This new research reveals something that some of us have suspected for quite a while. Starchy foods can cause tooth decay in some genetic makeups. The study, originally published in Microorganisms, focuses on the interactivity between starch and the microbiome. The key finding is that those of us with a certain number of copies of the gene – AMY 1 – when in combination with starch alters the complex composition of bacteria playing a role in oral health. This means that the bacteria in your mouth around your teeth and gums excitedly feed on starch for those with this particular genetic makeup.

How Starchy Foods Can Cause Caries For Some Of Us?

“Most people have been warned that if you eat a bunch of sugar, make sure you brush your teeth,” said Angela Poole, senior author and assistant professor of molecular nutrition.
“The takeaway finding here is that depending on your AMY1 copy number, you may want to be just as vigilant about brushing your teeth after eating those digestible starches.”
– Cornell University. “Do starchy carbs cause cavities?.” ScienceDaily, 26 February 2025

Personally, this writer consciously reduced his consumption of refined sugars many years ago. However, despite this fairly stringent dietary behaviour I continued to suffer from tooth decay and consequent failing teeth. This was despite my vigilant oral hygiene regimes and drinking plenty of pure water in my daily diet. Now, I know it is likely that I am one of those with a genetic makeup in relation to the number of copies of AMY 1 gene who is prone to an oral microbiome excited by starch. End result is cavities in the oral region and a greater likelihood of gum disease.

What Are Digestible Starches?

Most of us are familiar with starchy foods as being things like pasta, potatoes, and rice dishes. However, the truth is that the majority of plants store energy as starch. Starch a.k.a. amylum is a complex carbohydrate and is found in grains, fruits and vegetables. Wheat, maize, tapioca and potatoes are the main sources of starch for most of us.

“Starch is a natural polymer, or polysaccharide, meaning that it is a long chain comprising one type of molecule. Starch consists of glucose molecules. It can occur in two forms: amylose and amylopectin.
Amylose is a linear or straight-line polymer that scientists describe as amorphous or solid. Amylopectin forms a branched chain and is crystalline. Different plants contain varying ratios of these polysaccharide units. However, amylose generally makes up a maximum of 30% Trusted Source of starch, with the rest being amylopectin.“
– Medical News Today

Nutritional fibre is derived from non-digestible plant carbohydrates and most of us do not get enough fibre in our diets. Our microbiome (the bacterium colonies inside our bodies) are best served by fibre and the pay off for our health and wellbeing is substantial. Eat lots of green leafy vegetables and wholegrains.

Researchers Discover Starchy Evolutionary History

Results discovered by the researchers in this study found evidence indicating that the oral microbiome has co-evolved to respond to the increasing copies of AMY 1. This has occurred within populations of people where there has been a lengthy history of agricultural and starch consumption.

“In the pool of 31 samples, taken in Ithaca, N.Y., the AMY1 number ranged from two to 20 copies.
In saliva samples with a high AMY1 copy number, the researchers saw increased populations of bacteria, like Streptococcus, that feed off the starch’s sugars.
“If someone has a high copy number, they break down starch efficiently, and bacteria that like those sugars are going to grow more in that person’s mouth.”
– Science Daily

Can I Get Tested For My AMY 1 Gene?

Yes, you can get tested locally in Australia at a number of facilities listed online if you type the request into your search engine. Plus, there is a clinical trial listed below, which focuses on the AMY 1 gene for the digestion of carbohydrates.

What are the effects on carbohydrate digestion and absorption of variations in the salivary amylase gene in healthy adults?

“The aim of this study is to identify the variation of the salivary amylase (AMY1) gene copy number in the Australian population and to investigate the effect of AMY1 copy number on carbohydrate digestion, acute metabolic and satiety responses, and potential associations with obesity and diabetes risk. This project will screen Australian adults for their number of copies of the AMY1 gene. This gene produces a protein, salivary amylase, which is secreted in the mouth and begins starch breakdown. Individuals with varying AMY1 copy numbers will be asked to perform a series of starch challenge tests during which they will consume different high carbohydrate foods. Fingerprick blood samples will be taken at regular intervals over 2 hours to measure their metabolic responses to starchy foods. To assess the efficiency of starch digestion, salivary amylase activity, breath hydrogen and methane responses, and postprandial glucose and insulin responses will also be assessed over an 8 hour period following the consumption of different high carbohydrate meals. Information on how AMY1 copy number influences carbohydrate metabolism and usual dietary intake may have important implications for the dietary management of diabetes and obesity and/or identify those at greater risk of developing these conditions.”
– Australian Clinical Trials, New South Wales

Be Vigilant Re-Starchy Foods & Your Oral Health

Starchy foods can cause tooth decay in some genetic makeups – what can we do about it? Perhaps, the takeout from this new data is to be equally vigilant in your oral hygiene in regards to the consumption of both starchy foods and refined sugars in your diet. I would not have a knee jerk reaction by cutting out starchy food from my diet, as we need the nutritional benefits.

The advice is to drink plenty of pure water throughout the day. Keep your mouth moist with lots of small sips. Rinse your oral cavity after snacks, drinks and meals. Don’t smoke or vape. Reduce the amount of alcohol you consume. If you would like to preserve the health and wellbeing of your natural teeth and gums take the necessary precautions now.

When I write dental pieces I regularly get up from my desk and go and clean my teeth. Actions speak louder than mere thoughts when it comes to oral care. It is no use getting down about the fact that we may have yet another thing to concern ourselves with. Rather, rise up now and go and brush your own teeth. Do it with care and consideration for your own wellbeing. Talk to your local dentist about any concerns you may have in regard to this information about starchy foods and the bacteria in your mouth after eating.

BOOK NOW

Note: All content and media on the Bacchus Marsh Dental House website and social media channels are created and published online for informational purposes only. It is not intended to be a substitute for professional medical advice and should not be relied on as health or personal advice.

Services we mentioned: