Edamame: When Green and Natural Doesn’t Equal Healthy

by Sarah Healthy LivingComments: 17

fresh green edamame in the pod

Edamame can be found in some form or fashion on nearly every aisle of healthfood stores these days. Dry roasted, raw, steamed/chilled, or fresh edamame pods are featured in a variety of packages enticing shoppers into thinking this pleasant looking, sweet tasting bean can help them reach their health goals.

Even supermarkets and warehouses like Costco are cashing in on the edamame craze, with conventionally grown versions displayed en masse with the freezer foods next to innocuous and less enticing bags of broccoli, carrots, and peas.

Preparation of Edamame

Sourced from immature green soybeans, edamame pods are typically cut on the ends and then steamed, boiled or microwaved. If boiled, salt is usually added to the water. If steamed or microwaved, the salt is added after cooking with the soft green beans removed from the pods.

Edamame is usually served salted and cold as an appetizer in Japanese restaurants. Edamame is also found in modern cuisine from China, Korea and Hawaii, although the latter is largely due to Japanese influence rather than ancestral Polynesian traditions.

If frozen, fresh edamame is blanched first.

History of Edamame

It seems to make sense that edamame would be a traditional food since it is unprocessed and simple to prepare. Historical references appear to bear this out as the earliest documented reference for the word edamame occurred in 1275 AD when the Japanese monk Nichiren wrote a note thanking a parishioner for the gift of “edamame” he had left at the temple.  However, it was not known if this edamame was for consumption or for simple crop rotation purposes.

Kaayla Daniel PhD, The Naughty Nutritionist writes in her article What’s Edamame? And Other Questions about Green Vegetable Soybeans that historian William Shurtleff of the Soyfoods Center in Lafayette, CA, knows of no early references to green vegetable soybeans in China. Further, she writes:

An herbal guide from 1406 (Ming Dynasty) indicates the whole pods of young soybeans could be eaten or ground for use with flour, but it recommended such uses only during times of famine.  A Materia Medica from 1620  recommends edamame, but only for the medicinal purpose of killing “bad or evil chi.”  By 1929, however, edamame was definitely on some menus. William Morse of the USDA reported on a field trip to China that “as early as May, small bundles of plants with full grown pods were seen on the market. At the present time the market is virtually flooded with bundles of plants with full grown pods, the seeds of which are also full grown.  The pods are boiled in salt water and the beans eaten from the pods.”

Dr. Daniel also disputes the claims by industry that Asians have consumed soy for 5,000 or even 10,000 years. She says that digging into anthropology and history texts absolutely does not support this common claim that seems to have become regarded as fact in some health circles. “The oldest soyfoods, miso and tofu date back only about 2,500 years. Contrary to popular belief, soy was not eaten as a food 5,000 years ago, but it was highly regarded for its role in crop rotation.”

Green and Natural Doesn’t Always Equal Healthy

Looking a bit like a cross between cannellini beans and green peas, edamame seem like a dream come true for a parent seeking healthy snack alternatives. Children gobble them up by the handful due to their addictive sweetness, and adults who prefer salty snacks can chow down on the dry roasted versions available in large, economy sized bags.

While simple and quick to prepare and even easier to eat, edamame simply do not make the grade as a food that is healthy to eat on a regular basis.

One big reason why is because most edamame on the market in the United States is sourced from genetically modified soybeans. GMOs are not labeled in North America as of this writing and hence can stay under the radar of even alert shoppers. Most of the rest of the world requires labeling of GMOs, so edamame is not usually genetically modified in those locations because consumers simply won’t buy it if GMO is emblazoned on the label akin to a skull and crossbones.

Beware that most edamame served in Japanese restaurants and featured on salad bars in North America is also GMO! So enjoying that edamame appetizer that is served before your meal at the local sushi joint isn’t the healthy first course that most presume it to be.

