Una serie di articoli in lingua inglese che mostrano le proprietà medico scientifiche della soia: ad esempio i suoi benefici nella menopausa, nell'abbassamento del colesterolo, nella riduzione dei rischi cardiaci.
La soia può inoltre aiutare gli uomini contro l’alto rischio del cancro della prostata, gli isoflavoni possono aiutare a ridurre la mortalità infantile.

EVIDENCE MOUNTS FOR SOY'S MENOPAUSE BENEFITS

Date posted: Apr 09, 2009

Soy isoflavones in the aglycone form may reduce cholesterol, improve antioxidative properties of the liver, and prevent degeneration of the vaginal wall, suggests a new study with rats.

The animal study, published in the online open access journal Nutrition & Metabolism, adds to previous science about the benefits of soy isoflavones for reducing the symptoms of the menopause.
"These ovariectomised animals are a good model for study of the menopause as the loss of oestrogen from the ovaries mimics the natural reduction in oestrogen seen in menopausal women,” explained lead researcher Robin Chiou from the National Chiayi University in Taiwan.
“SAI (soy aglycons of isoflavone) itself has weak oestrogenic properties and we've shown here that menopause-related syndromes can be prevented or improved by dietary supplementation with the compounds it contains,” he added.
Isoflavones are well known phytoestrogens - active substances derived from plants that have a weak oestrogen-like action.
Isoflavones from soy have been shown to provide a number of health benefits, including the promotion of heart health and the maintenance of bone health in post-menopausal women.
They have also been studied for their role in cancer prevention and slowing down the ageing process in peri-menopausal women, and have proved to be a popular alternative to hormone replacement therapy for those wishing to control menopause symptoms without resorting to drugs.
Study details
The researchers divided 30 ovariectomisedSprague-Dawley rats were distributed into three groups: control group; a low SAI group (0.0135 per cent SAI in the diet, equivalent to 80 mg per day for a 60 kg-human), and a high dose SAI group (0.027 per cent SAI). A further 10 rats acted as the negative controls and did not have their ovaries removed.
The soybean supplement contained 80 per cent soy bean flour, 4.5 per cent daidzein, 14.5 per cent genistein, and about 1.0 per cent other isoflavones, (Glory Biotech Co., Taiwan).
After three months, the researchers found that the ovariectomised animals gained more weight than the negative control animals. Animals fed the soy isoflavones had higher blood levels of isoflavones, said the researchers, and significantly lower LDL-cholesterol levels, and higher HDL-cholesterol levels.
"It is generally agreed that the higher HDL and the lower LDL concentrations are of benefit in chemoprevention of cardiovascular diseases. Our findings support the indication that soybean consumption may prevent coronary heart disease,” said Chiou.
Furthermore, liver antioxidative activities were increased, as evidenced by decreased values of TBARS (thiobarbituric acid-reactive substance). Finally, the decline in the lining of the vagina observed for the ovariectomised control group was “noticeably improved by dietary supplementation with SAI”, said the researchers.
Importance for supplements
“The observations that dietary SAI supplementation in performance of estrogenic effectiveness in improvement of serum biochemical attributes, enhancement of liver antioxidative capacities and protection of vaginal epithelium are of importance from the viewpoint of healthcare and development of dietary supplements,” wrote the researchers.
“Apparently, diets supplemented with soy aglycons of isoflavone have conferred health benefits to the ovariectomised rats. This further supports the effectiveness that menopausal-related syndromes could be prevented or improved by dietary supplementation with soy aglycons of isoflavone,” they concluded.
Source: Nutrition & Metabolism
2009, 6 http://www.nutritionandmetabolism.com
“Supplementary health benefits of soy aglycons of isoflavone by improvement of serum biochemical attributes, enhancement of liver antioxidative capacities and protection of vaginal epithelium of ovariectomized rats”
Authors: T.-F. Lien, Y.-L. Hsu, D.-Y. Lo, R.Y.-Y. Chiou

Source: Journal of Nutrition
October 2007, Volume 137, Pages 2270-2278
"Pasta Naturally Enriched with Isoflavone Aglycons from Soy Germ Reduces Serum Lipids and Improves Markers of Cardiovascular Risk"
Authors: Carlo Clerici, K.D.R. Setchell, P.M. Battezzati, M. Pirro, V. Giuliano, S. Asciutti, D. Castellani, E. Nardi, G. Sabatino, S. Orlandi, M. Baldoni, O. Morelli, E. Mannarino and A. Morelli

EARLY SOY INTAKE MAY SLASH BREAST CANCER RISK LATER IN LIFE

Date posted: Mar 30, 2009

High intakes of soy during childhood may reduce a woman’s risk of breast cancer later in life by 58 per cent, according to a new study.

