Jack and the Beanstalk: Soy and health

By Karen Kier, Pharmacist 
On behalf of the ONU HealthWise team

The fairy tale Jack and the Beanstalk is believed to originate in the 1700s.  The story tells the tale of young Jack trading his family cow for magic beans. After planting the beans, he climbs the beanstalk and comes face to face with the giant. Jack is able to get away by chopping down the beanstalk.  

Why beans? A study presented at a national nutrition meeting evaluated soybeans in children.  This study is novel since the only other data is in adults.

Soy has a beneficial effect on the adult brain.  Multiple studies have shown a benefit in short-term and long-term memory in healthy adults.  Other soy studies have proven an overall benefit in cognitive function and visual memory in those under the age of 60.  In the adult studies, the best results were with doses of soy of more than 100 mg per day.  

With these encouraging results for healthy adults, studies were done to see if soy could improve brain function in individuals with dementia including Alzheimer’s disease.  Unfortunately, those studies did not provide a beneficial improvement with 100 mg/day of soy.  

Given the adult data, neuroscience researchers from the University of Illinois Urbana-Champaign designed a study to evaluate dietary soy intake and the impact on children’s brains.  The study evaluated 128 children aged 7 to 13 years and assessed their daily soy intake over 7 days.  The researchers controlled for grade level and intellectual ability.  The study involved paper testing as well as evaluating brain activity with an EEG for attention and information processing. An EEG requires electrodes to be placed on the head to map brain function.  

Children who consumed higher levels of soy in their diet were more likely to have a quicker information processing speed and faster response to assigned tasks compared to children with low soy consumption. The researchers demonstrated there was no association between soy intake and intellectual ability. The children with higher soy intake did a better job of processing information and completing tasks with no change in intelligence.  The researchers are encouraging more soy studies in children to better understand this relationship.  

In the United States, soy is not a mainstay in most children’s diets and the study revealed an average soy intake of 1.33 mg per day.  The highest soy intake in children was 35mg per day.  This value is significantly less than the 100mg per day intake in the adult studies.  

Soybeans are a plant-based source of phytoestrogens, which includes isoflavones known as highly active antioxidants.  Isoflavones have been promoted for heart health, lowering cholesterol, lowering blood pressure, controlling hot flashes of menopause, strengthening bones, and improving brain function.  The study results vary in terms of effectiveness.  Most of the controlled clinical trials with isoflavones and menopause have not shown significant improvement in hot flashes.  The bone studies have shown a benefit in bone strength.  However, most bone supplements rely on calcium and vitamin D with only a few products containing soy.  There are several studies showing improved heart health.    

Soy (isoflavone) supplements can be purchased in different formulations, but there are many ways to add soy to your diet.  Products can include soy milk, tofu (curdled soy milk), tempeh (fermented soybeans), soy nuts, and edamame (immature soybeans in the pod).  An 8-ounce glass of soy milk provides about 28 mg of isoflavones, while a tofu serving is 35 mg. There are many second-generation sources of soy such as tofu sausages, burgers, pastas, breads, and yogurt.  

Jack knew the benefits of those magic beans!

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