There's a pH war in my mouth, why can't toothpaste and food be friends?

January 15, 2013 10:07 AM

I normally use a "natural" toothpaste, Jason Powersmile Whitening with Fluoride. I'm travelling and ran out a few days ago so I've been using a regular tube of Colgate or Crest (whichever I find). I've never had a problem with pH clashing in my mouth when eating food shortly after brushing with Jason. However, Colgate/Crest-mouth combined with food is like those childhood mornings of feeling like I've been poisoned by breakfast. I've noticed that couple of hours after I brush my teeth with Colgate/Crest, and then eaten, I still have that "freshly brushed minty" taste and sterile feel in my mouth. Why does it take so long to go away? (Does it last so long because I don't drink coffee?) And, ingredients-wise, what is it in regular toothpaste that is causing this? Why doesn't Jason toothpaste do this as severely?

Ingredients comparison of Jason with a random tube of regular toothpaste:

Jason Powersmile:
Active Ingredient: Sodium Monofluorophosphate (Fluoride) 0.76% Anti-cavity
Inactive ingredients: Glycerin, Aqua (Water), Silica, Sodium Cocoyl Glutamate, Xylitol, Mentha Piperita (Peppermint) Oil , Aloe Barbadensis Leaf Juice (1), Aphanizomenon Flos-Aquae Powder, Bambusa Arundinacea Stem Powder, Carum Petroselinum (Parsley) Extract, Citrus Grandis (Grapefruit) Seed Extract, Perilla Ocymoides Seed Extract, Stevia Rebaudiana Leaf/Stem Extract, Calcium Carbonate, Cellulose Gum, Dimethyl Sulfone, Sea Salt, Tocopheryl Acetate, Sodium Bicarbonate, Sodium Magnesium Silicate, Ubiquinone (2)
(1) Certified Organic Ingredient (2) Coenzyme Q10

Crest Cavity Protection:
Active Ingredient: Sodium Fluoride 0.243% (0.15% W/V Fluoride Ion)
Anticavity Toothpaste Inactive Ingredients: Sorbitol, Water, Hydrated Silica, Sodium Lauryl Sulfate, Trisodium Phosphate, Cellulose Gum, Flavor, Sodium Saccharin, Carbomer 956, Mica, Titanium Diozide, Blue 1

posted by mayurasana to science & nature (6 answers total)

good chance the difference is the sodium lauryl sulfate, which is a surfactant, and has removed the film layer (called the pellicle) from your teeth. the pellicle reforms, it just takes longer because the commercial toothpaste has been designed with this soap to give you that long lasting clean feeling.
posted by OHenryPacey at 10:19 AM on January 15 [1 favorite]

Seconding that it's SLS. It's not actually a pH issue, SLS messes with your tastebuds and alters your ability to taste sweetness.
posted by tau_ceti at 11:11 AM on January 15

Definitely SLS. Interestingly, SLS is totally useless for cleaning teeth. It's a lathering agent, and they put it in toothpaste because we expect toothpaste to be foamy. They put the same crap in shampoo to make it foam.
posted by Afroblanco at 12:30 AM on January 16

I'm sure Dr Ellie Phillips would be up for answering your question, considering that she heavily promotes crest cavity protection as part of her system (and she seems to have genuinely good reasons for doing so).

Here's her blog
posted by spacediver at 9:06 AM on January 16

Thanks everyone! I knew SLS/SDS were foaming agents, but I had no idea that's what contributed to a temporary alteration of taste. With your leads I found a couple of articles that explain more of the science behind it. Anecdotally, I found some kids toothpaste, and it must contain less SLS because my morning taste clash has been a bit milder.

Addressing sweet taste buds:
Here's a quote from a 1998 article in Chemosensory Function and Disfunction:
"This effect on sweet taste, but not on other taste qualities, is transitory and can be explained by the action of the detergent sodium dodecyl sulfate (SDS), a common ingredient in toothpastes (Rollin, 1978; Toyano and Nabeshima, 1983). SDS apparently denatures the sweet taste receptors. Loss of sweet-tasting lasts for several minutes, during which time the sweet receptors may become renatured (DeSimone et al., 1980)."

Yes, the references are to works from the 1980s but from what I've read in other places, that's still the generally accepted explanation. (And I can't access the journal database I usually go to right now..) This article also has some nice basic schematic diagrams of the cellular level.

And addressing bitterness and other details from How Stuff Works:
"The likeliest culprit for the offensive reaction is the foaming agent found in almost all toothpastes. Sodium lauryl sulfate (SLS) is a surfactant -- a sudser -- added to toothpaste. It creates the froth that toothpaste becomes after you begin brushing by lowering the surface tension of the saliva in your mouth and allowing bubbles to form. While it aids in spreading the toothpaste throughout your mouth, it also creates the impression of cleanliness; a mouthful of foam just feels cleaner.

"But SLS has other properties, too. For one, it suppresses your sweet receptors, so it has a dampening effect on the generally sweet taste of orange juice. In addition, SLS destroys phospholipids. These fatty compounds act as inhibitors on your bitter receptors. So by inhibiting sweet receptors and destroying phospholipids, SLS dulls the sweetness and promotes the bitter taste in orange juice."
posted by mayurasana at 9:39 AM on January 19

And, this 2008 clinical dental text, Dental Caries, has a few paragraphs about SDS.
posted by mayurasana at 9:54 AM on January 19