Milk signaling_Dr. Melnik, NutriScience, Portugal, 2012

Milk Signalling and Western Diseases

Bodo C. Melnik

University of Osnabrück Germany

Scientific Program, ISCSEM, May 26, 2012

•  The nutrient-sensitive kinase mTORC1 •  Milk: an endocrine mTORC1-activating signalling

system of mammalian evolution •  Milk consumption and insulin resistance •  Milk consumption and type 2 diabetes •  Milk consumption and obesity •  Milk consumption and cancer •  Milk consumption and acne •  Conclusion

Introduction

The nutrient-sensitive kinase mTORC1

mTORC1: mammalian target of rapamycin complex 1

S6K1 S6K1 P

N-terminal C-terminal

PI3K-like kinase

300 kD multiprotein complex

mTORC1: a central metabolic regulator of all mammalian cells

mTORC1

Protein synthesis

Lipid synthesis

Cell growth

Cell proliferation

Auto-phagy

Leucine Insulin IGF-1 Glucose

LAT IR IGF1R GLUT

PI3K PTEN Akt TSC1/TSC2 Rheb

Leucine Rag GTPases

inactive mTORC1 mTORC1 activated

4EBP1 SREBP S6K1

ATP

AMPK

Translocation

IRS-‐1

Nutrient signalling is integrated at mTORC1

Insulin resistance

Reduced TOR signalling in C. elegans by impaired amino acid- (pep-2 deletion) and daf-2 signalling (daf-2

deletion) strongly extends life span

Meissner B et al. (2004)

C. elegans

mTORC1: the central hub of metabolism

Zoncu R et al. (2011)

Functional and structural role of L-leucine

•  Most important amino acid for activation of mTORC1 •  Important component of the leucine zipper (myc, fos, jun)

•  Structural precursor for de novo-lipid synthesis •  Structural component of protein synthesis (muscle protein) •  Precursor of acetoacetyl-CoA (citrate cycle) gluconeogenesis

•  Leucine: the „hidden messenger“ of milk´s signalling proteins

L-leucine: a branched-chain essential amino acid

Milk: a mammary gland secretion that functions as a donor of easily accessible leucine

Milk

an endocrine mTORC1-activating signalling system of mammalian evolution

Leucine and BCAA content of foods

Millward DJ et al. (2008)

Protein source Leucine BCAAs

Whey protein isolate 14% 26% Milk protein 10% 21% Egg protein 8.5% 20% Muscle protein 8.0% 18% Soy protein isolate 8.0% 18% Wheat protein 7.0% 15%

Comparison of the insulinotropic effects of various protein test meals

each contained 18.2 g protein 12 healthy volunteers

Nilsson M et al. (2004)

Amino acid content of different test meals (mg/serving)


Postprandial leucine increase


Whey proteins induce the stongest effects on postprandial insulin serum levels



Whey proteins: the predominating insulin secretagogues of animal proteins

Leucine exhibits the highest insulinogenic index


Whey proteins: the strongest inducers of GIP


Strong insulinotropic effects of whey protein and BCAAs, especially of leucine


Whey protein

Glucose

Highest postprandial insulin levels after a milk protein meal compared with soy protein and fish (cod) protein

von Post-Skagegard M et al. (2006)

Milk = Cottage cheese (80% casein + 20% whey)

Signalling proteins versus structural proteins

Signalling proteins promoting growth & proliferation

Structural proteins providing muscle function

Whey proteins Highest content of leucine (14%) small soluble proteins with low MW

fast intestinal hydrolysis High postprandial leucine pulses High insulin secretion High insulinemic index > 100

Meat / fish proteins

High leucine content (8%) complex proteins with high MW

retarded intestinal hydrolysis Slow postprandial rise in leucine Moderate insulin secretion Low insulinemic index ≈ 50

Paleolithic diet Western diet

Functional differences in leucine-TORC1-signalling of various common protein sources

