From GeroVital Romania
Clinical
Studies on Soy/Soya on:
Menopause: Soy isoflavones have been shown to ameliorate
the effects of menopause. A recent six-year study
involving 1,106 women in Japan demonstrated that soy does appear to
reduce the occurrence of hot flashes associated with menopause.
Soy product intake and hot flashes in
Japanese women: results from a community-based prospective study.
Nagata C, Takatsuka N, Kawakami N, Shimizu H.
Department of Public Health, Gifu University School of Medicine, Gifu,
Japan.
The
association between soy product intake and the occurrence of hot
flashes was examined in a cohort of 1,106 female residents of Takayama,
Gifu, JAPAN: The women were aged 35-54 years and premenopausal at their
entry into the study in 1992. Diet, including intake of soy products
and isoflavones, was assessed by means of a validated semiquantitative
food frequency questionnaire at study entry. A follow-up mail
questionnaire asking about experiences of hot flashes was sent in 1998.
During the 6 years of the study period, 101 women had new moderate or
severe hot flashes according to the Kupperman test of menopausal
distress. After data were controlled for age, total energy intake, and
menopausal status, hot flashes were significantly inversely associated
with consumption of soy products in terms of both total amount (highest
tertile of soy product intake (g/day) vs. lowest: hazard ratio = 0.47;
95% confidence interval: 0.28, 0.79; p for trend = 0.005) and
isoflavone intake (highest tertile of isoflavone intake (mg/day) vs.
lowest: hazard ratio = 0.42; 95% confidence interval: 0.25, 0.72; p for
trend = 0.002). These data suggest that consumption of soy products has
a protective effect against hot flashes.
Osteoporosis:
Osteoporosis is a disease that primarily affects older women in which
the bones become porous and fracture easily. Japanese women, who
generally consume soy products, have half the rate of hip fractures as
U.S. women. A study
involving 85 postmenopausal Japanese women showed soy to be associated
with a higher bone density and a decreased rate of bone resorption (the
decrease of bone density), thereby slowing the onset of osteoporosis.*
Given
the large body of evidence supporting a variety of benefits of soy, and
since the typical American diet consists of very little soy products,
you may want to consider supplementing your diet with the most active
part of the soybean -- Soy Isoflavone capsules from GeroSoya.
Effect of soy protein on bone metabolism in
postmenopausal Japanese women.
Horiuchi T, Onouchi T, Takahashi M, Ito H, Orimo H.
Department of Endocrinology, Tokyo Metropolitan Geriatric Hospital,
Japan.
We
conducted a cross-sectional study of the effects of soybean protein
intake on bone mineral density and biochemical markers in 85
postmenopausal Japanese women. Nutrients in the diet of postmenopausal
Japanese women visiting the osteoporosis unit, including subjects with
normal lumbar spine bone mineral density (L2-4 BMD), were investigated
by questionnaire, and the calculated daily energy, protein, soy protein
and calcium intake were obtained. L2-4 BMD was measured with
dual-energy X-ray absorptiometry, and assays done of serum alkaline
phosphatase (ALP) and serum intact osteocalcin (IOC) as bone formation
markers and urinary pyridinoline (UPYR) and urinary deoxypyridinoline
(UDPYR) as bone resorption markers. Soy protein intake was
significantly associated with the Z-score for L2-4 BMD (r = 0.23,p =
0.038) and UDPYR (r = -0.23, p = 0.034). Stepwise multiple regression
analyses showed that soy protein intake is significantly associated
with the Z-score for L2-4 BMD (beta = 0.225, p = 0.04) and UDPYR (beta
= -0.08, p = 0.03) among four nutritional factors. These results
suggest that high soy protein intake is associated with a higher bone
mineral density and a lower level of bone resorption, but further
studies are needed to confirm the causal dynamic mechanisms.
Heart
Disease: A recent study
involving monkeys demonstrated that the isoflavone component of soy
protein significantly reduces cholesterol levels and the risk of
atherosclerosis. A substantial amount of additional evidence that soy
reduces unhealthy LDL-Cholesterol levels while either not affecting or
increasing healthy HDL-Cholesterol levels is summed up in an analysis
of 38 controlled clinical trials. In fact, the evidence has been so
overwhelming as to the benefits of soy with regard to heart disease
that the FDA has concluded
that soy may reduce the risk of coronary heart disease by lowering
blood cholesterol levels and has authorized the labeling of food to
state this finding.
Effects of soy isoflavones on
atherosclerosis: potential mechanisms.
Anthony MS, Clarkson TB, Williams JK.
