lignans and Osteoporosis--Postmenopausal

Interest in the physiological role of bioactive compounds present in plants has increased dramatically over the last decade. Of particular interest in relation to human health are the class of compounds known as the phytoestrogens, which embody several groups of non-steroidal oestrogens including isoflavones & lignans that are widely distributed within the plant kingdom. Data from animal and in vitro studies provide plausible mechanisms to explain how phytoestrogens may influence hormone dependent states, but although the clinical application of diets rich in these oestrogen mimics is in its infancy, data from preliminary studies suggest potential beneficial effects of importance to health. Phytoestrogens are strikingly similar in chemical structure to the mammalian oestrogen, oestradiol, and bind to oestrogen receptors (ER) with a preference for the more recently described ER beta. This suggests that these compounds may exert tissue specific effects. Numerous other biological effects independent of the ER (e.g. antioxidant capacity, antiproliferative and antiangiogenic effects) have been ascribed to these compounds. Whether phytoestrogens have any biological activity in humans, either hormonal or non hormonal is a contentious issue and there is currently a paucity of data on human exposure. Much of the available data on the absorption and metabolism of dietary phytoestrogens is of a qualitative nature; it is known that dietary phytoestrogens are metabolised by intestinal bacteria, absorbed, conjugated in the liver, circulated in plasma and excreted in urine. Recent studies have addressed quantitatively what happens to isoflavones following ingestion--with pure compound and stable isotope data to compliment recent pharmacokinetic data for soy foods. The limited studies conducted so far in humans clearly confirm that soya isoflavones can exert hormonal effects. These effects may be of benefit in the prevention of many of the common diseases observed in Western populations (such as breast cancer, prostate cancer, menopausal symptoms, osteoporosis) where the diet is typically devoid of these biologically active naturally occurring compounds. However since biological effects are dependent on many factors including dose, duration of use, protein binding affinity, individual metabolism and intrinsic oestrogenic state, further clinical studies are necessary to determine the potential health effects of these compounds in specific population groups. However we cur

Topics: Animals; Breast Neoplasms; Coronary Disease; Diet; Endometrial Neoplasms; Estrogens, Non-Steroidal; Female; Humans; Infant; Infant Food; Intestinal Absorption; Isoflavones; Lignans; Male; Menopause; Osteoporosis, Postmenopausal; Phytoestrogens; Plant Preparations; Premenopause; Risk Factors

Hormone replacement therapy has traditionally been used to treat the accompanying symptoms of oestrogen deficiency in menopause. However, not all women can, or prefer to, receive this treatment and alternatives should be considered to reduce the increased risk of osteoporosis and heart disease in menopausal women. This chapter reviews the current literature on the efficacy of phyto-oestrogens in preventing cardiovascular disease, various cancers and osteoporosis, as well as treating the vasomotor and other menopause-related symptoms. Select herbal therapies, as well as selective oestrogen receptor modulators, are also considered.

Topics: Cardiovascular Diseases; Estrogens; Female; Humans; Hypercholesterolemia; Isoflavones; Lignans; Menopause; Middle Aged; Neoplasms; Osteoporosis, Postmenopausal; Phytotherapy; Plant Preparations; Raloxifene Hydrochloride; Selective Estrogen Receptor Modulators

To review the sources, metabolism, potencies, and clinical effects of phytoestrogens on humans.. The MEDLINE data base for the years 1980-1995 and reference lists of published articles were searched for relevant English-language articles concerning phytoestrogens, soy products, and diets with high-phytoestrogen content.. We identified 861 articles as being relevant. Human cell line studies, human epidemiologic studies (case-control or cohort), randomized trials, and review articles were included. Animal studies regarding phytoestrogens were included when no human data were available concerning an important clinical area.. Included were studies containing information considered pertinent to clinical practice in the areas of growth and development, menopause, cancer, and cardiovascular disease. When findings varied, those presented in this study reflect consensus. All studies concurred that phytoestrogens are biologically active in humans or animals. These compounds inhibit the growth of different cancer cell lines in cell culture and animal models. Human epidemiologic evidence supports the hypothesis that phytoestrogens inhibit cancer formation and growth in humans. Foods containing phytoestrogens reduce cholesterol levels in humans, and cell line, animal, and human data show benefit in treating osteoporosis.. This review suggests that phytoestrogens are among the dietary factors affording protection against cancer and heart disease in vegetarians. With this epidemiologic and cell line evidence, intervention studies are now an appropriate consideration to assess the clinical effects of phytoestrogens because of the potentially important health benefits associated with the consumption of foods containing these compounds.

