Personalised nutrition: the next big thing?

If you’ve ever felt the way you respond to certain meals and diets seems… inexplicable, you’re not alone. But as Dna-derived diet advice gets buzzier, how much can it actually tell you?

After ‘how do we make weightloss lollipops disappear?’, the million dollar question for most nutrition professionals is ‘why does a certain dietary intervention work for one person, but not someone else?’

The idea that biological responses to food are down to more than just their nutritional make-up isn’t new. In the wake of the launch in 1990 of the Human Genome Project – which aimed to map out all human genes – the buzzword was ‘nutrigenomics’, the study of the links between genes, nutrition and health.

The discovery that genetic variants may determine your response to different foods led to claims that personalised nutrition plans based on your genetic make-up would be the future. Fast forward to 2020 and the bubble has somewhat deflated, with studies producing underwhelming results.

Take the 2015 Food4me trial, in which 1,200 adults tested two interventions – standard healthy eating guidance or personalised advice. Individuals in the latter group were split in two again, with one half receiving guidance based on their baseline diet and phenotype (measurable traits like weight), and the other guidance based on their diet, phenotype and genotype. After six months, the participants who received personalised advice achieved greater improvements in dietary habits than the control group, but there was no evidence that including genetic-related information added any value.

More recent evidence supports the idea that the role of genetics in nutrition-related outcomes may have been overstated. For example, while specific genetic variants have been linked with an increased propensity for weight gain, that’s not the only factor that determines body weight. Your personal biology, meal timing, sleep and even gut microbes all influence your response to food.

So, in short? It’s complicated.

One initiative looking to unravel these complexities is the Personalised Responses to Dietary Composition Trial (Predict), in which scientists are researching whether individual responses to foods could be predicted using AI. The first trial saw participants eat self-selected meals and meals with precise quantities of macronutrients, while researchers measured post-meal metabolic responses (blood glucose and blood fats), body composition, exercise, sleep, hunger and the gut microbiome. Wide variations in individual responses to the same meals was an expected result; less so was that these variations existed between identical twins (who have the same DNA), demonstrating that genetics play a minor role in meal response.

Factors such as the gut microbiome and the time of day meals were eaten played a greater role.

Next came Zoe – a test kit and app teaming blood and microbiome samples with AI to predict individual responses and generate personalised nutrition advice. Zoe was piloted in a second study, with results finding further links between specific gut microbes and individual responses to food. With Predict-3 now in progress, the prospect of effective personalised nutrition is drawing closer, and the results look promising – 86% of Zoe’s pilot users report having more energy, less hunger between meals and better bowel movements.

There’s no one-size-fits-all approach to nutrition, but it’ll be a while until this tech is widespread. Until then, follow the evidence and focus on nurturing your gut microbes.