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?