Dietary proteins

Dairy proteins

Animal proteins Plant proteins

Meat proteins Fish proteins

Whey proteins Caseins

Leucine

mTORC1 Insulin

Insulin resistance

S6K1 IRS-1

β-Cell proliferation

β-Cell apoptosis

T2D

natural plant-derived mTORC1 inhibitors

Adipogenesis

Obesity

Leucine Amino acids

Leu Insulin IGF-1

mTORC1

IRS1

Insulin

4EBP1 S6K1

β

Milk: an mTORC1-driving signalling system

Whey proteins Caseins

Cell growth Cell proliferation

mTORC1

Leu

β-Cell

Peripheral cell

Fast intestinal hydrolysis Slow intestinal hydrolysis

Abundant whey protein-based dairy products of Western diet

•  Whey protein concentrates (bodybuilding)

•  Whey drinks •  Milk: whole milk, low fat milk, skim milk, buttermilk

•  Cocoa drinks

•  White coffee (Latte macchiato)

•  Yogurts

•  Ice creams

•  Curd cheeses

•  Milk chocolates and sweets

•  Puddings

•  Sausages

0

5

10

15

20

25

Annual per capita cheese consumption in Germany [kg]

1935 ´50 ´55 ´60 ´65 ´70 ´75 ´80 ´85 ´90 ´95 2000 ´05 2010

23 kg 2011

3.9 kg 1935

Widespread distribu4on of refrigera4on technology

Steady increase of leucine-rich milk proteins in Western Diets

Melnik BC et al. (2012)

Does milk protein consumption induce insulin resistance?

Milk consumption and insulin resistance

Um SH et al. (2006)

S6K1-mediated insulin resistance by nutrient and amino acid overload

Amino acid-mTORC1-S6K1-mediated insulin resistance via inhibitory phosphorylation of IRS-1

(insulin receptor substrate-1)

Boura-Halfon S et al. (2009)

Leucine

Amino acid-mTORC1-S6K1-mediated insulin resistance

Um SH et al. (2006)

Overactivation of S6K1 as a cause of human insulin resistance during increased amino acid availability

Tremblay F et al. (2005)

mTORC1 via S6K1 increases insulin resistance in humans (11 healthy men)

Krebs M et al. (2007)

mTORC1 via S6K1 increases insulin resistance in humans (11 healthy men)

Krebs M et al. (2007)

Amino acid over-nutrition in humans induced S6K1-mediated inhibitory phosphorylation of

IRS-1 Ser-1101 as a cause of insulin resistance


Amino acids + insulin induced S6K1-mediated inhibitory phosphorylation of IRS-1 Ser-1101

within 30 minutes


•  Insulin resistance is not a medical „blood parameter“ •  but a tissue-specific state and degree of IRS-1-dependent

downstream insulin signalling •  HOMA measurements rely only on fasting levels of insulin and glucose •  and do not reflect the real state of insulin resistance of any specific

insulin-dependent tissue like muscle, liver or adipose tissue

A more critical view on „insulin resistance“ is urgently needed, which has primarily to appreciate tissue-specific alterations of insulin signalling and not fasting parameters obtained from venous blood outside the organ system

Most nutritional studies do not consider the biochemical kinetics of fast signalling hormones

and nutrients in cell metabolism

•  The mTORC1 system responds within minutes to changes of amino acid- or growth hormone levels.

•  The cell has to respond quickly to changes of nutrient

availability and withdrawal to maintain cell homeostasis. •  Insulin exhibits fast kinetic (minutes) postprandial

responses to changes of glucose and amino acids.

•  Overnight fasting serum levels of insulin, glucose or amino acids do not reflect the daily metabolic burden but show metabolic events at their minimum.

Milk protein versus meat consumption in 8 y-old boys increased fasting insulin, insulin resistance and

β-cell function (7 days intervention)

Milk-group (53 g milk protein) Meat group (53 g meat protein)

Hoppe C et al. (2005)

Weakness: Only fasting levels and no postprandial effects have been measured in this study. Insulin resistance has been determined by HOMA and calculated from fasting levels

?

10 days-intervention in 11 adults consuming either 2.5 l semi-skimmed milk or cola

Measurement of fasting serum values and not postprandial parameters. HOMA data have been calculated from fasting serum levels of glucose and insulin and not from functional postprandial tests like OGTT or a clamp test.

Hoppe C et al. (2009)

?

