9/12/18 Supported by Dietary Characteristics of the Traditional - - PDF document

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Supported by

Dietary Characteristics of the Traditional Mediterranean Diet

• A variety of minimally processed wholegrains and legumes as the staple food
• Plenty of - and a huge diversity of - fresh vegetables consumed daily
• Fresh fruits as the typical daily dessert; sweets based on nuts, extra virgin olive
• il and honey consumed only during celebratory occasions
• Extra virgin olive oil, nuts and seeds the principal source of fat
• Moderate consumption of fish
• Dairy products (mainly local cheese and yoghurt) consumed in low amounts;

butter, cream and milk never used, except for milk in coffee and for infants

• Red and processed meat consumed only once every week or two
• Wine consumed in low to moderate amounts with meals

Tosti et al 2018

In 1993 Oldways created the Mediterranean Diet Pyramid – in partnership with the Harvard School of Public Health and the WHO – as a healthier alternative to the USDA’s original food pyramid.

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The Hypothesised effectors of the Mediterranean Diet

Tosti et al 2018

Lipid Lowering Effect

Intake of saturated fat is ~8% energy due to low intake of milk, meat & butter Total fat 25-35% energy from evoo, nuts, seeds & germ of wholegrains Nuts also provide plant sterols High intake of soluble fibres from wholegrains, beans and fruit Fermentation by microbiota - increased short chain fatty acids – inhibits cholesterol synthesis Extremely low in trans fats

Reduced Inflammation & Oxidative Stress

Rich in beta-carotene, vit C, vit E, folate, polyphenols & selenium Reduction in oxidised LDL & inflammatory markers Phytoprotectants in the aleurone layer of wheat bran – ferulic acid is the major polyphenol & has antioxidant + anti-inflammatory effects Germ of wholegrains contains spermidine – cardioprotective, neuroprotective & anti-inflammatory effects (Madeo et al 2018) EVOO contains several potent antioxidants & oleocanthal which acts via the same anti-inflammatory pathway as ibuprofen – although the dose matters to have an effect

Reduced Inflammation & Oxidative Stress

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Modification

• f hormones

& growth factors

• Energy restricted but nutrient dense diets shown to be

effective in reducing cancer in animal models – traditional Med diet achieves this being low GI, whole food & high fibre

• Short chain fatty acids produced induce satiety by inhibiting

gastric emptying & increasing gut hormones

• In women Med diet shown to decrease the activity of

hormones that stimulate cancer cell growth such as IGF-1, testosterone & oestrogen (Kaaks et al 2003)

• Low GI, high omega-3 & mono fats, lower branched chain

amino acids – reduce insulin resistance & hyperinsulinaemia

• High fibre – increases excretion of carcinogenic substances
• High in phytoestrogens & wealth of anti-cancer

phytochemicals

EVOO Phenolic Subclasses

Oleocanthal

• First documented in literature in early 90’s
• Around 2000 ws identified as the

phytochemical responsible for the distinct peppery taste and pungency in evoo (oleo for

• live, canth for sting, and al for aldehyde)
• Levels vary in evoo – more robust oils have

higher levels

• Mimics ibuprofen – inhibits COX1 and COX2

enzymes = anti-inflammatory action

• 50ml evoo a day corresponds to ~10%

ibuprofen pain relieving dose

Parkinson & Keast 2014

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Oleocanthal & Cancer

• Lower incidence of many cancers in Med populations

including breast, prostate, lung & GI cancers

• COX2 enzyme implicated in pathogenesis of many

cancers – oleocanthal of interest being a COX2 inhibitor

• Also been shown to encourage cell apoptosis, anti-

proliferative effects on cancer cell lines & prevents tumour growth

Other Potential Benefits

• Anti-inflammatory effect beneficial in joint-degenerative

disease – decreases markers of arthritis (Parkinson & Keast 2014)

• Ibuprofen known to have beneficial effects on neuro-

degenerative disease therefore much interest in

• leocanthal (Giusti et al 2018)
• In elderly Australian cohort those with Alzheimer’s

disease & mild cognitive impairment had a lower adherence to a Med diet than healthy controls (Gardener et al 2012) (The Australian Imaging, Biomarkers and Lifestyle Study of Ageing (AIBL) study)

