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How soy can change the body

Compounds in soy products may help lower blood pressure, says a recent study that explained there's a benefit among African Americans of particular note. Soy-based food products have taken grocery store shelves by storm, and the benefits of soy are steadily beginning to emerge. Eating foods that contain isoflavones – a key compound in soy milk, tofu, green tea and even peanuts – every day may help young adults lower their blood pressure. You can check out the abstract of the study , "Dietary Isoflavone Intake is Associated with Lower Systolic Blood Pressure: the Coronary Artery Risk Development in Young Adults (CARDIA) Study," published online March, 2012 in the Journal of the American College of Cardiology. When it comes to soy, are you eating organic or GMO soy?

How soy can change the body.
How soy can change the body.Photo by Cancan Chu

Moreover, and for the first time, there appears to be a particular benefit for African Americans, who have hypertension prevalence rates near 42 percent, according to research presented in 2012 at the American College of Cardiology's 61st Annual Scientific Session. The Scientific Session, the premier cardiovascular medical meeting, brings cardiovascular professionals together to further advances in the field.

"What's unique about this study is that the results are very applicable to the general population. Our results strongly suggest a blood pressure benefit for moderate amounts of dietary isoflavone intake in young black and white adults," said Safiya Richardson, according to the March 25, 2012 news release, "Compound in soy products may help lower blood pressure." Richardson is (at the time of the news release) a graduating medical student at Columbia University's College of Physicians and Surgeons and the study's lead investigator. "Our study is the first to show a benefit in African Americans, who have a higher incidence of high blood pressure, with an earlier onset and more severe end-organ damage."

Compared to those consuming less than 0.33 mg of isoflavones per day, those reporting the most isoflavone intake (more than 2.5 mg per day) had a significantly lower systolic blood pressure on average. To help put this into context, an 8 ounce glass of soy milk has about 22 mg of isoflavones, and 100 g of roasted soybeans have as much as 130 mg.

"This could mean that consuming soy protein, for example, in combination with a DASH diet – one that is high in fruits and vegetables, low-fat dairy and whole grains – could lead to as much as a 10 mmHg drop in systolic blood pressure for pre-hypertensives, greatly improving their chances of not progressing to hypertension," said Richardson, according to the news release. "Any dietary or lifestyle modification people can easily make that doesn't require a daily medication is exciting, especially considering recent figures estimating that only about one third of American hypertensives have their blood pressure under control."

How isoflavones work

Isoflavones are thought to work by increasing the production of enzymes that create nitric oxide (NO), a substance that helps to dilate or widen blood vessels, thereby reducing the pressure created by blood against the vessel walls. Richardson said this mechanism may partially explain why the study was able to find an association with smaller amounts of isoflavone intake than examined previously.

The relatively pronounced results in the overall biracial cohort may be driven by a more intense effect of isoflavones in African Americans, Richardson said, according to the news release. This is because endothelial dysfunction, a condition in which the blood vessels have a hard time either producing or using NO, plays a bigger role in hypertension in African Americans than it does in whites.

"It's possible that these foods may help compensate for this," she said, according to the news release. "Based on our results and those of previous studies, we would encourage the average adult to consider including moderate amounts of soy products in a healthy, well-balanced diet to reduce the chances of developing high blood pressure. For people with hypertension, it's important that they talk with their doctor about isoflavones as a possible addition to a low sodium DASH diet that could reduce the need for medication."

Richardson added that different soy products have different concentrations of isoflavones, so it is important for consumers to do their homework

Researchers analyzed data from year-20 of the Coronary Artery Risk Development in Young Adults (CARDIA) study, which is an NIH-funded study created to examine the development and determinants of cardiovascular disease. This study began in 1985 with 5,115 African American and white Americans aged 18-30 years old who have been followed and reexamined at various intervals.

Year-20 was the first year that participants completed an extensive dietary survey. Multivariable linear regression models evaluated the relation between daily isoflavone intake and systolic BP (SBP) after dividing patients across quartiles according to self-reported isoflavone intake. Even after controlling for age, sex, BMI, smoking, alcohol, physical activity and total caloric intake, the relationship between daily isoflavones and lower systolic blood pressure remained.

Richardson says, according to the news release, that this study helps lay the groundwork for randomized controlled trials to help better understand the association between isoflavones and blood pressure. She reports no conflicts of interest. Richardson presented the study "Dietary Isoflavone Intake is Associated with Lower Systolic Blood Pressure: the Coronary Artery Risk Development in Young Adults (CARDIA) Study" on Sunday, March 25, 2012.

You also may wish to check out another recent study published online April 2014 in Eating Behaviors, "Dispelling Myths about a New Healthful Food can be More Motivating than Promoting Nutritional Benefits: The Case of Tofu," that research examines what factors impact the adoption of certain types of healthy foods, such as Tofu, by future nutritional gatekeepers.