Study of whey protein versus casein on insulin fasting levels and HOMA2 in overweight/obese individuals

(12 weeks) G: Glucose control group 27 g glucose (n=25) W: Whey group (27 g whey protein concentrate) (n=25) C: Casein group (27 g sodium caseinate) (n=20) Pal S et al. (2010)

G

C W

G C

W

HOMA data refect fasting insulin levels when fasting glucose has not changed

Critical remark: This study measured fasting insulin levels and not postprandial insulin responses

?

Of biological importance is not the insulin fasting level but the postprandial insulin secretion, which reflects

the metabolic burden (AUC) of the secreting β-cell

von Post-Skagegard M et al. (2006)

Milk = Cottage cheese (80% casein + 20% whey)

AUC Overnight fas4ng level

?

Conclusions: Milk consumption and insulin resistance

•  Available experimental data (Hoppe et al.; Pal et al.) do not reflect biochemical reality of milk-induced insulin resistance as they are only based on fasting serum levels of insulin, glucose and HOMA.

•  Experimental studies in humans with infused amino acids

resembling real postprandial amino acid challenge provided evidence for increased inhibitory IRS1-phosphorylation.

•  Determination of tissue mTORC1 activity by measuring 4EBP1-,

S6K1- and IRS1-phosphorylation after a milk protein challenge versus meat-, fish- or soy protein are urgently needed to characterize milk/leucine-mediated insulin resistance of other non-dairy protein sources.

Does persistent milk consumption disturb β-cell homeostasis?

Milk consumption and type 2 diabetes

Dietary protein intake and risk of T2D

•  Hong Kong Dietary Survey more vegetables, fruits and fish 14% lower risk of T2D more meat and milk products 39% greater risk of T2D (Hu R et al. 2011)

•  Meta-analysis of the Health Professionals Follow Up Study,

Nurses Health Study I and Nurses Health Study II

red meat consumption increased risk of T2D (Pan A et al. 2011)

T2D is an mTORC1-driven disease

•  Zoncu R et al. (2011) mTOR: from growth signal integration to cancer, diabetes and ageing. Nature Rev 12: 21

•  Proud CG (2010)

mTOR signalling in health and disease. Biochem Soc Trans 39: 431

•  Mieulet V et al. (2010)

Tuberous sclerosis complex: liking cancer to metabolism. Trends Mol Med 16: 329

•  Dann SG et al. (2007)

mTOR Complex 1-S6K1 signaling: at the crossroads of obesity, diabetes and cancer. Trends Mol Med 13: 252

BCAAs and leucine in β-‐cell mTORC1 ac@va@on

•  Xu G et a. (1998) Branched-‐chain amino acids are essen@al in the regula@on of PHAS-‐I and p70 S6 kinase by pancrea@c β-‐cells.

•  Xu G et al. (2001)

Metabolic regula@on by leucine of transla@on ini@a@on through the mTOR-‐signaling pathway by pancrea@c β-‐cells.

•  McDaniel ML et al. (2002)

Metabolic and autocrine regula@on of the mammalian target of rapamycin by pancrea@c β-‐cells.

•  Kwon G et al. (2004)

Signaling elements involved in the metabolic regula@on of mTOR by nutrients, incre@ns, and growth factors in islets.

The biological func@on of mammalian milk

Effects of high dietary leucine intake on β-cell mTORC1 signalling during periods of growth and adulthood

Leu Fetal life

Post- natal

Puberty Adulthood

High milk intake in

pregnancy

High Leu of Infant formula

High milk intake

in puberty

Milk and milk products

Leu Leu Leu

Diabetogenic effects by impaired β-cell development and disturbed postnatal metabolic programming

Early onset of T2D by persistent mTORC1-mediated β-cell proliferation and early β-cell apoptosis

?

Neurogenin3 expression: the critical step for the development of endocrine cells in the pancreas

Jorgensen MC et al. (2007)

Crititical role of high leucine intake during pregnancy for fetal β-cell differentiation and β-cell mass in the rat

Leucine

mTORC1

HIF1α

PDX-‐1 expressing islet progenitors

NGN3-‐expressing islet progenitors

β-cell formation

Increased risk of T2D

Rachdi L et al. (2012)

Increased leucine intake during pregnancy increases birthweight

Olsen SF et al. (2007) Rachdi L et al. (2012)

Rat Human neonate

Breast feeding in comparison to formula feeding protects against the development of T2D

Owen CG et al. (2006)