GMO soy is not good for your health even when it it is green and unprocessed. Some of the most worrisome animal studies to date that should give any edamame lover pause include:

  •  A study of GMOs reported in the June 2013 issue of the peer-reviewed Journal of Organic Systems involved research conducted over 22.7 weeks using 168 newly weaned pigs in a commercial U.S. piggery. One group of 84 pigs ate a diet that incorporated genetically modified (GMO) soy and corn, and the other group of 84 pigs ate an equivalent non-GMO diet.  The pigs that ate the genetically modified soy and corn had a higher rate of severe stomach inflammation – 32 percent of GMO-fed pigs compared to 12 percent of non-GMO-fed pigs. The inflammation was worse in GMO-fed males compared to non-GMO fed males by a factor of 4.0, and GMO-fed females compared to non-GMO-fed females by a factor of 2.2. (1)
  • Scientists at the Russian Academy of Sciences reported between 2005 and 2006 that female rats fed GMO soy produced excessive numbers of severely stunted pups with more than half of the litter dying within three weeks, and the surviving pups completely sterile.  (2)
  • Russian research from 2010 found that hamsters fed GMO soy for two years (over three generations) developed sterility. In addition, the pups that did get born suffered from slow growth and a high mortality rate. Most disgustingly, the third generation of hamsters raised on GMO soy developed unnatural and profuse hair growth in their mouths (3).

Profuse hair growth in the mouth … from eating GMO soy for only 3 generations? Yes, this is what the Russian researchers were horrified to discover. No wonder Russia has imposed a ban on all GMOs essentially kicking Monsanto to the curb.

What About Organic Edamame?

Ok, so you know all about the dangers of GMO soy and edamame and have made every effort to source only organic. Isn’t this a better choice?

Yes, it is definitely better and avoids the potential for chronic health problems observed in animal studies involving GMO soy.

However, even organic edamame presents a health threat when it is consumed on a regular basis. This is due to the high amount of hormone disrupting phytoestrogens and anti-nutrients called protease inhibitors (primarily trypsin) in soy even when picked young and green for edamame.

While eating edamame raw is the biggest no-no, cooking the pods doesn’t do enough to resolve these issues either. The phytoestrogens in edamame are basically untouched by cooking and the protease inhibitors are not reduced by very much. For decades, the USDA and other researchers put their efforts into finding safe and inexpensive ways to deactivate these protease inhibitors which wreak havoc with both digestion and the pancreas. Boiling, roasting and steaming can help, but don’t do enough. The only way that comes close is with traditional fermentation methods like those used to make miso, tempeh and natto.

Since edamame is only lightly cooked in most cases, you can count on most of the anti-nutrients remaining along with all of the hormone disrupting plant estrogens.

How Edamame Disrupts Digestion

With regard to the green bean’s effect on digestion, the protease inhibitors present in high amounts in edamame suppress some of the key enzymes that help digest protein.

Because these inhibitors block the protease enzyme needed to digest protein, the pancreas has to work overtime to produce more. If this happens only occasionally, the pancreas quickly recovers, no big deal. But if edamame is consumed frequently and in large amounts, there is no recovery period and this leads to an increase of both the number of pancreatic cells (hyperplasia) and the size of those cells (hypertrophy).

Pancreatic hypertrophy and hyperplasia in humans results in the loss of the ability to secrete sufficient enzymes. Insufficient enzyme production by the pancreas means digestive distress for adults and growth problems for children.

Irvin Liener, PhD, professor emeritus at the University of Minnesota and the world’s leading expert on anti-nutrients and toxins in plant foods, has issued a warning to those who might be addicted to edamame, “Soybean trypsin inhibitors do in fact pose a potential risk to humans when soy protein is incorporated into the diet.”

How Edamame Disrupts Hormone Balance

Below are just a few of the many studies on how plant estrogens (also called isoflavones or phytoestrogens) in soy (edamame too) is can disrupt hormonal balance:

  • Isoflavones (phytoestrogens) genistein and daidzein in soy appears to stimulate existing breast cancer growth indicating risk in consuming soy products if a woman has breast cancer. (Annals of Pharmacotherapy 2001 Sep;35(9):118-21).
  • Direct evidence that isoflavones genistein and daidzein suppress the pituitary-thyroid axis in middle-aged rats fed 10 mg soy isoflavones per kilo after only 3 weeks as compared with rats eating regular rat chow (Experimental Biology and Medicine 2010 May;235(5):590-8).
  • Don’t eat edamame or any other form of soy either when you are pregnant ladies!  Scientific research has shown that the developing male fetus which is exposed to soy phytoestrogens may suffer from higher susceptibility to prostate cancer later in life (Prostate 1994;24(2):67-78).
  •  A study of 12 men aged 18 years and older experienced a 19% drop in serum testosterone in only 28 days when supplemented with 56 grams of soy protein over that same time period (Prev 2007;16:829—33).

