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Natural Resistant Starch:
Health Benefits and In Vitro Measurements
________________________________
7th International Food Data Conference:
Food Composition and Biodiversity
Sao Paulo, SP, Brazil,
October 21-24, 2007
E. T. Finocchiaro, Ph.D.,
Nutrition R&D Director,
National Starch Food Innovation
Bridgewater, NJ USA
Presentation Overview
• Resistant Starch (RS) Background
• Scientific Evidence of Key Health Benefits
– Fermentation
– Glycemic Response
– Emerging Research
• In Vitro Analytical Measurements
– McCleary Method for RS
– Englyst Methof for RS
– AOAC Method for today dietary fiber
What is Resistant Starch?
The Gastrointestinal System Resistant Starch
is the sum of starch and
products of starch
Stomach
degradation not absorbed
in the small intestine of
healthy individuals.
Small Intestine
Large Intestine
** A Physiological Definition **
Natural Sources of Resistant Starch
Food Serving Size Resistant Starch,
(grams)
Navy beans 1/2 cup cooked 9.8
Raw banana One medium, peeled 4.7
Cold potato One 2” diameter 3.2
Lentils 1/2 cup cooked 2.5
Hi-maize® 260 1 tsp (4 grams) 2.2
Cold pasta One cup 1.9
Pearl barley 1/2 cup cooked 1.6
Oatmeal One cup cooked 0.7
Wholegrain bread Two slices 0.5
Average natural RS consumption in US = 5 grams
Types of Resistant Starch
RS Type 1 RS Type 2
+
Physically Resistant
inaccessible granules
RS Type 3 RS Type 4
Retrograded Chemically
starch modified starch
Tolerance and Comfort
4
3.5
3
2.5
Response 2 * 0g/d RS
1.5 60g/d RS
1
0.5
0
movements bloating abdominal consistency
per day pain
Subjects showed high tolerance to resistant starch.
n=19 healthy subjects; 1wk;
bread and cookies containing 0, 50, 75 or 100g of Hi-maize
*p<0.05, mean ± SEM, scale 1-6
Kendall et al, FENS, 2003
Fermentation Related Health Benefits of
High Amylose Maize Resistant Starch
Outcomes of Resistant Starch Fermentation
Fermentation
Insulin Satiety
Colonic
Glucose
Function
Lipid Colonic
Metabolism Tissue
Health
Prebiotic
Benefits from HA maize Resistant Starch Fermentation
Glycemic Benefits
Reduced glycemic response of a subsequent meal
Increased insulin sensitivity
Weight Benefits
Reduced abdominal fat (animal models)
Increased lipid oxidation / fat burning (1 human clinical trial)
Increased production of satiety hormones GLP-1 and PYY (animal
models)
Other Benefits
Increased absorption of minerals
Increased immune biomarkers
GLYCEMIC Benefits
Acute Glucose and Insulin Response
Clinical Study
Glucose (mmol/L) Insulin (pmol/L)
Control bread
7 400
High RS bread
6.5 350
300
6
250
5.5
200
5
150
4.5
100
4 50
3.5 0
0 20 40 60 80 100 120 0 20 40 60 80 100 120
Time (min) Time (min)
n=20 healthy subjects
RS from Hi-maize, flour replacement basis
1 meal (b.fast): 2 slices of bread (approx 70g)
~36g CHO; 2g vs. 9g fibre
mean ± SEM; AUC & peak difference p<0.05
GI Testing Inc, Canada
Key Consumer Benefits from Low Glycemic
Response of HA maize Resistant Starch
• Helps balance your energy following a meal
• Helps to maintain healthy blood sugar
• Implications for multiple benefits
• Diabetes
• Heart disease
• Weight management
• Performance and energy
Emerging Research
1. Lipid Oxidation
2. Satiety Hormone Expression
3. Prebiotics
4. Mineral Absorption
5. Insulin Sensitivity
Lipid Oxidation
Clinical Study – Short Term Response
Meal fat oxidation (g oxidized/g FFM)
14 24 h
12
* 0.06 * 6h
Total fat oxidation (g)
10 0.05
8 0.04
6 0.03
4 0.02 *
2 0.01
0 0.00
0 2.7 5.4 0 5.4
RS in meal (%) RS in meal (%)
↑ total fat oxidation ↑ dietary fat oxidation
(by indirect calorimetry) (by labelled tracer)
mean ± SE; * p≤0.003 vs. 0%; RS from Hi-maize mean ± SE ; * p≤0.0006; RS from Hi-maize
Higgins et al, NM 2004
Satiety
High-amylose maize RS2 triggered satiety hormones. Cellulose did not.
