Let your gut determine your diet

The notion of a healthy balanced diet, suitable for all, has been challenged by a new study. The study, led by a group of Israeli scientists, stipulates that even if we all ate the same meal, each individual would metabolise it differently, meaning that diets should be personally tailored to our unique gut microbiome.

Typically, the glycaemic index is used by doctors and nutritionists to develop healthy diets based on how different foods affect glucose levels in the blood. However, the new studyreveals a significant difference in people’s glycaemic response to food.

The study initially involved a group of 800 volunteers, some of whom were healthy, and some of whom had pre-diabetes. The participants were fixed with devices that recurrently monitored their blood sugar levels, and were also equipped with an app to record their meals and movements over the course of one week.

The results revealed striking differences in each person’s blood sugar response to different foods. Dr Elan Elinav, from the Immunology Department at the Weizmann Institute of Science, explained that the researchers found that an individual’s gut bacteria was a key factor influencing whether a food delivers a long, slow rise in blood sugar, or a shot, sharp spike. What this means is that some of the food ingredients included in some people’s healthy diets are actually unhealthy for other people; meaning that diet is completely individualised.

For example, we would expect that in most people, their blood sugar would increase more after consuming ice cream, rather than rice. Elinav revealed, however, that the research actually discovered that some of the participants did exactly the opposite; ‘They were not responsive to ice cream at all, and actually, close to 70 per cent of the participants did not even spike on ice cream’.

What these findings mean, according to Elinav, is that ‘if my and your response to the same food are opposite then by definition a similar diet cannot be effective for both of us’.

Researchers also took blood samples from the participants to test individual gut bacteria, looking not only at the makeup of their gut bacteria, but also at the functional profile of the microbiome. Using the collected data, the researchers developed an algorithm to predict an individual’s glycaemic response to a food, based on factors such as their microbiome, daily activity, cholesterol levels, and food content.

When applied to the participants, the algorithm accurately predicted what each individual’s blood glucose response would be to each meal. Furthermore, when the algorithm was used on a group of people with pre-diabetes, it proved highly proficient in devising a diet that would improve these people’s blood sugar profile.

This study therefore provides a viable and effective way of assisting at-risk people to devise individual diets that suit their own unique gut microbiome.

Source: Cell