Cow milk-based infant formula-feeding exceeds leucine-, IGF-1- and C-peptide serum concentrations

in comparison to breast-feeding

Socha P et al.(2011) Melnik BC et al. (2012)

Persistent milk intake may disturb β-cell homeostasis by continued stimulation of β-cell proliferation

Continued leucine-mediated β-cell proliferation and the risk of early replicative β-cell senescence

Poten@al risk of persistent milk-‐mediated leucine-‐mTORC1-‐signalling in the pathogenesis of T2D

Postnatal β-cell mTORC1 hyperactivation by TSC2 ablation

Intitial increase and later decrease of β-cell numbers in mTORC1-hyperactivated β-cells

Shigeyama Y et al. (2008)

High fat-high casein diet promoted excessive β-cell loss by apoptosis in prediabetic nonobese diabetic mice

A high fat-high protein diet (43%fat, 38% casein,19% carbohydrates) has promoted a higher reduction of β-cell mass (84%) and more apoptotic β-cells at 30 weeks than a high fat-low protein diet (39% fat, 17% casein, 43% carbohydrates), which was associated with a lower reduction of β-cell mass (14%)

Linn T et al. (1999)

weeks

Misleading results of epidemiological studies analysing the risk of „dairy consumption“ for T2D

•  Questionaires of most studies have selected insufficient and incomparable data like: Total dairy consumption; Dairy intake; Milk and dairy food Low fat dairy products versus high fat dairy products Milk/milk products except cheese and cheese

•  Meta-analyses performed on the basis of these data are not appropriate.

•  All studies are performed in milk consuming populations and are not controlled against a non-milk-drinking population.

•  No intervention study with and without milk protein intake over diabetes-relevant long time periods of several decades has been performed.

•  No study has calculated total daily intake of milk protein mass in gram •  No study has considered the insulinotropic functionality of milk proteins and

has differentiated between highly insulinotropic whey protein intake and less insulinotropic casein protein intake

•  No study has evaluated total daily leucine intake of dairy proteins against the background of other animal and plant-protein-derived leucine intake.

•  Most studies have been performed in adults and no study has considered early sensitive perinatal periods of metabolic programming.

Conclusions (I) Milk and type 2 diabetes

•  Milk is an endocrine signalling system of mammalian evolution. •  Milk proteins via leucine activate β-cell mTORC1. •  mTORC1 plays a pivotal role in the regulation of insulin synthesis,

insulin secretion as well as β-cell mass homeostasis linking milk protein consumption to the pathogenesis of T2D.

•  Milk proteins are highly insulinotropic signalling proteins in

comparison to structural proteins like meat and fish. •  Increased leucine intake during pregnancy may impair fetal β-cell

mass differentiation via mTORC1-HIF1α-mediated suppression of NGN3-progenitor cells, thus reducing β-cell mass.

Conclusions (II) •  Infant formula feeding provides higher amounts of leucine than

breast-feeding, a possible explanation for the lower prevalence rates of T2D in breast-fed individuals.

•  Exaggerated leucine-driven mTORC1 signalling by persistent milk

consumption and high meat intake may accelerate the onset of T2D by induction of replicative β-cell senescence and apoptosis.

•  The transition of China from a leucine-poor vegetable-based to a

leucine-rich Western diet explains the increase of mTORC1-driven diseases like T2D as shown in the Hong Kong Dietary Survey.

Melnik BC (2012) Leucine signaling in the pathogenesis of type 2 diabetes and obesity. World J Diabetes, 3: 38-53

Melnik BC (2012) Excessive leucine-mTORC1-signalling of cow milk-based infant formula: the missing link to understand early childhood obesity. J Obesity, 2012: article ID 197653

Conclusion (III)

•  The glucose lowering effects of milk protein consump4on should not be mistaken as a protec4ve mechanism in the pathogenesis of T2D

•  Most epidemiological studies which have addressed the dairy-‐T2D rela4onship are misleading as they did not precisely differen4ate between intake of highly insulinotropic whey protein-‐based milk/products and less insulinotropic casein-‐based milk products.

