
"The beginning of wisdom is to call things by the right names." -Chinese Proverb
Cancer is a group of dis-eases characterized by the uncontrolled fermentation and degeneration of body cells. Over 10 million Americans today are cancer survivors, and about 1.4 million Americans are expected to be diagnosed each year.1
There has been much focus during the past 15 years on the anticancer effects of soy foods.2There are several presumed chemopreventive agents in the soy bean,6 but the isoflavones have received the most attention.3 A particular interest lies in the role of soy foods and isoflavones in reducing the risk of breast and prostate cancer.2
Data modestly supports the hypothesis that soy food intake may reduce the incidence of breast cancer. A recently published analysis found the relative risk for breast cancer was 95 percent when comparing high- vs. low-soy consumers.5 However, many of the case-control and prospective studies included in this analysis were of poor quality.6
Rodent studies have generally shown that isoflavones, or soy protein, inhibit chemically induced mammary tumors when given prior to tumor initiation7-9, although there are a number of exceptions.10-12 Interestingly, the chemopreventive effects of isoflavones appear to be affected by the background dietary choices.
When the isoflavone genistein was added to the semi-purified diet, chemically induced rodent mammary tumors were not inhibited, but when added to the regular chow diet, tumor development was suppressed by approximately 50 percent.13 This suggests that animal research, which most commonly uses semi-purified diets, may actually underestimate the potential anticarcinogenic effects of soy and other foods.
Soy & Markers of Breast CancerIn contrast to the animal and epidemiologic data, there is little clinical evidence that soy or isoflavones favorably affect markers of breast cancer risk including breast tissue density,14, 15serum estrogen levels,16, 17 and breast cell proliferation.18 There is limited evidence that estrogen metabolism is favorably affected19 and that menstrual cycle length is increased (which decreases cancer risk).16
Nevertheless, there remains considerable enthusiasm for the possibility that soy food intake contributes to the low breast cancer rate in Japan.
Early Intake of Soy May Reduce Breast RiskThere is both epidemiologic 20-22 and animal 23, 24 data in support of the hypothesis that early soy intake reduces later risk of developing breast cancer. This hypothesis is consistent with mounting evidence that early life influences — parity, lactation, age at menses, birth weight, etc. — impact risk of developing breast cancer.25-36 Studies of migrants suggest that the first 20 years of life have an especially profound impact on risk.36-38 The epidemiologic data suggest just one to two servings of soy foods is protective.
Breaking News - Soy Breast Cancer StudySoy Breast Cancer Study Holds Promise, But Calls for Further Research
For more than 15 years, soy foods have been actively investigated for their possible role in reducing breast cancer risk. Initial enthusiasm about this hypothesis was based on several observations. These include the low breast cancer rates in Japan, early animal research indicating that soy beans in rodent diets reduced mammary tumor development and evidence suggesting that the isoflavones (phytoestrogens) in soy foods may exert anti-estrogenic effects.
However, establishing a relationship between cancer risk and diet – especially specific foods – is much more difficult than establishing such links in the case of other chronic diseases such as coronary heart disease. This is because there are few well-established non-invasive indicators of cancer risk, and studies are very rarely conducted for long enough to measure actual differences in tumor incidence. Consequently, it is difficult to claim with confidence whether a particular intervention increases or decreases the chances of developing cancer.
Epidemiologic research is a useful mode of investigation for exploring a relationship between diet and cancer. Epidemiology is the study of the patterns, causes, and control of disease in groups of people. There are two primary types of epidemiologic studies, case-control and prospective studies. In case-control studies, scientists compare people with cancer to those without in hopes of identifying characteristics such as lifestyle or diet that are more common to one group than the other. In prospective studies, scientists first evaluate the characteristics of a large group of healthy people, then follow those subjects for many years in hopes of identifying whether certain factors are more common to those who develop cancer than to those who don't. Generally, prospective studies are considered more credible than case-control studies. It is important to recognize, however, that epidemiologic studies cannot establish cause and effect relationships. Only clinical trials can do that. But epidemiologic studies are often used as a basis for clinical research.