 

The study, limited to Asian Americans, found that high soy intakes during adolescence and as adults were associated with a 20 to 25 per cent reduction.
Scientists from the US National Cancer Institute report their findings in the journal Cancer Epidemiology, Biomarkers and Prevention.
"Historically, breast cancer incidence rates have been four to seven times higher among white women in the US than in women in China or Japan,” explained lead researcher Regina Ziegler from the NCI Division of Cancer Epidemiology and Genetics.
“However, when Asian women migrate to the US, their breast cancer risk rises over several generations and reaches that of US white women, suggesting that modifiable factors, rather than genetics, are responsible for the international differences.
“These lifestyle or environmental factors remain elusive; our study was designed to identify them.”
Population studies have shown that a diet rich in soy is associated with fewer cases of breast cancer, linked to the presence of soy isoflavones. China has the world's lowest incidence and mortality from breast cancer - a disease that has over one million new cases every year worldwide.
The new research of Asian-American women adds to an ever-growing body of research supporting potential cancer-protecting properties of soy.
Study details
The researchers focused on women of Chinese, Japanese and Filipino descent and living in San Francisco, Oakland, Los Angeles or Hawaii. Ziegler and her co-workers interviewed 597 women with breast cancer and 966 healthy women.
Additionally, for a subset of 255 participants whose mothers were alive and living in the US, the mothers were asked about their daughter's early childhood exposures.
By comparing the highest and lowest soy intake values for soy-based foods such as tofu, miso and natto, Korde and co-workers calculated that women with the highest soy intake during childhood (ages 5 to 11) had a 58 per cent lower risk of breast cancer as adults as the women with the lowest soy intake as children.
The corresponding reductions for adolescent and adult intake were about 25 per cent, they added.
"Since the effects of childhood soy intake could not be explained by measures other than Asian lifestyle during childhood or adult life, early soy intake might itself be protective," said lead author Larissa Korde.
Mechanism
The underlying mechanism is not known, said the researchers, but they hypothesised that the oestrogenic effects of soy isoflavones cause changes in breast tissue during childhood that may decrease sensitivity to carcinogens later in life. A similar protective effect has been found in studies of overweight girls, perhaps because fat tissue also secretes oestrogen.
"Soy isoflavones have estrogenic properties that may cause changes in breast tissue. Animal models suggest that ingestion of soy may result in earlier maturation of breast tissue and increased resistance to carcinogens," said Korde.
The study does have several limitations, including asking women to evaluate and quantify adolescent dietary intakes, as well as asking mothers about a daughter's dietary intake during childhood, the accuracy of both are dependent on the recall ability of the interviewees.
In a final note of caution, Ziegler added: "This is the first study to evaluate childhood soy intake and subsequent breast cancer risk, and this one result is not enough for a public health recommendation. The findings need to be replicated through additional research."
Source: Cancer Epidemiology, Biomarkers and Prevention
Published online ahead of print, doi: 10.1158/1055-9965.EPI-08-0405
“Childhood Soy Intake and Breast Cancer Risk in Asian American Women”
Authors: L.A. Korde, A.H. Wu, T. Fears, A.M.Y. Nomura, D.W. West, L.N. Kolonel, M.C. Pike, R.N. Hoover, R.G. Ziegler

Source: Journal of Nutrition
October 2007, Volume 137, Pages 2258-2263
"Soy Protein Isolate Increases Urinary Estrogens and the Ratio of 2:16-Hydroxyestrone in Men at High Risk of Prostate Cancer"
Authors: J.M. Hamilton-Reeves, S.A. Rebello, W. Thomas, J.W. Slaton and M.S. Kurzer

