The former That's Life presenter spoke out when she visited volunteers at Glasgow's Childline base in the East End.
The 73-year-old is urging west of Scotland residents to consider becoming counsellors to help deal with children's issues.
Ms Rantzen said she had noticed more youngsters calling the help line with low self esteem problems compared to when Childline was launched 27 years ago, suggesting the number of young people suffering with depression may be increasing.
She said: "In 1986 children were talking about abuse and bullying but they weren't actually talking about depression and suicide.
"I mean, yes, if a child was being abused they might have talked about that. But this profound sadness wasn't on the same scale."
Ms Rantzen said she felt the combination of children not getting "emotional support" at home and the exposure to celebrities was resulting in mass low self esteem.
She said: "Why are there eating disorders? Why do they seem to have such low self esteem?
"I think it's a combination of the so-called celebrity culture, where everyone wants to look like Rihanna and sound like Adele or whatever.
"You've got to have a golden life, a golden body and live like a golden boy or girl."
The broadcaster also said a high number of calls and emails to counsellors were connected to internet-related problems.
But, she said, Childline was helping to tackle issues such as cyber bullying, so-called 'sexting' or 'revenge porn', where naked photos or media are shared without the consent of the individual, with a free mobile phone app called Zip It.
She said: "I've heard some really awful stories - there was a disabled girl who was persuaded to send inappropriate pictures which then ended up on the internet.
"The girl said: 'He told me I was beautiful and I'd never been told I was beautiful before.'"
Glasgow volunteers spoke of their experiences of helping at Childline.
Lily Shand, 74, a retired midwife from Kilmacolm, Renfrewshire, who has been a helpline counsellor for five years, said: "I had time on my hands and wanted to give something back.
"There are serious things you hear and you can be quite taken aback but you must never be judgmental."
Fionnuala O'Neill, 26, from the West End, is a schools service volunteer.
She educates primary school children on how they can recognise abuse and do something about it.
Ms O'Neill said: "We try and empower them about issues like grooming, abuse or bullying."
Visit nspcc.org.uk for more details. Childine: 0800 1111