To evaluate the relationship between soy intake and breast cancer risk, Bruce Trock and colleagues from the Johns Hopkins School of Medicine and Georgetown University conducted a meta-analysis of epidemiologic studies. A meta-analysis is the statistical analysis of a large collection of results from individual studies for the purpose of integrating the findings. This particular analysis included 12 case-control studies and 6 prospective studies. The major finding of this analysis was that when all women (Asian and non-Asian, pre- and postmenopausal) were considered, soy intake was associated with a 14% reduction in breast cancer risk. That is, women consuming higher quantities of soy were 14% less likely to develop breast cancer than women who consumed relatively little soy. However, subgroup analysis revealed that soy was more protective against pre- compared to postmenopausal breast cancer, and was protective in studies involving non-Asian women but not Asian women.
The analysis by Trock and colleagues provides modest support for the notion that soy may protect against breast cancer. A 14% reduction is certainly noteworthy, but for several reasons the study results should be interpreted with caution.
First, in many studies, soy intake was not actually quantified. Rather, it was estimated based on the urinary excretion of isoflavones. Because urinary isoflavone excretion varies so much from person to person, it provides only a rough approximation of soy intake. Furthermore, although soy was found to be protective in studies involving non-Asian women, the intake of soy by the women in these studies was quite low. There is some doubt as to whether such low intakes are sufficient to exert biological effects. Since soy foods are still consumed by only a minority of people in non-Asian countries – and are often favored by especially health-conscious individuals – we must consider the possibility that the perceived cancer-protective effects of soy may result from an overall healthy lifestyle, rather than soy consumption per se. Although the researchers employed statistical techniques to try to separate the effects of soy from other factors common to people who eat soy, this is very difficult to do.
While some evidence, including the new analysis by Trock and colleagues, suggests soy foods may reduce breast cancer risk, no conclusions can be made at this time. Nevertheless, because soy foods provide excellent nutrition, they can play an important role in an overall healthy diet, regardless of their possible relationship to breast cancer protection.
The soy bean isoflavone genistein inhibits the growth of both androgen-dependent39-42 and androgen-independent39, 42-45 prostate cancerous cells, depending on the level of soy doses administered. In addition, genistein inhibits the invasive capacity of prostate cancerous cells 42and enhances the ability of radiation to kill these cells.46 However, the concentration of genistein required to exert these effects is higher than the serum isoflavone levels of people who eat soy foods.47-49 Nevertheless, several observations suggest these effects are biologically relevant.39,44-49
Regional Diets Can Impact Prostate CancerIn Japan, although many men have prostate cancer, few die of this dis-ease. This is because the small tumors often referred to as latent prostate cancer, not uncommon to Japanese men, rarely progress to the more advanced form of this disease.51, 52 Isoflavones in combination with tea extracts were shown to reduce tumor growth in mice more effectively than either agent alone.9
In Asia, and especially in Japan, where prostate cancer mortality rates are low, both soy foods and tea are important components of their diet. There are likely several factors that contribute to this clinical situation in Japanese men and according to the International Prostate Health Council, and isoflavone intake from soy foods may be one.53
There has been limited epidemiologic investigation of the relationship between soy intake and prostate cancer. These studies have produced mixed results but can be said to be consistent with the hypothesis that soy intake reduces prostate cancer risk.
A recent analysis of 10 epidemiologic studies found that soy intake was associated with a one-third reduction in prostate cancer risk.5 However, many of the epidemiologic studies involved a small number of cases54, 55 and/or did not comprehensively evaluate soy food intake. However, a recent comprehensive Japanese case-control study found that when comparing the highest with the lowest soy food intake cases, risk was reduced by nearly 50 percent.56
Soy May Help Treat Existing Prostate CancerData suggests that soy foods may be useful in the treatment of existing prostate cancer, but this remains speculative. A study of 11 trials, three involving healthy subjects57-59 and eight involving prostate cancer patients,60-67 examined the effects of isoflavones on PSA levels. No benefits were noted in healthy subjects, but among the cancer patients one-half noted favorable effects.68Recent intervention data demonstrate that reducing prostate cancer risk is not dependent upon reductions in PSA levels.69
Infertility is on the rise in Canada, according to the first study in nearly two decades to measure the proportion of Canadian couples who are having difficulty conceiving.
