food makes the difference

In the 1980s in the United States, two teams of researchers asked themselves a seemingly simple question: can animals live longer if they eat less? A team from the National Institutes of Health (NIH) in Bethesda, Maryland, and one from the University of Wisconsin at Madison gave a group of rhesus macaques (mulatto monkey) 30% fewer calories than a control group. According to the Wisconsin results, calorie restriction allows the monkeys to live longer and healthier lives; but according to the NIH, it has no such effect.

To understand the reason for this difference, the researchers analyzed the conditions of the two experiments. Thus, they realized that the discrepancies observed might be due to the particularities of the food provided to the animals, even though the levels of caloric restriction were similar. “Diet is one variable among others”, explains Kristin Gribble, a molecular biologist at the Marine Biological Laboratory in Woods Hole, Massachusetts.

“If it is not identical in two experiments, it constitutes an additional variable to be taken into account when analyzing the results.”

In the past, researchers often ignored the importance of animal nutrition when designing their experiments, points out Stephen Watts, an expert in the nutrition of aquatic organisms at the University of Alabama at Birmingham. “As long as the animals looked happy and healthy, the researchers were satisfied,” he said. it sums up.

standardized pellets

The tide began to turn in 1977, when a report by the American Institute of Nutrition in Rockville, Maryland, offered guidelines for eliminating dietary confounders in medical research. Since then, scientists have developed several standardized diets for farms and laboratories; a variety of standardized pellets were produced for laboratory rats and mice. “We realized that nutrition was a key element in improving the rigor and reproducibility of the experiments”notes Stephen Watts.

However, these standardized diets still have many variations and are not available for many commonly used animals. When they were developed, the goal was often to limit their cost and maximize their practicality, rather than to mimic the habits of animals in the wild.

Therefore, it is crucial to carefully document experimental conditions to improve the replicability of experiments, points out David Allison, a biostatistician at Indiana University in Bloomington who works on divergences of r

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article source

Nature (London)

Since 1869, this well-deserved scientific journal has received – after several months of verification – reports on the main innovations in all fields: from biology to physics and passing through astronomy. His age doesn’t stop him from remaining surprisingly dynamic. In addition to articles aimed at researchers and scientists, the journal also offers news pages, debates and archives accessible to the general public.

Like other newspapers, Nature it offers archives dating back to 1987. But its grouping with all the more specialized publications of its press group, Nature Publishing Group, allows the visitor to access a very substantial mass of information. The very simple classification by scientific areas – chemistry, pharmacy, oncology, biotechnology, immunology – makes research much easier. Another very practical point, all articles are dotted with numbered bibliographic notes, which refer directly to another article online. In the paper version, a summary of the articles accessible on the Network is proposed.

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