According to Polit and Hungler (1999), researchers often undertake a literature review to familiarize themselves with the knowledge base. The term literature review refers to the activities involved in identifying and searching for the information on a topic and developing an understanding of the state of knowledge on that topic, the term is also used to designate a written summary of the state of art on research problem. The available literature and studies are organized under the following headings.
Literature regarding menopause
Literature regarding soy
Studies related to menopausal problems
Studies related to effectiveness soy
Section :1. Literature Regarding Menopause:
The word menopause simply refers to the permanent end of menstruation. It is derived from the Greek word for 'month' (meno) and 'cessation' (pauses). Menopause is not a disease but a natural event in a women's life that result from a decrease in the ovarian production of sex hormones, estrogen, progesteron and testosterone. These hormones allow a woman to become pregnant, cause menstruation and affect many other function in the body, such as the circulatory system, urogenital system and the bone. While some women have no menopausal symptoms, in others, symptoms may last several years usually between of 40 and 55. In a striking contrast to the perspective of many cultures in which menopause is a natural physiological event, current medical opinion have labeled menopause as a disease.(Wikipedia,2009)
With the prolongation of life's expectancy, today's women is assumed to spend one third of her life in postmenopausal phase. (Tamilmani, 2006).
Menopause:
Menopause is defined as the time of cessation of ovarian function resulting in permanent a menorrhea. It takes 12 months of amenorrhea to confirm that menopause has set in and therefore it is retrospective diagnosis.
Climacteric is derived from the Greek work meaning "critical point in human life" indicates the period of time when a women passes through transition from the reproductive stage of life to the post menopausal years. (Tamilmani, 2006).
Stages of Menopause:
Premenopause: The reproductive year before the menopause
Menopause: The permanent cessation of menstruation
Perimenopause: The periods beginning with signs of approaching menopause i.e. irregular menses and hot flushes.
Postmenopause: The period beginning 12 months after, last menstrual period.
Age of Menopause:
Menopause normally occur between the age of 45 and 50 years, the average age being 47 years. Menopause setting before the age of 40 is known as premature menopause. Smoking induces premature menopause.
An international study of 18,977 women in 11 countries found the median age at natural menopause to be 50 years with a range of 49-52 years. It is reported that in Iran (47.8 years), Egypt (46.7 years) ,Turkey (47.8 years), UAE (48 years) Malaysia (50.7 years), Britain (47 years) -( Wast et al 1999).
In the United Kindgom the manage for the menopause is 50 year 9 months. The median onset of perimenopause is between 45.5 and 47 years. (Rymer J. Morris EP, 2000).
The menopause usually occurs between the ages of 45 and 52 years, but it is not uncommon to meet women of 53 or 54 years who are still menstruating regularly. The average age of menopausal women's in USA is 51 years, and in India it is 45 years (Tamilmani, 2006).
Pathophysiology:
As ovarian function diminishes, a sequential loss in the function of estrogen dependent tissue occurs. Ovulation and menstruation cease. There are changes in vaginal and vulvar tissue and other estrogen dependent tissue such as the breasts, with aging, fever follicles respond to gonadotrophin stimulation, reducing the level of estrogen resulting in the symptoms associated with menopause.
Diagnosis of Menopause:
The only best way to diagnose menopause is to observe lack of menstrual periods for 6 - 12 months in a women in the expected age above 40 years
Raised serum FSH level
Decreased estrogen and progesterone levels.
Management of Menopause: Counseling
Hormone replacement therapy CHRT
Other drugs
Tibolone (livial) is a synthetic derivative of 19 nortestosterone and has a weak estrogenic progestogenic and androgenic action.
Reloxifene (Evista) is a selective oestrogen receptor modulator (SERM), which reduce the risk of fracture by 50%.
Soya: Soya beans contain isoflavone (phyto estrogen genstein and daidzain) which is plant product. 45-60mg soya daily is protective without the potential risk of breast center, liver disease and other side effect of estrogen. It is a safe alternative to hormonal therapy.
Bisphophonates such as etidronate and tiludronates reduce bone resorption
Clonidine therapy
Daily weight bearing exercise
Take a balance diet with low fat content
Yoga
Section :2 LITERATURE REGARDING SOY:
Soy:
Soy Isoflavones represent one of the classes of "phytoestrogen". These bioactive non nutrient are strikingly similar in chemical structure to estradiol, the main female hormone, almost exactly the structure of estradiol and isoflavon are same so they become indistinguishable, therefore they fit beautifully into the pocket representing the binding domain of the estrogen receptor.
Phytoestrogen:
Phytoestrogen, sometimes called "dietary estrogen", are a diverse group of naturally occurring nonsteroidal plant compounds that, because of their structured similarity with estrodiol (17-B-estrodiol), have the ability to cause estrogenic or/ and antiestrogonic effects.
