Amylase: Another Clue for Precision Nutrition?

New research from the University of Sydney is offering another clue for developing the science of personalized nutrition. Starch is the most common carbohydrate in our diets. And we have an enzyme in our saliva – amylase – that helps us start digesting starch even before we eat it. But different people will have very different responses in their blood sugar when they eat a starchy food.

This new research found that differences in a gene for salivary amylase might explain these differences in responses to starchy food. The gene that codes for amylase in your saliva is AMY1.

Effects on Digestion and Gas (Methane)

Fiona Atkinson and colleagues published a series of studies in AJCN to provide this insight. In their studies they found that having more copies of the AMY1 gene predicts that people will digest starchy foods faster. Their blood sugar levels will spike higher.

But perhaps even more interesting is the fact that people with less of the AMY1 gene will produce more intestinal gas – methane. (No jokes about passing gas, please.)

The reason this is interesting is simple. That’s because it suggests a difference in a person’s microbiome. And others have demonstrated that the microbiome has important implications for glycemic responses and personalized nutrition. In fact, in this same issue of AJCN, Lars Christensen  and colleagues offer a concise perspective on this subject.

More Questions to Sort

If someone tells you that this is all cut and dried, don’t buy it for a minute. The science of microbiomes and personalized nutrition has many moving parts. Our understanding of how these factors relate to our genetic profiles is far from complete.

These data suggest that salivary amylase interacts with the microbes in our guts in ways we don’t yet fully understand. Emily Sonestedt makes this point in an editorial alongside Atkinson’s research. “The role of salivary amylase is still rather unclear,” she says.

Nonetheless, Atkinson et al are raising important questions for further research. Their insights will bring us closer to a solid evidence base for precision nutrition. Without discounting the questions that remain, Jennie Brand-Miller, senior author on the Atkinson paper, sees great potential:

The message I take from this research is that salivary amylase is doing quite a lot of the work involved in starch digestion, otherwise we would not see these differences in glycemia at all.

The difference in microbial metabolism (±methane excretion) was completely unexpected. I think we need at least one confirmatory study, but if it’s true, then wow. This may be bigger than any other gene-diet interaction we’ve seen so far.

Click here for the the research by Atkinson et al and here for the editorial by Sonestedt. For Christensen’s review, click here. And finally, you can find more personalized nutrition and glycemic responses here.

Columbus Corn Starch, advertising card © Boston Public Library / flickr

Subscribe by email to follow the accumulating evidence and observations that shape our view of health, obesity, and policy.

October 19, 2018