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The role of carbohydrate in human health: a case for new

productsFunctional Foods

Melton Mowbray

Complex nature of the relationship between food and health

A Round Table of dietary and obesity factors in the prevention ofcoronary heart disease

ATHEROMA ANDFIBROUS PLAQUE

FORMATION

THROMBOSIS

INJURY TOCORONARYARTERIES

HEARTATTACK

PRO-COAGULANTSTATE

ATHEROGENICLIPID PROFILE

RAISEDBLOOD

PRESSURE

INTRAVASCULARINFECTION ANDINFLAMMATION

INCREASEDLIPID

OXIDATION

RAISEDBLOOD

PRESSURE

ARRHYTHMIA

PRO-COAGULANT

STATE

PLATELETAGGREGATION

INSULINRESISTANCE

INCREASEDHOMOCYSTEINE

INCREASEDHOMOCYSTEINE

IMPAIREDENDOTHELIAL

FUNCTION

IMPAIREDENDOTHELIAL

FUNCTION

REDUCESFA

n-3 PUFA

REDUCE SODIUM

REDUCE ‘BINGE’ALCOHOL

ANTIOXIDANTS,VITS C and E

n-3 PUFA

NOT TOOHIGHPUFA

REDUCEFAT

MODERATEALCOHOL

NSP

MODERATEALCOHOL

n-3 PUFA

REDUCEFAT

MODERATEALCOHOL

REDUCESODIUM

REDUCE‘BINGE’

ALCOHOL

n-3PUFA

FOLATE

FOLATE

VITAMINSB6, B12

n-6 PUFA AND cis MUFA

NSPMODERATEALCOHOL

REDUCE SFA, TFA & CHOL

FOLATE

VITAMIN E

VITAMIN C

FOLATE

VITAMINS B6,B12

PLANTSTEROLESTERS

SOY PROTEIN/PHYTOESTROGENS

FLAVONOIDS

POLYPHENOLS

CopyrightDr Margaret Ashwell OBE, 2000

VITAMIN C

VITAMIN E

FOODS WITHLOWGLYCEMICINDEX

POTASSIUM

POTASSIUM

SFA=SATURATEDFATTY ACIDS

PUFA=POLYUNSATURATEDFATTY ACIDS

MUFA=MONOUNSATURATEDFATTY ACIDS

TFA= TRANS FATTYACIDS

REDUCE TOTAL BODY FAT

REDUCE TOTAL BODY FAT

REDUCE TOTAL BODY FAT

REDUCE VISCERAL BODY FAT

REDUCE VISCERAL BODY FAT

REDUCE VISCERAL BODY FAT

REDUCE TOTAL BODY FAT

2000

Disease Risk and Body Mass

Obesity – Past and Future

The problem we are faced with

• An ever increasing rate of obesity– 1000 deaths a week are directly related to

obesity– It will soon become the most common

preventable cause of cancer

• Type 2 diabetes

• CHD rates remain high

Massive changes in life style

Massive changes in the life style

• Energy expenditure down

• Access to cheap calories energy dense calories

• Public health looking into a bottomless precipice

• If we go on as we are in the few generations time will be the first where children die before parents

Role of carbohydrates

Carbohydrate is a complex groupwith complex absorption

Gut lumen Epithelium Portal vein

Small intestine

Monosaccharides Glucose, Fructose

Monosaccharides

Disaccharides Sucrose, Lactose

Brush boarder enzymes

Monosaccharides

Rapidly absorbed and slowly absorbed starch

Pancreatic amylase

Brush boarder enzymes

Glucose

Large intestine

Non starch polysaccharidesResistant starch

FermentationButyrate

AcetatePropionate

Carbohydrate: The complex group

Class

Free sugars

Short-chain CHO

Starch

Fibre (non-starch polysaccharides)

Components

Mono & disaccharidesSugar alcohols

OligosaccharidesInsulin

Rapidly digestible starchSlowly digestible starch

InsolubleSoluble

Comments

Sorbitol

Large bowel effects, stimulate bacterial growthProbiotic

AmyloseAmylopectin

Little metabolic effectMetabolic effect

Dietary fibre (non-starch polysaccharides)

Water Soluble Water Insoluble

HemicellulosesPectinsGumsMucilagesCarageenanAgar

CellulosesLigninResistant starch

Problems with definitions

• Physiological definition does not help chemical analysis

• Does not help interpretation of scientific work (dietary fibre v whole grain)

• Does not help public understanding

• Does not help labelling of produces

What is Glycaemic IndexWhat is Glycaemic Index

Incremental area under the bloodglucose response curve for food

Corresponding area after equi-carbohydrate portion of glucose

X 100

Glycaemic response of carbohydrates

0

2

4

6

8

10

12

0 30 60 90 120

Time (minutes)

Delta change in glucose

(mmol/l)

White Bread Wholemeal Bead White pasta Kidney beans

Glycaemic indexGlycaemic indexFOOD

White bread

Wholemeal bred

Brown rice

White rice

Boiled potato

Pasta

Yam

Green banana

Sucrose

Baked beans

Chickpeas

GI100

100

81

81

98

65

74

65

83

70

60

Second meal effectsSecond meal effects

0

2

4

6

8

10

12

14

0 30 60 90 120 150 180 210 240 270 300 330 360

Time (minutes)

Glucose (mmol/l)

Low GI breakfast High GI breakfast

Standard Meald

Epidemiological evidence

Overall view of GI and diabetes

Review of glycaemic index and lipids (Ludwig 2002)

Insulin Resistance

• Insulin sensitivity = insulin stimulated glucose disposal

• Insulin resistance = abnormal carbohydrate + lipid metabolism

• Insulin Resistance Syndrome (Reaven, 1988)

The Insulin Resistance Syndrome

Insulin Resistance

Hyperinsulinaemia

Glucose intolerance

Triglycerides HDL- chol

B.P.