•  Study determinants like „dairy product consump4on „total dairy intake“, „high fat versus low fat dairy products“ and short study periods (< 12 yrs) of adult subjects are not suitable to detect the rela4onship between persitent milk consump4on and T2D

Conclusions (IV)

•  Future studies have to differentiate between –  high insulinotropic whey-based milk products and –  less insuinotropic casein-based milk products and –  should calculate total daily leucine intake against the background

of meat/fish-derived leucine intake –  and should consider the effect of cow milk consumption over the

whole life span with special attention to intrauterine and perinatal phases of growth and metabolic programming.

Is milk an anabolic system that promotes adipogenesis and obesity?

Milk consumption and obesity

The adipogenic effects of milk

•  Leucine stimulates mTORC1 and S6K1- and 4EPB1 phosphorylation of adipocytes.

•  The mTORC1 inhibitor rapamycin inhibits adipocyte differentiation. •  mTORC1 stimulates lipid synthesis by phosphorylation of lipin1, the

stimulator of nuclear SREBP-1 activation •  mTORC1 activates PPARγ, the key transcription factor of adipogenesis. •  Milk increases postprandial insulin serum levels. Insulin inhibits lipolysis

and stimulates cellular lipid accumulation. •  Milk consumption increases serum levels of IGF-1, which promotes the

differentiation of pre-adipocytes to adipocytes. •  mTORC1 plays a fundamental role in the differentiation of

mesenchymal stem cells into adipocytes. •  Milk consumption in children increased BMI. •  Breast feeding in comparison to infant formula feeding has a preventive

effect on the development of obesity.

Amino acid effects on translational repressor 4E-BP1 are mediated primarily by L-leucine in

isolated adipocytes

Fox HL et al. (1998)

Amino acids stimulate phosphorylation of S6K1

and organization of rat adipocytes into multicellular clusters

Fox HL et al. (1998)

Leu 16x

Porstmann T et al. (2009)

mTORC1 controls SREBP1 the master transcription factor of lipogenesis

Amino acids via mTORC1 increase lipin phosphorylation in a rapamycin-sensitive manner linking the nutrient-sensing (mTORC1) pathway to adipocyte development

Huffman TA et al. (2002)

mTORC1 controls nuclear SREBP by phosphorylation of lipin1

Peterson TR et al. (2011)

Peterson TR et al. (2011)

Porstmann T et al. (2009)

Molecular crosstalk between amino acids, mTORC1 and SREBP1

Leucine stimulates PPARγ mRNA expression and adipose tissue increase in the rat

Zeanandin G et al. (2011)

Regulation of PPARγ activity by mTORC1 and amino acids in adipogenesis

Kim JE et al. (2004)


PPARγ is dependent on amino acid availabity and is regulated via mTORC1


Leucine

Leucine: strongest activator of mTORC1-mediated 4EBP1-phosphorylation in adipocytes

Lynch CJ et al. (2000)

mTORC1 substrate S6K1 promotes differentiation of adipocytes from multipotent stem cells

Carnevalli LS et al. (2010)

NCD= normal chow diet HFD= high fat diet

S6K1-/-

mice

mTORC1 suppresses lipolysis, stimulates lipogenesis, and promotes fat storage

Chakrabarti P et al. (2010)

Activation of mTORC1 in 3T3-L1 adipocytes •  inhibits expression of adipose triglyceride lipase (ATGL) •  and inhibits expression of hormone-sensitive lipase (HSL) at the

level of transcription •  suppresses lipolysis •  increases de novo lipogenesis •  promotes intracellular accumulation of triglycerides

Conclusions: Milk and adipogenesis

•  Milk consumption activates adipogenesis by up-regulation of mTORC1-SREBP- and mTORC1-PPARγ-signalling.

•  Cow´s milk based infant formula feeding increases serum levels of the mTORC1 activators leucine, insulin and IGF-1 and thus increases the risk of early mTORC1- driven adipogenic programming.

•  In mice mTORC1-S6K1 hyperactivity increased the differentiation of adipocytes from mesenchymal stem cells and increased the number of adipocytes during life time with the risk of adipose tissue hyperplasia and hypertrophy.

Does milk consumption increase the risk of common Western cancers?

