Moo-ve over from a significant beef and dairy diet to more vegetarian fare to avoid certain types of cancer. An international team of researchers from Israel, France, Italy and the US has for the first time succeeded in finding a direct molecular link between high consumption of meat and dairy diets and the development of antibodies in the blood that raise the chances of developing colon and breast cancer. 

High consumption of these products especially – Roquefort cheese (from sheep’s milk), feta cheese, goat cheese, sheep yogurt, and red and processed meat such as beef steak, lamb and pig meat and sausage – raise the risk. This connection may explain the high incidence of cancer among those who consume large amounts of red meat and dairy products, 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 have been published in the journal BMC Medicine under the title “Association between Neu5Gc carbohydrate and serum antibodies against it provides the molecular link to cancer: French NutriNet-Santé study.”

Neu5Gc is a sugar molecule found in mammalian tissues (and not in poultry or fish). Human anti-Neu5Gc IgG and red meat are both independently proposed to increase cancer risk, yet how diet affects these antibodies has been largely unknown, they wrote. Humans develop antibodies to Neu5Gc in infancy, when they are exposed to certain 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 doctoral student in Padler-Karavani’s lab, together with other team members, measured the amount of Neu5Gc sugar in a variety of meat and dairy 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, 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 one. Consuming a food with an index value lower than one 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. 

Apart from intakes of totalNeu5Gc, three additional classes of dietary Neu5Gc sources were computed – from meat, dairy cows and sheep and goats. In general, cow dairy has the lowest Gcemic index, while sheep/goat dairy has the highest, while it varies in different types of meat, they wrote. 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.

From the index developed by the researchers:

Athree-fold increase in incidence of cancer and 2.5-fold rise in deaths from cancer was found in nations that consume more than 120 grams of meat per day Interestingly, countries of high beef-meat intake

Include the US, Australia, and France, as well as

many counties in South America such as Argentina,

Brazil, Uruguay, and Chile. While the Gcemic index can

provide a simple estimate on Neu5Gc content in food, they added, a

direct correlation between specific amounts of consumed

food with cancer risk requires further investigation to account

for other common risk factors.

“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,” noted Padler-Karavani. “For years, there have been efforts to find such a connection, but no one succeeded. 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.”

Padler-Karavani added 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 could 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.