Diet has long been reported to potentially affect breast cancer risk. Growing evidence suggests that n-3 polyunsaturated fatty acids (PUFAs) may play a role in the pathogenesis of breast cancer. A new study documents an inverse association between breast cancer risk and n-3 PUFA consumption, especially in premenopausal women who are obese.
Breast cancer is by far the most common malignant tumor in women worldwide, so it’s little wonder that so many studies focus on ways to limit the risk of this highly prevalent disease. Previous studies have been conducted to investigate the association of n-3 PUFAs with breast cancer risk but have shown mixed results. Many of these studies were performed only in postmenopausal women because the peak age for breast cancer is 60 to 70 years in western countries, whereas it is age 40 to 50 years in Asian countries.
In this latest hospital-based, case-control study including nearly 1,600 cases, researchers not only examined the association between the intake of n-3 PUFAs in general with breast cancer, but they also looked at the effect of individual n-3 PUFAs. Good sources of n-3 PUFAs include fish, vegetable oil, nuts (especially walnuts), flax seeds and flaxseed oil, and leafy vegetables. Because the human body does not produce n-3 fatty acids naturally, these food sources are essential. In addition, researchers also examined whether the association was modified by menopause status, hormone-receptor status, or linoleic acid intake.
The study concluded that a higher intake of marine n-3 PUFAs and total n-3 PUFAs was associated with a lower risk of breast cancer. Dietary a-linolenic acid, eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid also were inversely associated with breast cancer risk. Such inverse associations were more evident in premenopausal women and women with certain types of breast tumors. In addition, a decreased risk of breast cancer was significantly associated with increasing n-3 PUFA intake in women who were overweight or obese but not in women of normal weight. There was a significant interaction between linoleic acid and marine n-3 PUFAs.
Objective: This study aimed to evaluate the associations between breast cancer risk and intake of n-3 polyunsaturated fatty acids (PUFAs) and/or n-3 PUFA subclasses in Chinese women, and determine whether these associations varied with menopausal status or clinical characteristics.
Methods: A hospital-based case-control study including 1,589 cases and 1,621 age-frequency-matched controls was conducted. Dietary data were assessed by a validated food frequency questionnaire. Odds ratios (ORs) and 95% confidence intervals were obtained using multiple unconditional logistic regression models after controlling for potential confounders.
Results: Higher intake of marine n-3 PUFAs and total n-3 PUFAs was associated with lower risk of breast cancer, with adjusted OR quartile 4 v.1 (95% confidence intervals) of 0.68 (0.55-0.84) and 0.56 (0.42-0.75), respectively. Dietary a-linolenic acid, eicosapentaenoic acid, docosapentaenoic acid, docosahexaenoic acid were also inversely associated with breast cancer risk, with adjusted ORs (95% confidence intervals) of 0.51 (0.38-0.70), 0.68 (0.55-0.84), 0.68 (0.55-0.85), and 0.76 (0.61-0.94), respectively. In stratified analyses, these inverse associations between risk and dietary n-3 PUFAs were more evident among premenopausal women and women with ER+, PR+ and ER+PR+ tumors. A decreased risk of breast cancer was significantly associated with increasing n-3 PUFA intake in obese/overweight women, but not in women of normal weight. There was a significant interaction between linoleic acid and marine n-3 PUFAs.
Conclusions: High intake of n-3 PUFAs and n-3 PUFA subtypes was associated with a lower risk of breast cancer, especially among premenopausal women and women with ER+ and/or PR+ subtype breast cancer.
Content created August 2022