Milk consumption and cancer

Epidemiological evidence: Dairy protein consumption increases

serum IGF-1 levels

Crowe FL et al. (2009)

Correlation between dairy protein intake and serum IGF-1 levels

Crowe FL et al. (2009)

Correlation between serum IGF-1 levels and breast cancer- and prostate cancer risk

All cancers express up-regulated IGF-1 receptor

Does milk consumption increase the risk of the most common cancer in men?

Milk consumption and prostate cancer

Incidence rate of prostate cancer and per capita milk consumption

Ganmaa D et al. (2002)

Strong epidemiological evidence for the association between dairy protein intake and

prostate cancer

Allen NE et al. (2008)

Prospective study over 8.7 years European multi-centric study 142,251 men 35 g increase in dairy protein associated with a risk increase of prostate cancer of 32%

Epidemiological evidence for dairy protein consumption and prostate cancer

Allen NE et al. (2008)

Increased risk of advanced prostate cancer in men with daily milk consumption during adolescence

(Island Study)

Daily milk consumption during adolescence has been associated with a 3.2-fold increased risk of advanced prostate cancer

Torfadottir JE et al. (2011)

Milk consumption promotes the progression of prostate cancer

Men with the highest versus lowest intake of whole milk were at an increased risk of prostate cancer progression

Pettersson A et al. (2012)

Milk stimulates growth of prostate cancer cells in vitro

Cow´s milk stimulated the growth of LNCaP prostate cancer cells in each of 14 experiments producing an average increase in growth rate of 30%.

Tate PL et al. (2011)

Common mutations or aberrations in the mTORC1 signalling cascade of prostate cancer cells


IRS$1& RAS&

RAF&

MEK&

ERK1/2&

&&TSC1&/&TSC2%

mTORC1!%%%!

4EBP1& S6K1&

AMPK&&&&&&&&&&&LKB1&&

PDK1&

mTORC2%

PRAS40& &FoxO1&

mTORC1&inac&ve!!

Leucine&Rag%GTPases%

Insulin&&&

Glucose&

&LAT%

GLUT%

%IGF1R%

PTEN%

%%%%%Androgen&

Estrogens&

&Leucine%

&&&&&&&&&Glu&

ATP&

Akt%

PI3K%

Rheb%

&&IR%%IGF$1&

!lysosomal!

Increased&transcripIon,&mRNA&translaIon,&ribosome&biogenesis,&&cellular&growth,&proliferaIon,&and&cell&survival&&

Prostate%tumorigenesis% Fig.&3&

Milk signalling augments activated mTORC1 signalling pathways of prostate cancer cells

IRS$1& RAS&

RAF&

MEK&

ERK1/2&

&TSC1&/&TSC2%

mTORC1!!%%%!

4EBP1% S6K1%

AMPK&&&&&&&&&&&LKB1&&

PDK1&

mTORC2%

PRAS40&&FoxO1&

mTORC1&

inac&ve!!

Leucine%

Rag&GTPases&

Insulin%%%

Glucose%

&LAT%

GLUT%

%IGF1R%

PTEN%

%%%%%Androgen%

Estrogens*%

&Leucine%

&&&&&&&&&Glu&

ATP&

Akt%

PI3K%

Rheb%

&&IR%

IGFH1%&&&&&&&&&%%%%%%%%MILK*%%

%

Androgen$&

precursors*&

!lysosomal!

MilkHmediated%mTORC1HoveracLvaLon%%

promoLng%prostate%tumorigenesis%%

Induc&on!

Fig.&5&


Conclusions: Milk consumption and prostate cancer

•  Most epidemiological studies support the association between milk protein consumption and increased risk of prostate cancer.

•  In vitro evidence confirms the stimulatory effect of milk on the growth

of prostate cancer cells.

•  Growth-promoting mTORC1-mediated milk signalling stimulates already activated cellular pathways of mutated prostate cancer cells, which results in hyper-activated mTORC1 signalling, thus promoting the development and progression of prostate cancer.

•  Milk consumption during prostate morphogenesis and sexual mTORC1-dependent maturation and differentiation of the prostate during puberty may stimulate tumorigenesis and may increase the risk of advanced prostate cancer in adulthood.

Does milk consumption increase the risk of the most common cancer in women?

