Does Your Fruit Smoothie Cause Tooth Decay and Wear Away Teeth Enamel?

smoothies and teeth enamelResearchers from Scotland’s Dundee Dental School and Hospital studied the ability of different fruit smoothies to wear away dental enamel and cause tooth decay.

The researchers took five different types of fruit smoothies from local smoothie shops to their laboratory for extensive analysis. At issue was whether – and if so which – fruit smoothies could wear away at the enamel lining of the teeth.

Their laboratory analyses judged the tested the smoothies for their pH and their relative acidity. They also measured the smoothie’s effects upon microsurfaces that mimicked the hardness and profile of human teeth.

The pH of enamel averages about 5.5. A food that is lower has the potential of eroding the teeth enamel assuming the enamel is exposed.

pH higher than 7 is considered alkaline, while pH lower than 7 is considered acidic. The 7 pH is the approximate level of drinking water.

They also compared the smoothie’s effects to mineral water and orange juice. In addition they compared the commercial smoothies with “homemade” versions.

The researchers discovered that all but two of the drinks tested were at a pH that was less than the pH of enamel – giving them the potential of eroding enamel. The two drinks that had a higher pH than enamel’s 5.5 was the mineral water and a yogurt-based smoothie with honey and vanilla bean.

However, even those that were below the pH of enamel resulted in little actual erosion upon testing, except for two smoothies – the cranberry-blueberry-cherry smoothie and the strawberry-banana homemade smoothie. The others resulted in little if any dental erosion.

In terms of surface depth loss, the smoothie with the greatest effect upon the dental surfaces was the kiwi-apple-lime smoothie. Certainly kiwis and limes also have significant total acidity, while apples render malic acid.

The researchers also determined that they could quite easily reduce and eliminate erosion potential by removing or adding certain foods/fruits.

They concluded that:

“Within the limitations of this study some fruit smoothies have the potential to bring about dental erosion if consumed irresponsibly. This can be influenced by ingredient variations.”

The take-away here is making a wise choice regarding the smoothie ingredients. A sweet syrupy smoothie can taste great, but is it healthy for our teeth? What about our oral probiotics? What about the relative acidity of our saliva?

Even the researchers suggest that a smoothie offers a convenient way to get our five-plus servings of fruits and vegetables every day:

“Recent health promotion campaigns have encouraged the public to consume at least five portions of fruit and vegetables per day. Many see consuming fruit smoothies as a way of achieving this.”

As the research suggests, adding yogurt to our smoothies can significantly reduce its dental erosion potential. Incremental to that, adding other pH-positive (more alkaline) ingredients such as flax seeds, greenfoods, yeast powder and other supplements can neutralize the acidic elements and render a pH balanced smoothie.

These supplements also bring about a more nutritionally complete smoothie as well.

Commercial smoothies sometimes add yogurt, but many are notorious for adding sugar or high fructose corn syrup to their smoothie mixes. These elements can not only increase dental erosion, but can feed our pathogenic yeast and bacteria.

Learn more about oral probiotics to delay and prevent dental decay.

The relative pH of our saliva and the population of probiotics and other bacteria significantly contribute to the ability of our foods eroding the enamel as well. This is something we can control with our diet and lifestyle factors.

In general, the most acidic fruits include citrus, followed by kiwis, cherries and cranberries. Plums, apples, pears and apricots follow in acidity. Sweeter fruits approach neutrality, including watermelon, figs, mangoes and peaches.

Most vegetables are neutral to alkaline, but this can vary. Spinach, for example, is typically slightly acidic.

This type of alkalinity and acidity is often confused with the body’s relative acidity or alkalinity following the eating of certain foods. While this form of acidity can affect the teeth enamel, the body will reach a higher state of alkalinity in response to eating fresh fruits and vegetables in general, regardless of their relative pH.

This is because these foods also contain phytonutrients and antioxidants that serve to neutralize the acid-forming free radicals within the body. As those oxidative free radicals are neutralized, the body reaches a more neutral state of pH.

Learn more about foods, acidity and antioxidant potential.

Written by Case Adams, Naturopath


Blacker SM, Chadwick RG. An in vitro investigation of the erosive potential of
smoothies. Br Dent J. 2013 Feb 22;214(4):E9.

Adams C. Oral Probiotics: Fighting Tooth Decay, Periodontal Disease and Airway Infections Using Nature’s Friendly Bacteria

Case Adams is a California Naturopath with a PhD in Natural Health Sciences, and Board Certified Alternative Medicine Practitioner. He has authored 26 books on natural healing strategies. “My journey into writing about alternative medicine began about 9:30 one evening after I finished with a patient at the clinic I practiced at over a decade ago. I had just spent the last two hours explaining how diet, sleep and other lifestyle choices create health problems and how changes in these, along with certain herbal medicines and other natural strategies can radically yet safely turn ones health around. As I drove home that night, I realized I needed to get this knowledge out to more people. So I began writing about health with a mission to reach those who desperately need this information. The strategies in my books and articles are backed by scientific evidence along with wisdom handed down through traditional medicines for thousands of years.” Case connects with the elements by surfing, hiking and being a beach bum.

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