Say Goodbye to Clif Bars and Soy Protein Isolates

Today, Dixon sent me a text from the grocery store:  “Clif Bars contain soy protein isolates. Is that bad?”
At first, I thought, “No. Can’t be bad. Soy is good – a complete source of protein; consumption is correlated with reduced cholesterol; isoflavones may have anti-cancer benefits…right?”  I remembered there was some controversy, though. So I began researching the topic. Quickly I found several sites that provided hyperbolic arguments against soy. “It’ll make you a girl!” “Erectile dysfunction!” “Cancer!” Yes, it’s true that soy does contain estrogen-like compounds, but I think that the research indicates that the dosage is low and there’s no effect. (1)
Another argument against soy is that 93% of the plants grown are genetically modified. (2)  This will take us to a whole other discussion about the risks of GMO foods. But let’s say it’s the rare non-GMO soy organically grown plant. This isn’t about the merits of soy, after all; rather, it’s about a processed form of it. Is there something wrong with soy protein isolates?

I started to dig deeper.

From what I can gather, yes. There are several potential reasons for why we should not eat soy protein isolates.

The highly sophisticated manufacturing process requires machinery and toxic chemicals which have the potential to contaminate your food.

To show you the various points of contamination, I’ll describe the step by step process of taking the living seeds through crushing, solvents, centrifugation and finally a massive blow dryer that is used to amass the isolated proteins.

1. The first step is straightforward: clean off the soil, crack, and dehull the seeds.

Heat the soybeans to 140-190F, roll them into flakes, and immerse in hexane to extract the oils. 
Yes, the suppliers of Clif Bar Soy Protein Isolates use hexane (C6H14) — a byproduct of gasoline refining and a neurotoxic, flammable, volatile chemical. Clif Bar says it’s not present in the final product.


FaceBook screen capture of Clif Bar response to a question regarding Hexane in the manufacturing of soy protein isolates.

Most likely, the amount of hexane remaining is pretty small. I’m willing to bet huffing some gasoline fumes is worse for you (since air breathed in bypasses the liver) but that’s just conjecture on my part. The hexane helps to remove fats (20% of the original building blocks in a soybean) by acting as a solvent. With the hexane and oils removed, you’re left with proteins, fibers, carbs, salts and water.

3. To separate the water soluble from the not water soluble, put this mix into water. Most of the proteins, some of the smaller carbohydrates, and a few other molecules will dissolve while the bigger stuff like fibers, larger carbohydrates and some of the big proteins will stay solid. Put this mixture of solids and dissolved stuff into a centrifuge and remove the solids and keep the liquid.

4. Now we want the proteins to go back into being solids. Add acid. This is done in an aluminum tank, which has some folks worried since it can leach high levels of aluminum into the mixture.

The isoelectric point of soy proteins is around a pH of 4.5, I think.

Fish in water with a 4.5 pH + aluminum = dead fish.

I’m guessing it’s probably not great for humans either. (3) Again, this is conjecture, I’ve not researched thoroughly to see if there are other studies. Centrifuge the mix and the proteins settle on the bottom. Pour off the liquid and your product is now called a “curd.”

5. The curd needs to be washed and the acid neutralized through the addition of a base. This step forms a renal toxin called lysinoalanine. (4)(5) I’ve lost track of the potential toxins we may or may not have added, and we’re not even done yet. This is a wet slurry that needs to be dried out.

6. To do so, the curds are spray dried at high temperatures. During this step, nitrites (potent carcinogens) are formed and added to the final product. From the FDA: “The presence of up to 50 ppm nitrite in soy protein isolates raises other possibilities of concern. The potential for nitrisamine formation in vivo from the ingestion of foods containing nitrite, and the latter reacting with other nitrogen- containing compounds in foods, drugs and endogenous amines, must be considered.” (5)

The result? A product that contains approximately 70% water soluble proteins that may or may not also include hexane, nitrites, lysinoalanine, and aluminum salts. Furthermore, these proteins don’t even resemble their original shape.

Think of a protein as an origami-like folded structure. Now put that origami into water, acid, base, centrifuges, and a firehose. The paper fibers are still there, but the structure’s form is obliterated.

The more I think about it, the more I wonder about the value of any processed food. And for now, I think I’ll reach for a Snickers over a Clif Bar.
At least it’s not claiming to be healthy.
References, all accessed 11-17-2013


3 Comments on “Say Goodbye to Clif Bars and Soy Protein Isolates

  1. No wonder Clif Bars upset my stomach… allergic to soybean oil…

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