by Wei Perng, PhD
However, according to a study led by Drs. Eran Segal and Eran Elinav at the Weizmann Institute of Science called “The Personalized Nutrition Project,” whether a food is high vs. low GI depends on the person. In a recent BBC article, Dr. Saleyha Ashan provided a participant’s point-of-view of the study. During the week-long study period, Ashan received a glucose monitor implant to monitor blood sugar levels in response to standardized meals over the course of a week. She was paired with another female participant, with whom she ate exactly the same meals for 6 days. At the end of the week, Ashan discovered that her favorite healthy snacks, like grapes and sushi, elicited major blood sugar spikes while bad foods like chocolate and ice cream did not. Her study partner’s results were the exact opposite. What could explain these differences?
Along with the blood sugar assessments, participants also provided a stool sample, which was analyzed to unveil the composition of gut microbes, also known as the gut microbiome. As discussed in a previous post, our gut microbiome influences many aspects of health, including metabolism. Segal and Elinav suspect that the type of microbes in our guts holds the key to understanding why certain foods cause elevations in blood sugar for some but not others. So far, it seems that healthier people have a broader diversity of gut bacteria. What is intriguing (and relieving) is that unlike our genes, our gut microbiome is potentially modifiable. The second phase of the Personalized Nutrition Project involves formulation of a diet plan for each participant based on findings from the blood sugar monitoring phase. Ultimately, Segal and Elinav hope to be able to develop a personalized diet to stabilize blood sugar levels for anyone via a single analysis of their stool sample.
However, as discussed in a recent paper, the road to developing personalized nutrition may be bumpy. Additional research is required to understand which foods correspond to which gut microbes, whether altering specific microbes is effective to modify physiological responses to food intake, and whether these relationships differ by age, race/ethnicity, and sex. Ultimately, we must also consider whether the cost-to-benefit ratio of personalized nutrition is indeed an improvement over more general recommendations to limit consumption of unhealthy fats, sugars, and refined grains, and to increase intake of fruits, veggies, and healthy fats.