An international team of researchers from Israel, France, Italy and the United States has for the first time succeeded in finding a direct molecular link between meat and dairy diets and the development of antibodies in the blood that increase the chances of developing cancer.
This connection may be able to explain the high incidence of cancer among those who consume large amounts of dairy products and red meat, similar to the link between high cholesterol and an increased risk of heart disease.
The study was led by Dr. Vered Padler-Karavani of the Department of Cell Research and Immunology at the Shmunis School of Biomedicine and Cancer Research at Tel Aviv University’s George S. Wise Faculty of Life Sciences. The results of the innovative study were published in the journal BMC Medicine.
Neu5Gc is a sugar molecule found in mammalian tissues (and not in poultry or fish). Humans develop antibodies to Neu5Gc in infancy, when they are exposed to dairy and meat products.
It is already known that these antibodies increase the risk of cancer, especially colorectal cancer, but so far no direct link has been found between the dangerous antibodies to meat and dairy consumption.
For the study, the researchers used examples from an extensive national nutritional survey conducted in France, called NutriNet-Santé.
Salam Bashir, a PhD student in Dr. Padler-Karavani’s lab, together with other team members, measured the amount of Neu5Gc sugar in a variety of dairy and meat foods common in the French diet and calculated the daily Neu5Gc intake of 19,621 adults aged 18 and over, who reported all of their food intake online for a period of several days.
The research team then took a representative sample of 120 participants, who submitted an average of 21 non-consecutive 24-hour dietary records and denoted a high or low intake of the sugar, then tested the levels and repertoires of the anti-Neu5Gc antibodies in their blood.
Based on these findings and the quantification of Neu5Gc sugar in various food products from France, Dr. Padler-Karavani and her team created an index called the Gcemic index. This index ranks foods whose excessive consumption can lead to an increase in the antibodies – and thus, probably also to an increase in the risk of cancer.
Of the mammalian food products, beef steak is the most popular and most consumed in the world. Therefore, the researchers used it as the basis for the Gcemic index and gave it the value 1.
Consuming a food with an index value lower than 1 means that you would have to eat a lot of it to consume a high level of the sugar, and vice versa. Mozzarella cheese, for example, contains only 0.03 of the amount of Neu5Gc per gram compared to steak, cow’s milk has a value of 0.13, and mutton received a value of 0.41 – about half of a beef steak.
On the other hand, there are foods that are much riskier than steak, such as sheep yogurt (1.69), sheep feta (1.71) and Roquefort cheese (3.35), which contain more of the sugar per gram of food, though they are usually consumed in smaller amounts than steak.
“We found a significant correlation between high consumption of Neu5Gc from red meat and cheeses and increased development of those antibodies that heighten the risk of cancer,” says Dr. Padler-Karavani.
“For years there have been efforts to find such a connection, but no one did. Here, for the first time, we were able to find a molecular link thanks to the accuracy of the methods used to measure the antibodies in the blood and the detailed data from the French diet questionnaires.”
Dr. Padler-Karavani adds that this combination of methods allowed the researchers to predict that those who eat a lot of red meat and cheese will develop high levels and a different repertoire of the antibodies, and therefore may be at higher risk for cancer; especially colorectal cancer, but other cancers too, such as breast cancer.
In conclusion, the researchers note that as with anything in life, the consumption of dairy and meat products should be done in moderation. The association between Neu5Gc carbohydrate and serum antibodies against it provides the molecular link to cancer, the Sante study documents.