Healthy heart or risk of cancer? Meet Nutrition’s Jekyll and Hyde

For a long time, nitrate was viewed with suspicion, with previous research showing it could potentially be linked to the cause of cancer.

However, subsequent research found that dietary nitrate also has various cardiovascular health benefits, which may help reduce the risk of related diseases such as heart disease, dementia, and diabetes.

So how can a dietary compound have such contrasting potential risks and benefits?

The Edith Cowan University Nutrition and Health Innovation Research Institute (ECU) hopes to uncover how and why nitrate has such contrasting potential risks and benefits.

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Dr Catherine Bondonno conducted a review of research on nitrates and said the key may lie in their origin.

“We get nitrate from three main food sources: meat, water and vegetables,” she said.

“Nitrate’s reputation as a health threat dates back to 1970, when two studies showed it could form N-nitrosamines, which are highly carcinogenic in laboratory animals.

“However, no human studies have confirmed its potential dangers, and our clinical and observational studies support that nitrate prevents cardiovascular disease if it comes from vegetables.

“So the review sought to unpack all of that, identify new paths forward and ways to solve this puzzle, because it really is time to tackle it: it’s been 50 years.”

Emergency required

Despite recent research indicating that the source of nitrate can affect its health benefits and risks, current nitrate dietary guidelines have been in place since the 1970s and do not differentiate between nitrate in meat, vegetables and water.

Dr Bondonno said that while animal studies from the 1970s reported a low incidence of malignancies, there was evidence that not all nitrates deserved to be “tarred with the same brush”.

“For example, unlike meat and water-derived nitrates, nitrate-rich vegetables contain high levels of vitamin C and/or polyphenols that can inhibit the formation of these harmful substances. NOT-nitrosamines associated with cancer,” she said.

Dr Bondonno said it was vital that more research was carried out so that the guidelines could be updated.

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

However, she pointed out that while official guidelines had not changed, the apparent benefits of nitrate had seen many people potentially put themselves at risk.

“We need to make sure that nitrate-rich vegetables don’t actually have an increased risk of cancer if we eat more of them,” she said.

“High-dose nitrate supplements are already used to improve physical performance in sports, while vegetable nitrate extracts are added to deli meats with a ‘clean label’ claim, supposedly better for you.

“So we really need to get it right.”

What do we eat then?

Given his divided experts in the field, Dr Bondonno said it’s understandable that people might be confused about whether nitrate is good or bad for them.

“They’re probably thinking, ‘If I can’t have salad, what CAN I have?'” she said.

Despite the debate, she said current evidence suggests people should aim to get their nitrate from vegetables – but there was no need to go overboard.

“Dark green leafy vegetables and beetroot are good sources, our research shows that one cup raw or half a cup cooked a day is enough to have beneficial effects on cardiovascular health,” she said. .

“We know that processed meat is not good for us and we should limit our consumption, but if it’s the nitrate in it that’s causing the problem or something else, we don’t know.

“It only further underscores the need to investigate dietary nitrates to get the message across to people.

“The potential link to cancer was hinted at 50 years ago, now is the time for a thorough analysis to separate fact from fiction.”