• n=15 rats per group, 4wk, control vs RS from Hi-maize vs cellulose diet
• Genes different: 3192 p<0.05; 1769 p<0.01 (RS vs control)
• PYY gene: ↑ expression, x1.3 (RS vs control)
• Proglucagon (GLP-1) gene: ↑ expression, x 3.2 (RS vs control)
12 Gene Expression –
pg/100ul
b Clustering Analysis
Plasma
PYY
up
down
6
a a
mean
± SE
0
Ctrl RS
300
pM
down
up
b
Plasma
150
GLP-1
mean
a a ± SE
0
Control RS
Ctrl RS In conjunction with
Louisiana State University
NAASO Oct 2006
Prebiotics
Excellent support of Bididobacterium and “good” bacteria
10
9
* *
8 *
7
6
log 10 / g wet Control Diet
5
caecal content RS Diet
4
3
2
1
0
Bifido- Lacto- E.coli Total
bacteria bacilli Coliforms
n=12 rats, 4wk, 10% Hi-maize in diet, mean+/-SEM, *p<0.05
AOM injection, killed 6h later
Le Leu et al, JN 2005
Mineral Absorption
70
* Control Diet
60 RS Diet
*
50 *
Apparent
Absorption 40
(%) * *
30
20
10
0
Ca Mg Zn Fe Cu
RS increased mineral absorption.
Proposed mechanism: ↑ solubility at lower pH, ↑ absorptive area, ↑ blood flow
n=8 rats; 20% Hi-maize in diet; p<0.05; 3 wk
apparent absorption = intake less faecal excretion.
Lopez et al, J Nutr, 2001
New 2007 Research
“Effects of resistant starch on insulin sensitivity in diabetic patients”
`
Zhang et al, Chinese Journal of Preventive Medicine, March 2007, 41(2): 101-104
40 diabetics consumed 30 grams of Hi-maize resistant starch/day for 4 weeks
FINDINGS
– Significantly reduced their Body Mass Index (weight)
– Significantly reduced their fasting insulin levels, glucose response, fructosamine, total
cholesterol and triglyceride levels
– Significantly increased insulin sensitivity
Summary of Health Benefits of
HA maize Resistant Starch
Overview: Nutritional Benefits
• well tolerated within the body
• easily fermented, with a possible role for digestive health
• synergistic action with other fibres
• used to replace digestible carbohydrates like flour, to lower glucose and
insulin response
• have a broader metabolic role for the body, via enhanced insulin
sensitivity and increased lipid oxidation
• animal studies indicate RS can impact food intake regulation (satiety),
mineral absorption, and microbial composition
In Vitro Analytical Methods
to Quantify RS Content
Key In vitro Analytical Methods
Method Measures Key Advantages
McCleary RS •Good research tool
Method (resistant •AOAC approved
(AOAC 2002.02) starch)
Englyst RS •Good research tool
Method •Measures digestion profiles
AOAC TDF Total fiber •Most precise & accurate,
(#991.43) particularly in food products
•AOAC approved
The McCleary Method
In Vitro Measurement of Resistant Starch
AOAC 2002.02
Enzymatic Digestion
Pancreatic
Incubation at 37oC 16 hr α-amylase
Amyloglucosidase
Isolate undigested components
Dissolve undigested components
Quantify RS as glucose from solubilized undigested components
McCleary & Monaghan, J. AOAC Int., 2002, 85 (3): 665-675
The Englyst Method
In Vitro Measurement of Resistant Starch
Englyst Method
Enzymatic Digestion
Pepsin
Pancreatin
Incubation at 37oC 2 hr
Invertase
Amyloglucosidase
Measure glucose released from digested fraction
Englyst et al., Euro J Clinical Nutr, 1999, 46 Suppl 2, S33-S50 & Englyst et al., Am J Clin Nutr 1999, 69, 448-54
The TDF Method
Total Dietary Fiber Methods
AOAC 985.29 & 991.43
Enzymatic Digestion
Amylase
Protease
Incubation at 95 o C
Amyloglucosidase
Filtration
Filtrate Insoluble DF
+
Alcohol Precipitation Soluble DF
Supernatant TDF
W aste AOAC Official Methods of Analysis, 1997, 16 th Ed.