Soy foods found to be associated with lower sperm concentrations

Men who eat an average of half a serving of soy food a day have lower concentrations of sperm than men who do not eat soy foods, according to a study, "Soy food and isoflavone intake in relation to semen quality parameters among men from an infertility clinic."published online in Europe's leading reproductive medicine journal, Human Reproduction, July 24, 2008. Isoflavones (daidzein, genistein and glycitein) are plant-derived compounds with estrogenic effects that are found mainly in soy beans and soy-derived products.

The association was particularly marked in men who were overweight or obese, the study found. In the largest study in humans to examine the relationship between semen quality and phytoestrogens (plant compounds that can behave like the hormone, estrogen), Dr Jorge Chavarro, a research fellow in the department of nutrition at Harvard School of Public Health, Boston, USA, and his colleagues found that men who ate the most soy food had 41 million sperm per millilitre less than men who did not consume soy products. (The "normal" sperm concentration for men ranges between 80-120 million/ml).

Animal studies have linked the high consumption of isoflavones with infertility in animals, but so far there has been little evidence of their effect in humans

Dr Chavarro and his colleagues analyzed the intake of 15 soy-based foods in 99 men who had attended a fertility clinic with their partners to be evaluated for sub-fertility between 2000 and 2006. They asked them how often and how much they had eaten in the previous three months; the foods included tofu, tempeh, tofu or soy sausages, bacon, burgers and mince, soy milk, cheese, yoghurt and ice cream, and other soy products such as roasted nuts, drinks, powders and energy bars.

Different foods have different levels of isoflavones in them, and so the researchers related the size of the serving to the particular food. For instance, a standard serving of tofu was 115g and for soy milk it was one cup (240 millilitres).

The men were divided into four groups according to their intake of soy foods and isoflavones. After adjusting for factors such as age, abstinence time, body mass index (BMI), alcohol and caffeine intake and smoking, Dr Chavarro found that men in the highest intake category had, on average, 41 million sperm/ml less than men who did not eat soy foods.

"Men in the highest intake group had a mean soy food intake of half a serving per day: in terms of their isoflavone content that is comparable to having one cup of soy milk or one serving of tofu, tempeh or soy burgers every other day," he said, according to the July 23, 2008 news release, Soy foods are associated with lower sperm concentrations. "It is important to highlight that the figure of half a serving a day is the average intake for men in the highest intake group. Some men in this group had intakes of soy foods as high as nearly four servings per day."

The researchers found evidence that the association between soy food intake and sperm concentrations were stronger in men who were overweight or obese (and 72% of them were)

Researchers also found the relationship between soy foods and sperm concentration was strongest in men with the higher sperm concentrations. "The implication is that men who have normal or high sperm counts may be more susceptible to soy foods than men with low sperm counts, but this remains to be evaluated," explained Dr Chavarro, according to the news release.

The study does not reveal why soy foods have this effect on sperm, but Dr Chavarro speculates that increased oestrogenic activity may have an adverse effect on the production of sperm by interfering with other hormonal signals. This effect could be strengthened further in overweight and obese men because men with high levels of body fat produce more oestrogen than slimmer men, leading to high overall levels of oestrogen in the body and reproductive organs.

Soy foods are the most important source of phytoestrogens in people in the Western world, and the researchers say they were able to comprehensively assess the men's soy intake

They did not assess intake of isoflavones from other sources, such as bakery products made with soy flour. "However, the most likely effect of not assessing intake of these foods is that the associations reported in this study are attenuated," said Dr Chavarro.

The researchers say that the clinical significance of their research remains to be determined, and further randomized trials are needed. For more information, you may wish to see the study, "Soy food and isoflavone intake in relation to semen quality parameters among men from an infertility clinic." published online in Europe's leading reproductive medicine journal, Human Reproduction, July 24, 2008.

You also may wish to see another study, "Dairy food intake in relation to semen quality among physically active young men." That study appears online in the August 2013 issue of Human Reproduction. That study found full-fat dairy intake was also associated with significantly lower percent progressively motile sperm (P= 0.05). Another study looked at fatty acid intake and sperm count.

You may wish to see the abstracts of studies such as: "Trans fatty acid intake is inversely related to total sperm count in young healthy men." You might also be interested in the abstract of still another study, "Dairy foods, dietary calcium and obesity: a short review of the evidence.[Nutr Metab Cardiovasc Dis. 2006]." Or check out these study abstracts, "Dairy food intake in relation to semen quality and reproductive hormone levels," or "Soy food and isoflavone intake in relation to semen quality parameters among men from an infertility clinic."

