MAY 06, 2019 11:16 AM PDT

How a Human Starch Gene and a Gut Bacterium are Connected

WRITTEN BY: Carmen Leitch

As researchers and clinicians learn more about small changes in genes, called variants, as well as the microbiome, the community of microbes that lives in and on our bodies, they are getting closer to creating personalized dietary recommendations. Now scientists have identified a connection between variations in the number of copies of a gene, AMY1, which codes for an enzyme called amylase, and certain bacteria in the gut and mouth. The amylase enzyme acts in the saliva to break down starches. When people have many copies of the AMY1 gene, they tended to have a certain gut and mouth bacteria profile.

Image credit: Max Pixel

If amylase levels (a salivary enzyme) are high in the intestines, it encourages the growth of a group of bacteria called Ruminococcaceae. These bacteria can help metabolize hard-to-digest resistant starches, which human amylases aren’t able to do. There are nutritional benefits to the break down of resistant starches. It may be that prehistoric humans with extra copies of the AMY1 gene may have been better off when food sources were limited.

"It likely provided additional nutrition from starch," explained Angela Poole, assistant professor in the Division of Nutritional Sciences. Poole is the lead author of a publication outlining these findings in Cell Host & Microbe.

The researchers also found that higher levels of Porphyromonas bacteria correlated with more copies of the AMY1 gene. These mouth bacteria have been associated with periodontitis (gum disease). However, that connection is still not well-understood, and it may only be coincidental. 

Personalized nutrition is a new field, and researchers are still settling on exactly what it means. But there is plenty of evidence, including this work, that some people can benefit from a tailored diet. This research suggested that in some people, the number of copies of the AMY1 gene should be considered when dispensing health recommendations. Other research has connected certain genetic variants with obesity and other metabolic disorders, for example. 

This work gathered genetic data and stool samples from almost 1,000 British volunteers, looking to see if the number of AMY1 gene copies impacted the microbiome. The researchers looked at a subset in their data; fifty people with high numbers of the gene, and fifty with low copy numbers, representing the top and bottom five percent of the cohort, respectively.

In the video, watch starch get broken down by amylase.

"High copy numbers correlated with a certain profile of gut bacteria," Poole noted.

Poole then turned to volunteers in New York and found between two and thirty copies of the gene in the participants. Stool samples were collected to identify the bacteria associated with the various copy numbers. The study volunteers then ate a standardized diet for two weeks.

"I wanted to make sure they were eating the same thing, and that they were eating starch," Poole said. The researchers took saliva and stool samples after the diet and showed that the volunteers’ gut bacteria confirmed their findings from the British study. 

Learn more about personalized nutrition from the video above featuring Eran Segal, a computational biologist at the Weizmann Institute of Science.


Sources: AAAS/Eurekalert! Via Cornell University, Cell Host & Microbe

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
SEP 01, 2020
Genetics & Genomics
Women's Genes May Help Protect Against the Worst Alzheimer's Cases
SEP 01, 2020
Women's Genes May Help Protect Against the Worst Alzheimer's Cases
Women tend to get Alzheimer's more than men, but the female genome gives them some protection from the worst aspects of ...
SEP 07, 2020
Immunology
CRISPR Pumps the Brakes on the Immune System to Support Gene Therapies
SEP 07, 2020
CRISPR Pumps the Brakes on the Immune System to Support Gene Therapies
The ability to edit the human genome using CRISPR has been heralded as a revolution in medicine. However, one of the big ...
SEP 14, 2020
Cancer
MiR-107 and Its Role in Radiosensitivity in Prostate Cancer
SEP 14, 2020
MiR-107 and Its Role in Radiosensitivity in Prostate Cancer
It is often unknown whether a patient will respond to a treatment until it is in full swing. New research is attempting ...
OCT 18, 2020
Genetics & Genomics
'Silent' Mutations Might Have Given SARS-CoV-2 an Edge
OCT 18, 2020
'Silent' Mutations Might Have Given SARS-CoV-2 an Edge
The pandemic virus SARS-CoV-2 is thought to have originated in bats, like many viruses. To make the leap and infect anot ...
OCT 19, 2020
Genetics & Genomics
Early Childhood Trauma Affects Metabolism in the Next Generation
OCT 19, 2020
Early Childhood Trauma Affects Metabolism in the Next Generation
Traumatic experiences can have a lasting impact, and kids that suffer through them can feel the effects for a lifetime. ...
OCT 29, 2020
Genetics & Genomics
Severe Genomic Damage in Human Embryos Treated With CRISPR
OCT 29, 2020
Severe Genomic Damage in Human Embryos Treated With CRISPR
The CRISPR-Cas9 genomic editing system holds great promise for treating genetic errors that cause human disease. But we ...
Loading Comments...