Low Fat Center for Energy Balance Journal Club Shannon Armbruster MD Gynecologic Oncology October...

The Clash of the Diets

Low Fat

Center for Energy Balance Journal ClubShannon Armbruster MD

Gynecologic OncologyOctober 15, 2015

Overview

• Background– Breast Cancer Facts– Diets and Breast Cancer Risk

• Paper Presentation– Design, Setting, Participants– Intervention– Results– Conclusion/Relevance

The Facts:

• In 2012: 224,147 women in the United States were diagnosed with breast cancer.*†

• In 2012, 41,150 women in the United States died from breast cancer.*†

†Source: U.S. Cancer Statistics Working Group, CDC.

40 50 60 700

5

10

15

20

25

30

35

40

45

14.7

23.8

35.738.5

Risk of Breast Cancer Stratified by Age (SEER)

Age (years)

Dea

ths

per 1

000

Wom

en

ACOG and ACS: Mammograms at “age 40 years and older, offered annually”

Recommendations:

What does the Mediterranean diet (MeDiet)

have to do with it?

Methods: 605 patients (mostly men) with Cardiovascular disease (CVD) randomized to MeDiet or control

Results: Reduction in Risk of cancer 61% in Experimental Group (12 v 2 cancers of all subtypes)

Methods: 121,700 women from Nurses’ Health Study followed from 1984-2002

Results: • Greater adherence to the MeDiet resulted in lower risk of ER –

breast cancer

Methods: 335,062 women followed in a cohort study for 11 years

Results: • Mediterranean diet (MeDiet) reduced breast cancer by 6% overall• 7% reduction in post menopausal women• ER/PR- tumors reduced by 20% in postmenopausal women• Lack of association between MeDiet and breast cancer in premenopausal

women

Methods: 33,731 women followed in a cohort study for 9 years

Results: • No significant association between MeDiet and breast cancer • Premenopausal women: Non-significant trend of increasing

compliance with MeDiet and lower risk of breast cancer• No clear trends in post menopausal women

Methods: 49,258 women aged 30 to 49 years at recruitment, followed from 1991/1992 to 2008

Results: • No significant association between MeDiet and breast cancer in

this cohort

The next step…

Purpose: Evaluate the incidence of breast cancer after implementation of 2 Mediterranean diet interventions (olive oil v. nuts) or a low-fat diet

Participants

• Framed with the PREDIMED (Prevencion con Dieta Mediterranea) trial

• Women 60-80 years of age– Diabetes Mellitus Type 2– At least 3 major CVD risk factors

– Smoking, hypertension, elevated low-density lipoprotein cholesterol level, low high-density lipoprotein cholesterol level, overweight /obesity, or family history of premature coronary heart disease

Randomization and Intervention

4282 Women

MeDiet with EVOO

N=1476

MeDiet with Nuts

N=1285

Control Diet (Low-Fat)N=1391

Interventions

MeDiet Groups:• Sessions:– Baseline and quarterly

assessment – Personalized Advice

• Incentives:– Given Extra Virgin

Olive Oil or Nuts

Control Group• Yearly low-fat diet

leaflets• Sessions*• Incentives:– Non-food items*

* Protocol modification in Oct. 2006

Baseline Characteristics of Female PREDIMED Participants

Risk of Invasive Breast Cancer: Per Intervention Group

Results

• High consumption of EVOO needed to obtain significant protection

• Non-significant reduction with nuts

Strengths

• Randomized design• Little residual confounding• Blinding of medical info while assessing

outcomes

Limitations

• Secondary analysis• Small number of breast cancer cases identified• No proof baseline mammograms were free of disease• No confirmation that all women even received a

mammogram• Lack of diversity• Reproductive factors are unknown for participants• Changes due to diet or olive oil?• For the first 3 years, the control group was less

“intense”

Limitations: Low-Fat Diet

• High fat diets associated with a higher risk of breast cancer– WHI (Women’s Health Initiative): higher risk of

breast cancer with higher total fat consumption• There is a possibility that the low-fat group

would have had better outcomes, if they truly followed a low-fat diet

Proposed Biologic Mechanisms

Anti-carcinogenic properties of EVOO

Oleic Acid: Anti-proliferative properties

Polyphenols: role in breast cancer prevention

Oleocanthal: inhibition of tumor growth, proliferation, migration, and invasion of BC cells

Oleuropein: increased apoptosis of cultured breast cancer cells

Hydroxytyrosol: reduce intracellular reactive oxygen species and prevent oxidative DNA damage

Lignans: seen in association with lower rates of post menopausal breast cancer

The Clash of the Diets

Low Fat

Comments/ Discussion

• Weight as a factor?• Impact of Reproductive Factors– Breast feeding– When a patient had children

• Generalizability?