Elevated Serum Aflatoxin B1 -Lysine and Liver Function Abnormalities Associated with Traditional Home-made Peanut Oil Consumption in Guangzhou

In the warm, humid climate of southern China, a specific type of fungus thrives on crops like peanuts. This fungus produces invisible toxins known as aflatoxins, which are among the most dangerous substances found in food. When people eat food contaminated with these toxins, their bodies absorb them, and the liver, which acts as the body's primary filter, works to break them down. During this process, the toxins can leave behind chemical marks on the proteins circulating in the blood. Scientists can measure these marks to determine how much of the toxin a person has been exposed to over the last few months. Because these toxins are known to damage the liver and can even cause cancer, understanding how much people are exposed to in their daily lives is a critical public health question.

A team of researchers from the Guangzhou Center for Disease Control and Prevention set out to investigate this issue in their own city. They focused on a specific dietary habit common in the region: the consumption of traditional, home-made peanut oil. Unlike mass-produced oils found in supermarkets, this oil is often pressed in small, family-run workshops or village mills. While it is a cherished part of local culinary culture, the lack of industrial processing and strict quality control can sometimes allow the fungus to grow on the peanuts before they are pressed, leading to higher levels of contamination. The researchers wanted to know if people who drank this oil regularly were absorbing more of the toxin and if this extra exposure was showing up as damage to their livers.

To find the answer, the team studied residents in two different areas of Guangzhou over a three-year period. One area, Xiao Lou, was chosen because it represented a community where nearly everyone drank large amounts of this traditional oil. The other area, Dashi, represented a community where the oil was consumed much less frequently. The researchers gathered blood samples from hundreds of volunteers in both towns. They used a sensitive laboratory test to measure the level of the toxin's chemical mark, known as an adduct, attached to a protein called albumin in the blood. This measurement served as a precise record of the toxin intake over the previous two to three months.

The results were clear and consistent. The people living in the high-consumption area of Xiao Lou had significantly higher levels of the toxin in their blood compared to their neighbors in Dashi. On average, the concentration in the high-consumption group was 4.58 nanograms per milliliter, while the lower-consumption group averaged 3.10 nanograms per milliliter. This difference was not a fluke; it appeared every year of the study. To ensure that this difference was truly due to the oil and not other factors like age, income, or pre-existing health conditions, the researchers used a statistical method to pair individuals from both towns who were as similar as possible in every way except for their oil consumption.

Even after matching the groups so perfectly that they were virtually identical in age, gender, education, and health history, the pattern held. The residents of the high-consumption area still had higher toxin levels in their blood. More importantly, the study found that these residents were also at a significantly higher risk of having abnormal liver function. In the matched groups, people from the high-consumption area were nearly three times more likely to show signs of liver stress than those from the low-consumption area. The researchers noted that while the toxin levels themselves did not directly predict liver problems in every single individual, the fact that the high-consumption group had both higher toxin levels and higher rates of liver issues suggests a strong link. The data indicates that living in an area where this traditional oil is a daily staple increases the burden of toxin exposure, which in turn raises the risk of liver damage.

The study also looked at the broader picture of food safety in the region. While regulatory efforts have successfully lowered the average amount of toxin found in these oils compared to a decade ago, the levels remain higher than in commercial vegetable oils. The researchers concluded that even with these improvements, the long-term, daily consumption of traditional home-made peanut oil continues to expose residents to enough toxin to affect their health. They suggest that the solution lies not in banning the oil, but in improving how the raw peanuts are stored and pressed to prevent mold growth, and in educating consumers to use the oil more moderately. The findings serve as a reminder that traditional foods, while culturally important, require careful management to ensure they remain safe for the communities that rely on them.