A doctor says a Government proposal to inject folic acid into
all bread sold in New Zealand is safe, despite claims it could see
several hundred additional cases of cancer occur in the population
Proponents say folic acid helps to prevent growth conditions in new-borns, such as spina bifida.
In 2008, the Government shelved a proposal to make fortification mandatory after a public outcry from the Bakers Association and the Food and Grocery Council, saying the science was a "mass medication experiment".
Now, the Government is considering a plan to force bakers to fortify their bread products with folic acid after calls from doctors and parents of children with spina bifida.
Folic acid researcher, Oxford Emeritus Professor of Pharmacology David Smith told TVNZ's Q+A programme that his study estimates that there will be a reduction of five babies born with neural tube defects each year if the proposal goes through.
However, he says the benefit is "relatively small" and the potential for harm is far greater.
"You're affecting the health of the whole population if you add something to food it's got to be a very serious decision to be taken. You can't just do it lightly."
He said it is difficult to quantify it precisely, but he believed that several hundred additional cases of cancer may occur in the population every year as a result.
"Folate is required to protect cells against cancers, but once there is cancerous or pre-cancerous cells in the body giving folate actually stimulates their growth.
"We estimate that 10% of New Zealanders will be of increased risk of cancer if folate is added to flour."
Paediatrics specialist doctor Andrew Marshall told Q+A that Smith claims are "completely false".
Marshall said there is no increased risk of cancer and said there has actually been decreased incidents of cancer throughout the United States since the mandatory fortification of folic acid in bread.
He said about 40% of fertile New Zealand women are low in folate.
"There's no way we can get our folic acid levels up high enough in the population to prevent this without introducing it to a common food source."
Smith said the amount you can gain if it is voluntary is about half what you can gain if it is mandatory.
"The United States research is really robust, and what they've shown in the United States is with mandatory, the average amount of increase in the US population since mandatory is 132 micrograms of folate.
"And that increase - three to four slices a day - takes the whole population up to the point where you've got the floor level, the minimum amount of neural tube defects possible."
Marshall also disagreed with Smith's estimation that there would be five less cases per year of spina bifida if it is introduced.
"The Ministry of Primary Industries has done a very robust calculation - the numbers are about 24 neural tube defects pregnancies that are likely to be prevented with mandatory," he said.
He said Smith is very selective in the studies he chooses.
"He talks about a meta-analysis of 38,000, there is a different meta-analysis using a similar population of 35,000 which is much stronger and it shows no relationship with cancer."
Smith also said that folic acid is a natural vitamin.
"I think Dr Smith is somewhat disingenuous saying that there's a difference between folic acid and folate.
"Yes, folic acid is the chemical that you take, and it's converted in your body into folate, so it is a vitamin."
The New Zealand public has just over a week to put in submissions on whether to make fortification mandatory.
The Ministry of Primary Industries has asked for feedback on the issue. Submissions close on July 16.
Smith said he thinks it should happen.
"I think the Ministry of Primary Industries report is very clear to the Government about the benefits and is very clear about the absence of risk. So it's up to the politicians to decide.
"But the Paediatric Society of New Zealand very strongly supports mandatory fortification to help all members of the population not just unborn babies but also people dying of stroke.
"Everybody needs folate."
The Food and Grocery Council said they stood by previous statements, saying most countries that do implement folic acid programmes are third world or developing countries.
"New Zealand has little in common with the likes of Guadeloupe, Senegal, Togo and Guatemala."