Genetics plays less of a role than age in our health as we get older

There are many elements that determine how we age. This includes our genetics, the environment, and our age itself. But what key component has the most profound impact on aging?

According to a new study by researchers at the University of California – Berkeley, aging and the environment play more of a key role in determining our health in later years, than genetics. The study was published in the journal Nature Communications.

Aging affects health more than genes

In the study, the research team looked at genetics, aging, and the environment, and how these three components affected 20,000 human genes. They found that both aging and the environment affect our genes as we get older, more than genetic variation. This factor determines things such as our hormone levels, metabolism, and how the body repairs itself. It also impacts diagnosis for certain diseases such as dementia or diabetes.

“How do your genetics -- what you got from your sperm donor and your egg donor and your evolutionary history -- influence who you are, your phenotype, such as your height, your weight, whether or not you have heart disease?” asked Peter Sudmant, UC Berkeley assistant professor of integrative biology and a member of the campus's Center for Computational Biology, also a co-author of the study.

Genes and variation

He mentioned that there have been numerous studies on determining how genes are changed by human genetic variation. The study questions how such variation is influenced by a person’s age. Sudmant stated that “the first result we found was that your genetics matter less the older you get.”

This means that genetic makeup can help predict gene expression when younger, however, it is not as useful in predicting expression when older. In this study, the age reference was 55 years and older.

The example given in the study involved identical twins. Although identical twins have the same type of genes, this factor is irrelevant as they age, showing a divergence in their gene expression, therefore making them age differently despite having the same genes.

The study

For the study, the researchers analyzed 948 people and set a median age of 55 years old. Then, the researchers determined the impact of aging on 27 human tissues. After studying these tissues, they discovered that human tissues are more likely to have cancerous mutations in tumors as they age.

The study suggests that we all age differently, regardless of genetics. This study also lined with Medawar's hypothesis, which states that "genes that are turned on when we are young are more constrained by evolution because they are critical to making sure we survive to reproduce, while genes expressed after we reach reproductive age are under less evolutionary pressure,” according to a press release published by the research department by University of California - Berkeley.

“Across all the tissues in your body, genetics matters about the same amount. It doesn’t seem like it plays more of a role in one tissue or another tissue,” Sudmant said. “But aging is vastly different between different tissues. In your blood, colon, arteries, esophagus, fat tissue, age plays a much stronger role than your genetics in driving your gene expression patterns.”

Overall, a person’s age plays a much larger role in determining health when compared to gene expression.