Milk consumption and breast cancer

Milk consumption: a suspected dietary risk factor of breast cancer and ovarian cancer

Relative increase in the consumption of milk and dairy proteins in Japan after World War II

Milk and dairy products

Li XM et al. (2003)

Correlation bewteen milk consumption and breast cancer mortality in Japan

Li XM et al. (2003)

Correlation between per capita milk consumption and incidence rates of breast cancer

Ganmaa D et al. (2005)

High mammographic breast density is a risk factor of breast cancer which correlates with increased serum levels of IGF-1

Milk promotes the progression of DMBA-induced mammary tumors in rats

5 mg anthracen DMBA

Carcinogen

Rats with breast cancer

Rat chow without milk proteins

Rat chow with commercial milk

Tumor incidence, tumor numbers and tumor volume

?

Experimental design of the study of DMBA-induced mammary tumors in rats to dietary cow´s milk exposure

Milk intake increased incidence, tumor numbers and tumor volume of DMBA-induced mammary tumors in rats

Qin LQ et al. 2007

Milk (whole + nonfat)



Tumor incidence

Tumor numbers

Tumor volume

Control

Control

Control

Dose-dependent increase in breast cancer risk by daily milk consumption

•  Study of 25 892 Norwegian women (Cancer register of Norway)

•  Daily intake of > 750 ml whole milk

increased the relative breast cancer risk by 2.91 •  in comparison to women with < 150 ml milk intake, who

exhibited a relative risk of 1.0

Gaard M et al. (1995)

Commercial milk produced from pregnant cows contains substantial amounts of pregnancy-

derived estrogens, well-known breast cancer- promoting hormonal stimuli

Milk protein intake during pregnancy

Increased birthweight

Increased risk of breast cancer

•  Milk consumption during pregnancy increases birthweight

The association between birthweight and breast cancer

Increased birthweight and breast cancer risk

Conclusions (I): Milk consumption and breast cancer (BC)

•  Worldwide milk and dairy protein per capita intake correlates with the incidence rate of BC.

•  Epidemiological evidence supports the association between milk protein

consumption and increased serum levels of IGF-1. •  Increased serum IGF-1 levels are associated with increased risk of BC. •  Increased serum levels of IGF-1 are associated with increased

mammographic breast density, a high risk factor of BC. •  Growth-promoting mTORC1-mediated milk signalling stimulates cellular

pathways of mutated BC cells, which results in hyper-activated mTORC1 signalling, thus promoting the progression of BC.

Conclusions (II): Milk consumption and breast cancer (BC)

•  Milk consumption of DMBA-induced mammary tumors in rats increased tumor incidence, tumor numbers and tumor volume.

•  Estrogens introduced into the human food chain by milk and milk

product consumption of pregnant cows may be an important co-stimulatory factor increasing BC-promoting mTORC1 signalling

•  There appears to be a dose-dependent increase of BC risk by

increased daily milk intake of women in Norway. •  Milk protein intake during pregnancy may not only increase infant´s

birthweight but may deviate developmental mTORC1-dependent pathways of mammary gland morphogenesis increasing the risk of BC later in life.

Does milk consumption promote or aggravate acne?

Milk consumption and acne

Pathogenesis of acne

Follicular hyperproliferation

Hyperproliferation and hyperplasia of sebaceous glands

Follicular and peri-follicular inflammation comedo

formation

Common types of acne

Acne comedonica with sehorrhea

Moderate acne papulopustulosa

Severe acne papulopustulosa

Acne: a disease of Western civilization

Cordain L et al. (2002)

Systematic meta-analysis of studies related to the association between diet and acne

Spencer EH et al. (2009)

Smith RN et al. 2007

At baseline After 12 weeks

Improvement of acne by glycemic load reduction

Acne improvement by reduction of glycemic load

SREBP expression

Before diet During diet

Kwon HH et al. (2012)

Nurse Health Study (II) USA retrospective cohort study (n = 47 355)

Adebamowo CA et al. (2005)

Growing Up Today Study USA (prospective cohort study)

•  4273 boys and

•  6094 girls age range 9-15 years

Significant correlation between daily milk intake, especially skim milk, and acne prevalence

Adebamowo CA et al. (2006, 2008)

Clinical evidence for the acne-promoting effect of milk, especially skim milk

Di Landro A et al. (2012)

Paleolithic versus Western diet

Science 326, Dezember 2009 Evolu7on of Diseases of Modern Environments Charité University Medicine Berlin, Humbold University,