Comparative
Medicine Clinical Research Center, Bowman Gray School of Medicine of
Wake Forest University, Winston-Salem, NC 27157-1040, USA.
manthony@wfubmc.edu
It has long been recognized that
coronary
heart disease rates are lower in Japan, where soy consumption is
common, than in Western countries. In experimental studies,
atherosclerosis was reduced in animals fed diets containing soy protein
compared with those fed diets with animal protein. Recently, several
lines of evidence have suggested that the components of soy protein
that lower lipid concentrations are extractable by alcohol (eg, the
isoflavones genistein and daidzein). We recently evaluated the relative
effect of the soy protein versus the alcohol-extractable components of
soy on cardiovascular disease and its risk factors. Young male and
female cynomolgus monkeys were fed diets that contained either 1)
casein-lactalbumin as the source of protein (casein), 2) soy protein
isolate from which the isoflavones were alcohol extracted (SPI-), or 3)
isoflavone-intact soy protein (SPI+). The SPI+ group had significant
improvements in LDL cholesterol and HDL cholesterol. Only HDL
cholesterol was significantly improved in the SPI- group males compared
with the casein group. The casein group had the most atherosclerosis,
the SPI+ group had the least, and the SPI- group was intermediate but
did not differ significantly from the casein group. Potential
mechanisms by which soy isoflavones might prevent atherosclerosis
include a beneficial effect on plasma lipid concentrations, antioxidant
effects, antiproliferative and antimigratory effects on smooth muscle
cells, effects on thrombus formation, and maintenance of normal
vascular reactivity.
Meta-analysis of the effects of soy protein
intake on serum lipids.
Anderson JW, Johnstone BM, Cook-Newell ME.
Metabolic Research Group, Veterans Affairs Medical Center, Lexington,
KY 40511, USA.
BACKGROUND.
In laboratory animals, the consumption of soy protein, rather than
animal protein, decreases serum cholesterol concentrations, but studies
in humans have been inconclusive. In this meta-analysis of 38
controlled clinical trials, we examined the relation between soy
protein consumption and serum lipid concentrations in humans. METHODS.
We used a random-effects model to quantify the average effects of soy
protein intake on serum lipids in the studies we examined and used
hierarchical mixed-effects regression models to predict variation as a
function of the characteristics of the studies. RESULTS. In most of the
studies, the intake of energy, fat, saturated fat, and cholesterol was
similar when the subjects ingested control and soy-containing diets;
soy protein intake averaged 47 g per day. Ingestion of soy protein was
associated with the following net changes in serum lipid concentrations
from the concentrations reached with the control diet: total
cholesterol, a decrease of 23.2 mg per deciliter (0.60 mmol per liter);
95 percent confidence interval, 13.5 to 32.9 mg per deciliter [0.35 to
0.85 mmol per liter]), or 9.3 percent; low-density lipoprotein (LDL)
cholesterol, a decrease of 21.7 mg per deciliter (0.56 mmol per liter);
95 percent confidence interval, 11.2 to 31.7 mg per deciliter [0.30 to
0.82 mmol per liter]), or 12.9 percent; and triglycerides, a decrease
of 13.3 mg per deciliter (0.15 mmol per liter; 95 percent confidence
interval, 0.3 to 25.7 mg per deciliter [0.003 to 0.29 mmol per liter]),
or 10.5 percent. The changes in serum cholesterol and LDL cholesterol
concentrations were directly related to the initial serum cholesterol
concentration (P < 0.001). The ingestion of soy protein was
associated with a nonsignificant 2.4 percent increase in serum
concentrations of high-density lipoprotein (HDL) cholesterol.
CONCLUSIONS. In this meta-analysis we found that the consumption of soy
protein rather than animal protein significantly decreased serum
concentrations of total cholesterol, LDL cholesterol, and triglycerides
without significantly affecting serum HDL cholesterol
Food labeling: health claims; soy protein and
coronary heart disease. Food and Drug Administration, HHS. Final rule.
[No authors listed]
The
Food and Drug Administration (FDA) is authorizing the use, on food
labels and in food labeling, of health claims on the association
between soy protein and reduced risk of coronary heart disease (CHD).
Based on its review of evidence submitted with comments to the proposed
rule, as well as evidence described in the proposed rule, the agency
has concluded that soy protein included in a diet low in saturated fat
and cholesterol may reduce the risk of CHD by lowering blood
cholesterol levels.
Cancer: Soy isoflavones
have demonstrated a significant anti-cancer effect. This statement is
supported by the fact that the Japanese
breast cancer mortality rate is one-fourth that of the U.S. A recent
controlled study found that soy was associated with an almost 50
percent decreased risk of breast cancer in premenopausal women. Soy has
also been shown
to inhibit chemically induced mammary cancer in rats. More than 100 in
vitro (outside the body) studies have confirmed that soy isoflavones
inhibit the growth of a wide
range of cancer cells, including breast, colon, lung, leukemia and
prostate cells.
Protection against breast cancer with
genistein: a component of soy.
Lamartiniere CA.
Department
of Pharmacology and Toxicology and the Comprehensive Cancer Center,
University of Alabama at Birmingham, 35294, USA.
coral.lamartiniere@ccc.uab.edu
Breast cancer is the most common
cancer in women. Because genetics is believed to account for only
10-15% of breast cancer cases, the environment, including nutrition, is
thought to play a significant role in predisposing women to this
cancer. Studies of Asian women suggest that those who consume a
traditional diet high in soy products have a low incidence of breast
cancer, but that among emigrants to the United States, the second
generation, but not the first, loses this protection. These findings
suggest a possible common mechanism of action for breast cancer
protection from early, specific nutritional exposure. Genistein, an
isoflavone found in soy, has been reported to have weak estrogenic and
antiestrogenic properties, to be an antioxidant, to inhibit
topoisomerase II and angiogenesis, and to induce cell differentiation.
