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Archive for the ‘Soy’ Category

New Study Now Links Soy Intake

Regular consumption of soy products could decrease the risk of lung disease and breathlessness, according to a new respiratory health study from Japan.

Published in the Journal Respiratory Research, the new study
examined nearly 300 patients diagnosed with lung disease, and
measured their reported soy food intake. “Soy consumption was
found to be positively correlated with lung function and inversely associated with the risk of chronic obstructive pulmonary disease (COPD). The epidemiological evidence also indicated an inverse association between total soy intake and breathlessness,” wrote the researchers from Japan and Australia.

Questionnaires

The study was conducted on 278 Japanese patients aged 50-75,
who had been diagnosed with COPD within the past four years.
Another 340 participants recruited from the general Japanese
population were used as a control group. All participants were
tested for respiratory function. Food consumption and lifestyle
characteristics were determined based on structured questionnaires.

The researchers identified the self-reporting of dietary intake as a limitation to their study, but said that they also included individual interviews with relatives in order to increase response rate and improve the accurac y of answers. They also said all interviews were conducted by the same investigator to eliminate inter-interviewer bias.

Participants were asked specifically about their soy food
consumption for the five years prior to the interview date.
For the purposes of the study, soy foods includeded tofu, natto, bean sprouts, and soy milk. Other variables measured were age, gender, body mass index, education level, physical activity, smoking status, and dietary intake of fruit, vegetables, fish, red meat and chicken.

Cautious Benfits

Overall, the researchers found that those participants diagnosed with COPD had significantly lower soy intake than controls. Researcher then examined the relationship with lung function, and found that this was positively correlated with total soy consumption.

“A significant reduction in COPD risk was evident for the highest versus lowest quartile of daily total intake of soybean products,” wrote the researchers.

The observed benefits, consistent with findings from previous
studies, could be a result of the anti-inflammatory benefits of
soyfoods, they said, but added that more research is needed
to understand the underlying biological mechanism.
“The present case-control s tudy has suggested an inverse
association between soy products and COPD risk for Japanese
adults,” concluded the researchers.

“More research and/or replications are required to ascertain whether the observed findings can be generalized to other populations, before incorporating these foods into dietary guidelines so as to encourage consumption.”

“Besides experimental studies, long-term prospective cohort studies collecting detailed dietary exposure information are recommended to provide epidemiological evidence on both morbidity and mortality due to COPD.”

Source: Soy consumption and risk of COPD and respiratory symptoms: a case-control study in Japan Respiratory Research 2009,

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Good Cholestero​l Benefits From Soy: New Study

Study Supports Soy Cholesterol Benefits…                                    

Soybean seeds

Soybean seeds (Photo credit: IITA Image Library)

Despite past evidence suggesting that eating soy might only lower cholesterol in those whose bodies are able to convert it to an estrogen-like compound called equol, a new study shows soy might benefit a wider range of people.

Canadian researchers discovered that a diet high in soy isoflavones lowered  “bad” cholesterol ( LDL ) about equally in people who were considered equol producers and in those who were not. The equol producers, however, maintained their previous levels of “good” HDL cholesterol, while the non-producers’ HDL levels also dropped.

Nutrition researchers at the University of Toronto in Canada used three previous studies to test whether the ability to produce equol from soy products was linked to changes in cholesterol.

The researchers analyzed data on 85 people who participated in one of the three studies. In each of the studies the participants ate between 30 grams and 52 grams of soy foods including: tofu burgers or tofu hot dogs every day over four weeks.

Before they started eating the soy, both equol and non-equol producers had LDL cholesterol in the range that would be considered high according to the American Heart Association (AHA). Their HDL cholesterol was also considered low.

For LDL cholesterol, the AHA says a reading between 160 milligrams per deciliter (mg/dL) and 189 mg/dL is high, while HDL cholesterol below 60 mg/dL is considered low and not protective against heart disease.

After the study, the 33 equol producers’ HDL stayed about the same, while the non-equol producers’ dropped from about 48 mg/dL to about 46 mg/dL.

As for their LDL cholesterol, the equol producers’ fell from about 169 mg/dL to about 152 mg/dL. The non-equol producers’ fell from about 174 mg/dL to about 153 mg/dL.

The LDL reductions are large, the researchers reported in the American Journal of Clinical Nutrition, although that was likely because one of the three studies looked at weight reduction, and that would influence the results.

A 2006 review by the AHA nutrition committee of 22 randomized trials looking at soy and the levels of cholesterol said the LDL reduction they observed was relatively small in given the amount of soy a person would have to eat every day to achieve it.

