According to a recent American study, crows living in urban areas have higher cholesterol levels than those in the countryside. Explanation: they would tend to feed on our leftovers.
Humans aren’t the only ones affected by excess cholesterol. According to a new study published on Monday August 26 in The Condor: Ornithological Applications, crows living in urban areas suffer from higher cholesterol levels than their congeners in the countryside. And this because they would tend to feed on our leftovers.
To reach this conclusion, Andrea Townsend of Hamilton College (USA) and her colleagues analyzed the blood cholesterol levels of 140 baby crows “living” in rural and urban areas of California. They discovered that the more urban the environment, the higher the blood cholesterol levels of the chicks.
To test the effects of human food on animals, the researchers regularly distributed McDonald’s cheeseburgers to crows settled in New York. They then compared their cholesterol levels with their neighbors who had to feed themselves. The result is clear: the crows fed at McDo had higher cholesterol levels than their comrades.
Cholesterol isn’t all bad
However, it is difficult to determine if cholesterol is really bad for crows, qualify the researchers. Indeed, if survival rates during the first three years of life were lower in urban crows than in rural ones, cholesterol was not at fault: among the New York population, the nestlings at the highest level cholesterol actually performed better when their body condition was measured.
“Despite all the bad press it gets, cholesterol has benefits and performs a lot of essential functions,” explains Andrea Townsend. “It’s an important part of our cell membranes and a component of some crucial hormones. We know that excess cholesterol causes disease in humans, but we don’t know what level would be ‘excessive’ in a wild bird.” .
Still, Townsend wouldn’t go so far as to recommend feeding cheeseburgers or other processed foods to birds. “Wild birds have not evolved to consume processed food and this could have consequences that we have not measured or that will only show up over longer periods of time,” she said. “Feeding wild birds can be a great way to connect with nature and it can feel good to know that we are helping animals. However, I am concerned about some foods that humans feed wild animals. elsewhere, living in an urban environment might not be good for their health,” she concludes.
In humans, ultra-processed foods increase the risk of cancer
But processed foods aren’t good for humans either. According to a recent report by INSEE, the share of ultra-processed products based on meat, fish and vegetables has more than doubled in recent years, reaching 41% in 2006 in France. Today, it represents 80% of our food consumption, to the detriment of products requiring more personal preparation.
However, according to a study carried out in February 2018, the consumption of these foods would increase the risk of cancer. In detail, a 10% increase in the proportion of ultra-processed products in the diet is associated with an increase of 6 to 18% in the risk of developing cancer in general and from 2 to 22% for the risk of cancer. breast. “Ultra-processed fats and sauces and sugary products and beverages are associated with increased cancer risk overall, and ultra-processed sugary products were associated with breast cancer risk,” the researchers noted.