Research showing calcium and Vitamin D supplements have no benefit, and can even cause harm, has won Auckland University scientists the Prime Minister's Science Prize.
The bone health scientists took the $500,000 top prize, while fellow Auckland University scientist Alex Taylor, a cognitive biologist, has been awarded the $200,000 MacDiarmid Emerging Scientist Prize.
Distinguished professor Ian Reid and associate professors Mark Bolland and Andrew Grey, who are all at Auckland University's School of Medicine, have demonstrated calcium and Vitamin D are ineffective in treating or preventing osteoporosis, and that taking calcium increases the risk of heart attacks in older people by as much as 30 percent.
Prof Reid said many people believed calcium was good for their bones but that was a medical myth.
"We didn't set out to be myth busters," he said.
"The key trial, the Auckland Calcium Study, which triggered our scepticism in this area, I designed with a view to prove once and for all the benefits of calcium on the skeleton and elsewhere … but what we found was quite the opposite."
Following the Auckland study, Prof Bolland led a project which analysed data from several other clinical trials of calcium supplements, involving thousands of people, which confirmed the supplements had no beneficial effects. Instead, they increased the risk of heart attack and caused several other side effects.
"In every trial there's a side effect that outweighs the benefit you get. In Ian's trial, there were actually more women who had hip fractures and heart attacks than benefited from taking calcium," he said.
"There's an increased risk of kidney stones in another trail, and in another one people were admitted to hospital suffering from stomach complaints, and that was more common than preventing fractures.
"So when you go through and systematically review the evidence, the risks of calcium supplements in all trials, either individually or collectively, outweigh the benefits from them.
Supplement prescriptions plummet
The findings prompted a huge drop of calcium supplement prescriptions in New Zealand, which translated to savings of $1.5 million a year.
Prof Reid said the response from the medical professions had been varied.
"Cardiologists know that there is calcium deposited in the arteries of their patients who have heart attacks, so they are not particularly surprised," he said.
"Likewise, doctors who look after patients with kidney disease are very conscious of calcium deposition in arteries as the cause of death of many patients on dialysis.
"Within the bone community, most of us have been reared on the idea that calcium is the cause and cure of osteoporosis, and it's taken people a bit longer to come to terms with this information."
The team found similar results for Vitamin D supplements, which are also widely used to treat bone disorders.
Many studies have found associations between low Vitamin D levels and a wide range of conditions, including depression, high blood pressure and cardiovascular disease.
Some had inferred the low Vitamin D levels caused the medical conditions but Prof Reid said Vitamin D deficiency was a consequence rather than a cause, because sick people spent less time in the sun, and that was essential for the body to produce its own Vitamin D.
"Those conditions may be associated with low levels, but giving people extra Vitamin D does not prevent those particular problems."
The exception was frail or chronically ill people who stay mostly indoors.
"Modest supplementation in hospitals and rest homes remains important to prevent the severe demineralisation of bones that happens with very low Vitamin D levels," Prof Reid said.
"Perhaps the single most important public health message in terms of osteoporosis prevention is not to be too thin, particularly for women, and that applies from puberty."
Osteoporosis remained a risk for post-menopausal women and older men but the team said the role of calcium in preventing or diminishing bone loss needed to be reviewed.
Women should get a bone density test about the age of 65 and, if the results indicated an issue with bone loss or fracture risk, they should consider taking medication to prevent further bone loss. He recommended the same for men, albeit about a decade later.
Prof Reid, who has been researching bone diseases since the 1980s, has also won the Rutherford Medal and the Liley Medal.
Dr Taylor, who won the MacDiarmid Emerging Scientist Prize, said he was fascinated with one of the greatest mysteries in biology and psychology - the evolution of intelligence.
His focus was on trying to understand how humans thought differently from the rest of the animal kingdom by studying the cognitive and problem-solving abilities of birds, particularly New Caledonian crows and kea.
Birds were separated from humans by millions of years of evolution but 32-year-old Dr Taylor said that evolutionary distance provided a great way of uncovering what kind of processes had developed, and whether evolution had "carved their minds in the same way as ours to get the same thought processes".
"We are beginning to realise that birds are feathered apes, rather than being birdbrains."
Dr Taylor works with New Caledonian crows because they are known for their skill in using and making tools, something usually associated only with humans and apes.
"It's amazing to see this level of technology in a bird species. This obviously begs the question of what's going through their mind that allows them to create these behaviours."
To study just how smart the birds are, he gives them problems to solve and analyses how they tackle the task. Recently, he has also started working with young children to compare their cognitive skills and learning to those processes in the birds.
"Essentially we are going to be giving children and crows identical tasks and we're looking to see what the children do well at, what the crows do well at, do they make the same kinds of mistakes. That's going to allow us to look for similarities."
He was also working with adults and expected the results could knock us off our perceived evolutionary perch.
"Humans like to think of themselves as being the top of the tree and very smart but when it comes to a lot of problems involving causality we actually tend to do really poorly."
Chimpanzees could remember up to 16 numbers in the order they were flashed at them - giving them a much better working memory than humans, Dr Taylor said.
"If we can map out how the crows are thinking, it might give us an understanding of how we were thinking two million years ago," he said.
"You can't rerun history. We have amazing artefacts, including hand axes and bone tools but we don't have any idea of how our ancestors were thinking."
Dr Taylor said he would put his prize money towards testing the cognitive skills of one of our smartest birds, the kea.