Phytoestrogens Soybeans

Monday, November 17, 2008

Soybeans contain isoflavones called genistein and daidzein, which are one source of phytoestrogens in the human diet. Because most naturally occurring estrogenic substances show weak activity, normal consumption of foods that contain these phytoestrogens should not provide sufficient amounts to elicit a physiological response in humans.

Plant lignans associated with high fiber foods such as cereal brans and beans are the principal precursor to mammalian lignans which have an ability to bind to human estrogen sites. Soybeans are a significant source of mammalian lignan precursor secoisolariciresinol containing 13–273 µg/100 g dry weight. Another phytoestrogen in the human diet with estrogen activity is coumestans, which are found in beans, split-peas, with the best sources being alfalfa, clover, and soybean sprouts. Coumestrol, an isoflavone coumarin derivative is the only coumestan in foods.

Soybeans and processed soy foods do not contain the highest "total phytoestrogen" content of foods. A study in which data were presented on an as-is (wet) basis per 100 g and per serving found that food groups from highest to lowest levels of total phytoestrogens per 100 g are nuts and oilseeds, soy products, cereals and breads, legumes, meat products, various processed foods that may contain soy, vegetables, and fruits.

Women
A 2001 literature review suggested that women with current or past breast cancer should be aware of the risks of potential tumor growth when taking soy products, based on the effect of phytoestrogens to promote breast cancer cell growth in animals.

A 2006 commentary reviewed the relationship with soy and breast cancer. They stated that soy may prevent breast cancer, but cautioned that the impact of isoflavones on breast tissue needs to be evaluated at the cellular level in women at high risk for breast cancer.

Men
Because of the phytoestrogen content, some studies, but not all, have suggested that there is an inverse correlation between soybean ingestion and testosterone in men. For this reason, they may protect against the development of prostate cancer. A theoretical decrease in the risk of prostate cancer should, however, be weighed against the possible side-effects of decreased testosterone, which are still unclear. The popular fear that soybeans might cause reduced libido and even feminine characteristics in men has not been indicated by any study; the popularity of the notion seems to be based on the simplistic misapprehension that estrogen and testosterone have a simple, inverse relationship in sexual hormone systems and sex-related behaviour. Their interplay is very complicated and largely still unknown.

Studies published in July 2008 show that Soy products and, more specifically, the phytoestrogen they contain might lower a man's sperm count.

Soy allergy

Allergy to soy is often said to be rather common, and the food is listed with other foods that commonly cause allergy, such as milk, eggs, peanuts, tree nuts, shellfish. However, a critical review of medical literature reveals surprisingly little solid information on the topic. The problem has been reported amongst younger children and the diagnosis of soy allergy is often based on symptoms reported by parents and/or results of skin tests or blood tests for allergy. Only a few reported studies have attempted to confirm allergy to soy by direct challenge with the food under controlled conditions. In these circumstances it is clear that skin/blood tests considerably overestimate the problem, as do parental reports. It is very difficult to give a reliable estimate of the true prevalence of soy allergy in the general population. To the extent that it does exist, soy allergy may cause cases of urticaria (hives) and angioedema (swelling), usually within minutes to two hours of ingestion of the food. In rare, severe cases true anaphylaxis may occur, a condition that is much more common with allergy to foods such as peanut and shellfish. The reason for the discrepancy is likely that soy proteins, the causative factor in allergy, are far less potent at triggering allergy symptoms than the proteins of peanut and shellfish. An allergy test that is positive demonstrates that the immune system has formed IgE antibodies to soy proteins. However, when soy is ingested proteins must evade digestion and be absorbed in a form capable of triggering allergy and also in sufficient quantities to reach a threshold to provoke actual symptoms. The low potency of soy proteins as allergens may help explain why allergy skin/blood tests suggest that soy allergy is common, yet few cases are confirmed when the food is eaten under observation.

Soy can also trigger symptoms via food intolerance, a situation where no immunologic (allergic) mechanism can be proven. One scenario is seen in very young infants who have vomiting and diarrhoea when fed soy-based formula. The symptoms resolve when the formula is withdrawn and recur when it is re-administered. Older infants can suffer a more severe disorder with vomiting, diarrhoea that may be bloody, anemia, weight loss and failure to thrive. The commonest cause of this unusual disorder is a sensitivity to cow's milk, but there is no doubt that soy formulas can also be the trigger. The precise mechanism is unclear and it could be immunologic, although not through the IgE-type antibodies that have the leading role in urticaria and anaphylaxis. Fortunately it is also self-limiting and will often disappear in the toddler years.

Promotion as health food
Soy consumption has been promoted by natural food companies and the soy industry's aggressive marketing campaign in various magazines, television ads and in health food markets. Research has been conducted examining the validity of the beneficial health claims with regard to the increase in consumption of soybeans which mimic hormonal activity.

A practice guideline published in the journal Circulation questions the efficacy and safety of soy isoflavones for preventing or treating cancer of the breast, endometrium, and prostate (although the same study also concludes that soy in some foods should be beneficial to cardiovascular and overall health) and does not recommend usage of isoflavone supplements in food or pills. A review of the available studies by the United States' Health and Human Services' Agency for Healthcare Research and Quality (AHRQ) found little evidence of substantial health improvements and no adverse effects, but also noted that there was no long-term safety data on estrogenic effects from soy consumption.

Brain
Estrogen helps protect and repair the brain during and after injury. The mimicry of estrogen by the phytoestrogens in soy has introduced a controversy over whether such a replacement is harmful or helpful to the brain. Several studies have found soy to be harmful for rats. Nevertheless the cited study was based on rats fed with concentrated phytoestrogens and not common soybeans. The common amounts of phytoestrogens in soy beans are not to be compared to concentrated estrogen. One study followed over 3000 Japanese men between 1965 and 1999, and that showed a positive correlation between brain atrophy and consumption of tofu. This study by L.R. White, et al., from the National Institute of Aging, NIH, was rejected as not credible by the Food and Drug Administration.

