Can supplementary dietary fibre suppress breast cancer growth?

Abstract

Summary Case -control studies in diverse populations around the world have reported a lower risk of breast cancer in association with higher intake of dietary fibre and complex carbohydrates. Although this has not been confirmed in prospective studies in the USA, the observations have prompted the hypothesis that prolonged use of dietary fibre supplements might reduce breast cancer risk in high-incidence populations. Several possible mechanisms of action have been suggested, all involving a reduction of bioactive oestrogen levels in the blood. The various mechanisms are not necessarily mutually exclusive. First, a high-fibre diet might reduce circulating oestrogen levels by reducing the enterohepatic recirculation of oestrogen. Second, many plants and vegetables contain isoflavones and lignans capable of conversion in the bowel into weak oestrogens that may compete with oestradiol for target binding-sites. Third, a high-fibre diet is less often associated with obesity, which tends to increase availability of the biologically active 16-alpha metabolites of oestrone. Fourth, a high-fibre diet usually has a lower content of fat and a higher content of antioxidant vitamins, which may protect against breast cancer risk. Finally, diets rich in fibre and complex carbohydrates have been shown to improve insulin sensitivity, with an associated reduction in circulating oestrogen levels. Synergism between these effects offers a possible mechanism by which a high fibre intake might suppress breast cancer growth in women.

Wheat bran: its composition and benefits to health, a European perspective

“…Pre-menopausally, fibre from cereals was inversely associated with risk of breast cancer and fibre from fruit had a borderline inverse relationship. Mechanisms of effect are postulative, but plausible mechanisms could be the role in fibre and weight management and the potential for fibre to bind with estrogens (Goldin et al 1986; Rose et al 1991; Stoll 1996). …”

Survival Impact of Integrative Cancer Care in Advanced Metastatic Breast Cancer

“…The recent finding of improved relapse‐free survival in patients assigned to a low‐fat diet in a large randomized trial (33) is of particular interest in relation to the low‐fat eating plan of the Center. Other specific factors that may contribute to prolonged survival or treatment tolerance in the BCICT program include increased intakes of antioxidants and phytochemicals (34), improved body composition and weight reduction due to increased exercise (associated with a 50% decrease in mortality for 3–5 hours weekly of moderate exercise) (35), reduction of stress hormones with mind‐spirit interventions (36), lower overall dietary intake of fat (29,37), and higher vegetable (38), fiber (39) and omega‐3 fatty acid intake (40).…”

Integrative approaches in breast cancer patients: A mini-review

“…The same trend is observed in Europe. A survey among cancer patients in 14 European countries confirmed that nearly 40% had used IT [6]. This study also assessed that recourse to complementary therapies varies from 15% to 73% among countries.…”

“…Finally, a high-fiber, low-fat diet works to reduce serum estradiol that may be involved in the progression of hormonal dependent breast cancer [14][15][16]. In addition, these foods appear to increase serum insulin and serum IGF-I levels which appear to stimulate cancer cell growth [17].…”