Olive oil consumption probably reduces breast cancer and cancer of the digestive system

Objectives:
There is no published systematic review and meta-analysis regarding the effect of olive oil consumption on cancer occurrence. Therefore, this review article has been conducted.

Does olive oil consumption reduce cancer risk?

Study design:
This review article included 19 case-control studies (13800 cancer patients and 23340 controls).

Random effects meta-analysis was applied in order to evaluate the research hypothesis.
Heterogeneity of the effect-size measures was observed in studies performed in the Mediterranean region (n = 15, p = 0.0002), whereas no heterogeneity was observed in non-Mediterranean studies (n = 4, p = 0.12).

Results and conclusions:
The investigators found when comparing with the lowest, the highest category of olive oil consumption was significantly associated with lower odds of having any type of cancer [log odds ratio = -0.41, 95% CI = -0.53 to -0.29, Cohran's Q = 47.52, p = 0.0002, I2 = 62%].

The investigators found both Mediterranean and non-Mediterranean people reported olive oil intake were less likely to have developed any type of cancer.

The investigators found olive oil consumption was significantly associated with lower odds of developing breast cancer [logOR = -0.4,  95% CI = -0.78 to -0.12] and a cancer of the digestive system [logOR = -0.36, 95% CI = -0.50 to -0.21] compared with the lowest intake.

The investigators concluded olive oil consumption probably reduces risk of any type of cancer, especially breast cancer and cancer of the digestive system. Probably, because this review article only included case-control studies and there was heterogeneity.
The reduced risk is similar to studies performed in Mediterranean as well as non-Mediterranean countries. However, it is still unclear whether olive oil's monounsaturated fatty acid content or its antioxidant components are responsible for its beneficial effects.

Original title:
Olive oil intake is inversely related to cancer prevalence: a systematic review and a meta-analysis of 13800 patients and 23340 controls in 19 observational studies by Psaltopoulou T, Kosti RI, […], Panagiotakos DB.

Link:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3199852/

Additional information of El Mondo:
Find more studies on olive oil consumption and fat.