SOY FOOD BETTER THAN TABLETS FOR ISOFLAVONE DOSE: STUDY
Date posted: Feb 09, 2009

Soy foods could be a better source of isoflavones than supplements, according to a new study from Stanford.
Blood levels of the soy isoflavone genistein were higher after consuming soy food with an isoflavone content of 96 mg than for isoflavone-rich supplements, according to new data published in the Journal of Nutritional Biochemistry.
“The findings from this investigation suggest that bioavailability may be higher from food sources of isoflavones than from tablets, and that spreading the intake out in multiple doses over the course of the day will lead to more constant steady-state plasma concentrations,” wrote lead author Christopher Gardner.
Soy isoflavones are well known phytoestrogens - active substances derived from plants that have a weak estrogen-like action. They have been studied for their role in cancer prevention and slowing down the ageing process in peri-menopausal women, and have proved to be a popular alternative to hormone replacement therapy for those wishing to control menopause symptoms without resorting to drugs.
Despite numerous studies reporting the potential health benefits of soy, controversy and contradiction still exists, particularly in terms of how bioavailable the isoflavone forms (glycoside versus aglycone) are.
Some studies have reported no difference between bioavailability of the isoflavone type, whereas others have reported higher bioavailability for aglycones.
“This is relevant because many soy isoflavone supplements and food products contain primarily the glycoside forms versus pure isoflavones in their aglycone forms,” wrote the Stanford researchers.
“A greater understanding of isoflavone pharmacokinetics that may differ by source and dose could help to explain some of the heterogeneity of results among the large and growing number of trials testing the effects of soy isoflavones on a variety of potential health outcomes,” added Gardner.
Study details
The Stanford researchers recruited 12 generally healthy people to take part in the randomized, cross-over trial. All participants completed the three phases of the trial. These included six days on each of the following interventions: daily supplements containing a low dose (144 mg/day) or a high dose (288 mg/day) of isoflavones (Novasoy, ADM), or consumption of soy foods providing a daily isoflavone dose of 96 mg. All the doses are noted in aglycone equivalents. The supplements contained isoflavones predominantly in the glycoside form.
Gardner and his co-workers report that both the soy food and the high dose isoflavone supplement produced blood levels of isoflavone over four micromoles per liter.
Blood levels of genistein were “higher overall in the soy food versus both the lower and the higher dose supplement phases of the study”, wrote the researchers. “When comparing plasma concentrations for the two doses of tablets, saturation appeared more evident for genistein than for daidzein at the higher dose level,” they added.
“We observed important differences in the pharmacokinetics of genistein and daidzein contrasting the sources and doses of isoflavones when administered three times daily, including a possible advantage for increasing serum concentrations of isoflavones from consuming soy foods relative to isoflavone supplements,” wrote the researchers.
Gardner and his co-workers noted that future studies should match the isoflavone doses between food and supplements, as well as comparing intakes for a single bolus against those of multiple intakes during the course of the day.
The study was supported financially by the National Institutes of Health.
Source: Journal of Nutritional Biochemistry
Volume 20, Pages 227-234
"Effects of isoflavone supplements vs. soy foods on blood concentrations of genistein and daidzein in adults"
Authors: C.D. Gardner, L. M. Chatterjee, A.A. Franke

Source: Andres, Aline et al. "Isoflavones at concentrations present in soy infant formula inhibit rotavirus infection in vitro." Journal of Nutrition. 2007 137: 2068-2073.

SOY MAY AID MEN AT HIGH RISK OF PROSTATE CANCER

Date posted: Oct 09, 2007

Men at high risk of prostate cancer, a cancer on the rise worldwide, may benefit from increased intake of soy isoflavones, suggests a new study from the University of Minnesota.

 