Carcinogen
Raw soy flour is known to cause pancreatic cancer in rats. Whether this is also true in humans is unknown because no studies comparing cases of pancreatic cancer and soy intake in humans have yet been conducted, and the doses used to induce pancreatic cancer in rats are said to be larger than humans would normally consume. Heated soy flour may not be carcinogenic in rats. Existing cancer patients are being warned to avoid foods rich in soy because they can accelerate the growth of tumours.

Iron
One single small-scale study published in 1995 concluded that "a vegetarian diet that is rich in soybean products and restricted in animal foods is limited in bioavailable iron and is not adequate for maintaining iron balance in men and women".

A soy biodiesel success story

Thursday, November 13, 2008

Soy 2020 a vision for a strong future
As the soybean industry grows, opportunities for U.S. farmers are expanding as well. The purpose of Soy 2020 is to create an action plan that will help the industry take advantage of the opportunities and meet the challenges it will face through the year 2020.

Soy 2020 engages members of all segments of the soybean value chain in the creation of a dynamic vision for the industrys future. By looking at positive factors such as the expansion of the biodiesel industry and the growth of domestic animal agriculture and examining potential negative scenarios like a loss of global competitive advantage, the initiatives participants have created winning strategies to address whatever the future holds. Already, the industry is realigning itself to the points of the Soy 2020 vision outlined below:

• Strive for economic sustainability and a global leadership position through the innovation, adoption and delivery of soy production and trait technologies.
• Create a wide variety of output choices for food, feed, fuel and other outputs and increase demand for soy by promoting benefits.
• Take an environmentally responsible leadership role to ensure a secure, safe, sustainable and abundant global food supply to feed a hungry world.
• Enable success of all soybean sectors and prepare to work in a coordinated leadership capacity through any situation the future may hold for U.S. soy.
  

As an inclusive, industry-wide initiative, its vital for all soybean stakeholders to take part in the Soy 2020 vision and to help that vision evolve.

To find out more about Soy 2020 and to find out what you can be doing today to prepare for tomorrows soybean market, visit the Soy 2020 Web site.

A soy biodiesel success story
Your soybean checkoff investment funded the research that developed soy biodiesel - a fuel made from soybeans that can be used in any diesel engine. And now your investment is funding marketing efforts that are moving more soy biodiesel than ever before.

Today, nearly half of all soybean farmers use a biodiesel blend, but there's still room to grow. If every farmer and rancher used B2, a 2% blend of soy biodiesel, it would use almost 48 million bushels of soybeans every year.

To find out more about soy biodiesel and how your soybean checkoff helped create and promote this amazing fuel, click on the links below.

Biodiesel basics
Soy biodiesel is actually better for your engine than conventional diesel. Because it has a higher fuel lubricity, soy biodiesel can decrease wear-and-tear that can shorten your engine's life or lead to equipment downtime. Even a two percent (B2) blend of soy biodiesel can increase fuel lubricity by up to 66 percent.

Soy biodiesel is competitively priced. A federal tax incentive can make it more affordable than ever. And as more people choose soy biodiesel, more suppliers and distributors are offering it.

You can use soy biodiesel year-round. With a B20 blend, you should use the same cold weather handling and storage practices that you would with conventional diesel. And you'll be glad to know that soy biodiesel is safer to use, handle and store than any other fuel.

Biodiesel and your soybean checkoff
In 1990, state soybean checkoff boards began funding soy biodiesel research. After it's founding, USB followed suit. To this day, USB and state soybean checkoffs still fund almost all major soy biodiesel promotion and research. Many of these promotion efforts are focused on informing our fellow farmers and ranchers of the benefits of soy biodiesel. Because of these efforts, almost half of all soybean farmers now use soy biodiesel in their equipment. To find out what your state is doing to promote soy biodiesel, click here.

The history of soy biodiesel

• 1990: Soybean checkoff in Missouri funds first soy biodiesel research in the United States.
• 1991: Soybean farmer-leaders drive soy biodiesel demonstration vehicle to the U.S. Capitol.
• 1992: Soybean checkoff helps organize the National Biodiesel Board (NBB).
• 1993: Soy biodiesel vehicle fleet pilot demonstrations begin.
• 1994: Soybean checkoff sponsors Zodiac global voyage fueled by B100.
• 1995: Soy biodiesel quality study funded by the soybean checkoff.
• 1996: First soy biodiesel manufacturers register with the U.S. Environmental Protection Agency (EPA).
• 1997: Some school bus fleets start to use B20 to reduce emissions.
• 1998: American Soybean Association (ASA) helps secure law to allow soy biodiesel for federal clean air regulatory compliance.
• 1999: President Clinton calls for expanded use of biobased fuels.
• 2000: Soybean checkoff funds EPA soy biodiesel health-effects testing.
• 2001: Several ag co-ops and fuel suppliers begin offering soy biodiesel to farmers and ranchers.
• 2002: Original soy biodiesel demonstration vehicle makes return trip to U.S. Capitol with 300,000+ miles logged.
• 2003: Soybean checkoff launches major effort to boost on-farm soy biodiesel use.
• 2004: Some major fuel suppliers speed up soy biodiesel distribution by installing rack injection blending and loading systems at fuel terminals.
• 2005: Federal tax incentive passed and implemented, which makes soy biodiesel more affordable than ever.
• 2006: About half of all U.S. soybean farmers indicate they use soy biodiesel in their farming operations.