Feed Your Gut: Sweet Potatoes, Rich in Polyphenols and Soluble Fibers

As a functional nutritionist, I help people uncover the missing pieces in their nutrition and lifestyle choices to address their health concerns and long-term health goals. My passion for this work grew out of my own story. My daughter and I were both struggling with our health, and I discovered that nutrition was the missing piece that restored our health.

Nutrition is inseparable from the gut microbiome, which has become one of the foundations of my work. Every bite of food interacts with the digestive tract and with the trillions of microbes that live there. I love showing clients how the diversity of their food choices can nourish this ecosystem, and in turn improve overall well-being. The key to unlocking your potential is learning to love foods that love you back. 

During my time here at Good Bacteria, I hope to be one of your guides in building a better plate, one that truly supports you. Together, we’ll lay the foundation for simple but powerful shifts that nourish your metabolism, gut microbiome, and energy. Along the way, I’ll share insights on everything from protein to soluble and insoluble fiber, the benefits of fermented foods, healthy fats, herbs, the diversity of my favorite plants, and the protective power of polyphenols — plant compounds with potent antioxidant and anti-inflammatory properties. My goal is to help you reimagine what’s on your plate and discover how food can be both sustaining and transformative.

As fall sets in, I often turn to root vegetables and the comfort of warm, nourishing soups. Sweet potatoes are one of my favorite ingredients, not only for their versatility in cooking, but also for their vibrant orange, purple, and white hues. Those rich colors are a signal that they are rich in polyphenols. They are also a great source of soluble fiber and can offer a form of resistant starch. 

Polyphenols are powerful plant compounds that help guard the body against oxidative stress, a process tied to inflammation, aging, and chronic disease. Research shows polyphenols, through their interaction with the gut microbiota, can reinforce the intestinal barrier, calm inflammation, and shape important metabolic pathways related to conditions such as obesity, diabetes, inflammatory bowel disease, and neurological disorders^(1-6). The intestinal barrier matters because it’s our gatekeeper, allowing nutrients in while keeping harmful microbes, toxins, and undigested food particles away from the rest of the body. When the barrier is supported with polyphenols, the whole body benefits.

Sweet potatoes are also an excellent source of soluble fiber, which plays an important role in digestion and metabolic health by promoting the movement of food through the digestive tract, better glycemic control, and the regulation of blood lipids^(7-8). Diets rich in fiber and whole foods improve the composition and stability of the gut microbiome, supporting long-term health. Soluble fiber dissolves in water to form a gel-like texture in the digestive tract^(9-12). This gel-like material slows the absorption of glucose, helping to stabilize blood sugar, which improves your energy throughout the day. In addition, soluble fiber can bind to excess cholesterol to carry it out of the body. It also promotes a sense of fullness, while nourishing microbes that influence both digestive and immune function. Unlike other nutrients, soluble fiber is not digested and absorbed in the small intestine; instead, it continues its journey to the large intestine (the colon), where it becomes food for the gut microbiota.

Leftover cooled sweet potatoes can be a great source of resistant starch. Most of the carbs you eat get broken down into sugar in your small intestine. Resistant starch is different; it “resists” digestion, which means it passes through your small intestine unchanged and lands in your colon. Once it gets there, it becomes food for your gut microbes⁽¹³⁾. They ferment it — kind of like how yeast ferments sugar in bread or beer. This process makes short-chain fatty acids, such as butyrate^(14-16). Butyrate is a superstar for gut health, because it fuels the cells lining your colon, strengthens the gut barrier, regulates appetite, reduces inflammation, and even communicates with your immune system and metabolism^(17-23). Great sources of resistant starch include cooked and cooled potatoes, rice, as well as green banana flour, plantains, and beans. 

This recipe doesn’t just feature sweet potatoes but also protein-rich soluble fiber–filled lentils, prebiotic-packed onions, and curry powder full of additional polyphenols. It’s simple to prepare and has been a family favorite for years. To me, it’s the perfect illustration of how food can provide comfort while also building a foundation for lasting health.