Small, dense LDL Uric acid PAI-1

Coronary Heart Disease

Insulin Resistance

“Relative inability of insulin to stimulate glucose disposal”

Insulin sensitive Insulin resistant

GENES ENVIRONMENT

RISK CHD AND TYPE II DIABETES

Possible model of insulin resistance

0 30 60 90 120

TIME

0

100

200

300

400

500

600

700

800

900

INSULIN PMOL/L

Low Glycaemic IndexInsulin response to OGTT

WEEK O WEEK4

0 30 60 90 120

TIME

0

10

20

GLUCOSE MMOL/L

Low Glycaemic IndexGlucose Response to OGTT

WEEK O WEEK4

*

* = P<0.001

HGI LGI

Diet

0

1

2

3

4

Uptake (attomol/min/cell)

basal stimulatedHGI=high glycaemic index, LGI=glycaemic index

*

* = inter-group significant difference P<0.05.

Insulin stimulated in vitro glucose uptake in adipocytesfollowing low or high glycaemic index diet.

*

Effect of a HGI and LGI diet on glucose day profiles in middle aged men

0 30 60 90 120 150 180 210 240 270 300 330 360 390 420 450 480

Time (minutes)

4.00

5.20

6.40

7.60

8.80

10.00

Glucose (mmol/l)

High GI day 1 High GI day 21 Low GI day 1 Low GI day 21

Post prandial metabolism

1.00 72.75 144.50 216.25 288.00 4.00

5.60

7.20

8.80

10.40

12.00

Glucose (mmol/l)

BASELINE LOW GI

6 am 12 pm 6 pm 12 am 6 am

Obesity evidence

• 16 single-day studies in humans, 15 found lower satiety, increased hunger, or higher voluntary food intake after consumption of high- compared with low-glycemic index meals

• obese children were given high-glycemic index instant oatmeal or low-glycemic index steel-cut oats with identical energy and macronutrient content at breakfast and lunch, and ad libitum energy consumption was monitored throughout the afternoon. Energy intake was 53% higher after the high- compared with the low-glycemic index meals

• Slabber et al found significantly more weight loss in obese hyperinsulinemic women after 12 weeks of consuming an energy-restricted low-compared with high-glycemic index diet

• Bouche et al found lower adiposity by DXA scan in 11 obese men after 5 weeks on an energy- and nutrient-controlled low- compared with high-glycemic index diet

GastrinGhrelin

PancreaticPolypeptideSecretin

CCK

GIPMotilinGLP1GLP2

OxyntomodulinNeurotensin

PYYGLP1

OxyntomodulinPYY

The Gut HormonesThe Gut Hormones

GHRELIN

PYY3-36

HYPOTHALAMUS

PERIPHERAL SIGNALS REGULATING APPETITEPERIPHERAL SIGNALS REGULATING APPETITE

LEPTIN

Can food release gut peptides

The big challenge

Nutrient Release of Gut hormones

• Consistency of food makes a difference to peptide realise– Gasrtic emptying (Frost etal 2000)

• Products of fermentation make a difference– Ileo break– Effect gastric emptying (Frost etal 2003)

• Adding propionic acid increases GLP-1 release, lows gastric emptying and decreases hunger (Frost 2003)

Evidance of effect of Low GI diets and gut hormones

• Evidence from a number of short term studies– Holt etal 1992 CCK– Juntunen etal 2002 GLP-1 and GIP

(wholegrains)– Tappy etal 1986 GIP

Effect of GI on postprandial metabolism

Gut peptides

Gut peptides

Gut peptides

Glycaemic indexGlycaemic indexFOOD

White bread

Wholemeal bred

Brown rice

White rice

Boiled potato

Pasta

Yam

Green banana

Sucrose

Baked beans

Chickpeas

GI100

100

81

81

98

65

74

65

83

70

60

Problems of intake in whole grains

• Benefit is seen at 2-3 servings a day

• Consumption in a lot of Western countries is less then 1 serving a day– Scandinavians consume more whole grain.

Norway has 4x US intake– Main sources are limited to wholemeal

bread, rye bread and whole grain cereal

Problem of who eats high fibre/wholegrain foods

• US and UK– Older

– High socio-economic group

– Less likely to smoke

– Do more exercise

– Part of a healthy middle class lifestyle

• Many chronic diseases are associated with low income, smoking, lack of exercise and are rooted in the young

Need a new raft of products

• Need to compete with commonly consumed foods

• Need to be seen as products with added value• Ongoing research collaboration with Holgrain

and RHM is trying to do this with with bread• Is it possible to product a low GI white bread

which will compete in the market place

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