Adding low-sodium soy sauce or tofu will enhance the benefits of the omega-3 fatty acids in fish

If you eat fish to gain the heart-health benefits of its omega-3 fatty acids, baked or boiled fish is better than fried, salted or dried, according to research presented at the American Heart Association's Scientific Sessions in 2009. You can check out the news release, "How fish is cooked affects heart-health benefits of omega-3 fatty acids." And, researchers said, adding low-sodium soy sauce or tofu will enhance the benefits.

"It appears that boiling or baking fish with low-sodium soy sauce (shoyu) and tofu is beneficial, while eating fried, salted or dried fish is not," said Lixin Meng, M.S., according to the news release, "How fish is cooked affects heart-health benefits of omega-3 fatty acids." Meng is lead researcher of the study and Ph.D. candidate at the University of Hawaii at Manoa. "In fact, these methods of preparation may contribute to your risk. We did not directly compare boiled or baked fish vs. fried fish, but one can tell from the (risk) ratios, boiled or baked fish is in the protective direction but not fried fish."

Children want food cut into tiny bites they can chew with ease

Kids who have to take a bite out of a drumstick at the dinner table can be more aggressive than if the meat is cut up into small, bite-size pieces, says a new study, "Biting versus Chewing: Eating Style and Social Aggression in Children," published online April 4, 2014, in the journal Eating Behaviors. You also can check out the "Pre-cut food makes kids mellow" cartoon, "but biting food makes them rowdy."

The researchers note that when children need to bite into food with their front teeth, they are more likely to get rowdy. The bottom line for parents is this "If you want a nice quiet, relaxing meal with your kids, cut up their food," according to BrianWansink, Professor and Director of the Cornell Food and Brand Lab.. He had different bottom line advice for school lunchroom staff, "If drumsticks, apples, or corn on the cob are on the menu, duck."

You also may wish to check out another study published online April 2014 in Eating Behaviors, "Dispelling Myths about a New Healthful Food can be More Motivating than Promoting Nutritional Benefits: The Case of Tofu," that examines what factors impact the adoption of certain types of healthy foods, such as Tofu, by future nutritional gatekeepers.

In the study, "Biting versus Chewing: Eating Style and Social Aggression in Children," researchers found that there's a new secret to get your child to behave at the dinner table: Cut up the kid's food.

This new (Cornell University) study found that when 6- to 10-year-old children ate food that they had to bite with their front teeth, chicken on the bone, they were rowdier than when the food had been cut into bite-sized pieces. Just cut up their food and they'll relax.

The new Cornell University study on biting versus chewing behavior of food appearing online in the journal Eating Behaviors, found that when 6-10 year old children ate foods they had to bite with their front teeth— such as drumsticks, whole apples, or corn on the cob— they were rowdier than when these foods had been cut. "They were twice as likely to disobey adults and twice as aggressive toward other kids," said Brian Wansink, according to the April 22, 2014 news release, "Biting vs. chewing." Wansink is Professor and Director of the Cornell Food and Brand Lab.

During a 4-H summer camp, 12 elementary children were observed for this 2-day study. On the first day, half of the children were seated at one picnic table and were given chicken on the bone that had to be bitten into with their front teeth; the other half were seated at a nearby picnic table and given chicken cut into bite sized pieces.

On the second day, the conditions were reversed. Each day, two camp counselors instructed the children to stay inside a circle with a 9-foot radius. Both meal sessions were videotaped and evaluated by trained coders who indicated how aggressive or compliant the children were, and if they exhibited any atypical behaviors, such as jumping and standing on the picnic tables.

On another note, If you want to serve tofu to a kid or anyone else, for the first time, add some fruit such as a few mango chunks, a handful of clean spinach, and a teaspoon of fresh lime juice, then puree it to a mousse in a food processor or blender. Add coconut water to thin the emulsion. Makes a great smoothie or mousse dessert instead of whipped cream for those who can't tolerate or don't want dairy products.

Children were more aggressive and disobedient when served chicken on the bone

Results from both the counselors and coders observations indicated that when children were served chicken on the bone, they acted twice as aggressively, and were twice as likely to disobey adults, than when they were served bite sized pieces of chicken. The suggestion from researchers is to cut the food in small bite-size pieces when serving meals or snacks to kids.
When it comes to vegetables and fruits such as an apple or whole vegetable, but those up also into small, bite-size pieces.

Furthermore, the children who were served chicken on the bone left the circle without permission more frequently and were more likely to jump and stand on the picnic tables. Along with Wansink, the research was conducted with Guido Camps now at Wageningen University and Research Center; Francesca Zampollo now at Auckland University of Technology; and Mitsuru Shimizu, now at Southern Illinois University Edwardsville.