The researchers didn't set out to discover why the numbers are increasing. But possible explanations range from the growing number of women who are pushing back pregnancy ever later in life, to rising rates of obesity and heavy drinking among women, to declining sperm counts in men — though experts aren't convinced about that final factor.
The use of assisted-procreation technologies has increased dramatically over the past decade, yet "little is known about the prevalence of infertility in the population," the authors write in the journal, Human Reproduction.
The research was supported by funding from Assisted Human Reproduction Canada, a federal agency. The lead author is from Statistics Canada.
According to their estimates, up to 16 per cent of heterosexual couples where the woman is age 18 to 44 are experiencing infertility — a near doubling since the previous time infertility was measured in the nation in 1992.
Not surprisingly, the older the woman, the higher the prevalence of infertility.
Yet infertility appears to be rising among younger women as well, the study finds.
In 1984, about five per cent of couples with a female partner age 18 to 29 were infertile.
By 2009-10, the prevalence for the same age group ranged from seven to 13.7 per cent.
For their analysis, researchers used data from a sample of 4,412 couples from the 2009-2010 Canadian Community Health Survey.
Infertility ranged from 11.5 per cent, to 15.7 per cent.
Those estimates are based on whether couples had reported becoming pregnant or not in the past 12 months, were not using any form of birth control within the past 12 months while having sexual intercourse, and had tried to become pregnant with their current partner. Regardless of how it was defined, each estimate represented an increase in infertility when compared with previous national estimates, said first author Tracey Bushnik, a senior analyst at Statistics Canada.
In 1992, 8.5 per cent of women age 18 to 44 who were married or living common-law were considered infertile.
In 1984, the figure was 5.4 per cent.
Not only are the emotional, physical and financial costs to couples substantial, the researchers write, but the health system also has to bear the costs of caring for premature babies or multiple births born from asssisted reproductive technology.
The new study "just confirms everything we've been gnawing on for the last little while," said Dr. Roger Pierson, a world leader in research into ovarian physiology at the University of Saskatchewan.
Canada's pregnancy specialists have been sounding an alarm over the risks of deferred motherhood. The Society of Obstetricians and Gynaecologists of Canada — which has just issued new guidelines to doctors on "advanced reproductive age" and fertility — worries that women are placing too much blind faith in high-tech fertility treatments to help them conceive once they're ready to have a baby.
For women over 40, the failure rate approaches 90 per cent.
"We're not miracle workers," said Dr. Al Yuzpe, co-author of the new study and co-founder of the Genesis Fertility Centre in Vancouver, one of the largest in-vitro-fertilization clinics in the country.
"We know that there's a precipitous drop in conception rates as women get older," he said.
The other authors of the report were: Jocelynn L. Cook, of the Department of Obstetrics and Gynecology at the University of Ottawa; Suzanne Tough, of the Departments of Pediatrics and Community Health Sciences at the University of Calgary; and John Collins, of the Department of Obstetrics and Gynecology at McMaster University in Hamilton, Ont.
In addition to the well-documented impact of age, other factors affecting female fertility include obesity, alcohol use and sexually transmitted infections.
While fewer women are smoking, more younger women are boozing heavily: reported rates of heavy drinking — defined as five or more drinks at a time at least once a month — among women age 20 to 34 increased from nine per cent in 1994, to 20 per cent in 2010.
Reported rates of chlamydia and gonorrhea are also rising, with the majority of infections reported for women under 30.
And obesity rates are climbing: In 2007-09, 21 per cent of women ages 20 to 39 in Canada were obese, up from four per cent in 1981. Obesity can interfere with a woman's normal ovarian function.
Obese men, meanwhile, have been found to have lower volumes of semen and a higher proportion of abnormal sperm. But just how much a role sperm count deterioration may be having on declining fertility is controversial.
Yuzpe said the data are not convincing.
"The question keeps coming up: Are men's sperm counts getting worse?" he said. "There might be a slight overall reduction in sperm counts, but not from 'normal' to 'abnormal' sort of thing," he said.
Yuzpe said people are much more likely today to report difficulty conceiving than they would have been in the past, "because of the stigma associated with it," but also because people didn't seek help "because there wasn't much we could do for them.
"It's only in the last 35 or 40 years that we've had anything of any significance that we could do for women, or for couples," he said.
Pierson said the study raises important individual and societal questions, including when is the right time to have a child?