The research, published in the Journal of Nutrition, adds to earlier studies that claimed to be the first prospective study to report an inverse association between isoflavone and prostate cancer in Japanese men (J. Nutrition, Vol. 137, pp. 1974-1979; Cancer Epidemiol Biomarkers Prev, Vol. 16, pp. 538-545).
Over half a million news cases of prostate cancer are diagnosed every year world wide, and the cancer is the direct cause of over 200,000 deaths. More worryingly, the incidence of the disease is increasing with a rise of 1.7 per cent over 15 years.
The new randomised controlled trial investigated the potential of soy isoflavones to increase the excretion of urinary estradiol (E2) and lower ratio of urinary 2-hydroxy estrogens to 16-hydroxyestrone (2:16 OH-E1), two oestrogen metabolites suggested to initiate hormone-related cancers.
Indeed, according to background information in the new study, soy supplementation has been shown to increase the ratio 2:16 OH-E1 in women. However, no studies to date have looked at such effects in men.
Lead researchers Jill Hamilton-Reeves recruited 58 men at high risk for developing advanced prostate cancer and supplemented their normal diets with one of three protein isolates: isoflavone-rich soy protein isolate, providing 107 mg isoflavones per day; isoflavone-poor soy protein isolate, providing less than six mg isoflavones per day; or milk protein isolate. All supplements provided 40 grams of protein per day.
After three and six months of supplementation, the researchers report that both soy groups had higher E2 urinary excretion than subjects receiving the milk protein. Moreover, after six months of supplementation, a significantly higher urinary 2:16 OH-E1 ratio was observed amongst individuals receiving the isoflavone-rich soy protein isolate than the milk protein.
"Increased urinary E2 excretion and 2:16 OH-E1 ratio in men consuming soy protein isolate are consistent with studies in postmenopausal women and suggest that soy consumption may be beneficial in men at high risk of progressing to advanced prostate cancer as a result of effects on endogenous oestrogen metabolism," wrote the researchers.
The earlier study (Cancer Epidemiol Biomarkers Prev) linking isoflavones to potential protection from prostate cancer stated that the benefits could be due to the weak oestrogenic activity of soy isoflavones, which may act to reduce testosterone levels and inhibit 5 alpha-reductase - an enzyme involved in the metabolism of testosterone.
Moreover, an animal study published in Biology of Reproduction (2004, Vol. 70, pp. 1188-1195) claimed that the metabolite of the soy isoflavone daidzein stopped the effect of the male hormone dihydrotestosterone (DHT), which has been linked to prostate growth and male baldness.

Source: Journal of Nutrition
October 2007, Volume 137, Pages 2258-2263
"Soy Protein Isolate Increases Urinary Estrogens and the Ratio of 2:16-Hydroxyestrone in Men at High Risk of Prostate Cancer"
Authors: J.M. Hamilton-Reeves, S.A. Rebello, W. Thomas, J.W. Slaton and M.S. Kurzer

ISOFLAVONE-RICH PASTA EFFECTIVE TO BOOST HEART HEALTH - STUDY

Date posted: Sep 28, 2007

Pasta, enriched with soy isoflavones in the aglycone form, can effectively reduce blood levels of total and LDL cholesterol by about eight per cent, new research from Italy has reported.

 

The study, published in the October issue of the Journal of Nutrition, has implications for using soy isoflavones as functional ingredients for heart healthy foods, with the manufacturing process key to the natural enrichment of the pasta with isoflavone aglycons.
During fermentation isoflavones change from the glucoside form to the aglycone form, said to be more bioavailable. A study by Yakult last year (The Journal of Nutrition, Vol. 136, pp. 2291-2296) stated that it made sense that aglycones are more bioavailable since they are smaller molecules and are more hydrophobic, and so do not dissolve as easily in water and thus rapidly excreted.
"Most studies of soy and cholesterol have tested foods made from purified soy proteins containing mainly isoflavone glycosides," explained lead author Carlo Clerici from Universita degli Studi di Perugia.
"The aim of this study was to compare a novel soy germ pasta, naturally enriched in isoflavone aglycons as a result of the manufacturing process, with conventional pasta for effects on serum lipids and other cardiovascular risk markers."
The researchers recruited 62 adults with high cholesterol levels (hypercholesterolaemia) to take part in the randomised, controlled, parallel study. The participants were assigned to eat the Step II diet, created by the National Heart, Lung, and Blood Association's National Cholesterol Education Program (NCEP) and endorsed by the American Heart Association for eight weeks. The diet was formulated to include one 80-g serving/d of conventional or isoflavone-enriched pasta, providing 33 milligrams of isoflavones and negligible soy protein.
Hypercholesterolaemia has a long association with many diseases, particularly cardiovascular disease (CVD), the cause of almost 50 per cent of deaths in Europe, and reported to cost the EU economy an estimated €169bn ($202bn) per year.
After eight weeks, Clerici and co-workers report that blood levels of isoflavones were 222 nanomoles per litre. Consumption of the aglycone-enriched pasta led to reduction of total and LDL cholesterol levels in the blood of 7.3 and 8.6 per cent from baseline, respectively. These reductions were equivalent to reductions of 0.47 and 0.36 millimoles more than amongst people consuming conventional pasta.
The soy pasta was also found to have benefits for arterial stiffness and C-reactive protein levels (CRP), a protein produced in the liver and is a known marker for inflammation. Increased levels of CRP are a good predictor for the onset of both type-2 diabetes and cardiovascular disease.
The researchers state that the measures returned to initial levels when patients were switched to conventional pasta.
"In conclusion, pasta naturally enriched with isoflavone aglycons and lacking soy protein had a significant hypocholesterolemic effect beyond a Step II diet and improved other cardiovascular risk markers," they stated.
The research adds and expands the science behind the observed benefits that have previously been linked to the effect of isoflavones on blood cholesterol levels. However, this point is controversial and a recent scientific statement by the American Heart Association (AHA) in the journal Circulation concluded that soy had little effect on cholesterol levels, and raised doubts about health claims associated with soy.