Possibly the most worrisome research of all regarding soy consumption are the precancerous changes to breast tissue that can occur over time. If you want to know the truth about how an edamame habit can harm your breast health, Breast Cancer Boot Camp, coauthored with William B. Hobbins MD, Sellens provides striking, irrefutable visual evidence of adverse, precancerous effects on the breasts from estrogenic foods like edamame.

Your breasts don’t lie and these pictures will no doubt have you rethinking your edamame consumption in a hurry if the green bean is your go-to snack.

Sprouted Edamame is Worse

According to Kaayla Daniel PhD, world renowned soy expert who has appeared on the Dr. Oz Show among others and authored the must read The Whole Soy Story: The Dark Side of America’s Favorite Healthfood, sprouted edamame is worse than unsprouted.

She says, ” I would not recommend sprouting soybeans as it concentrates the toxins. Long-term fermentation neutralizes them, but short-term sprouting concentrates them.”

Love Edamame? Here’s What to Do!

If you love edamame and want to toss some in your salad, go ahead. A few here and there isn’t going to cause any problems for someone who is healthy unless there is a soy allergy present.

But … don’t go munching it like popcorn and developing a regular snackie habit eating a bowl or several handfuls at a time. Most especially, edamame is not a good snack to give to growing children (soy formula is a disaster too) or hormonal adolescents going through puberty. Even adults including menopausal women would be well advised to avoid eating it on a regular basis.

Make sure if you enjoy a handful of edamame from time to time that it is always cooked and labeled organic. This means skipping the edamame appetizer at restaurants in North America no matter how hungry you are (wait for the main course or order another appetizer!) because chances are very good it is GMO.

Remember: hairy mouths in hamsters within three generations of eating GMO soy and most edamame on the market in the United States is genetically modified. Spare your grandchildren people!

Sarah, The Healthy Home Economist

Comments (17)

  • Suzanne McDonough

    Great article! What about the fact that soy lecithin and soybean oil are in everything from breads to cereals to salad dressings? It seems impossible to avoid. How does the USDA allow this? Was it always like this? Is it because it’s cheaper to process?

    June 13th, 2016 6:48 am Reply
  • Megha

    Thankyou for this piece and to food matters for re posting it. I was completely ignorant about edamame and husband and I would look over approvingly as our toddler polished it down at our fav japanese hangout along with karaage. Thankfully, we consume once in 3-4 weeks. But now I won’t be fooled into thinking its a healthy snack and definitely won’t be including it drepeat into our eating habits.

    June 12th, 2016 9:46 pm Reply
  • Alexandra

    Hi Sarah,

    Thank you so much for this informative article! I’ve been on the fence about soy and it was a pleasure to come across this post. I’m a recent vegetarian as I eliminated chicken breast from my diet 5 months ago and I have been consuming non-Gmo/organic soy on an almost daily basis. In the past I have ordered edamame in my salads and will definitely not do it again after reading this! I was wondering your thoughts on tofu? I have a few servings of Nasoya Non GMO life firm tofu a week and I was wondering if you thought I should eliminate/decrease my intake? I do have tempeh from time to time but not as often as the tofu. As a recent vegetarian/about to be vegan I’m just looking for a variety of protein sources but I definitely don’t want to be causing my body any harm or distress. Thanks so much for you time. Looking nice forward to hearing from you.

    May 26th, 2016 8:37 am Reply
  • Patty

    Bunch of nonsense. Part of the anti-soy campaign. Yes it should be nonGMO, but the hormone disrupting stuff is wrong.