Topics: Animals; Cardiovascular Diseases; Climacteric; Diet; Estrogens, Non-Steroidal; Female; Glycine max; Humans; Isoflavones; Lignans; Neoplasms; Osteoporosis, Postmenopausal; Phytoestrogens; Plant Preparations; Plants; Tumor Cells, Cultured

As one of the leading causes of bone fracture in postmenopausal women and in older men, osteoporosis worldwide is attracting more attention in recent decades. Osteoporosis is a common disease mainly resulting from an imbalance of bone formation and bone resorption. Pharmaceutically active compounds that both activate osteogenesis, while repressing osteoclastogenesis hold the potential of being therapeutic medications for osteoporosis treatment. In the present study, sesamin, a bioactive ingredient derived from the seed of Sesamum Indicum, was screened out from a bioactive compound library and shown to exhibit dual-regulating functions on these two processes. Sesamin was demonstrated to promote osteogenesis by upregulating Wnt/β-catenin, while repressing osteoclastogenesis via downregulating NF-κB signaling . Furthermore, DANCR was found to be the key regulator in sesamin-mediated bone formation and resorption . In an ovariectomy (OVX)-induced osteoporotic mouse model, sesamin could rescue OVX-induced bone loss and impairment. The increased serum level of DANCR caused by OVX was also downregulated upon sesamin treatment. In conclusion, our results demonstrate that sesamin plays a dual-functional role in both osteogenesis activation and osteoclastogenesis de-activation in a DANCR-dependent manner, suggesting that it may be a possible medication candidate for osteoporotic patients with elevated DNACR expression levels.

Topics: Animals; beta Catenin; Bone Resorption; Cell Differentiation; Dioxoles; Female; HEK293 Cells; Humans; Lignans; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; NF-kappa B; Osteoblasts; Osteoclasts; Osteogenesis; Osteoporosis, Postmenopausal; RANK Ligand; RAW 264.7 Cells; RNA, Long Noncoding; Wnt Signaling Pathway

Evidence has been accumulated that some phytoestrogens act as protective factors against development of cancer and also cardiovascular diseases. These are phytoestrogens of isoflavone and lignane series, found especially in soy. Beneficial effect of these compounds may be explained by a complexity of their actions at various levels: they interact with estrogen receptors, some of them are inhibitors of the key enzymes responsible in the final effect for cell growth and proliferation, and, due to their chemical nature they are scavengers of free radicals. In the presented work the authors, in collaboration with Finnish partners from the University of Helsinki, developed original immunoassays for determination of main phytoestrogens of isoflavone series--daidzein, genistein, formononoetin, biochanin A, their metabolite equal and lignane enterolactone. The methods are sensitive enough for follow-up of actual levels of phytoestrogens in serum. By using these methods, the levels of phytoestrogens in Czech population have been established. The group of patients suffering from osteoporosis has been investigated, too. Significantly lower levels of isoflavonoids in comparison with sex- and age-matched healthy subject have been found in the patients. The methods have also enabled us to follow up the dynamics of these compounds in the organism, as well as to determine their content in food and its sources. The original detection and quantification of four above mentioned isoflavonoids in beer is an example.

Topics: Anticarcinogenic Agents; Estrogens, Non-Steroidal; Female; Humans; Isoflavones; Lignans; Neoplasms; Osteoporosis, Postmenopausal; Plants; Radioimmunoassay

The hypothesis was tested that the rate of postmenopausal bone loss is inversely associated with long-term urinary excretion of phyto-oestrogens, as a marker of habitual dietary intake.. Secondary analysis of a 10-year follow-up study (1979 1989) among postmenopausal women in the Netherlands.. From the original population of 154 women, 32 women were selected with an annual rate of radial bone loss of < or = 0.5% over the first 5 years of the study and 35 women with a rate of > or = 2.5% per year.. The isoflavonoids genistein, daidzein and equol, and the lignan enterolactone were determined by gas chromatography mass spectrometry in aggregate samples from annually collected urine samples. Cortical bone density of the radius had previously been measured annually by single-photon absorptiometry.. Excretion of isoflavonoids did not differ between both groups, although in multivariate analysis equol excretion was weakly positively associated with rate of bone loss in the 5 years after the menopause. Enterolactone excretion was significantly higher in the group with high rate of bone loss. This positive association remained in multivariate linear regression analysis after adjustment for age, years since menopause, body mass index and intake of calcium, vegetable protein and dietary fibre.. Enterolactone excretion is likely to be an indicator of consumption of grains and legumes; it is not clear whether the observed positive association with rate of bone loss is a causal one. Our results do not support a preventive effect of low, unsupplemented dietary intake of phyto-oestrogens on postmenopausal cortical bone loss. However, no conclusions can be drawn about effects of higher doses of phyto-oestrogens.

Topics: 4-Butyrolactone; Aging; Bone Density; Chromans; Equol; Estrogens, Non-Steroidal; Female; Gas Chromatography-Mass Spectrometry; Genistein; Humans; Isoflavones; Lignans; Linear Models; Middle Aged; Osteoporosis, Postmenopausal; Phytoestrogens; Plant Preparations; Postmenopause; Prospective Studies; Time Factors