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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?