The hazelnut and chocolate spread was being pulled from shelves after the study.
It said palm oil was more likely to contain carcinogenic agents compared to other vegetable oils.
Ferrero say switching ingredients would result in an inferior spread which wouldn't be as smooth.
The report for the European Food Safety Authority (EFSA) came out last May.
It said palm oil contains particularly high levels of contaminants, when heated about 200 degrees Celcius.
However, it stopped short of telling people to stop eating the oil, insisting more research was needed.
But that didn't stop Italy's biggest supermarket chain, Co-op, from stopping selling the spread, along with many other products.
The news hit Nutella fans hard.
Palm oil is found in hundreds of foods and products - from peanut butter to noodles to soap and detergents.
But the spread's been getting all the publicity because it's such a famous brand.
And when sales started to dip after it was removed, Ferrero, put out TV and newspaper adverts, insisting its product was safe.
Now Ferrero has released another statement, in defence of the oil, which gives the spread its smoothness.
"Making Nutella without palm oil would produce an inferior substitute for the real product, it would be a step backward," Vincenzo Tapella from Ferrero told Reuters.
There's also the small matter of cost.
Reuters estimates switching to other vegetable oils could cost up to £18m a year.
Palm oil has been controversial for a long time, over fears that production of the oil has caused catastrophic deforestation and destroyed animal habitats.
At the moment, it's not thought there are plans to stop selling Nutella in UK stores.
And the World Health Organisation has not suggested people stop eating palm oil.