Source: Journal of Nutrition
October 2007, Volume 137, Pages 2270-2278
"Pasta Naturally Enriched with Isoflavone Aglycons from Soy Germ Reduces Serum Lipids and Improves Markers of Cardiovascular Risk"
Authors: Carlo Clerici, K.D.R. Setchell, P.M. Battezzati, M. Pirro, V. Giuliano, S. Asciutti, D. Castellani, E. Nardi, G. Sabatino, S. Orlandi, M. Baldoni, O. Morelli, E. Mannarino and A. Morelli

SOY ISOFLAVONES COULD REDUCE INFANT MORTALITY
Date posted: Sep 07, 2007

    A soy isoflavone used in soy infant formula could reduce diarrhea in infants, according to a new study, and thereby save lives in developing countries.
    Researchers at the University of Illinois at Urbana-Champaign (UIUC) found that the soy isoflavone genistin may reduce a baby's susceptibility to rotavirus infections by as much as 74 percent. The study, published in September's Journal of Nutrition, exposed cells in culture to rotavirus in both the absence and presence of soy isoflavones.
    According to the researchers, the results could flag up soy isoflavones as a potential alternative to expensive rotavirus vaccines that are inaccessible to poorer families.
    "It's exciting to think that the isoflavones in soy formula could be a cost-effective nutritional approach to decreasing the incidence and severity of rotavirus infections, especially among children in developing countries who are most at risk," said Sharon Donovan, professor of Nutrition at UIUC.
    During 2004 alone, the World Health Organization (WHO) estimates around 527,000 deaths in children worldwide were caused by the rotavirus infection. These deaths represented approximately five percent of all child deaths globally.
    "Rotavirus is the primary cause of diarrhea in infants, affecting virtually all children before age five," said Donovan. "In the United States, it mainly leads to dehydration, doctor's visits, and parents missing work to care for sick children."
    Soy isoflavones are the biologically active compounds in soy that are thought to have health benefits, such as relieving the symptoms of menopause, increasing bone density and reducing cholesterol. Genistin is the major isoflavone in soy.
Soy as an ingredient has already gotten a large plug from a US Food & Drug Administration approved health claim linking it to heart disease risk reduction: "Diets low in saturated fat and cholesterol that include 25 grams of soy protein a day may reduce the risk of heart disease. One serving of (name of food) provides ____ grams of soy protein."
    As part of the UIUC study, performed by doctoral candidate Aline Andres, different forms of soy isoflavones were tested individually as well as together in the complete mixture that is used in infant formula.
    "Genistin and the mixture significantly reduced rotavirus infectivity by 33 to 74 percent," said Donovan. "But when genistin was taken out of the mixture, anti-rotavirus activity was lost, suggesting that it is the active component in reducing infectivity."
    Throughout the course of the study, funded by the US Department of Agriculture and the Illinois Soybean Association, rotavirus inhibition began at the isoflavone concentrations used in soy formula, and then levelled off. According to the researchers, this points to the existence of a level of ingestion at which soy isoflavones is effective, beyond which there is no additional benefit for preventing rotavirus.
    "We then exposed the cells to different concentrations of rotavirus," said Donovan. "If an infant had a severe infection or was exposed to a lot of rotavirus, we wondered if the isoflavones would still be as effective."
    The researchers involved now plan to take their investigation one step closer to humans by conducted studies on neonatal piglets.
    "We'll be interested to see if we have the same results when we work with young animals," said Donovan.

