Plasma equol concentration is not associated with breast cancer and fibrocystic breast conditions among women in Shanghai, China

Tailoring Potential Natural Compounds for the Treatment of Luminal Breast Cancer

Breast cancer (BC) is the most diagnosed cancer worldwide, mainly affecting the epithelial cells from the mammary glands. When it expresses the estrogen receptor (ER), the tumor is called luminal BC, which is eligible for endocrine therapy with hormone signaling blockade. Hormone therapy is essential for the survival of patients, but therapeutic resistance has been shown to be worrying, significantly compromising the prognosis. In this context, the need to explore new compounds emerges, especially compounds of plant origin, since they are biologically active and particularly promising. Natural products are being continuously screened for treating cancer due to their chemical diversity, reduced toxicity, lower side effects, and low price. This review summarizes natural compounds for the treatment of luminal BC, emphasizing the activities of these compounds in ER-positive cells. Moreover, their potential as an alternative to endocrine resistance is explored, opening new opportunities for the design of optimized therapies.

Production of Bovine Equol-Enriched Milk: A Review

Simple Summary

Milk and dairy products contain many substances beneficial to human health; moreover, the contents of some of these substances can be enhanced. This is also the case of isoflavones which are compounds of plant origin that can be ingested and metabolized by cattle and, subsequently, secreted into bovine milk. An especially healthful substance called equol is ranked among isoflavone metabolites, commonly produced in the digestive tract of cattle. Equol content in milk can be modified by using feedstuffs with different contents of isoflavones or by milk processing and storage.

Abstract

Milk and dairy products are important sources of nutrients in the human diet because they contain a number of essential substances and other biologically active components. Many of these substances can be modified, and thus offer opportunities to use milk and dairy products as functional food. Isoflavones are particularly important in human nutrition due to their diverse pharmacological and antioxidant properties. The clinical effectiveness of isoflavone-rich products is believed to be dependent on their ability to metabolize daidzein to equol, which may directly exert cancer preventive effects. However, only approximately 30–40% of humans are able to produce equol, while animals, in general, produce equol. Equol is the predominant product of bacterial metabolism of isoflavones and can be found in various amounts in some food of animal origin, especially in milk. Therefore, milk and dairy products can be considered to be sources of equol for humans who are not able to produce this metabolite. When the content of isoflavones in milk is to be modified, two groups of factors should be considered, i.e., dietary factors that include the source of isoflavones and the processing effects on feedstuffs and animal factors that include the intake of isoflavones, ruminal and postruminal changes, and the health and physiological status of animals. The approximate content of isoflavones in milk can be predicted using carry-over rates for different dietary sources or using a formula that describes the relationship between equol concentration in milk and formononetin intake. Processing and storage can affect the content and profile of isoflavones in milk and dairy products.

Serum isoflavones and lignans and odds of breast cancer in pre- and postmenopausal Chinese women

OBJECTIVE

Isoflavones and lignans are phytoestrogens present in plant-based foods, which have a potential preventive effect on breast carcinogenesis. The effects of phytoestrogens on breast cancer may differ according to the hormonal environment. This case-control study aimed to investigate the association between serum phytoestrogens and odds of breast cancer among Chinese pre- and postmenopausal women.

METHODS

A total of 792 cases and 813 age-matched controls were included. Serum isoflavone (daidzein, genistein, glycitein, equol, and formononetin) and lignan (enterodiol and enterolactone) concentrations were measured using a liquid chromatography-tandem mass spectrometry method.

RESULTS

Significant inverse associations were found between serum total soy isoflavone precursors, daidzein, genistein, formononetin, total lignans, enterodiol, enterolactone, and the odds of breast cancer in premenopausal but not postmenopausal women. For premenopausal women, the adjusted odds ratios (95% confidence intervals) for the highest versus the lowest serum concentration groups were 0.60 (0.41-0.87) for total soy isoflavones precursors, 0.64 (0.44-0.93) for daidzein, 0.62 (0.43-0.90) for genistein, 0.49 (0.35-0.68) for formononetin, 0.38 (0.25-0.57) for total lignans, 0.49 (0.33-0.73) for enterodiol, and 0.49 (0.33-0.74) for enterolactone. However, the interaction between serum phytoestrogens and menopausal status on odds of breast cancer was statistically significant only for daidzein. No significant association was found between serum equol or gycitein and the odds of breast cancer among either pre- or postmenopausal women.

CONCLUSIONS

Higher levels of certain serum isoflavones and lignans were associated with reduced odds of breast cancer in premenopausal women, but the interaction was statistically significant only for daidzein.

Polyphenols: dietary assessment and role in the prevention of cancers

PURPOSE OF REVIEW

Polyphenols are a large and diverse family of phytochemicals widely consumed by humans. Here we summarize the latest epidemiological evidence for associations between cancer risk and polyphenol intake, taking into account difficulties in the accurate estimation of exposure.

RECENT FINDINGS

Flavonoids are the most studied subgroup of polyphenols with regard to cancer risk. In recent epidemiological studies, total flavonoid intake has rarely been associated with a reduction in cancer risk. However, isoflavones, whose main dietary source is soy foods, plausibly reduce the risk of colorectal, breast, and prostate cancers, especially in Asian countries. Findings depend heavily upon the assessment of polyphenol intake, which is usually measured by food frequency questionnaires coupled to databases of food polyphenol composition. To a lesser extent, nutritional biomarkers have been used whenever estimating associations of polyphenol intake with cancer.

SUMMARY

Polyphenol intake may mitigate cancer risk but this depends on cancer site, the subgroup of compounds under study, and accurate assessment of dietary exposure. Further work must better characterize the effects of intake of different flavonoid subclasses and begin to investigate the role of phenolic acids and other minor polyphenol classes.