Not Just Oleocanthal

• Great review: Bioactivity of Olive Oil Phenols in Neuroprotection (Angeloni et al 2017)
• Brain tissue is very prone to oxidative stress – high energy requirements, high oxygen

consumption, high PUFA content, low antioxidant defences

• “Oleuropein and hydroxytyrosol act as direct free radical scavengers, hydroxytyrosol and
• leocanthal are strong cyclooxygenases (COX) inhibitors and oleuropein counteracts low density

lipoprotein (LDL) oxidations”

• Describes potential benefits in spinal cord injury, stroke, Alzheimer’s, Parkinson’s, MS & ALS –

most studies only in animal or in vitro studies to date, but show promise

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Mechanisms of action of evoo phenols in preventing / counteracting AD

Black = Animal studies Red = In vitro studies Angeloni et al 2017

Lower Intake of Protein & Specific Amino Acids

• Total protein 20% lower than typical Western diet
• Mostly plant protein – from legumes & whole grains
• Protein >20% energy associated with increased cancer (4-

fold) & mortality (75%) in those aged <=65 – eliminated if plant protein (Levine et al 2014)

• Ratio of animal to plant protein results in 40% lower

methionine – in animal models methionine restriction extends lifespan & reduces cancer (Brown-Borg & Buffenstein 2017)

• Branched chain amino acids play key role in modulating

insulin sensitivity – circulating levels higher in insulin- resistance – associated with an 11-13% increase increased risk of type 2 diabetes (Lynch & Adams 2014)

Microbiota Mediated Effects

• Choline & L-carnitine (rich in meat, cheese

& eggs) 50% lower – gut microbiota produces tri-methylamine N-oxide (TMAO) & this increases CVD risk

• High fibre increases the levels of specific

bacterial groups that produce short chain fatty acids, particularly butyrate

• Long term adherence to plant-rich Med Diet

shown to increase microbiota diversity – essential for healthy immune function, gut health & potential knock-on effect on longevity & healthy ageing

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A Qualifier…

“In the past, the surplus of energy required to perform the high levels of physical labour (approximately 70–80 h of work per week) was provided by the consumption of energy-dense food, such as extra-virgin olive oil, wine, and dried fruits”

Tosti et al 2018

Retraction of the PREDIMED Trial

• In June the NEJM retracted the 2013 study “Primary prevention of

cardiovascular disease with a Mediterranean diet” (Estruch et al 2013)

• Published corrected version (Estruch et al 2018)
• Problems identified: household members not randomised, some

participants at 1 site (out of 11) not randomised & apparent inconsistent use of randomisation tables at 1 other site

PREDIMED Study

• Men (age 55-80) women (aged 60-80) with no CVD but type 2

diabetes or at least 3 major risk factors

• 3 dietary intervention groups: a Mediterranean diet supplemented

with extra virgin olive oil, a Mediterranean diet supplemented with nuts, or a control low fat diet

• 7447 recruited – 1588 participants known or suspected to deviate from

proper randomisation protocol

• Authors re-ran analysis without these participants

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Med diet + olive oil group – given a polyphenol-rich extra virgin olive oil Med diet + nuts – 30g serve daily (walnuts, almonds & hazelnuts given)

Summary of Dietary Recommendations What Changed?

• Not much!
• In both the original and republished study, the incidence of CVD in the Med diet groups was

lowered by ~30% cf low fat control group

• Conclusion: “In this study involving persons at high cardiovascular risk, the incidence of

major cardiovascular events was lower among those assigned to a Mediterranean diet supplemented with extra-virgin olive oil or nuts than among those assigned to a reduced-fat diet.”