Key Analytical Issues in Quantifying RS in Food Products
1. RS is measured as TDF in most TDF assays.
2. TDF analysis is a very precise and accurate method for measuring the RS content
of many food products.
3. Analysis by AOAC RS method 2002.02 shows consistently low and variable RS
contents in various foods products.
4. The modified Englyst method (original Englyst method using currently available
enzyme sources) shows higher results with more consistent RS data (vs AOAC
2002.02 method)
TDF and RS Contents of Hi-maize 260
by different methods
60
50
40 RS - AOAC 2002.02
% as is
30 RS - modified Englyst
20 TDF- AOAC 991.43
10
0
Hi-Maize 260
* Hi-maize 260 is a commercial form of granular Resistant Starch
Foods analyzed by Different Methods
TDF and RS Contents of Foods
with Hi-maize 260
20
15
RS - AOAC 2002.02
% a s is 10 RS - modified Englyst
TDF- AOAC 991.43
5
0
Breads Pasta Tortilla Biscuits
*Hi-maize 260 is a commercial form of granular Resistant Starch
Key Take Aways for In Vitro Analytical Methods.
1. RS is measured as TDF in most TDF assays.
2. Claims substantiation studies generally require the analytical
quantification of fiber (or RS) in the selected clinical food product.
3. TDF assay AOAC 991.43 is the preferred method to quantify
granular RS in food products.
4. More development work is needed for a comprehensive RS method.
THANK YOU
Resistant Starch and Glycaemic Response:
Strength of Evidence
Significant Decrease Significant Increase /
No Effect
Glucose response
10/13 +ve
Insulin response
8/12 +ve
Review of 15 clinical studies (Passclaim level I/II) utilising high amylose maize starch.
Strong evidence supporting effect of RS on short term response.
Increase / No Effect Decrease
Resistant Starch Fermentation:
Strength of Evidence
Review of 12 clinical studies (Passclaim level I/II) utilizing high amylose corn RS2 in
foods. Strong evidence supporting RS fermentation. Significant Non-significant
Decrease Increase
Fecal weight 8/9 +ve
Fecal frequency 4/4 +ve
Fecal SCFA 6/6 +ve
Fecal butyrate 4/5 +ve
Fecal pH 7/7 -ve
Recognition of Resistant Starch
Leading nutrition authorities
• Global: World Health Organization, 1997
• USA: Institute of Medicine, National Academies, 2002
• UK: British Nutrition Foundation, 2005
• Australia / NZ: National Health and Medical Research Council, 2006
Research community
• Medline database
in vitro, animal, clinical studies
Insulin Sensitivity
Clinical Study – Medium Term Response
12
mg gluc.kg-1.min-1
/ mU insulin-1
• Increased insulin sensitivity
11
* following a high RS diet.
10
• Associated with lower
9 insulin concentration, higher
glucose clearance, lower
8 adipose NEFA and higher
adipose SCFA uptake.
7
n=10 healthy subjects; 4wk; 30g RS from Hi-maize
6
*p=0.027; mean ± SEM; measured by H-E clamp
Control RS
Robertson et al, AJCN, 2005