In studies of the mammary glands of immature rats, we showed that
genistein up-regulates the expression of the epidermal growth factor
receptor shortly after treatment, which may be responsible for the
increased cell proliferation seen at that age. We hypothesize that the
early genistein action promotes cell differentiation that results in a
less active epidermal growth factor signaling pathway in adulthood
that, in turn, suppresses the development of mammary cancer. We
speculate that breast cancer protection in Asian women consuming a
traditional soy-containing diet is derived from early exposure to
soybean products containing genistein. We believe that early events are
essential for the benefits of cancer protection.
Inhibitory effects of
Bifidobacterium-fermented soy
milk on 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine-induced rat
mammary carcinogenesis, with a partial contribution of its component
isoflavones.
Ohta T, Nakatsugi S, Watanabe K, Kawamori T, Ishikawa F, Morotomi M,
Sugie S, Toda T, Sugimura T, Wakabayashi K.
Cancer Prevention Division, National Cancer Center Research Institute,
1-1 Tsukiji 5-chome, Chuo-ku, Tokyo, Japan.
High
consumption of soybean and soybean-related products is hypothesized to
contribute to protection against breast cancer. Soybean is a rich
source of genistein, a putative cancer chemopreventive agent. Fermented
soy milk (FSM), which is made of soy milk fermented with the
Bifidobacterium breve strain Yakult, contains larger amounts of the
isoflavone aglycones genistein and daidzein than unfermented soy milk.
In the present study, we examined the effects of FSM and its component
isoflavone mixture (genistein:daidzein 4:1) on
2-amino-1-methyl-6-phenylimidazo[4, 5-b]pyridine (PhIP)-induced mammary
carcinogenesis in rats. Starting at 7 weeks of age, female
Sprague-Dawley rats were given PhIP at a dose of 85 mg/kg body wt by
intragastric administration four times a week for 2 weeks. They were
fed control high fat basal diet or experimental high fat diet
containing 10% FSM or 0.02 or 0.04% isoflavone mixture during and after
carcinogen exposure. The incidences (percentage of rats with tumors) of
mammary gland tumors were 71% in the control diet group, 51% in the FSM
group and 68 and 61% in the groups treated with isoflavone mixture at
0.02 and 0.04%, respectively. Mammary tumor multiplicities (number of
tumors per rat) were 1.2 +/- 0.2 for 10% FSM, 2.2 +/- 0.4 for 0.02%
isoflavone mixture and 1.5 +/- 0.3 for 0.04% isoflavone mixture, being
clearly smaller than the control diet value (2.6 +/- 0.5). Furthermore,
feeding of FSM and the isoflavone mixture at both doses reduced the
sizes of mammary tumors. Since the amounts of isoflavones in 10% FSM
are approximately equivalent to those in the 0.02% isoflavone mixture,
the chemopreventive activity of FSM could be partly attributable to the
presence of isoflavones such as genistein and daidzein.
Soy intake and cancer risk: a review of the
in vitro and in vivo data.
Messina MJ, Persky V, Setchell KD, Barnes S.
National Cancer Institute, National Institutes of Health, Bethesda, MD.
International
variations in cancer rates have been attributed, at least in part, to
differences in dietary intake. Recently, it has been suggested that
consumption of soyfoods may contribute to the relatively low rates of
breast, colon, and prostate cancers in countries such as China and
Japan. Soybeans contain a number of anticarcinogens, and a recent
National Cancer Institute workshop recommended that the role of
soyfoods in cancer prevention be investigated. In this review, the
hypothesis that soy intake reduces cancer risk is considered by
examining relevant in vitro, animal, and epidemiological data. Soybeans
are a unique dietary source of the isoflavone genistein, which
possesses weak estrogenic activity and has been shown to act in animal
models as an antiestrogen. Genistein is also a specific inhibitor of
protein tyrosine kinases; it also inhibits DNA topoisomerases and other
critical enzymes involved in signal transduction. In vitro, genistein
suppresses the growth of a wide range of cancer cells, with IC50 values
ranging from 5 to 40 microM (1-10 micrograms/ml). Of the 26 animal
studies of experimental carcinogenesis in which diets containing soy or
soybean isoflavones were employed, 17 (65%) reported protective
effects. No studies reported soy intake increased tumor development.
The epidemiological data are also inconsistent, although consumption of
nonfermented soy products, such as soymilk and tofu, tended to be
either protective or not associated with cancer risk; however, no
consistent pattern was evident with the fermented soy products, such as
miso. Protective effects were observed for both hormone- and
nonhormone-related cancers. While a definitive statement that soy
reduces cancer risk cannot be made at this time, there is sufficient
evidence of a protective effect to warrant continued investigation.