Eating soy helps displace foods that can contribute to heart disease…

For example…”If you’re having a soy burger you may be displacing a hamburger,” they explained; “Overall, soy should only be one part of a cholesterol-lowering diet.” they concluded.

SOURCE: American Journal of Clinical Nutrition (online) February 1, 2012.

 

This article is for informational and educational purposes only;  It is not intended to provide medical advice, diagnosis or treatment. Consult your doctor or healthcare professional.

The Soy Renaissance

In addition to its many nutritional benefits, soy may offer relief from common discomforts associated with menopause. Learn more about this super food and how it might help you.

In last week’s newsletter, I touched on the value of dietary soy, especially for women’s wellness. Although the health benefits of soy have been questioned, I believe a negative reputation has been encouraged by lobbyists for the meat and dairy industries. That said, I’m not a “soy nut,” and I do think that traditional diets with meat, dairy or fish protein can be healthy.

Much of the health value of soybeans is actually found in an interesting series of soy components called isoflavones. Isoflavones are a category of natural substances called phytoestrogens (phyto = plant). These plant compounds are believed to have hormone-like effects, but there is more to these potent and versatile natural substances. Phytoestrogens have many biological effects, and they may be best viewed as “adaptogens,” or biological-response modifiers, rather than simple estrogens.

The most abundant and common source of isoflavones are soybeans, which contain the isoflavones genistein, daidzein and glycetein. Phytoestrogens are found in red clover, lignans, fruit or grain fibers and phytosterols. Phytosterols are present in beans, cereals and grass sprouts. Active occurring phytoestrogens are transformed by bacteria in the colon or body enzyme systems into isoflavones or related compounds with estrogen-balancing effects.

Population studies of menopausal women provide convincing evidence that isoflavone-rich soy foods may reduce the occurrence or severity of hot flashes and other discomforts of menopause. Women following traditional soy-enriched diets in Japan have been found to have much higher levels of phytoestrogens in their urine than women in Western societies who follow the Standard American Diet. Along with this finding of high isoflavone intake are reports of significantly less menopausal discomforts, especially a low occurrence of hot flashes, in Japanese women.

The beneficial effects of soy have been attributed to the presence of the isoflavones genistein and daidzein; and these isoflavones have been concentrated and added to many dietary supplements for menopause and PMS management. More than 20 recent clinical trials have tested the ability of soy isoflavones, taken in concentrated forms (pills or soy protein isolates), to reduce hot flashes in menopausal women. While results have been mixed, approximately half of study participants reported improvements in hot flashes in just a few weeks. I believe variations in dosage may account for variations in results.

Soy isoflavones have varying levels of potency in terms of an estrogen-like action. However, they are all weak estrogens or modulators of estrogen’s effects on the body. I have been impressed by the benefits of using isoflavones of different origins together in dietary supplements. With these combinations, additive benefits are seen, and lower dosages of each isoflavone can be used together for greater effects (synergy). In particular, a combination of soy isoflavones and red clover isoflavones may be more effective for hot flashes.

There is a long history of precedent for the safety of soy foods. There are no studies in humans showing significant adverse effects of soy isoflavones, even when taken in relatively large doses (100 mg or more). Reviews of medical and scientific literature suggest that isoflavones in soy may exert significant protective effects in both animals and humans. (See Holt, S., “The Soy Revolution,” Dell Publishing, N.Y., N.Y., 2000). Soy isoflavones are known to function as potent antioxidants and free radical scavengers.

Many women question whether or not plant estrogens (phytoestrogens) cause cancer. Scientists have attempted to address the safety of phytoestrogens in relationship to cancer, but there are many different types of these plant compounds. Certain phytoestrogens have beneficial effects on the body, especially when body estrogen levels are high (independent of actions on estrogen receptors). However, there is no evidence that phytoestrogens used in popular dietary supplements can lead to cancer.

Soy isoflavones appear to be quite safe when used in doses with an existing precedent for safety (up to approximately 80 mg to 100 mg of total soy isoflavones in dietary supplements). While it’s unlikely that anyone would consume more than a total daily intake of 150 mg of isoflavones even if he or she ate a heavily soy-enriched diet, isoflavone supplements are available in a wide range of doses. I would like to stress that continuous use of soy supplements with high doses of soy isoflavones should be avoided.

The complex, beneficial actions of isoflavones and other components of soy make soy foods an extremely valuable dietary addition. For a more complete account of the positive impact of soy on health, please feel free to read my books (“The Soy Revolution,” Dell Publishing, N.Y., 2000; “Soya for Health,” Mary Ann Liebert Publishers, N.Y., 1997; and “Combat Syndrome X, Y and Z”, www.stephenholtmd.com, N.J., 2002).

Be Healthy!
Stephen Holt, MD

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