Estruch et al 2018

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Estruch et al 2018

• Effect of heating to 240°C for 15 minutes
• Effect of heating to 180°C for 6 hours

2 Te s t s o n 9 c o m m o n c o o k i n g o i l s

• Most common chemical parameter used in industrial kitchens to determine the

moment that the oil is no longer safe to be used

% o f P o l a r C o m p o u n d s i n O i l

• Polar compounds include aldehydes, alkyl benzenes and other aromatic

hydrocarbons

• Linked to cancer and neurodegenerative diseases such as Alzheimer's and

Parkinson's

• Typically, different country standards place the level between 24 and 27%

P o l a r C o m p o u n d s L i n k s

New Research from Modern Olives

Preliminary results from the Evaluation of chemical and physical changes in different commercial oils during heating; Authors: De Alzaa, F.; Guillaume, C.; and Ravetti, L.; Modern Olives

Test 1: Effect of Heat

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Preliminary results from the Evaluation of chemical and physical changes in different commercial oils during heating; Authors: De Alzaa, F.; Guillaume, C.; and Ravetti, L.; Modern Olives

Test 2: Effect of Time

S m o k e P o i n t s o f O i l s i s a p o o r p r e d i c t o r o f o i l s p e r f o r m a n c e a n d s t a b i l i t y N o B e n e f i t c h o o s i n g a h i g h e r s m o k e p o i n t o i l w h e n t h e s m o k e p o i n t i s a l r e a d y a b o v e c o o k i n g t e m p e r a t u r e E V O O s h o w n t o p r o d u c e v e r y f e w p o t e n t i a l l y h a r m f u l c o m p o u n d s - T h e b e s t p e r f o r m e r i n t h i s r e g a r d G r a p e s e e d o i l , c a n o l a o i l & r i c e b r a n o i l – a l l s o l d a s h e a l t h y c o o k i n g o i l s … p e r f o r m e d w o r s t

Study Conclusions Potential Barriers in Australian Population

• Multi-ethnic population
• Availability of foods
• Familiarity with foods, recipes & methods of cooking
• Myths surrounding cooking with evoo
• Costs (see Chatterton et al 2018 for cost effectiveness of SMILES trial)

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Adopting a Med Diet in Multi-Ethnic Australia

• Prof Catherine Itsiopoulos at La

Trobe and colleagues have developed a Med diet model for use in Australia

George et al 2018

Med Diet in Australian Context

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AUSMED Heart Trial

• The AUSMED Heart Trial is a multisite randomized controlled trial

that will evaluate the efficacy of the Mediterranean diet for secondary prevention of CVD in the Australian health care setting.

• This trial aims to evaluate the effect of a 6-month Mediterranean diet

intervention (delivered by dietitians) versus a "standard-care" low-fat diet in reducing the composite incidence of cardiovascular events at 12 months and at trial end in participants with documented evidence of a previous acute myocardial infarction at trial entry.

Itsiopoulos et al 2018

Summary

• A Traditional Mediterranean Diet does not mean big bowls of pasta, pizza

and stacks of white bread!

• It is essentially a plant-rich diet with small amounts of animal foods
• It has a moderate to high fat intake, but is low in SFA & high in MUFA due

to dominance of EVOO

• Associated with reduced risk of CVD, several cancers, type 2 diabetes &

improved brain health

• The polyphenols supplied by EVOO seem to play key role
• Clearly to have an effect enough must be consumed – traditionally 40-60ml
• With appropriate adaptations it is affordable and able to be applied to

Australian population

References

• Tosti et al 2018 J Gerontol A Biol Sci Med Sci 73(3):318-326
• Madeo et al 2018 Science 359(6374)
• Kaaks et al 2003 Eur J Clin Nutr 57:1079–1088
• Levine et al 2014 Cell Metab 19:407-417
• Brown-Borg & Buffenstein 2017 Ageing Res Rev 39:87-95
• Lynch & Adams 2014 Nat Rev Endocrinol 10:723–736
• Estruch et al 2013 NEJM 368(14):1279-90
• Estruch et al 2018 NEJM 378:e34
• Parkinson & Keast 2014 Int J Mol Sci 15(7):12323-34
• Gardener et al 2012 Transl Psychiatry 2(10):e164
• Giusti et al 2018 Int J Mol Sci 19(8):2329
• Angeloni et al 2017 Int J Mol Sci 18(11):2230
• George et al 2018 Nutrients 10(4):465
• Chatterton et al 2018 BMC Public Health 18(1):599
• Itsiopoulos et al 2018 Am Heart J 203:4-11

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