You might recognize the words “soy lecithin” from reading labels in your local grocery store. It is a common additive to a large number of foods in the American diet. It is primarily used as an emulsifier. But what exactly is soy lecithin?
 
 

The Lowdown on Soy Lecithin

Lecithin is a mixture of phospholipids and oil derived from egg yolks, rapeseed, milk, and soy. Soy itself has been a controversial piece of nutrition for quite some time. Soy contains an anti-nutrient known as phytic acid that bind to minerals such as iron, zinc, and magnesium and disrupts their absorption by the human body. 
 
In a study published in Food and Chemical Toxicology, the researchers concluded by stating that soy lecithin was also found to be strongly estrogenic.1 These estrogenic compounds found in soy have been shown to disrupt thyroid and endocrine hormone production. 
 
You may be asking, “Don’t Asian populations consume high amounts of soy and have long lifespans?” Asian countries do consume high amounts of soy, but in the form of fermented soy products. The fermentation process breaks down some of the negatives parts of soy and makes it more easily digested. 
 

The Research on Soy Lecithin Needs More Analysis

The soy products we consume in the United States are not fermented and the majority are genetically modified. A meta-analysis looking at soy isoflavones in the West and in Asian countries concluded that soy consumption in Asian countries led to a decrease in breast cancer rates, but in the Western Hemisphere there was no correlation.2 Do keep in mind this was a meta-analysis of epidemiological research, so further research is necessary to determine the correlation.
 
When we genetically modify a food source, we are altering it in a way that can confuse our body. In 2008 a group of Canadian researchers performed an analysis on 22 randomized control trials looking at the health benefits of soy products. The researchers concluded that soy isoflavones slightly decreased LDL, but had no effects on HDL, triglycerides, lipoprotein(a), or blood pressure.3 Soy has been touted as a heart-healthy alternative to meat for some time now, but according to the analysis performed above these claims may be unsubstantiated.
 
Most research touting the heart-healthy benefits of soy were epidemiological in nature and looking at countries that consume fermented soy products. The researchers that performed the 2008 meta-analysis hypothesized that soybean processing plays a role because of its effects on certain bioactive protein subunits. If you are interested in learning more about the potential dangers of soy products the Weston A Price Foundation has a well laid out summary.
 
 

Should You Avoid Soy Lecithin?

Since soy’s health claims seem to be unsubstantiated and it may even be potentially dangerous, should we avoid anything that says it contains soy lecithin? If you are eating a diet that consists primarily of fruits, vegetables, nuts, seeds, meats, fish, and eggs you will not be consuming much soy lecithin, if any at all. However, soy lecithin is an additive to many supplements and even foods such as dark chocolate.
 
During growth and processing soybean oil is exposed to certain pesticides that may have negative effects on human health. These pesticides also seem to survive processing.4 This may seem like the perfect opportunity to abandon the soy ship, but the reality is we are exposed to thousands of toxic chemicals a day. Remember, unless you have an actual soy allergy, the poison is always in the dose.
 

The Negative Effects of Soy Lecithin

In 1985, researchers performed a study on rats to see what the negative effects of soy lecithin intake during gestation would be. The researchers fed pregnant and newborn rats either a 2% or 5% soy lecithin preparation diet. The research concluded by stating, “The results indicate that dietary soy lecithin preparation enrichment during development leads to behavioral and neurochemical abnormalities in the exposed offspring.”5
 
I have seen others break this study down and attribute the negative effects on the rats with choline toxicity. This does seem like a plausible scenario and a problem with this particular study. However, the study does show a potential risk for consuming soy products while pregnant and the potential dangers of soy-based formulas for infants. There is no risk for expecting mothers and infants in avoiding soy, while there may be potential dangers in consuming it, so in these populations it may be best to minimize consumption.
 
 

The Conclusion on Soy Lecithin

How dangerous is it to consume soy lecithin? The answer depends:
 
  • If you have a soy allergy or do not feel well when you consume soy products, then it is best to avoid it all together. 
  • Research has shown potential risks to the fetus when consuming soy products during pregnancy and in consuming soy products as an infant, so I would recommend expecting mothers and infants minimize soy consumption. 
  • Women who are breast cancer survivors, currently under breast cancer treatment, or at high risk of breast cancer should minimize or even eliminate soy due to the potential risk of increasing estrogen levels. 
 
For the rest of us, a little bit of soy lecithin in a piece of dark chocolate will be absolutely fine. If you are eating a diet that is mostly fruits, vegetables, nuts, seeds, meats, fish, and eggs, then you will be minimally exposed to soy products anyway. Remember, the poison is in the dose, so don’t sweat the small stuff.
 
References:
1. Maximillian B., et.al., "Estrogens in the daily diet: In vitro analysis indicates that estrogenic activity is omnipresent in foodstuff and infant formula." Food and Chemical Toxicology (2011). Retrieved on July 20, 2014. 
3. Chao, WX. "http://jn.nutrition.org/content/138/6/1244S.long " target="_blank">Health Effects of Soy Protein and Isoflavones in Humans." Journal of Nutrition (2008). Retrieved on July 20, 2014. 
4. Mounts, TL., "Chemical and physical effects of processing fats and oils." Journal of American Oil Chemists’ Society (1981). Retrieved on July 20, 2014. 
5. Bell, JM. and Lundberg, PK., "Effects of a commercial soy lecithin preparation on development of sensorimotor behavior and brain biochemistry in the rat." Developmental Psychobiology (1985). Retrieved on July 20, 2014. 
 
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