    Source: Andres, Aline et al. "Isoflavones at concentrations present in soy infant formula inhibit rotavirus infection in vitro." Journal of Nutrition. 2007 137: 2068-2073.

SOY ISOFLAVONES MAY CUT PROSTATE CANCER RISK IN HALF
Date Posted: Jul 27, 2007 

    Increased intake of soy isoflavones may cut the risk of prostate cancer by 58 percent, suggests a new study from Japan.
    The research, published in the Journal of Nutrition, adds to an earlier study that claimed to be the first prospective study to report an inverse association between isoflavones and prostate cancer in Japanese men.
    Over half a million new cases of prostate cancer are diagnosed every year world wide, and is the direct cause of over 200,000 deaths. More troubling, the incidence of the disease is increasing by 1.7 percent over 15 years.
    The new study recruited 200 Japanese men with different stages of prostate cancer and compared their dietary intakes with 200 healthy male controls.
    The intake of 12 food items was measured: tofu (soybean curd), natto (fermented soybeans), miso soup (soybean paste soup), bean curd refuse, fried bean curd, fried bean curd with vegetables, soy flour, dried bean curd, soy milk, soy sauce, green soybeans, and bean sprouts.
    The researchers report that an increased intake of the soy isoflavones genistein and daidzein was significantly associated with a decreased risk of prostate cancer. The highest average isoflavone intake was associated with a 58 percent reduction in risk compared with the lowest average isoflavone intake.
    They also report that the isoflavone intake was correlated with magnesium and omega-3 and omega-6 fatty acid intake, since soy products are also rich sources of these nutrients.
    "On the other hand, isoflavone significantly decreased the risk of prostate cancer regardless of adjustment by PUFA, (omega-6) fatty acids or magnesium," they said.
    The researchers indicated that the results may not be generalized to other populations since the traditional Japanese diet is a rich source of dietary isoflavones.
    The earlier study linking isoflavones to potential protection from prostate cancer stated that the benefits could be due to the weak oestrogenic activity of soy isoflavones, which may act to reduce testosterone levels and inhibit an enzyme involved in the metabolism of testosterone.
    Corresponding author Tomoko Sonoda said, "Our group is performing the intervention study of isoflavone supplement and analyzing the interaction of estrogen related gene and isoflavone intake on prostate cancer risk."

“In conclusion,” Sonoda continued, “our findings indicate that isoflavones might be an effective dietary protective factor against prostate cancer in Japanese men.”

 

SOY EFFECTIVE FOR CHOLESTEROL CUTS - META-ANALYSIS
Date Posted: May 7, 2007 

    The review adds to the science behind the observed benefits that have previously been linked to the effect of isoflavones on blood cholesterol levels. However, this point is controversial and a scientific statement by the American Heart Association (AHA) in the journal Circulation concluded that soy had little effect on cholesterol levels, and raised doubts about health claims associated with soy.
    Indeed, Dr Frank Sacks, a member of the AHA panel, said at the start of 2006: "It's really clear that isoflavones don't contribute anything to cardiovascular benefits."
    The new findings, published in the current issue of the American Journal of Clinical Nutrition, states that soy isoflavones may impact on LDL-cholesterol levels and soy proteins with or without isoflavones can decrease LDL levels and increase HDL levels, a result that does impact beneficially on heart health.
    If these findings are reproduced in future studies, they might lead to a re-evaluation of the science that led Dr. Sacks and the AHA to their conclusion.
    Soy isoflavones significantly reduced serum total and LDL cholesterol but did not change HDL cholesterol and triacylglycerol. Soy protein that contained enriched or depleted isoflavones also significantly improved lipid profiles," wrote lead author Kyoko Taku from Japan's National Institute of Health and Nutrition.
    The researchers selected 11 randomised controlled trials published between 1990 and 2006. After pooling the data, Taku and co-workers report that soy isoflavones significantly decreased total cholesterol levels by 1.77 per cent (3.9 mg/dL) and LDL cholesterol by 3.58 per cent (5.0 mg/dL), but did not have a significant impact on HDL cholesterol and triacylglycerol levels.
    When they looked at soy protein enriched with isoflavones significantly decreased LDL cholesterol by 4.98 per cent (7.0 mg/dL) and significantly increased HDL cholesterol by 3.0 per cent (1.6 mg/dL). Soy protein with isoflavones removed significantly decreased LDL cholesterol by 2.77 per cent (3.9 mg/dL).
    "Reductions in LDL cholesterol were larger in hypercholesterolaemic than in normo-cholesterolaemic subjects," stated the researchers.
    High cholesterol levels, hypercholesterolaemia, have a long association with many diseases, particularly cardiovascular disease (CVD), the cause of almost 50 per cent of deaths in Europe, and reported to cost the EU economy an estimated €169bn ($202bn) per year.