    May 26th, 2016 7:23 am Reply
    • Sarah

      If it’s so wrong, why are so many oncologists now quietly whispering to stay off soy to their patients?

      May 26th, 2016 1:18 pm Reply
      • Nancylee

        Because that’s an easier answer than listing the thousands of hormone disruptors we are surrounded by?

        May 27th, 2016 10:10 am Reply
        • Sarah

          Certainly avoiding those xenoestrogens (by not spraying pesticides in and around your home etc etc) is also very important. Living on a golf course would not be a wise thing to do for that very reason as they are so incredibly highly sprayed.

          May 27th, 2016 10:44 am Reply
  • Allison

    Sarah, if it is the case that soy was not consumed since antiquity, I wonder why the Chinese did not include soy in their diets in ancient times? I would really like to know if it was because of some intuition on their parts, or by seeing how it affected animals or their own digestion, or by its taste. It’s quite an interesting topic to see how different people groups turned to the sacred foods automatically (probably had a lot to do with the taste), how they knew how to prepare grains and such, or how they turned away from other foods that ended up being harmful like soy.

    February 23rd, 2016 11:32 am Reply
    • Sarah

      I would suppose that traditional cultures would have observed the health problems that people who eat a lot of soy suffer from … primarily hormonal and digestive disturbances. This is why soy beyond tiny amounts as a condiment (soy sauce, etc) was recommended for consumption only during desperation … aka times of famine.

      February 23rd, 2016 11:33 am Reply
  • Kathleen Garnett

    Very interesting, well researched article. The fact that there is very little evidence of traditional societies eating this says it all really. Edamame is not very big here in the EU though I have seen it served in Japanese restaurants in London. Luckily there is no commercialisation – yet – of GMO soya beans in Europe though Monsanto are bashing the door down to get in. Guess it is just a matter of time before they succeed!

    February 23rd, 2016 10:51 am Reply
  • Cheryl

    Great article! But what about soy sauce? Is that fermented? I try to use Braggs Liquid Aminos in its place but do occasionally use Tamari. Is that good or bad?

    February 20th, 2016 8:56 am Reply
  • Barbara Swain

    — And I was so pleased when a local supermarket chain added frozen organic edamame to their product line.! From now on it will just be an occasional appetizer treat. Thanks so much!

    I’ve found two brands of organic mayonnaise. One is made with organic soy bean oil and the other with organic canola oil. Would you prefer one over the other? It’s my understanding that Canola oil is made from genetically modified rape seeds — long before Monsanto got into the process. I believe the modification had to do with removing the bitter flavor natural to rape seeds.

    Anyway, I love mayonnaise and want to find the most wholesome option. Thanks, Sarah.

    February 19th, 2016 5:39 pm Reply
    • Sarah

      I’m with you. I LOVE mayo! I usually make my own, but when I do buy it when I am just too behind in the kitchen, I buy this one with avocado oil which is totally delish and tastes just like my homemade (which I also make with avocado oil). http://amzn.to/1L02LvL
      Unfortunately, it is best to skip the so called “healthy mayos” at the store made with organic soybean oil or organic canola oil neither of which are good choices as they are full of the fats you want to avoid (polyunsaturated), not the fats you want to eat for optimal health.

      February 19th, 2016 6:31 pm Reply
  • Linda

    I’m glad you posted this too. I had a feeling they weren’t a good idea so I’ve been avoiding them anyway. I’m just glad to know for sure. Keep up the good work informing us of these so-called healthy foods.

    February 19th, 2016 10:10 am Reply
  • Anna

    Sarah, thanks so much for this article. I avoid soy, but I am embarrassed to admit that I didn’t realize edamame was soy too! I will no longer be purchasing that either.

    February 19th, 2016 8:29 am Reply
    • Sarah

      So glad this post alerted you, Anna. I think a lot of shoppers are potentially making this error as edamame seems like such a healthy choice at the store the way it is packaged and marketed. It is rarely identified for what it is clearly on the packaging either … soybeans (almost always GMO too unless organic).

      February 19th, 2016 8:45 am Reply

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