance
Effect of a food on the extend and or duration of the rise in blood glucose levels
Glycemic response
Measured based on the extent to which a food contianing 50g of carbs increases blood glucose concentration
Glycemic index
What would a
- ) Low GI
- ) Medium GI
- ) High GI
Be?
- ) 55 or less
- ) 56-69
- ) 70 or more
Takes into account the glycemic index as well as the amount of carbohydrate typically in a single serving
Glycemic load
How do we calculate glycemic load?
GL = (GI/100) x Net Carbs
A low GL would be
10 or below
A high GL would be
20 or above
Increasing consumption of whole grains, fruits, and vegetables will help us to balance
Glycemic index
What is the RDA for carbs in a healthy adult?
130g/day
Is there a tolerable upper level for carbs?
No
We want our percentage of carb intake that is added sugars to be
Less than 25% of kcals
What is the Acceptable Macronutrient Distribution Range (AMDR) for carbs?
45%-65%
What are the recommendations for dietary fiber intake?
14g per 1,000 kcal
What is the adequate intake of dietary fiber?
21-38 g/day
Dietary carbohydrate and cardiovascular disease are associated with an increased production of triglyceride-rich particles of
VLDLS
Errors in the metabolism of fructose and galactose may occur as an
Autosomal recessive trait or enzyme deficiency
The breakdown of fructose in the liver is prevented by the absence or low amounts of
Fructokinase
The metabolic response to high-fructose corn syrup and sucrose is
The same
Extremely sweet, stable, and inexpensive sweetener
Saccharine (Sweet N’ Low)
Made up of 2 bonded amino acids
- 200X as sweet as sugar
- not heat stable
Aspartame (nutrasweet and equal)
Aspartame is a potential risk for people with
PKU
Salt that contains potassium
- heat stable
- used in refridgerated and frozen desserts and the like
Acesulfame K
Sugar molecule with a chlorine attached
-600x sweeter than sugar
Sucralose (splenda)
Half the sweetness and calories of sucrose
-sorbitol, mannitol, xylitol
Sugar alcohols
Does the FDA object to the use of Stevia?
No
Overstimulation of sugar receptors from frequent use of these hyperintense sweeteners may limit tolerance for more
Complex tastes
How many amino acids are there?
20 (9 essential)
Transferring an amino group form one amino acid to a keto acid to make a new amino acid
Transamination
How many conditionally essential amino acids are there?
6
A disease causing a lack of the enzyme that converts phenylalanine to tyrosine
Phenylketonuria (PKU)
Makes Tyrosine conditionally essential
PKU
Animal foods generally have more
Essential aminos
Contain adequate amounts of all essential amino acids
Complete proteins
Low amounts of at least one essential amino acid
Incomplete protein
Amino acids missing or in low amounts
-ex: corn has low amounts of lysine and tryptophan
Limiting amino acids
What are the two protein quality factors?
Digestibility and amino acid composition
Requirements of preschool-age children
Reference protein
Classified as a complete protein with bioavailable protein
High quality protein source
All animal sources of protein are high quality sources except
Gelatin
The only two plant protein sources with high quality protein are
Quinoa and soy
What are two major functions of proteins in the body?
Fluid balance and acid-base balance
Help to maintain the volume and composition of body fluids
Proteins
Help to maintain the acid-base balance of body fluids by acting as buffers
Proteins
Leads to nitric oxide synthesis
Arginine
A key regulator of numerous physiological processes including vasodilation and vasoconstriction
NO
A precursor for niacin and the neurotransmitter seratonin
Tryptophan
A principle donor of methyl groups for the synthesis of compounds such as choline and carnitine
Methionine
Also a precursor of cysteine and many other sulfur-containing compounds
Methionine
A precursor of tyrosine, thyroxine, and epinephrine
Phenylalanine
A precursor from which skin and hair pigment are made
Tyrosine
Combines with many toxic substances, converting them to harmless forms that are excreted
Glycine
