Maxim Vengerov may be a star-turn violinist, but he has not forgotten about his musical roots - nor about his health, writes Arminta Wallace

He mastered the violin in a year and gave his first concert when he was five. At 15 he burst onto the international scene. For some child prodigies, that's when the problems start. Cute kid turns into . . . what? Another note-perfect virtuoso? But for the sensation from Siberia - a.k.a. Maxim Vengerov - it was no problem. For one thing, he kept getting cuter. Alongside the usual rapturous praise of his "ravishing tone", "astonishing technique" or "emotional insights", his reviews have sported sidelong glances of the "smouldering looks" and "superstar and heart-throb" variety.

And when it comes to drama, he's a natural. There was a stunt for Swiss television in which, apparently to suggest to youthful audiences that classical music can be as exciting as extreme sports, he jumped off a mountain in a hang-glider while fiddling away on his $1.5 million Stradivarius. There was also a performance of Shostakovich's Violin Concerto No 1, at the Barbican in London, during whose climactic finale he broke a string. The audience held its breath, but Vengerov didn't miss a beat; grabbing a fiddle from the orchestra leader, he finished the piece, to thunderous applause.

Superstar. Genius. Classical music's next big thing, who, at 27, is being spoken of in the hushed tones generally reserved for very old and mostly dead big things. You can't help wondering, as you dial his hotel in Zurich as instructed, at precisely 12.20 local time on a Thursday morning, what he'll want to talk about, this playboy prodigy.

Will his mind be on the preparations for his recital in Lichtenstein the following day, or the appearance at Zurich's fabulous Tonhalle the day after that? Will he be distracted, sleepy, bored? Will he even answer the phone? He answers the phone. The voice is deep, the English accented but fluid: Sylvester Stallone with a Siberian spin. You make polite chit-chat about the lake in Zurich. You look at your list of carefully prepared questions about chamber music, cadenzas and conducting. And then you hear yourself ask: "So, are you still taking the pine health-food supplement?"

There is a moment of terrible silence, then the sound of classical music's next big thing chuckling down the phone. "How did you know about that? . . . No, really? Ah, the world is now a very small place."

A week ago, it transpires, he did a fund- raising concert in the United States for the Tampa Bay Research Institute, a natural- healing organisation that produces a pine-cone extract called Pinextra. "It's really something amazing," says Vengerov. "They've helped leukaemia patients now, and they have completely healed HIV patients. Can you believe that? It's fantastic." And how did a violin virtuoso get involved with experimental medicine?

"Through a good friend of mine, Yoko Ceschina. She also gave me a precious instrument to play. So she knew the founder of Pinextra company, Dr Tamaka. We are taking this liquid, which is really wonderful; it improves your immune system, especially during travel. Because one of the worst parts of my travel is the airplane. The air circulating is so, well, if somebody is sick, you get it."

Vengerov's distaste for flying makes it all the more surprising that he has voluntarily added extra air miles to a schedule that routinely sees him zoom from Salzburg to Chicago and Australia via Japan and Korea, in his work as a music envoy for Unicef. Why does he do it? "I want to dedicate time for children, too," he says. "They are our future. Many, many, many years ago, when I was a kid - I was three years old - I remember singing in my mum's choir."

His mother was the director of an orphanage in the Siberian city of Novosibirsk; Vengerov's father played oboe in the city's orchestra. The orphans' plight affected Vengerov, young as he was. "I remember how many kids she has saved by bringing them the joy of music," he says, "and since then I also dreamed to continue this musical dedication."

It is an arresting image - the former child prodigy playing for child addicts, some with HIV and AIDS, in Thailand, and for Ugandan children who had been kidnapped by terrorists and trained as killers - but as Vengerov talks, it becomes obvious that his experiences with Unicef have moved him deeply.

"In Uganda the kids were completely traumatised. In Thailand we visited a remote hill tribe, and to see how people live, in such a place, with absolutely nothing, it's fascinating. But I cannot ever forget my visit to central Serbia, where I saw a school for Albanian and Serbian children. It was divided in half; one half was painted in white and the other half was painted in yellow, in order that the kids shouldn't meet. Can you imagine that?

"And a Finnish tank was guarding those kids in case some crime was done to them. And I came and played for them. For both sides the same tunes: Russian dances and a little Hungarian music. And we danced and we had a lot of fun. And, of course, on both sides the kids reacted in the same way. They cheered; they smiled."

That response, at least, is nothing new to Vengerov. A London reviewer memorably described one of his concerts as "a performance of such unbridled passion and energy that it provoked one of the world's most stolid audiences to rise as one from their seats, pounding the floor and yelling for more". He may well provoke something similar at the National Concert Hall on Sunday, with a selection guaranteed to charm.

"This is a very interesting programme," he says, "because it includes the most precious composition of Mozart, which we all love - his sonata in E flat major - and then one of the best compositions ever written for violin, the Schubert fantasy. And the Strauss sonata, which is young Strauss - a very exciting piece, very inspiring. And, of course, at the end of the programme we do, as always, a little bit of fun, too, in the encores. We'll start with Kreisler and then see where it goes."

He will, as always, be playing his Strad, a 1727 instrument said to have been owned by the violinist and composer Rudolphe Kreutzer, to whom Beethoven dedicated his sonata Op 47. Stradivaris are expensive, hard to come by and de rigueur for anyone who hopes to get into the string stratosphere. No Strad, no superstardom. It's as simple as that.

"I think you have to own one, if you can," Vengerov says. "This instrument is mine now, and I'm thankful to Yoko Ceschina that she has helped me to get it. I've played many violins in my life, and I must say that I'm really a lucky man that I got to know this instrument in particular, because unlike many Stradivari it has an incredibly deep sound, you know? It has brilliance, of course, but it has also lower overtones, which is really quite rare with a Stradivarius; he achieved this mostly in his later years."

The instrument is known as the Kreutzer Stradivari, but does Vengerov have his own name for it? "We keep it strictly business," comes the reply, accompanied by another chuckle. "No names. We have so much time together that there's no time for sentiment - although, of course, it's half my life, so in a way it's really my partner."

The pair will be joined at the National Concert Hall by the pianist Vag Papian, whom Vengerov met when he signed up for Papian's conducting classes at Tel Aviv University. Conducting? Is the poacher to turn gamekeeper? "Actually, I've stopped conducting regularly," he says. "But I studied for two years, and it was a very necessary experience. To get into the kitchen, so to say, of conducting. I always wanted to know how does it look from other side, you know?"

Has the experience changed his interpretation of certain pieces? "Of course it has. Once you know all the process of working with the orchestra, it's a different attitude, and this has helped me enormously. Especially, of course, playing with orchestras, but also interpreting sonatas and playing chamber music. I feel more like partof the game."

It sounds as if he found conducting not only beneficial, but also enjoyable. Why has he given it up? He sighs. "Because, you know, you can't catch all rabbits. I have to continue playing; this I enjoy very much. I also teach one week a month in Saarbrucken Hochschule, so it's not easy for me to find time for other activities. I like committing myself to something very seriously and having a lot of time for that."

Then he remembers he's about to conduct Tchaikovsky and Beethoven concertos with the student orchestra in Germany and cheers up. "One of my students is going to the Tchaikovsky competition this year, a Turkish student, so for preparation we're making one performance, and we have a lot of hope that he will get to the final. For now, there's not much room for conducting in my schedule, but who knows? Maybe in the future." Given the amount he has managed to cram into his life so far, that may be putting it mildly.

Maxim Vengerov and Vag Papian are at the National Concert Hall, in Dublin, on Sunday at 8 p.m., as part of the NCH/Irish Times celebrity concert series