The dynamics of nutrient and lipid levels in blood after consuming a high-fat meal are important indicators of current and future cardiovascular health. Traditionally, measuring these circulating substances required invasive blood sampling, which is not suitable for routine health tracking. Researchers are investigating non-invasive methods to assess cardiovascular health that could improve monitoring of post-meal effects and help identify causative factors of cardiovascular disease. A promising approach is a non-contact optical imaging technique called “spatial frequency domain imaging” (SFDI), which quantifies tissue properties and hemodynamics.
A recent study from Boston University, Harvard Medical School, and Brigham and Women’s Hospital investigated how dietary components affect skin tissue properties shortly after eating. As reported in Biophotonics Discovery (BIOS), the team focused on peripheral tissues of the hand to understand the immediate effects of low-fat and high-fat diets.
The researchers used the SFDI to monitor 15 subjects who consumed both types of meals on separate days. The team photographed the back of each subject’s hand hourly for five hours after the meal, analysing three specific wavelengths to assess hemoglobin, water and lipid concentrations.
Results show significant differences in tissue responses. The high-fat diet led to an increase in tissue oxygen saturation, while the low-fat diet led to a decrease. This suggests that dietary fat may affect not only overall health, but also immediate physiological responses. The peak change occurred 3 hours after the meal, coinciding with a sharp rise in triglyceride levels.
In addition to taking images, the researchers tracked blood pressure and heart rate, and drew blood to measure triglyceride, cholesterol, and glucose levels, showing that changes in light absorption at specific wavelengths precisely matched changes in lipid concentrations.
Armed with these insights, the research team used SFDI data to train a machine learning model to predict triglyceride levels, achieving accuracy within 40 mg/dL, which could pave the way for non-invasive monitoring of cardiovascular health.
“This study suggests that SFDI may be a promising alternative, making it easier to monitor how diet affects cardiovascular health,” said lead author Darren Robler, a professor of biomedical engineering at Boston University.
Overall, these findings highlight the complex relationship between diet, the body’s response, and cardiovascular risk, and suggest the need for further investigation of non-invasive assessment methods.”
Darren Robler, Professor of Biomedical Engineering, Boston University
sauce:
SPIE – International Society for Optics and Photonics
Journal References:
Pilvar, A., et al. (2024) Measuring peripheral tissue oxygenation and hemoglobin concentration increases after a high-fat meal with spatial frequency domain imaging. Biophotonics Discovery. doi.org/10.1117/1.bios.1.2.025004.
