Patrick Holford is unperturbed by the flak he's getting.
It's to be expected if you reveal the darker side of the pharmaceutical industry, the bad science and fraud behind the development and prescribing of some drugs, in a very accessible book.
Especially if you offer nutritional alternatives to many chronic medications (like the statin drugs), backed by solid science.
He and co-author Jerome Burne are taking on Goliath. In South Africa he's been taken to task for his mention of research on vitamin C and Aids in an earlier book, and misquoted, he says (see sidebar). And as we speak there's a new vitamin scare, which he refers to in his book, Food Is Better Medicine Than Drugs (Piatkus).
He's also received a lot of support for his book. "Top experts in medicine are deeply frustrated at the deceit of the drug companies," says Holford.
"The medical profession is wanting more distance from the pharmaceutical industry. My book is not anti doctors: if they were to work with a nutritionist, it would be a marriage made in heaven.
"Every chapter of my book has been checked by top people in their fields, many of them medical professionals," he says.
GPs, he points out, don't have time to read up on the latest research especially on nutrition. Many have welcomed the book.
His book is dense with revelations and our hour passes rapidly as we talk about drugs, supplements and how to become a savvy consumer of them. It's fascinating stuff.
Holford, a psychologist, has spent the last 20 years researching nutrition after studying with Canadian psychiatrist Abram Hoffer, who treated schizophrenia with great success using nutritional therapy.
"I learned that the right combination of diet and supplements really can cure a wide range of serious health problems."
And that's the research he's collected at his Optimum Nutrition Centre.
Why, I ask, are people so reluctant to accept the nutritional approach to ill health?
A lot of it is ignorance. "We're fighting 50 years of brainwashing," he says. "Until the internet came along the medical profession was like a castle, with only doctors in the castle. Medical journals were read by doctors only, and the pharmaceutical industry marketed to the castle. It was not up to us, the public to question - end of story."
The myth of modern medicine started with antibiotics, which prevented thousands dying of infectious diseases. They were the magic bullet and ushered in the promise of a pill for every ill.
"But they were so good a drug - you give antibiotics and people are better in 10 days - that no one is now putting money into researching desperately needed new targeted antibiotics, for example for methicillin resistant Staphalococcus Aureus (a drug resistant infection).
"What companies want is millions of people to spend a lifetime on their drugs - that's the idea behind blockbuster drugs".
And there lies the problem. "In the mass drug market it's accepted that some people will die - that's just friendly fire."
And, according to Holford, the process of tracking side effects after the release of a drug is seriously flawed.
The first part of his book is about prescription drugs, and it's very sobering. For example, pharmaceutical companies go to great lengths to cover up the bad news about drugs; negative findings are suppressed; 10 000 people in the UK die each year from taking prescribed drugs, given in the right dose and taken correctly.
And a further 40 000 people are made ill enough to go to hospital. "And there's no outcry, no consumer group dealing with the issue, no government agency concerned about it," says Holford.
Many may remember the case of Vioxx, an anti-inflammatory drug which was withdrawn from the market in 2004 after it was shown to double the risk of heart attacks. It came as a shock to doctors and patients alike - after more than five years on the market, it was a billion-dollar blockbuster, prescribed to 80 million people.
You would have assumed, says Holford, that its safety was backed up by plenty of evidence. Not so. In fact, behind the scenes alarm bells had been ringing since 1998 about its links with heart attacks. They were deliberately ignored.
In May 2001 manufacturer Merck sent out an announcement to debunk concerns about cardiovascular effects; a month before it was withdrawn, Merck put out a press release to say Vioxx was safe.
The US Federal Drug Administration has estimated that Vioxx led to 27 000 heart attacks and cardiac deaths in the US and Merck now faces around 10 000 lawsuits.
But Vioxx is not the only drug where potentially fatal side-effects were hidden away. Co-author Jerome Burne found out how "extensive and determined a drug company's cover-up of a dangerous side effect could be" when he spoke to a psychiatrist who had been campaigning to have a possible link between the anti-depressant SSRI drugs and suicide officially recognised.
In 1990s a link was shown between suicide and SSRIs; no formal warning was issued until 2003. Today they are banned for use in children because the risk of suicide is twice as likely on the drugs. Although there's the same risk in adults, they're still in use, says Holford.
"People... should be aware of just how much of the bad news about drugs is being kept from them - and how much of the good news owes more to marketing than science," says Burne.
US drug companies spend around $15-billion a year on marketing their drugs, about half what they spend on research and development.
A large section of Holford's book is on "drugs versus food as medicine", for nine different conditions, including diabetes, depression, heart health and attention and learning problems.
Nutritional medicine is often said to be unscientific, but that's not so - and Holford is careful to use only sound scientific research.
"On a television show I said 'give me a man with high cholesterol, and give me three weeks'. A man volunteered, with a cholesterol level of 8.8. With statins, he'd reduced it to 8.7, and he's had a lot of side effects.
"I told him what to do - niacin, diet changes and omega 3 fatty acids. In three weeks it was down to 4.9."
Holford is not against the use of drugs. "Drugs have made a big difference in the treatment of Aids, multiple sclerosis and the kidney damage that can come with diabetes," he writes. "They can work brilliantly, but they are not the only way to provide medicine, and especially not as the starting point to treat or prevent the chronic diseases that increasingly affect us."
Our time runs out, and there's so much more to talk about. But Holford will be back - he's a frequent visitor to South Africa. And he's not going to stop the work he's doing: his Optimum Nutrition Bible, in hardback, is on the best-seller list - people are hungry for this information.