Digesting Carbohydrates: Amylase variants

Carbohydrate digestion begins in the mouth with an enzyme called amylase.  Saliva mixes with your food as you chew it, and the amylase in saliva begins breaking down carbohydrates into simple sugars.  Amylase is also produced by the pancreas and used for further breaking down carbs in the small intestines.

Breaking down carbohydrates:

While amylase isn’t the only enzyme involved in breaking down carbohydrates, it is the first step. Amylase helps convert starches eventually into maltose or maltotriose, which are then converted by the enzymes maltase into glucose in the small intestines. Glucose then is utilized by the body for energy production.

Interesting side note: Vampire bats are the only mammals not to produce maltase.

Amylase is coded for by the genes AMY1 in the saliva, and AMY2A and AMY2B in the pancreas. These genes vary widely in the number of copies of the gene that a person can have.  For example, AMY1 can vary between 2 and 17 copies, thus giving a wide variation in the amount of amylase a person normally secretes in their saliva. [ref]

Several studies found low AMY1 copy numbers are associated with higher BMI.[ref][ref][ref]

In contrast, a large study published in Nature Genetics in 2015 found no association between amylase copy numbers and BMI.

Part of the discrepancy between study may be differences in diet in the populations – perhaps it is a mismatch between the percentage of carbs in the diet and the ability to break down carbohydrates that cause an increase in BMI.

What else does research show about amylase?

  • Cellulose can inhibit amylase activity. [ref] This makes me wonder if the presence of cellulose gum in so many processed food products makes a difference in how we break down processed foods?
  • Tannins in sorghum reduce amylase activity. [ref]  Tea polyphenols also inhibit amylase. [ref]
  • Lower amylase activity is associated with higher reliance on fatty acids for energy. [ref]
  • Higher amylase activity was associated with lower blood glucose concentration after eating starch in a small study (14 people). [ref]

23andMe and Ancestry data do not give copy number variation information, but several studies have linked specific SNPs to higher or lower amylase activity and copies of the gene.


AMY1-AMY2 Genetic variant

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Several studies show associations between the rs11185098 variant and amylase activity. The  A allele has higher amylase activity and the G/G genotype has the lowest amylase activity.[ref] [ref] [ref]

study looking at the effects of different weight-loss diets over a two year period found that those with higher amylase activity (carriers of the A allele for rs11185098) were less likely to regain the weight that they had lost. Those that carried the G allele tended to regain the weight. This interesting study showed that the type of diet (low carb, low fat, high protein, etc) did not have an effect on weight loss based on amylase activity.

Another study linked a tendency towards higher carbohydrate and starch intake to those with the A allele, but, at least in a Caucasian population, those with the minor (A) allele also had a lower overall caloric intake. [ref]

Check your genetic data for rs1118509823andMe v4 only):

    • A/A: higher amylase activity

Great at breaking down carbs.

    • A/G: intermediate amylase activity

Good at breaking down carbs.

  • G/G: lower amylase activity

Members: Your genotype for rs11185098 is .

 


Lifehacks

Supplements:

There are many digestive enzyme supplements available that contain amylase.  One brand that I like is Enzymetica, but there are other good brands as well.

Diet:

Coming back to the study referenced above that found that cellulose inhibits the amylase enzyme… If you eat processed or packaged foods (like most everyone does), you are likely eating a lot more added cellulose that you think.  Check out the labels, and take a look at my article on emulsifiers and your gut microbiome.  Consider cutting out the processed, packaged foods.

It may be worth experimenting with your diet based on your amylase production — perhaps reducing the proportion of carbs in a meal if you are a low amylase producer would make a difference in how you feel after the meal? Experiment and see if replacing some of the carbs with lower carb alternatives makes a difference.


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Author Information:   Debbie Moon
Debbie Moon is the founder of Genetic Lifehacks. She holds a Master of Science in Biological Sciences from Clemson University. Debbie is a science communicator who is passionate about explaining evidence-based health information. Her goal with Genetic Lifehacks is to bridge the gap between scientific research and the lay person's ability to utilize that information. To contact Debbie, visit the contact page.