Advanced Nutrition

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Advanced Nutrition
Fiber
MargiAnne Isaia, MD MPH
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DIETARY FIBER
DIETARY FIBER No classic definition various
different definitions Remnant of PLANT cells
after hydrolysis by digestive enzymes - Plant
non-starch polysaccharides plus lignin -
Indigestible cell wall proteins - Resistant
starches their properties mimic some of those
of traditional fiber (may occur naturally in the
diet) - It can be manufactured - It can occur
as a product of the processing of foods Animal
polysaccharides ? (chitosan or glycosaminoglycans)
(A food manufacturer could add these
animal-derived substances to food and report
them as dietary fiber)
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DIETARY FIBER
STRUCTURE AND SOURCES
Structure Carbohydrates (multiple sugar
units) Non-carbohydrates
Sources Plant based food
Caloric value 0
F I B E R
SOLUBLE
INSOLUBLE
Pectines Gums Mucilage Algal substances
Cellulose Hemi-cellulose Lignin
Intercellular (cement material)
Special secretions
Cell secretions
Algae, sea weeds
Main cell wall constituent
Cell wall material
Woody part of plants
oatmeal, corn, legumes (beans), flaxseed, green
vegetables, citrus, berries, carrots, red beet
whole grains, bran, flaxseed, cabbage family,
beans, root vegetables, tomatoes
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DIETARY FIBER
DIETARY FIBER - Intact and in the food vs.
extracted/synthesized Database - the
physiologic effects of high fiber foods -
potential health benefits of high fiber
foods Not clear the same effects and benefits -
if the fiber were extracted from food or
synthesized in the laboratory. ? Possible an
isolated fiber to be more effective than its
original food source. an isolated fiber may
lose its efficacy - Purified fiber should
demonstrate health benefits
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DIETARY FIBER
DIETARY FIBER DEFINITIONS Dietary fiber
consists of non-digestible carbohydrate and
non CHO lignin that are intrinsic and intact in
plants Functional fiber consists of isolated,
non-digestible carbohydrates that have beneficial
physiological effects in humans. Total fiber
combines both
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DIETARY FIBER
DIETARY FIBER Non-starch polysaccharides -
Cellulose (Glucose units, b1-4 bond, cell
walls) - b glucans (Glucose units, b1-4 and b
1-3 bonds, oats, barley) - hemicellulose
(branched, hexose and pentose) - Pectines
(uronic acids, fruits) - Gums (galactomannans,
plants) Non- CHO (lignin) woody part of plant -
Phenyl propane polymer
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DIETARY FIBER
PHYSICAL PROPERTIES Water-holding capacity -
ability to hold water in the matrix - potential
to increase stool bulk - potential to slow
nutrient digestion and absorption - Soluble
fiber gt capacity than insoluble fiber
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DIETARY FIBER
PHYSICAL PROPERTIES Cation binding - ability
to bind Iron, Calcium, Zinc, Copper - adverse
effect when status is marginal - fibers with
phytates and uronic acid gt binding
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DIETARY FIBER
PHYSICAL PROPERTIES Binding to bile acids -
lignin gt pectin, gumgt cellulose - can also bind
glycerides, fatty acids, phospholipids - binding
is most effective at acidic pH - lignin - bile
(hydrophobic) - pectin bile (hydrophilic) -
interferes with micelle formation - potential to
increase dietary Cholesterol excretion
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DIETARY FIBER

EFFECTS ON CHOLESTEROL (all fibers, except
cellulose)
in liver 75 cholesterol becomes bile
bile 98 reabsorbed
Fiber binds bile acids sweep them into the
stool To replace them more Cholesterol
converted into bile --- blood Cholesterol
level lowers
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DIETARY FIBER
PHYSICAL PROPERTIES Fermentability action by
colonic bacteria products formed methane,
CO2, H2, SCFA (fuel for colonic cells) -
isolated fiber gt whole food fiber soluble gt
insoluble Viscosity - pectins, gums increases
viscosity - potential to influence gastric
emptying
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DIETARY FIBER
EFFECTS OF FIBER ON GASTRO-INTESTINAL
PHYSIOLOGY Effects of fiber on the stomach -
delay the rate of emptying of ingested food from
the stomach into the duodenum ( effect similar
to Gastric Inhibitory Peptide) (it depends on
the presence of other food components and the
amount or type of fiber consumed) Effect of
fiber on the small intestine - the gel-like
environment produced from viscous fibers has
potential to slow nutrient digestion and
absorption .
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DIETARY FIBER
EFFECTS OF FIBER ON THE LARGE INTESTINE FERMENTA
TION Depends on physicochemical properties of the
fiber and the colonic micro flora Formed H2,
CO2, methane and other gases,
SCFA acetate, propionate and butyrate Butyrate
paradox butyrate used by colonic epithelial
cells as an energy source decreases tumor cell
proliferation g Colon Cancer prevention IN
VIVO STUDIES providing butyrate in the diet (in
drinking water, as a fiber source, as a
slow-release pellet) - no protective role
(butyrate paradox) Prebiotics vs.
Probiotics( yogurt Lactic Bacillus) -
Propionate is cleared by the liver - Acetate is
taken by peripheral tissues
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DIETARY FIBER
EFFECTS ON COLONIC BACTERIA (some soluble
fibers)
FIBERS
SUBSTRATE FOR FERMENTATION
( SCFA)
ENERGY FOR THE CELLS LINING THE COLON
RISK FOR COLON CANCER
UN-DESIRABLE EFFECT -- GAS CAUTION - dont
combine fresh fruit and fresh vegetables at the
same meal - use special culinary herbs when
cooking legumes
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DIETARY FIBER
EFFECTS OF FIBER ON THE LARGE INTESTINE -
Laxation by increasing the weight of the
stool Increase in stool weight is based on fiber
type - wheat bran (fibers resistant to
fermentation) g the most - fruit, vegetables
g moderately - legumes g only slightly The
greater the weight of the stool, the more rapid
is the rate of passage through the colon, the
better the laxative effect - Health
benefits reduced risk for diverticular disease
(effect of constipation) reduced risk for colon
cancer (less exposure for toxins, carcinogens,
dilution of carcinogens)
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DIETARY FIBER

IMPROVING LARGE BOWEL FUNCTION
Transit time ( bowel movements) / Stool volume
Rural diet (high fibers) - 24 hrs
Transit time
Western diet (low fibers) - 72 hrs
Stool volume
Rural diet 500 g / day
Western diet 100g /day
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DIETARY FIBER
CONTRIBUTION OF FIBER TO ENERGY Fiber
negligible contribution to energy For
foodlabeling purposes 0 kcal/g, if it is
insoluble
4 kcal/g, if it is soluble FIBER,
SATIATION, SATIETY, AND OBESITY Fiber influences
meal termination ( intra meal satiety
satiation) Soluble fiber delays emptying of the
gastric content and provides an extended feeling
of fullness ( inter meal satiety) A consumption
of an additional 14 g/d of fiber decreases the
energy intake by 10 (decreases the incidence of
obesity)
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DIETARY FIBER

Fiber helps maintain ideal body weight!
Fiber Weight Management

gastric distension satiation
Gastric distension
Medium
Low
High
HIGH FAT FOODS
STARCHY FOODS high protein content
HIGH FIBER FOODS
caloric density
energy density
300 calories portion
300 calories portion
300 calories portion
Do not satisfy hunger
Intrameal satiety
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DIETARY FIBER
FIBER AND GLUCOSE TOLERANCE, INSULIN RESPONSE,
AND DIABETES Soluble fiber beneficial effect
on plasma Glucose and Insulin response in
patients with Type 2 Diabetes Mellitus
(intervention studies) Glycemic response the
measure of the food ability to elevate blood
Glucose influenced by amount of food,
fiber content, fat content, preparation
method Low Glycemic CHO foods Glucose enters
the blood stream slowly and helps
maintain stable blood Glucose level
Effect based on - delayed gastric
emptying - slowed rate of digestion and
absorption
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DIETARY FIBER

EFFECTS ON GLUCOSE (soluble fiber)
90
Stabilizes blood G curve
- Keep G from entering into blood stream too
rapidly
85
- Help avoid the sudden fall
(from a mountain pick of high G
80
to a valley of low G)
75
P l a s m a g l u c o s e l e
v e l
Apple
70
65
60
Apple Juice
55
30
60
90
120
150
180
M i n u t e s a f t e r m e a l
Legumes The greatest Glucose stabilizing effect!
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DIETARY FIBER
GODS NATURAL COLON CLEANSER
DRUGS, CHEMICALS, ADDITIVES, PESTICIDES
Targets different toxins
Dilutes the toxins
Decreases the contact time
THE CARCINOGEN SUBSTANCES HAVE DECREASED TIME IN
CONTACT WITH THE INTESTINAL WALL
The most effective BROOM !
Dietary fiber needs
. 35g / day
Western diet 11-18g / day
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DIETARY FIBER
FIBER AND HEART DISEASE Epidemiologic studies
Fiber- protective role against Coronary Heart
Disease by - lowering blood Cholesterol -
attenuating blood triglyceride levels -
normalizing postprandial Glucose level
(hyprerglycemia in pts with diabetes and in
general population. Hyperglycemia is a risk
factor for CVD)
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DIETARY FIBER
POTENTIAL CONCERN Overconsumption of fiber -
gastro-intestinal distress (flatulence) -
lowering nutrient availability (mineral
bio-availability, when phytate present,
decreased absorption of cations) - high lignin
in the diet may inhibit digestion of some lipid
components - pancreatic lipase inhibitor present
in wheat bran - amylase inhibitors in
legumes (heating inactivates many of these
inhibitors)
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DIETARY FIBER
RECOMMENDATIONS 5 servings of fruits, and
vegetables daily 6 servings of whole grains, and
legumes daily 20 - 35 g/d fiber DRI 14g/
1000 kcal/d
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DIETARY FIBER
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DIETARY FIBER

F A B U L O U S F I B E R
Obesity
CHD
GID
DM
i FBG levels (fasting blood G)
hSatiety rate

• Inhibit recirculation
• of bile acids

i Constipation
i Diverticular disease
i Glicosuria
i Colon cancer
iCholesterol
iEnergy density
iInsulin resistance
iTG
Body cleaner (toxins, metals)
hInsulin sensitivity
iBody weight
- Inhibit postprandial hyperglycemia
iTransit time
- Alter hormonal response
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REFERENCE Shils M. et al, Modern Nutrition in
Health and Disease, 10 th ed. www.pubmed.org http
//cme.medscape.com 5th International Congress of
Vegetarian Nutrition, Loma Linda, California
March 2008 www.pcrm.org
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