Nitrate risks and benefits leaving experts divided

Though understanding of nutrition has expanded remarkably in recent times, experts continue to be divided by some aspects of it, such as nitrate.

Nitrate has long been viewed warily, with research discovering possible links to cancer. However, subsequent research has also revealed various cardiovascular health benefits in dietary nitrate, which could help reduce the risk of related conditions such as heart disease, dementia and diabetes.

An Edith Cowan University (ECU) study within its Nutrition and Health Innovation Research Institute aims to find out how and why nitrate carries such contrasting risks and benefits.

According to lead author Catherine Bondonno, the key may lie in the source of the nitrate.

Nitrate comes from three major dietary sources: meat, water and vegetables. Nitrate sourced from vegetables has been found to prevent cardiovascular disease.

Its reputation as a health threat started in 1970, where two studies found it can form N-nitrosamines, which are highly carcinogenic in laboratory animals. There have not been any human studies confirming this danger.

“So the review looked to unpack all of that, identify new ways forward and ways that we can solve this puzzle, because it’s really time to address it: it’s been 50 years,” Bondonno said.

Despite recent research indicating the source of nitrate may affect its health benefits and risks, dietary guidelines relating to nitrate have been in place since the 1970s and don’t differentiate between the different sources of it.

The animal studies from the 1970s reported a small incidence of malignant tumours, but there was evidence not all nitrates were the same.

“For instance, unlike meat- and water-derived nitrate, nitrate-rich vegetables contain high levels of vitamin C and/or polyphenols that may inhibit formation of those harmful N-nitrosamines associated with cancer,” Bondonno said.

It is vital that more research is conducted to update guidelines.

“The public are unlikely to listen to messages to increase intake of nitrate-rich vegetables, if they are concerned about a link between nitrate intake and cancer,” she said.

While official guidelines are yet to change, people may still potentially put themselves at risk while seeking the benefits of nitrate.

“We need to be sure nitrate-rich vegetables don’t actually have an increased risk of cancer if we consume a higher amount,” Bondonno said.

According to Bondonno, high-dosage nitrate supplements are already being used to improve physical performance in sports while vegetable nitrate extracts are being added to cured meat products.

Despite division in the field, evidence suggests people should aim to get nitrate from vegetables.

“Dark green, leafy vegetables and beetroot are good sources — our research shows one cup of raw or half a cup cooked per day is enough to have the benefits on cardiovascular health.

“The potential cancer link was raised 50 years ago; now it’s time to conduct an in-depth analysis to distinguish fact from fiction,” Bondonno said.

Image credit: iStock.com/Tetiana Kolubai