Last Updated on August 4, 2020 at 12:08 PM
Health In Focus
Highlights :
  • Hair isotope analysis establishes a connection between diet, socioeconomic status, and health
  • Corn-based diet predominant in low socioeconomic areas
  • Carbon isotopes correlated with haircut price at the sampling location
  • Carbon isotopes correlated with obesity rates

Isotopes in hair reveal diet patterns according to socioeconomic status, according to a new study led by the University of Utah.

Hair isotopes could offer insights into health risks in a community. The study is published in the journal Proceedings of the National Academy of Sciences.
Hair Isotope Analysis Offers Insights into Diet and Health Risk

Isotope Clues

Isotopes are the same elements as found in the atmosphere but with slightly different atomic weights.

From the 1990s, Ehleringer, professors Denise Dearing and ThureCerling, along with their colleagues, began exploring the different methods that traces of mammal diets could be reflected in the hair.

Various food sources have various isotopes, including carbon and nitrogen. When the food breaks down into amino acids, the stable isotopes present in the food will find their way throughout the body, including the hair.

Water also contains different oxygen ratios and isotopes based on geographical location. In 2008, Ehleringer and colleagues published results proving that the isotopic composition of the hair could reveal a person's travel based on the water they drink.

Ehleringer and his colleagues then began investigating carbon and nitrogen isotopes present in the hair.

What Does Hair Know

The results from hair isotope analysis revealed variations in hair isotope ratios, locally and nationally.

The carbon isotopes correlated with the cost of living in the ZIP codes from where the samples were collected.

The samples collected from Salt Lake offered more specific detail into factors behind the isotope variation. Surprisingly, the researchers could correlate the price of the haircut in the sampling location by using carbon isotopes from the hair.

Corn-like isotope signatures were predominant in lower socioeconomic areas. Meat eaters also got their protein from cornfed animals.

The researchers further examined the relationship between and obesity isotope signatures. Driver's license data was used to calculate trends in the body mass index (BMI) for a particular ZIP code.

The authors found that isotope ratios correlated with obesity rates. This data draws potential connections between health, diet, and socioeconomic status.

How are Carbon and Nitrogen Isotopes Linked to Diet?

Based on the diet a person consumes, there would be different carbon and nitrogen isotopes.

In livestock fed with corn, the corn would be incorporated in their tissues. Corn belongs to a group of plants known as C4 plants.

C4 plants are those that use C4 carbon fixation. Pineapple, sugarcane, are other plants that belong to the C4 group. These plants also photosynthesize differently compared to C3 plants. C3 plants include legumes, vegetables.

Based on the type of protein one eats, their hair would contain either C3 signatures or C4 signatures.

How did the Researchers Collect Samples?

To study hair isotopes, the researchers needed hair samples. They collected hair samples from barbershops and salons in 65 cities across the United States.

To intensively study a single urban area, the researchers collected samples from 29 ZIP codes in Salt Lake Valley.

They collected hair samples from the trash bin and sorted them into identifiable clusters that represent individuals. Thus, the sampling technique was blind.

The researchers had no idea about the individual's age, income, gender, or any other factor except for their isotope record. Around 700 samples of hair were collected.

"This measure is not biased by personal recollections, or mis-recollections, that would be reflected in dietary surveys," says Ehleringer. "As an integrated, long-term measure of an individual's diet, the measurement can be used to understand dietary choices among different age groups and different socioeconomic groups."

In summary, hair isotope analysis can reveal data that can also be used to analyze a community's health risks.

  1. Stable isotopes in hair reveal dietary protein sources with links to socioeconomic status and health - (

Source: Medindia

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