Everything we eat – the apple, cucumber, overnight oats with chia, yoghurt and peanut butter, raw chocolate, homemade pizza and salad I had yesterday – leaves a metabolic imprint in our bodies.

The lipids from fish are different to those found in dairy, meat, fruit and so on. And the combination of these different imprints, from the different foods that make up our overall diet, creates a pattern.

But that pattern might show up a little differently in my body than yours, depending on our levels of physically activity, lifestyle, genetics, age, microbiome and health status. Perhaps, also the quality and quantities of those same foods and even our social connections and stress levels, too.

This mix of individual lipids in our blood and our individual response leaves a unique metabolic signature – like a molecular “fingerprint” – that can predict our disease risk and lifespan.

This is the finding of new Australian research, published in the journal, Nature Communications, which measured the unique “fingerprints” of 13,335 participants against their risk of cardiovascular disease and premature death 12 years later.

“What we eat isn’t just reflected in our waistline. It’s written in the chemistry of our blood,” says lead researcher Dr Habtamu Beyene, from the Baker Heart and Diabetes Institute.

Broadly, signatures reflecting Mediterranean-style diets, rich in nuts, vegetables and fibre were associated with around a 20 to 25 per cent lower risk of cardiovascular death.

Two servings of fish a week, with its distinctive lipid signature rich in omega-3 fatty acids, was also associated with lower cardiovascular risk.

The signatures of low-carb diets and those high in dairy or ultraprocessed meats, however, had a higher association with developing cardiovascular disease.

Meat and dairy contain lipids that are both beneficial and problematic. But, if someone’s diet is too heavily reliant on meat, the problematic lipids outweigh the beneficial ones.

The type of meat or dairy matters, too. For instance, the effects of dairy can vary based on factors such as probiotics, fermentation, intake amount and fat content.

The associations between a Mediterranean-style diet and good heart health and longevity are already known, as is the converse association between a low-carb, high-protein diet and poor heart health and lifespan. But, of course, given we have a unique response to the same foods, not everyone has the same risk profile.

This means that a person’s signature is better at predicting health outcomes than the current method of asking about their diet.

People also rarely recall accurately what they have eaten, making it an unreliable measure.

“The reliance on diet records for assessment really is a problem,” says Professor Leonie Heilbronn of Adelaide University. “Lipidomic signatures may therefore provide a more objective measure of diet quality.”

And herein lies the potential of mapping people’s signatures, says Professor Peter Meikle, the head of the Metabolomics laboratory at the Baker Heart and Diabetes Institute.

We know diet plays a key role in health and the development of many diseases, yet the underlying metabolic pathways remain unclear. Understanding those pathways, and the individual differences, lays the groundwork for tailored recommendations.

“If two people come in, and they’ve had the same diet, a dietitian will probably give them the same advice,” says Meikle.

By assessing how a person’s unique signature affects their risk of developing cardiovascular disease, they can personalise the dietary tweaks to reduce that risk.

“We can nudge people in the right direction, and [understand] what are the best nudges that will give them the biggest benefit.”

It is another step in the evolving field of personalised nutrition, which emerged about a decade ago, and helps to explain why some people can “get away” with certain foods, while others cannot.

While there are plans to test metabolically guided interventions in a clinical trial next year, the study’s findings reinforce the need to promote evidence-based, plant-rich dietary patterns like the Mediterranean diet and DASH, says Deakin University’s Dr Elena George.

“These tools show promise,” George says, “and, in the future, may be able to support risk stratification, dietary assessment and precision nutrition, but they don’t replace traditional dietary assessment in clinical practice – not yet, anyway.”

Eventually, Meikle says, people will be able to ask their doctors for the test that captures their unique metabolic signature.

“We are now moving into a national primary-care implementation study to establish how it can be delivered routinely and used to support clinical decisions,” he says.

“This is the first step towards making this technology available to the public. Subsequent tests could build more directly on an individual’s dietary and lifestyle-related metabolic signature, helping tailor preventive advice and monitor response to interventions.”

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