Source: American Journal of Clinical Nutrition
April 2007, Volume 85, Number 4, Pages 1148-1156
"Soy isoflavones lower serum total and LDL cholesterol in humans: a meta-analysis of 11 randomized controlled trials"
Authors: K. Taku, K. Umegaki, Y. Sato, Y. Taki, K. Endoh, and S. Watanabe

 

CONSUMING BROCCOLI AND SOY IN COMBINATION MAY PROVIDE PROTECTION AGAINST CERTAIN CANCERS
Date Posted: April 16, 2007

    Consuming broccoli and soy in combination has been linked to lower risk of certain cancers, and researchers have taken a step further, proposing a mechanism to explain how such foods may offer protection.
    Researchers from the University of California, Los Angeles (UCLA) report that diindolylmethane (DIM), a digestive product from cruciferous vegetables, and genistein, a major isoflavone in soy, may interfere with the "CXCR4/CXCL12 axis," known to play a central role in the spread of breast cancer. It is also thought to be a reason behind the development of ovarian cancer.
    This news may be of importance to supplements industry as well, since the doses used are comparable to use of a high dose of supplements, according to UCLA researchers Erin Hsu and Oliver Hankinson, but is unlikely to be achievable through consumption of food alone.
    Epidemiological and animal studies have shown that diets high in cruciferous vegetables and soy result in less instances of certain cancers, especially breast and ovarian cancer.
    Primary cancer cells are said to express very high levels of the CXCR4 chemokine receptor on the surface of their cells, and the organs to which these cancers spread secrete high levels of the CXCL12 chemokine ligand. In other words, this attraction between CXCR4 and CXCL12 draws cancer cells to the organs they spread to. This chemical attraction is thought to play a role in the development of over 23 different types of cancer.
    Presenting their research at the Annual Meeting of the American Association for Cancer Research, Hsu and Hankinson report that exposing breast and ovarian cancer cells to pure DIM and genistein decreased the levels of the CXCR4 and CXCL12 proteins in a dose-dependent manner.
    To further investigate if the compounds had any effect on the spread of cancer cells, the cells were placed in one end of a compartment and watched how they moved toward CXCL12 at the other end. "The cells degrade the extracellular matrix in the upper compartment in order to move toward CXCL12 in the lower compartment, a system that represents a cell culture model for invasiveness," explained Hsu.
    However, exposure with either DIM or genistein cut movement by 80 per cent, said the researchers.
    "Our data suggest that one mechanism whereby DIM and genistein protect against breast and ovarian cancers is through the repression of CXCL12 and/or CXCR4, thereby lowering the invasive and metastatic potential of these cells," they said.
    "We have also tested other phytochemicals and seen similar effects, indicating that this mechanism may mediate protective effects of other vegetable products as well," said Hsu.
    Hsu said results from the in-vitro experiments now need testing in vivo before any more definitive links between the compounds and potential anti-cancer effects can be achieved. Toxicity levels should also be investigated.

