A team of researchers from the Department of Biochemistry, Food Sciences and Nutrition at the Hebrew University's Faculty of Agriculture, examined for the first time ever the effect of ultra-processed food on the development of the skeleton.
The effects of processed food on our health have been in the headlines for many years. Obesity, diabetes, certain types of cancer and premature aging are just some of the well-known consequences of excessive consumption of the readily available and cheap food. Within the processed food category, there is the most extreme food group in the hierarchy - ultra processed food. It is about food that goes through countless processing and contains components that are not defined as food.
Not for nothing has the ultra-processed food earned the nickname "junk food". Such food usually comes packaged and ready to eat, either in fast food chains or in the freezer of supermarkets. In recent decades we have witnessed physical, mental and metabolic changes that began to gnaw at all age groups in the world's population as a result of the transition to an ultra-processed, fast, cheap and easy-to-prepare diet. The level of consumption of ultra-processed food has also increased among children, and about 70% of their caloric intake comes from this type of food. Despite the extensive research that has been done on the subject, the effect of this change on the development of the skeleton and its quality has not been examined in depth, especially in the growing ages.
A team of researchers from the Hebrew University led by Prof. Efrat Monsongo Ornan, Dr. Zhanna Zaretsky and my doctoral student Grace Fischenheimer, from the Department of Biochemistry, Food and Nutrition Sciences in the Faculty of Agriculture of the Hebrew University, examined for the first time ever the effect of ultra-processed food on the development of the skeleton. The research was done in young rats whose skeleton has not yet finished its development. Rats that were exposed to ultra-processed food during the growth period suffered from impaired growth, and a decrease in bone quality that included an osteoporotic phenomenon (perforated, sieve-like phenomenon) that is not characteristic of young, healthy rats. In addition, in a histological examination (of the tissue structure) of the bones in this group, an extensive cartilaginous plaque (abnormal accumulation of cells and cartilaginous tissue) was found in the growth plates. The study was published in the respected journal Bone Research from Nature.
What went wrong with the bones?
In order to understand what went wrong at the molecular level in the bones and why, the researchers performed a characterization of genomic transcription in the cells of the growth plate in rats that consumed ultra-processed food. The results of the test showed that rats that consumed ultra-processed food suffered damage to the normal processes in the growth plate that should lead to bone lengthening compared to the control group. In fact, the RNA profile of these rats demonstrated a gene expression pattern that indicates an imbalance in critical processes for normal bone development (the creation of the extracellular matrix and its breakdown, damage to the processes of division and differentiation and inhibition of the mineralization process).
In the next step, the researchers checked which ingredient in the ultra-processed food caused a decrease in growth and damage to the growth plate.
"In order to examine whether the composition of the fat and carbohydrates in the ultra-processed food is responsible for the harmful effect, we examined the two main components that characterize this type of diet, which are high levels of fat and sucrose," explains Prof. Monsongo Ornan. In this experiment, rats were given a high-fat diet and a high-sucrose diet and its effect on bone development and growth was examined. Both groups presented normal growth and bone indices and a growth plate with proper organization, which confirms that the macronutrients in the ultra-processed food are not responsible for the skeletal damage.
Low levels of calcium and phosphorus
An examination of the micronutrient composition of the processed food showed low levels of calcium and phosphorus as well as an inverse relationship between the two. Therefore, we built a diet that contained the same amount of calcium and phosphorus as in the ultra-processed food diet, while the other components were the same as the control diet. Rats that were fed this diet demonstrated impaired growth, a decrease in the quality of the morphological and mechanical parameters of the bone accompanied by an osteoporotic episode. In addition, these rats demonstrated a cartilaginous plaque similar to that demonstrated in the ultra-processed food group but less frequently. In addition, the calcium and phosphorus levels in the blood were more balanced in this group compared to the group that consumed ultra-processed food. "These results show that the low levels of calcium and phosphorus in the ultra-processed food diet, despite their effect, are not solely responsible for the destructive effect of this food on the developing skeleton," explains Dr. Zaretsky.
Finally, in order to test the effect of ultra-processed food in a manner consistent with human behavior, the researchers examined the consumption characteristics of ultra-processed food by humans. Prof. Monsongo Ornan: "Since about 70% of children's caloric intake comes from this type of food, we performed another nutritional experiment that simulates these consumption habits. In this experiment, rats received 30% of the week a balanced control diet and 70% of the week a diet based on ultra-processed food. These rats demonstrated moderate damage to the quality and structure of the bone, while the cartilaginous plaque was not visible in the growth plates. These results indicate that even with more moderate consumption, ultra-processed food damages bone development."
Severe skeletal injury
The results of the study show for the first time that ultra-processed food causes severe damage to the skeleton of young rats during growth. This damage is more extensive than the hitherto known metabolic effects of this type of diet. For the first time the spotlight is on the skeletal system as a target for metabolic damage of the modern diet. "This issue is of utmost importance, as studies show that children and teenagers consume ultra-processed food on a regular basis, and according to the data, 50% of children in the US consume ultra-processed food on a daily basis."
"And on a personal note," Prof. Monsongo Ornan continues, "once in a while we are witnessing an attempt by the scientific community to define what is the source of evil in our diet, who is the component on which all the blame can be placed. But there is no single component, since in fact it is a set of components, which may not even be separable. Prof. Carlos Monterio, one of the most respected nutrition researchers in the world, said that there is no such thing as a healthy ultra-processed food, and he is right. Even if we reduce fat, carbohydrates, sodium or any ingredient that is a "scapegoat" from it, still the ultra-processed food will not lose its harmful power. No system is immune from the damage that ultra-processed food may cause, certainly not systems that are in their development period."
Dr. Zhanna Zaretsky, Shelly Gries-Fischheimer, Dr. Adi Karmi, Tamara Trebinski-Shamul, Dr. Lior Ofer, Dr. Tali Sinai, Svetlana Penn, and Prof. Ron Shahar participated in the study.
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