Nutritional Quality of Oats

Nutritional Quality of Nutritional Quality of OatsOats

Lena DimbergDepartment of Food Science

Swedish University of Agricultural Sciences

OutlineOutlineMetabolic syndromOats-Glucan -structure and bioactivityAvenanthramides -structure and bioactivityConcluding remarks

Metabolic SyndromeMetabolic Syndrome

Obesity

Diabetes Type II

fat cells

insulin resistanceOxidativestress

Chronical inflammation

Hypertension

glucose/insulin imbalance

High TGA & cholesterol CVD

Why Oats?Why Oats?

A wonderful reservoir of natural nutrients and

biologically active substances

Lásztity; Food Rev. Int., 14, 99-119 (1998)

Characteristics of oatsCharacteristics of oats starch-energy vitamins (B and E) and minerals high protein content

- well balanced amino acid composition, no gluten

high lipid content, good FA composition-C18:1 (37%), C18:2 (37%), C18:3 (4%)

high content of dietary fibres-e.g. -glucan

high content of bioactive phytochemicalse.g. tocopherols/tocotrienols, avenanthramides

-

Whole Grain CerealWhole Grain Cereal

aleuron layer(s)

germ

starchy endosperm

fruit andseed coats

Fruit coat Fruit coat Seed coat Seed coat Aleurone layersAleurone layers

BranBran

Effective compounds?Effective compounds?Dietary fibres?Dietary fibres?

PhytochemicalsPhytochemicals??

-1-13,13,14-Glucan4-Glucan

nn = 1 or 2 (~90 %)n = 3 - 12 (~10 %)

O

OHHO

O

CH2OH O

OHHO

OCH2OHO

OH

HO O

CH2OH

O

OH

HO

CH2OH

O

OHHO

O

CH2OH

Health effects of Health effects of -glucan?-glucan?• Weight control• Improve glucose/insulin balance• Decrease blood cholesterol level• Inhibit constipation• May stimulate immune defence• May protect from colon cancer

development

Health effects of Health effects of -glucan?-glucan?

• Weight control–Less energy supply–Usually less fat and sugar

supply- incapsulated–Bulky, satiety feeling–Slow gastric emtying- delayed

hunger–Low GI

Physiological effects of Physiological effects of ββ-glucan-glucan

Untreated cerealsUntreated cereals ββ-Glucanase treated cereals-Glucanase treated cereals

Health effects of Health effects of -glucan, cont?-glucan, cont?

• Glucose/insulin balance–Low absorption of glucose–Decrease insulin release–Improve insulin sensibility

• Decrease blood cholesterol level–Excretion of bile acids-new bile

acids produced from cholesterol

Health effects of Health effects of -glucan?, cont-glucan?, cont

Health effects of Health effects of -glucan, cont?-glucan, cont?

• Inhibit constapation–Enlarged stool–Speed up transit time -

stimulate muscle movements

Health effects of Health effects of -glucan, cont?-glucan, cont?

• May decrease colon cancer development– Dilution and binding of cancer causing

agents– Provocative agents short time in

intestine– Prebiotic-lower pH; produce LMW fatty

acids– Attached bioactive components- dietary

complex

-1-13,13,14-Glucan4-Glucan

nn = 1 or 2 (~90 %)n = 3 - 12 (~10 %)

O

OHHO

O

CH2OH O

OHHO

OCH2OHO

OH

HO O

CH2OH

O

OH

HO

CH2OH

O

OHHO

O

CH2OH

To much fibers?To much fibers?

• Encapsulate compounds

• May result in energy and nutrient deficiencies

• May cause dehydration

• Causes gas production

Metabolic SyndromeMetabolic Syndrome

Obesity

Diabetes Type II

fat cells

insulin resistanceOxidativestress

Chronical inflammation

Hypertension

glucose/insulin imbalance

High TGA & cholesterol CVD

Oxidative Stress/Oxidative Stress/Inflammation in artherial wallsInflammation in artherial wallsFree radicals Free radicals

Cell proliferation, Cell proliferation, migration, migration, accumulation and accumulation and attachment attachment

Release of pro-Release of pro-inflammatory inflammatory signalling and signalling and adhesion substancesadhesion substances

Plaque formationPlaque formation

Increased blood Increased blood pressure pressure

InfarctInfarct

Tocopherols/tocotrienols, Tocopherols/tocotrienols, hydroxycinnamic acids, hydroxycinnamic acids, avenanthramidesavenanthramides

RORO•, ·•, ·OO22--

HOHO·· HOO HOO··

HH22OO2, 2,

RROOOO•, •, 11OO22, ,

AntioxidantsAntioxidants

OxidantOxidant : RO : RO•,•, ••OO22--

HOHO•,•, HOO HOO•,•, HH22OO2 2

RROOOO• ,• , 1 1OO22

AvenanthramidesAvenanthramides

Anthranilic acid moiety Hydroxycinnamic acid moiety

R=H, OH or OCH3; n=1 or 2

R

R

NH

O

OH

R

R

COOH

n

Health effects of Health effects of avenanthrmides?avenanthrmides?

• Antioxidants• Anti-inflammatory• Anti-atherosclerotic• Anti-cancer

Avenanthramides Avenanthramides -antioxidant effects?--antioxidant effects?-

Hydrogen donators

Radical scavangers

Metal ion chelators

Lipoxygenase inhibitors

Decrease reactive oxygen species (ROS) production

LDL-oxidation inhibitors

Enhance activities of antioxidative enzymes

AvenanthramidesAvenanthramides -anti-inflammatory effects?--anti-inflammatory effects?-

Supress secretion of pro-inflammatory compounds

Inhibit NF-kB activation

Reduce skin itch and irritation

Lipoxygenase inhibitor

AvenanthramidesAvenanthramides -anti-atherosclerotic effects?--anti-atherosclerotic effects?-

Inhibit proliferation of vascular smooth muscle cells

Supress release of adhesion molecules

Decrease cell adhesion

Increase NO production

AvenanthramidesAvenanthramides -anti-cancer effects?--anti-cancer effects?-

Inhibit cancer cell proliferation

TranilastTranilast

Tranilast MetabolitesTranilast Metabolites

Oat avenanthramide

Supression of Vascular Supression of Vascular Stenosis by TranilastStenosis by Tranilast

Control TranilastFukuyama et. al. 1996. European Journal of Pharmacology, 318, 327-332

Concluding RemarksConcluding RemarksOATS

Decrease the risk for the metabolic syndrome development

The whole is more than the refined

-Gucan and avenanthramides exert health-beneficial properties

Good candidate for a healthy food

Thank you!Thank you!