You don’t have to be a committed vegan to experience the benefits of plant-based diets on your health.
Epidemiology Assistant Professor Hyunju Kim has been studying how eating plant-based foods, from fruits and vegetables to nuts and coffee, can improve our health by preventing kidney and cardiovascular diseases. These findings are important because eliminating animal products from their diets can be a big barrier for many people, Kim said. But by encouraging less consumption of animal-based foods and more consumption of healthy plant-based foods, people can still experience the potential benefits.
Kim has been passionate about nutrition and health research since she was an undergraduate public health major, where she participated in a research project that delivered nutrition interventions to takeaway restaurant owners in low-income neighborhoods in Baltimore, Maryland. Through this first-hand experience, Kim observed that the high prevalence of cardiometabolic conditions in these communities may be due to dietary behaviors.
“I developed a strong passion for research, and for identifying healthy dietary factors for prevention and treatment of these clinical conditions,” Kim said.
In honor of National Nutrition Month this March, Kim, who works in the Department of Epidemiology at the University of Washington School of Public Health, shares more about her research studying the impacts of plant-based foods on our health.
How did you first become interested in your research?
I am originally from South Korea where many people follow some form of plant-based diets such as vegetarian, vegan, or flexitarian diets (flexitarian referring to people who practice vegetarian and vegan diets with some regularity). Much of the existing evidence on plant-based diets is based on results from subsets of the population, such as Seventh Day Adventists, health-conscious vegans, or monks. These populations have other health and lifestyle factors that differ from the general population, thus the research findings may not be generalizable to the general population. I was interested in expanding on research on health outcomes related to plant-based diets in community-dwelling U.S. populations, which is why I decided to focus on plant-based diets and cardiometabolic outcomes on middle-aged U.S. adults for my dissertation.
Why is it important to understand how plant-based diets can prevent kidney disease?
Kidney disease is prevalent nationally and globally, and the impacts on people are devastating. More than 10% of adults in the U.S. have chronic kidney disease, and there is no cure. Treatment for kidney disease is about delaying its progression, of which the end result can be kidney failure. People with kidney failure need transplantation or dialysis, which impacts their quality of life. Pharmacological treatments exist, but I think there are opportunities to incorporate dietary modifications because changes in diet have the potential to both prevent and help manage kidney disease.
What does your research help reveal about the impact of diet on disease that we didn’t know before?
A major challenge in studying plant-based diets is that the prevalence of plant-based diets is low in the U.S. To address this challenge, I used several sets of pre-defined plant-based diet scores which allows us to rank participants by their relative intake of plant foods and animal products, and distinguish the intake of healthy plant foods and unhealthy plant foods.
From my research, I found that the quality of plant foods is important for the prevention of cardiometabolic outcomes. Following a diet that is relatively higher in healthy plant foods (such as fruits, vegetables, whole grains, nuts, legumes, tea and coffee) and lower in animal products was associated with a lower risk of kidney disease, hypertension, and deaths from cardiovascular disease. However, following a diet that is relatively higher in unhealthy plant foods (which we defined as refined grains, potatoes, sugar-sweetened beverages, sweets and desserts) and lower in animal products were associated with a higher risk of these outcomes
Another important, related finding was on the role of plant-based diets for the prevention of kidney disease and the prevention of people who have kidney disease progressing to end-stage kidney disease or mortality. In individuals with chronic kidney disease, it has been thought that consuming diets high in potassium or phosphorus may be detrimental, and so people may have been more likely to avoid plant foods that have high potassium or phosphorus content. But in our research in those with and without kidney disease, following a plant-based diet was associated with favorable health outcomes, and blood potassium levels didn’t differ amongst those who followed a plant-based diet, suggesting that plant-based diets may be a safe and healthy choice in those with kidney disease.
Why is your research important to public health?
People often think of plant-based diets as a binary: either you completely exclude animal products (e.g., vegan diets) or you are someone who eats a lot of animal products. But in our research, diets that are relatively higher in plant foods and relatively lower in animal products were associated with better cardiometabolic outcomes. This result suggests that lower intake of animal products can be helpful, and doesn’t require people to completely give animal products up. These findings have public health implications, because reduction, rather than exclusion, of animal products is easier for people to adopt in their lives.
What impacts has your research had that you are most excited about, or what impacts do you hope it will have?
I am very excited to build evidence on the impact of healthy diets, like plant-based diets, for the prevention and management of cardiometabolic conditions, specifically kidney disease. I hope to conduct rigorous research which can eventually inform the dietary guidelines for individuals with kidney disease.
What have been some of the most interesting or surprising findings from your research?
Plant-based diets are associated with a lower risk of kidney disease in healthy individuals, but why this is the case is not well understood. I use techniques that study hundreds to thousands of compounds and proteins in biofluids (like blood and urine) to investigate what it is about plant-based diets that promote health. Using these approaches, I found compounds and proteins that were modified by plant-based diets. I plan to continue pursuing this line of research to identify pathways modifiable by plant-based diets, which could provide a basis for formulating prevention and treatment of kidney disease.
What research questions are you most interested in pursuing next?
I plan to integrate information from several biological layers, like genes, epigenetic events, metabolites and proteins, to improve our understanding of why plant-based diets are associated with a lower risk of cardiometabolic conditions. I also would like to seek partnerships with community organizations to better understand opportunities and challenges to adopting plant-based diets, especially households with limited access to fresh fruits and vegetables.