Their name comes from phyto = plant and estrogen = estry with period of fertility for female mammals + gen = to generate.
The similarities, at molecular level, of estrogens and phytoestrogens allow them to midly mimic and sometimes act as antagonists of estrogen. Phytoestrogens were first observed in 1926. (Setchell 1988).
Daily soy consumption may support substantial health benefits:
Menopause and perimenopause discomforts support
Weight loss support
Beautiful hair, skin and nail appearance support
Energy and workouts support
Promotion of normal cholesterol and heart health
Promotion of normal bone health
Maintenance of normal blood sugar health
Promotion of better antioxidant health
Support of colon and digestive tract health
Support for normal kidney health
Thyroid and fertility health
- (Revival food, 2010)
The Optimal dose of Isoflavone:
The optimal dose of isoflavone required to have clinical effects remains to be established. It is generally believe that 50mg per day of aglycones is sufficient to have a clinical / biological effect. And it is level at which demonstrable endocrine effects occur in premenopausal women.
Isoflavones are present in relatively large amounts in virtually all soy and soy product. The whole soy contain about 200mg isoflavones per 100g.
Absorption of Soy:
After ingestion, soy isoflavones are hydrolyzed by intestinal glucosidases, which releases the aglycones, daidzein, genistein and glycitein. These may be absorbed or further metabolized to many specific metabolites, including equal and P-ethl phenol. It has fewer side effects like diarrhea ect.
Section :3. STUDIES RELATED TO MENOPAUSAL PROBLEMS:
Keenan etal (2003) conducted a cross sectional phone survey to assess severity of menopausal symptoms and use of both conventional and complementary therapies. In this study 2,602 women aged 45 years or older were selected, the participants were asked a series of questions about their menopausal states, menopausal symptoms, healthcare provider selection and therapies used for menopausal symptoms, the highest prevalence estimates were reported for hot flashes (62.9%), night sweats (48.3%) and trouble sleeping (41.1%). The researcher concluded that. 46% of women used complementary / alternative therapies either alone or in combination with conventional therapies, whereas a one third of the women did not use any therapy in relation to menopause.
Ayranci etal (2008) conducted an epidemiological study to assess the menopause status and attitudes in a Turkish midlife female population. The study group consisted of 1551 women selected is a random sample of individuals aged 40-65 years. The questionnaire included pertaining to women's menopausal status, some statements about the climacteric, use of hormones at menopause or before menopause and some climacteric myths. The result was, that the mean age of the women were of the negative opinion that the climacteric is "the end of youth", "the end of fecundity", and "the end of uncleandays". Among the women, hot flushes were the most common complaint occurring in 96.5% of women, being severe in 32.9%, moderates in 43% and mild in 20.4%, this followed by low backache 95%. The researcher concluded that most of the women in this study had mixed ideas of opinions concerning the climacteric and the majority was also suffering from climacteric complaints. This data could assist health care to midlife Turkish women.
Gharaibeh etal (2009) conducted descriptive study to assess the severity of menopausal symptoms of Jordanian women. Cross-sectional design was used. Data were collected from 350 Jordanian women using a self administered questionnaire consisting of socio demographic, medical and obstetrical history form and the Greene climacteric scale. The result 0f the study on the severity of menopausal symptoms showed that 15.7%, 66.9% and 17.4% were experiencing severe, moderate and mild menopausal symptoms, respectively. Vasomotor signs were reported to have the highest scores of severity as manifested by hot flushes and night sweating. There was a significant relationship between the severity and occurrence of menopausal symptoms and age, family income, level of education, number of children, perceived health status and menopausal status. The researcher concluded that health care providers need to play a more visible and instructional role in continuously assessing menopausal women's needs as well as to implement appropriate health educational programs.
Rahman etal (2010) conducted a descriptive study to assess the menopausal symptoms using modified menopause rating scale (MRS) among middle age women in sarawale. In this study by using modified MRS questionnaire, 356 sarawakian women aged 40-65 years were interviewd to document of all symptoms (divided into somatic, psychological and urogenial domain) commonly associated with menopause. The result of study was, the mean age of menopause was 51.3 years (range 47-56 years). The most prevalent symptoms reported were joint and muscular discomfort (80.1%), physical and mental exhaustion (67.1%) and sleeping problems (52.2%). Followed by symptoms of hot flushes and sweating (41.6%), irritability (37.9%), dryness of vagina (37.6%), anxiety (36.58%), depressive mood (32.6%). Other complaints noted were sexual problem (30.9%), bladder problem (13.8%) and heart discomfort (18.3%). It was concluded that the prevalence of menopausal symptoms using modified MRS in this study correspond to other studies on Asian women.
Section :4 STUDIES RELATED TO EFFECTIVENESS SOY:
Mc Carthy (1999) stated soy that protein provokes a greater release of hormone glucagons. Glucagons is responsible for the obstruction of fat storing enzymes and increasing fat metabolism (fat burning). It is also responsible for decreasing cholesterol synthesis. Thus soy lowers elevated serum lipid levels and promote weight loss.
