For centuries, the importance of incorporating plant foods into our diets has been well recognized, dating back to as early as 300 BC. The wisdom of ancient civilizations has been validated by modern science, which continues to reveal the many health benefits of plant-based diets. While dietary fiber, found abundantly in plant foods, has long been heralded for its positive impact on health, new research published in Nutrients suggests that the protective properties of plant-based diets extend beyond just fiber. Specifically, researchers found that each plant source of insoluble fiber contains unique bioactives—compounds such as antioxidants and certain vitamins that have been linked to lower incidence of cardiovascular disease, cancer and type 2 diabetes—offering potential health benefits beyond those of the fiber itself. 

“People understand the need for fiber and how it relates to gut health—an area of wellness that is becoming increasingly important as scientific research continues to reveal its impact on overall health and well-being,” explains Joanne Slavin, coauthor of the paper and a professor in the College of Food, Agricultural and Natural Resource Sciences at the University of Minnesota. “Fiber is the marker of health that is included in our dietary guidelines and found on product labels, but our research indicates that we need to ensure the other valuable components of fiber-containing plant sources—the bioactives—are also recognized as providing valuable benefits for human health.” 

The study aggregated the available literature on the health benefits of bioactives in plant sources of insoluble dietary fiber. Here are a few of their findings:

• A variety of plant foods, including fruits, vegetables, legumes, nuts, seeds and whole grains contain insoluble dietary fiber, and each source contains unique bioactives that support health in different ways.
• Desirable bioactives like quercetin, resveratrol, catechins, anthocyanins, lutein, lycopene and beta-carotene were found in a variety of plant foods that also contain insoluble dietary fiber.
• Plant sources with bioactives and insoluble dietary fiber could be used to fortify processed foods to increase their nutritional value. Food production byproducts such as peel, hulls, pulp or pomace are generally high in fiber and bioactives and offer unique nutritional value from sustainable sources.
• Consumer research found that utilizing this fortification at a low level did not decrease consumer acceptability of the food product. 

While dietary fiber has been a dietary hero for its role in promoting digestive health and regulating blood sugar levels, this research suggests that plant-based foods offer more than just fiber. The protective properties of plant-based diets are likely attributed to a complex interplay of various dietary components, including vitamins, minerals and phytochemicals. These bioactive compounds have been shown to offer a wide range of health benefits, from reducing the risk of chronic diseases to supporting overall well-being.

This most recent research on the impact of bioactives on human health further illuminates the need to champion broad awareness and education of bioactives in food and health systems.

“The collection of literature we reviewed and the results of this research can serve as a paradigm shift in how the food and health industries, as well as consumers, view insoluble dietary fiber and bioactives,” explains lead author Madeline Timm, who coauthored the research for her graduate project at the University of Minnesota. “Continued research and broad inclusion of bioactives in foods and supplements can have a real impact on human health.”

What the Research Means to Health and Exercise Professionals

Plant-based diets have stood the test of time as a cornerstone of human nutrition, and modern research continues to unveil their incredible health benefits. While dietary fiber remains a crucial component, this new research reminds us that plant-based foods offer much more than meets the eye. Bioactive compounds contribute to the protective properties of these diets, making them a powerful ally in our quest for good health.

“The suggestion to eat more fruits and vegetables isn’t a novel idea, but it’s something most people still struggle to do,” explains Jan-Willem Van Klinken, coauthor of the study and senior vice president of medical, scientific and regulatory affairs for Brightseed.

To help a client shift to a healthy plant-based diet that contains more bioactive compounds, consider the following recommendations from Dominque Adair, MS, RD, a private-practice nutrition and fitness advisor, and member of ACE’s Scientific Advisory Panel:

• Don’t overprocess your food. Whole, minimally processed foods tend to have the most nutrition and confer the greatest health benefits. For example, choose a piece of fruit rather than fruit juice or a potato rather than a bag of potato chips. Additionally, less-processed plant foods tend to have less sodium and more potassium, a ratio that is extremely important to the maintenance of healthy blood pressure.
• Pattern matters. Ask clients to focus on the entire dietary pattern rather than individual foods. For example, a client who starts eating a few pieces of fresh fruit a day, but also eats a lot of fast food, highly processed foods or restaurant-prepared foods more than a few meals a week, may not benefit as much as someone who shifts their dietary pattern to include many more plants as well as fewer processed foods and foods prepared outside of the home. 
• Have a plan. Whole-food, plant-based diets require some advanced planning to make sure intake is adequate and to avoid nutrient deficiencies. There are loads of nutrients in plants, but if the selection is too narrow, or it does not include grains and legumes (or some animal products), it may be too low in protein and some vitamins and minerals. Working with a registered dietitian for a session or two to determine nutrient needs and whether the diet is adequate might be a good investment. 
• Avoid the boredom trap. As is the case with any dietary program, if it is too restrictive over time, it may become less appealing. People who abandon an overly restrictive pattern may replace it with lots of unhealthy foods that were previously “forbidden.” Over time, the net effect could be a less-healthy diet.

As a health and exercise professional, you are in a great position to educate your clients about the benefits and the potential considerations of adopting a plant-based diet. Helping them to incorporate a variety of fruits, vegetables, whole grains and legumes into their diets not only ensures an ample intake of dietary fiber but also provides a rich source of bioactive compounds that can enhance their well-being and protect against chronic diseases.