Levels of sex-hormone binding globulin, as previously mentioned, play a role in numerous conditions. Low levels are associated with hormone-related conditions such as breast cancer, polycystic ovary syndrome, and insulin resistance. Furthermore, decreased levels of this protein are associated with cardiovascular risk factors as well. A recent study showed that low SHBG is significantly associated with metabolic syndrome, increased triglycerides, and decreased high-density lipoprotein (HDL) in men and women. In women, decreased SHBG was also associated with elevated apolipoprotein B and diabetes.10 SHBG has also been shown to inhibit the estradiol-induced proliferation of breast cancer cells.11
DIET, LIFESTYLE, HORMONES, AND BREAST CANCER
Chronic hyperinsulinemia is intimately linked to diet, lifestyle, and the development of a hormonal profile that correlates with increased breast cancer and hormone-related disease risk. What is noteworthy is the ability of insulin to inhibit hepatic synthesis of SBHG and enhance ovarian production of androgens.12-14 Addressing the cause of hyperinsulinemia is a significant clinical intervention, thus lowering the adverse risk associated with this hormonal disturbance. Overweight women with high intra-abdominal fat stores have a particular risk for developing breast cancer as a result of hormone-modifying factors, including insulin resistance, increased insulin levels and insulin-like growth factor-I, low serum levels of SBHG, and high sexhormone levels.15-18
Clinicians are challenged daily when diagnosing hormon-ally related disease states.
Consuming a low-carbohydrate diet, while focusing on high-fiber and antioxidant-abundant vegetables, is a must for these patients. Increased fiber intake helps to ensure more regular bowel movements, with the goal being two to three bowel movements per day to increase elimination of toxic digestive products, hormones, and deleterious metabolites. Equally important is the ability of fiber-rich foods to prevent reabsorption of hormonal metabolites back into circulation.
DIETARY INTERVENTIONS FOR HORMONE MODULATION Isoflavone- and Indole-Rich Foods
Dietary interventions, particularly phytoestrogen-rich foods,19,20 can help to control and modulate the availability of sex hormones. These plant-derived diphenolics have both estrogenic and antiestrogenic properties that can help to diminish breast-cancer risk.21,22 Classical phytoestrogen sources include soy (Glycine soja) isoflavones, lignans from flax (Linum usi-tatissimum) and other seeds and fiber-rich vegetables, and coumestrol from legumes and alfalfa sprouts.23-25 (See the box on page 192 entitled "Phytoestrogen-Rich Foods.'') Indole-3-carbinol (I3C)-abundant foods, such as cruciferous vegetables, are equally worth integrating into a hormone-modifying regimen because of these foods' estrogen-modulating activity.26 It is advisable for patients to consume organic produce (and organic food in general) whenever this is possible, to minimize exposure to lipid-soluble pesticides and herbicides that can have numerous adverse effects in the body. What is noteworthy is that several agricultural chemicals, such as polychlorinated biphenyls (PCBs) and other organochlorines, can affect hormone function within the body, thus introducing another risk factor into the health equation.
There is a significantly lower prevalence of cancer risk in Asian populations.27 The main risk factor for the Caucasian women, as opposed to the Oriental women, may be their higher estrogen levels that result from a higher-fat diet, higher estrogen production, and lower fecal estrogen excretion. In approximately 50% of the current studies available on this topic, Asian women have higher serum levels of SBHG. As mentioned previously, low levels of SHBG are associated with increased risk of breast cancer.
Maintaining and restoring intestinal microflora can augment the effects of isoflavone consumption.
Was this article helpful?