fiber Flashcards
Pompe Disease
Autosomal recessive inheritance
• Due to an inborn lack of -1,4 glucosidase
(acid maltase), an enzyme which cleaves
1,4 and 1,6 -glycosidic linkages.
• Absence of this enzyme leads to an
accumulation of glycogen in lysosomes.
Organs affected by accumulation of glycogen
– skeletal muscles (mostly), CNS, heart, liver,
• leading to:
– bulky muscles including macroglossia (enlarged
tongue) and cardiomegaly (enlarged heart)
– hypotonia (loss of muscle tone) and muscle
weakness, including congestive heart failure
(from heart muscle weakness)
McArdle Disease
Cori’s type V glycogenosis
Results from a defect in muscle glycogen phosphorylaseB
.
• More than 30 known mutations can produce the same
clinical picture (phenotype).
• In about half of patients, there is a single base change
(R49X) in which the codon for Arg becomes a stop codon,
resulting in a partially completed non-functional protein.
• The remaining mutations are a mixture of nonsense (stop
codons) and missense (changed amino acid) mutations
that result in incorrect folding and/or loss of catalytic
activity
Glycogen phosphorylase activity is lost.
Notice the difference between normal pattern dark
staining for phosphorylase (figure A) compared to the
lack of dark staining (except in a few blood vessels) in a
patient with McArdle disease (figure B).
Occasional vacuoles are filled with glycogen (asterisks
in figure C) since glycogen can not be broken down to
glucose.
During normal exercise, O2 can not be transported
to muscles cells fast enough. Thus, a stored
reserve of glucose (glycogen) is used as fuel.
• Since glycogen can not be broken down to glucose
in patients with McArdle disease, lactate does not
build up.
• After several minutes of exercise, patients
experience severe muscle pain, probably from
increased ADP.
symptoms of mcardle disease
Symptoms: - muscular pain - fatigability - muscle cramping following exercise, which disappears with rest - later in life - severe cramps and myoglobinuria after exercise. - kidney failure can be associated with rhabdomyolysis (muscle breakdown)
limited ability to perform strenous exercise due to painful cramps
what is fiber- health Canada
Health Canada Definition:
• non-digestible carbohydrate and lignin
(of plant origin)
us/ cdn institute of medicine
U.S./Cdn Definition Institute of Medicine
‘Dietary Reference Intakes’ (2002):
Dietary Fiber: non-digestible carbohydrate and lignin that are
intrinsic and intact in plants.
Functional Fiber: isolated, non-digestible carbohydrate
that have beneficial effects in humans.
Total Fiber: sum of Dietary and Functional Fiber.
functional fiber
Functional Fiber: isolated, non-digestible carbohydrate
that have beneficial effects in humans.
dietary fiber
Dietary Fiber: non-digestible carbohydrate and lignin that are
intrinsic and intact in plants.
fiber classification
soluble (viscos) and insoluble (non-viscous fiber)
insoluble fiber
cellulose (β-[1,4]-linked glucose) wheat bran
some hemicelluloses (glucose, arabinose, mannose, xylose)
vegetables and fruit (associated with cellulose)
lignin (polyphenolics) all plant foods (‘woody’ plant cell walls)
soluble fiber
some hemicelluloses (glucose, arabinose, mannose, xylose)
vegetables and fruit (associated with cellulose)
pectin (galacturonic acid and rhamnose) fruits and vegetables
gums (galactomannans–highly viscous) seeds
β-glucans (highly branched β-linked glucose) oats, barley
effects of insoluble fiber
Slowly fermented - fecal bulking [laxation, colonic health, ulcerative
colitis, colon cancer]
e.g., wheat bran: fecal bulking 5.7 g / g bran
bulks it by 6 times
soluble fiber
Fermented - produce short chain fatty acids
(butyrate, propionate, acetate) [colonic health, CHD?]
High Viscosity - increases bile acid excretion [CHD]
- slows carbohydrate absorption [diabetes, CHD]
which fiber reduces cholestrol due to bile
soluble fiber- highly viscose
which one decreases the glycemic index
the soluble fibers- slows absorption
Glycemic Index / Glycemic Load
GI: the relative blood glucose response to dietary CHO (compared to control food – usually white bread or pure glucose) • GL: takes into account the quality and quality of CHO in a food. Calculated by multiplying the glycemic index by the amount of CHO in grams provided by a food and dividing the total by 100
why doesnt the red lone go down in soluble fiber
baby isnt responding to the insolin so its still being produced- still better than without the fiber
Cardiovascular Disease, Canadian
Statistics (1999)
- Cardiovascular Deaths: 79,000 per year
- 35% of all deaths for men
- 38% of all deaths for women
• 48% of men & 43% of women have elevated
cholesterol
Health Agencies
First line of intervention to reduce cholesterol
and CHD risk is through lifestyle change
(diet, ↑physical activity, weight control)
Cholesterol Reduction
↓ Cholesterol 1% = ↓ CHD 2%
What is a Heart-Healthy Diet?Working Group on Hypercholesterolemia and Other
Dyslipidemias (Canadian):
Working Group on Hypercholesterolemia and Other
Dyslipidemias (Canadian):
• <30% total fat
• <10% saturated fat and trans fatty acids
• <300 mg/d dietary cholesterol
• 25-30 g/d fiber
• healthy whole foods (Canada’s Food Guide)
• whole grains (5-10 servings per day)
• fruit and vegetables (5-10 servings per day)
• low-fat milk products (2-4 servings per day)
• low-fat meat and alternatives (2-3 servings per day)
“Portfolio Diet” – University of Toronto researchers- devines which fiber to have- the viscose fibers
Plant sterols (1.0 g/1000 kcal)
• Soy protein (22.5 g/1000 kcal)
• Viscous fibers (10 g/1000 kcal)
• Almonds (22.5 g/1000 kcal)
National Cholesterol Education Program (Step III):
National Cholesterol Education Program (Step III):
• 25-35% total fat
• <7% saturated fat; <10% PUFA; <20% MUFA
• <200 mg dietary cholesterol
• 20-30 g/d fiber
• healthy whole foods (whole grains, fruit & vegetables)
• viscous (soluble) fiber (10-25 g/d)
• plant stanol/sterols (2 g/d
What is a Heart-Healthy Diet?
American Heart Association:
• Balance calorie intake and physical activity to achieve or maintain a
healthy body weight
• Consume a diet rich in vegetables and fruits
• Choose whole-grain, high-fiber foods
• Consume fish, especially oily fish, at least twice a week
• Limit your intake of saturated fat to <7% of energy, trans fat to <1% of
energy, and cholesterol to <300 mg per day
• Minimize your intake of beverages and foods with added sugars
• Choose and prepare foods with little or no salt
• If you consume alcohol, do so in moderation
Current FDA Health Claims
for CHD Risk Reduction
Vegetable Proteins • Soy Viscous Fibers Phytosterols • Oat ß-glucan • Sterols • Psyllium • Stanols Nuts (under consideration)
if you were 60kg and you only ate soy as a protein
10% decrease in t-chol, 13% decrease in LDL chol, 10% decrees in trig and a 2% increase in hdl
what is in nuts that are so good for you
- Viscous fibers = increase Bile acid loss
- Soy Protein = decrease Cholesterol synthesis
increase LDL receptor uptake - Phytosterols = decrease Cholesterol absorption
nuts contain alot of MUFA (increase in HDL and decrease in LDL)
its a vegetable (decrease LDL)
has vit e and phenolics (decrease )