"If we were to suddenly stop ART (assisted reproductive technology) and say, 'We're going to support women having children in their early 20s,' I would say that most of the infertility issue would go away.
"That's not our cultural reality," Pierson said. "We have to come to a better understanding of our biological imperatives, and our social expectations."
http://www.canada.com/health/Infertility+rates+rising+Canadian+couples/6157547/story.html
Red Meat Consumption Increases Risk of Early Death
Over the years, eating too many burgers, steaks pork chops or other red meat products has been linked to heart disease, diabetes and some cancers. In particular, processed red meat, such as bacon, hot dogs or bologna, has especially strong links to chronic diseases.
But the latest research brings even more dire news for hardcore carnivores. In addition to increasing the odds people will get sick, red meat—whether it is processed or not—can actually increase the risk of premature death overall, according to a study that was published online March 12 in Archives of Internal Medicine.
Steak image courtesy of iStockphoto/Kativ
Researchers, led by An Pan of the Harvard School of Public Health, analyzed health and diet information from more than 121,000 U.S. men and women participating in two long-term health studies. Everyone in the group the researchers assessed had been free of both heart disease and cancer at the outset of the studies.
Over long-term follow-up, as long as 28 years in some cases, more than 13,900 people died—about 9,460 from cancer and almost 6,000 from cardiovascular disease. After adjusting for other factors, the researchers found each daily serving of red meat (beef, pork, lamb or a processed meat, such as bacon, bologna, hot dog, salami or sausage), increased the risk of a premature death by about 12 percent. Processed meat consumption in particular increased these odds even more than did unprocessed meats. And hot dogs and bacon seemed to be the most likely to lead to an early death.
If everyone in the study had limited themselves to 42 grams or less of red meat a day (considered to be about half a standard serving), more than 9,860 early diet-related deaths could have been prevented in the study alone, the researchers estimated.
So if that lamb and ham are off the table, along with all the all-too familiar beef, many people worry that they might not get enough protein with each meal. Fear not, say many health experts, there are plenty of other ways to put protein on your plate that don’t come with such high risks of chronic diseases. Chicken breasts actually have more grams of protein by weight than a piece of beef, and fish isn’t too far behind. The researchers also found that beans, nuts, low-fat dairy and whole grains made for healthful replacements for a red meat meal portion.
And for folks worried about getting enough iron, excess iron from diet has actually been linked to heart attacks and fatal heart disease as well as possibly to cancer, the researchers noted.
Getting to a healthful level of red meat consumption in the U.S. might be an uphill battle. Only about 9.6 percent of the women and 22.8 percent of the men in the studies fell in the low-risk category (of a half-serving-or-less per day) for red-meat consumption.
But contrary to popular thinking, a good diet is as much about what you put in to your mouth as what you omit.
The study found that trading out a serving of red meat for fish or poultry didn’t just negate the red meat risk; rather, it actually improved people’s odds of living longer. Replacing a serving of red meat each day with fish reduced premature mortality risk by 7 percent; for poultry, the reduction was twice that: 14 percent.
Veggies are even better. “Plant-based foods are rich in phytochemicals, bioflavonoids and other substances that are protective,” wrote whole-food diet advocate Dean Ornish in a related essay also published online Monday in Archives of Internal Medicine. “So substituting healthier foods for red meat provides a double benefit to our health.”
Ornish noted that the focus for a healthful diet should be on high-quality over high-quantity: “smaller portions of good foods are more satisfying than larger portions of junk foods.” In addition, he highlights current research-based suggestions for the healthiest diet:
o Little to no red meat; instead obtain protein from poultry, fish, legumes, nuts or other products
o Plenty of good, whole-food carbohydrates, such as whole grains, beans, fruits and vegetables
o Little processed or refined carbohydrates, such as white flower, sugar or corn syrup
o Some good fats, such as omega three fatty acids that are in flax and fish oils
o Little bad fats, such as hydrogenated, saturated or trans fats
Another benefit to cutting red meat consumption: dialing back out-of-control medical costs, Ornish noted. Avoiding chronic diseases linked to excess red meat consumption could decrease medical spending by billions of dollars.
\Medicine\Red Meat Consumption Increase Risk of Early Death - 03.12.12