Rumours began circulating online last week after Ali, who recently signed a multi-year contract with NEXT Model Management, appeared in new photographs looking extremely thin with seemingly enhanced features on her face.
"They actually think I would let Ali get Botox or surgery? So beyond ridiculous. She grew three inches over the summer," Dina told The Huffington Post.
A family friend added that the controversy surrounding Ali is not surprising and that the Lohan family is used to dealing with such gossip, saying: "The speculation and rumours are nothing new to the Lohans.
"Remember the rumours that Lindsay [Lohan] had had breast implants when she was Ali's age? At first the family was just going to ignore them but now they have had enough and are fighting back."
Lindsay recently defended Ali, insisting that she has never had surgery and that her new look was achieved naturally.