Upmatis etal (2000) conducted the double blind, randomized place to controlled study to find effectiveness of soy in reliciving vasomotor symptom in postmenopausal women. This study carried out with 177 post-menopausal women, with mean age of 55 years. The test was double blind and before the test the postmenopausal women daily five or more not flushes, the most important menopausal symptom. The women were randomized to receive either 50mg soy isoflavones or placebo. At the start and end of the study physical examinations and endometrial and biochemistry more performed. After 2 weeks a decreases in the group who took isflovnes was noticed . It was concluded that soy isoflavones was effective in reducing frequency and severity of flushes but did not stimulate the endometrium in menopausal women.
Somekawa (2001) conducted study to investigate the influence of soy isoflavones on menopausal symptoms, bone mineral density and lipid profiles of Japanese menopausal women. In total 478 postmenopausal women were involved in the study. After selection, they were divided in four groups depending on quantity of daily isoflavones consumption. Question were asked to determine soy intake at the present age and at the age of 40 years. Each of these groups was subdivided in tow subgroups, women in early menopause and women in late menopause. The women reported typical menopause symptoms at the time of enrolment such as hot flushes, sweating, chills, sleep problems, irritability depression, headaches, palpitations and backache. The average (mean) daily intake of soy isoflavones was 54.3mg. The study concluded that high consumption of soy isoflavones is associated with increased bone density in postmenopausal women. Consumption of soy isoflavones might be useful to prevent symptoms related with low estrogen levels.
Russo, Corosu (2003) conducted a double blind randomized study to find the effectiveness phytoestrogen in the treatment of menopausal disorders. The study was done on 50 women to get a representative result. The group was divided into groups of 25 women, group I (with an average age of 53.3+/3.5 years and an average menopausal of 51.6+/-1.8years) and group 2 (with an average age of 53.1+/-2.9 years and an average menopausal +/-1.2 years) Group I got treatment with soy isoflavones product and group 2 with placebo. After 3 months it is treated with a placebo, received the phytoestrogen and vice versa. As the result of this trial, the use of soy product based on phyto estrogens can have a positive influence symptoms of menopause, especially the hot flashes.
Ikeda (2006) conducted to investigate the relationship between fermented soy (Natto) intake and bone mineral density in healthy Japanese women. The researchers found that the body mass index of post menopausal women increased with increasing dietary intake of soy .The study concluded that soy intake may help to prevent osteoporosis of postmenopausal women.
Fuchs (2007) conducted a study to identify biomarkess of response to a dietary supplementation women isoflavone extract in post menopausal women. The study with healthy postmenopausal women was performed in a placebo controlled sequential design. Peripheral mononuclear blood cells were collected from 10 volunteers after 8 weeks of receiving daily 2 placebo cereal bars and after a subsequent 8 weeks of intervention with 2 cereal bar each providing 25mg of isoflavones. The study was concluded asproteome analysis identified in vivomarkers that respond to a dietary intervention with isoflavone enriched soy extract in postmenopausal women. The nature of the proteins identified suggests that soy isoflavones may increase the anti-inflammatory response in blood mononuclear cells that might contribute to the atherosclerosis preventive activities of a soy rich diet.
Borchers (2008) conducted study to find effectiveness of soy isoflavones modulate immune function in healthy post menopausal women. Post menopausal women aged 50-65 year enrolled in this 16 weeks double blind, placebo controlled trial were randomly assigned to 1 of 3 experimental group: 1) control, 706ml cow milk/day plus a placebo supplement 2) Soy milk, 71.6mg isoflavones derived from 706ml soy milk/day plus a placebo supplement 3) Supplement, 70mg isoflavones in a supplement plus 706 ml cow milk/day. Plasma and 24 hrs urine sample were obtained at baseline and at 16 weeks. The researcher concluded that soy milk and supplemental isoflavone modulate Bull populations and appear to be protective against DNA damage in postmenopausal women.
Khaodhiar et al (2008) conducted study among 147 post menopausal women given daily supplements of the diadzeinrich isoflavone aglycone supplement at a dose of 40 or 60mg for 12 weeks. At the end of the study, the researcher report that the number of hot flashes in the group receiving the lower dose was reduced by 52%, while the women receiving the higher dose experienced 51% reduction of in number of hot flushes. The placebo group reported as 39% reduction in hot flush frequently.
Kuzer (2008) conducted the study to review current research on the effects of soy consumption on menopausal symptoms. Researcher concluded that consumption of 30mg/day of soy isoflavones reduced hot flashes by up to 50%. This total reduction includes that provided by "the placebo effect". The greatest benefit may be realized when the isoflavone rich food or supplement is taken, the subjects experience at least four hot flashes /day.