SOURCE: NutraIngredientsUSA: Annual Meeting of the American Association for Cancer Research

 

STUDY INDICATES HEART HEALTH BENEFITS OF SOY DECREASES CARDIO RISK FACTORS
Date Posted: October 20, 2006

    New research helps explain how soy may contribute to heart health, through a process scientists refer to as "decreased platelet aggregation."  
    By reducing the density of platelet receptors, isoflavones, a natural component in soy, may contribute to a reduced risk of blood clotting, which in turn decreases the risk of heart attack and stroke.
    According to the study published in the journal Maturitas, Chilean researchers recruited post-menopausal women to take part in the double blind, randomized, placebo-controlled study.         The study randomly assigned participants to receive a daily supplement of 100 mg isoflavones or an identical placebo for three months. At the end of the test period, the group receiving the isoflavone supplement showed a significant decrease in the density of a particular platelet receptor (known as TxA2), while the placebo group remained mostly unchanged.  
    Excessive aggregation of platelets may contribute to cardiovascular diseases, such as heart attack and stroke. By decreasing the density of platelet receptors, such as the TxA2, the risk of forming a blood clot that could lead to heart attack or stroke is also reduced.  
    Lisa Kelly, MPH, RD commented, "These findings are significant because they suggest a new understanding of the ways in which soy isoflavones may positively effect cardiovascular health."  Kelly, a dietitian speaking on behalf of the United Soybean Board, explained further, "Previous research has shown that soy offers a modest reduction of LDL cholesterol -- the bad cholesterol -- which may help reduce the risk of heart disease by 10 percent on a population-wide basis. There are also studies linking soy to lowered blood pressure. This study uniquely demonstrates that soy may contribute to heart health through a reduced risk of blood clotting as well, and therefore a reduced risk of heart attack and stroke."  
    These findings create a more nuanced understanding of the American Heart Association (AHA) Nutrition Committee's recent statement in the journal Circulation that downplayed the degree to which soy can help reduce cholesterol, pointing to a more modest benefit than previously thought. However, by linking soy isoflavones to reduced platelet aggregation, the new study suggests the need for scientists to examine a variety of heart health factors, including but not limited to cholesterol, in order to gain a thorough understanding of the ways in which soy may contribute to heart health.  

 

SOY PROTEIN MAY HELP CONTROL CVD, DIABETES AND OTHER DISEASES - MEXICAN STUDY
Date Posted: July 28, 2006

    Obesity & Diabetes Week -- Soy protein intake may reduce the clinical and biochemical abnormalities in diseases mediated by lipid disorders.
    "Soybeans have a high-quality protein that has been consumed for approximately 5000 years in Oriental countries. The awareness that soy products are healthy has increased their consumption in Western countries. Substantial data from epidemiological surveys and nutritional interventions in humans and animals indicate that soy protein reduces serum total and low-density lipoprotein (LDL) cholesterol and triglycerides as well as hepatic cholesterol and triglycerides," scientists in Mexico report in their review.
    N. Torres and colleagues at the Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran summarized, "This review examines the evidence on the possible mechanisms for which soy protein has beneficial effects in diabetes, obesity and some forms of chronic renal disease. Consumption of soy protein due to low methionine content reduces serum homocysteine concentration, decreasing the risk of acquiring a cardiovascular disease."
    "On the other hand," they continued, "soy protein reduces the insulin/glucagon ratio, which in turn downregulates the expression of the hepatic transcription factor sterol regulatory element binding protein (SREBP)-1. The reduction of this factor decreases the expression of several lipogenic enzymes, decreasing in this way serum and hepatic triglycerides as well as LDL cholesterol and very LDL triglycerides in diabetes and obesity, reducing lipotoxicity in the liver.
    "Soy protein intake also reduces hepatic lipotoxicity by maintaining the number of functional adipocytes, preventing the transfer of fatty acids to extra adipose tissues. Furthermore, soy protein isoflavones stimulate the transcription factor SREBP-2, increasing serum cholesterol clearance. The reduction of serum cholesterol and triglyceride concentrations by soy protein intake produces beneficial effects in the kidney preventing the inflammatory response, increasing the renal flow by releasing endothelial nitric oxide (NO) synthase from the caveolae, facilitating the synthesis of NO."
    The authors finished, "Thus, soy protein consumption may reduce the clinical and biochemical abnormalities in diseases mediated by lipid disorders."
    Torres and colleagues published their review in the Journal of Nutritional Biochemistry (Regulation of lipid metabolism by diseases mediated soy protein and its implication in by lipid disorders. J Nutr Biochem, 2006;17(6):365-373).