Whey protein abuse in the body building environment

80 g Whey protein = 12 L milk

Leucine + BCAAs Insulin + IGF-1 DHEAS mTORC1

Whey acne

Acne cure by the paleo diet

Increased prevalence of prostate cancer in patients with severe long-lasting acne

Sutcliffe S et al. (2007)

The cause for this relationship should not be explained by the appearance of P. acnes in the prostate gland but most likely by the overlap of exaggerated mTORC1 signalling in sebaceous glands promoting acne and exaggerated mTORC1 signal transduction promoting aberrant prostate differentiation during sexual maturation

mTORC1: the convergence point of nutrient-signalling in acne

Melnik BC (2012)

Conclusions: Milk consumption and acne

•  Epidemiological evidence strongly supports the association bewtween milk consumption and acne.

•  Recent clinical evidence confirmed the association between milk consumption, especially skim milk consimption and acne.

•  Milk signalling by increasing insulin and IGF-1 serum levels mimics the endocrine signalling of puberty.

•  High glycemic load of Western diet combined with milk intake in a synergistical fashion augment mTORC1 signalling of the sebaceous follicle increasing sebaceous lipid synthesis (seborrhea) and promoting keratinocyte proliferation (comedo formation).

•  Dietary intervention in acne is of crucial importance. Paleolithic type

diets provide a great chance for the prevention of acne, a visible mTORC1-driven skin disease of Western malnutrition.

Anthropological conclusions

•  The dietary change from less insulinotropic and less mTORC1-activating structural proteins like meat and fish to increased consumption of signalling proteins for mammalian neonatal growth promotes exaggerated mTORC1-signalling – the crucial underlying cause of all chronic mTORC1-driven diseases of civilization like fetal macrosomia, acne, obesity, type 2 diabetes, cancer and most likely neurodegenerative diseases.

•  Permanent milk consumption by continued and increasing exposure

to the endocrine growth-promoting species-specific signalling system of Bos taurus is a violation against human´s natural endocrine homeostasis and against the laws of human´s natural physiology.

Comparison between populations with high versus moderate dietary mTORC1 activity

Western diet Paleolithic diet

High flux of milk-derived insulinotropic amino acids combined with high load of hyperglycemic carbohydrates

Consumption of less insulinotropic amino acids derived from fish or meat combined with low glycemic carbohydrates

Milk-driven mTORC1 signalling and mTORC1-associated diseases of civilization

mTORC1 Type 2 diabetes

Insulin resistance

Obesity

Cancer: prostate, breast

Acne

Fetal macrosomia with increased birthweight

It´s never too late for a change: We are Homo sapiens and not Homo bovinus

Thank you for your attention !

References Literature request: [email protected]

•  Melnik B (2009) Milk consumption: aggravating factor of acne and promotor of chronic diseases of Western societies. J Dtsch Dermatol Ges 7: 364-70.

•  Melnik BC (2009) Milk – the promoter of chronic Western diseases. Med Hypotheses 77: 631-9.

•  Melnik BC (2011) Milk signalling in the pathogenesis of type 2 diabetes. Med Hyptheses 76: 553-9.

•  Melnik BC (2011) Evidence for acne-promoting effects of milk and other insulinotropic dairy products. Clemens RA, Hernell O, Michaelsen KF (eds): Milk and Milk Products in Human Nutrition. Nesté Nutr Inst Workshop Ser Pediatr Program, vol. 67, pp 131-145.

•  Melnik BC (2012) Excessive leucine-mTORC1-signalling of cow milk-based infant formula: the missing link to understand early childhood obesity. J Obesity 2012: 1-14, article ID 197653

•  Melnik BC (2012) Leucine signaling in the pathogenesis of type 2 diabetes and obesity. Word J Diabetes 3: 38-53.

•  Melnik BC (2012) Dietary intervention in acne. Attenuation of increased mTORC1 signaling promoted by Western diet. Dermatoendocrinology 4:1: 1-13

•  Melnik BC (2012) Diet in acne: further evidence for the role of nutrient signalling in acne pathogenesis. Acta Derm Venereol 92: 228-31.

Health & Medicine

Milk signaling_Dr. Melnik, NutriScience, Portugal, 2012