Recipe

Sweet potato curry soup

Adapted from Super Natural Every Day by Heidi Swanson 

Ingredients

• 2 tablespoons olive oil

• 3 cups peeled and diced sweet potatoes, cut into 1-inch cubes (can be swapped for butternut squash or yams)

• 3/4 teaspoon sea salt 

• 1 large yellow onion, finely chopped

• 2 teaspoons Indian curry powder

• 1 ½ cups green or black lentils, rinsed and debris removed

• 1 ½ vegetable bouillon cubes, cut into smaller pieces (Rapunzel Pure Organics No Salt Added/Low Sodium recommended)

• 6 cups water (or more, enough to cover sweet potatoes and lentils)

Instructions

1. Heat olive oil in a pot over medium-high heat.

2. Add sweet potatoes (or squash/yams) and onions along with a large pinch of sea salt. Stir and cook until onions soften and become slightly translucent.

3. Stir in curry powder until vegetables are evenly coated.

4. Add lentils and pour in the water, making sure lentils and vegetables are covered.

5. Add vegetable bouillon cubes. Stir and bring the mixture to a boil.

6. Once boiling, reduce to a simmer, cover. Cook for 20–30 minutes or until lentils are tender.

7. Taste and adjust seasoning with additional sea salt if needed.

8. Remove from heat and serve warm.

Garnish and serve.

Top with fresh herbs of your choice (cilantro is especially delicious). 

Notes: 

- For those who tolerate dairy, top each bowl with a dollop of full-fat Greek yogurt, stir it in, and enjoy the added creaminess.

- If you’d like to boost nutrient density, you can swap the water and 1 ½ vegetable bouillon cubes for 6 cups of chicken bone broth.

Citations 

1. Hao Cheng et al., “Interactions Between Gut Microbiota and Polyphenols: A Mechanistic and Metabolomic Review,” Phytomedicine 119 (2023), https://doi.org/10.1016/j.phymed.2023.154979.

2. Boris V. Nemzer et al., “Health-Improving Effects of Polyphenols on the Human Intestinal Microbiota: A Review,” International Journal of Molecular Sciences 26, no. 3 (2025), https://doi.org/10.3390/ijms26031335.

3. Sara Dobani et al., “A Review on the Effects of Flavan-3-ols, Their Metabolites, and Their Dietary Sources on Gut Barrier Integrity,” Food & Function 16, no. 3 (2025), https://doi.org/10.1039/d4fo04721d.

4. Stephanie MG Wilson et al., “Fine-Scale Dietary Polyphenol Intake Is Associated with Systemic and Gastrointestinal Inflammation in Healthy Adults,” The Journal of Nutrition 154, no. 11 (2024),  https://doi.org/10.1016/j.tjnut.2024.08.010.

5. Natalia Drabińska and Elżbieta Jarocka-Cyrta, “Crosstalk Between Resveratrol and Gut Barrier: A Review,” International Journal of Molecular Sciences 23, no. 23 (2022), https://doi.org/10.3390/ijms232315279.

6. Yueqin Li et al., “Dietary Polyphenols: Regulate the Advanced Glycation End Products-RAGE Axis and the Microbiota-Gut-Brain Axis to Prevent Neurodegenerative Diseases,” Critical Reviews in Food Science and Nutrition 63, no. 29 (2023), https://doi.org/10.1080/10408398.2022.2076064.

7. Zhiguo Zhang et al., “Effects of Steaming on Sweet Potato Soluble Dietary Fiber: Content, Structure, and Lactobacillus Proliferation In Vitro,” Foods 12, no. 8 (2023), https://doi.org/10.3390/foods12081620.

8. Shan Zhao et al., “Comparative Analysis of Nutrients, Phytochemicals, and Minerals in Colored Sweet Potato (Ipomoea batatas L.) Roots,” Foods 13, no. 22 (2024), https://doi.org/10.3390/foods13223636.

9. Kari K. Koponen et al., “Associations of Healthy Food Choices with Gut Microbiota Profiles,” The American Journal of Clinical Nutrition 114, no. 2 (2021), https://doi.org/10.1093/ajcn/nqab077.

10. Daniel So et al., “Dietary Fiber Intervention on Gut Microbiota Composition in Healthy Adults: A Systematic Review and Meta-Analysis,” The American Journal of Clinical Nutrition 107, no. 6 (2018), https://doi.org/10.1093/ajcn/nqy041.

11. Samantha K. Gill et al., “Dietary Fibre in Gastrointestinal Health and Disease,” Nature Reviews Gastroenterology & Hepatology 18, no. 2 (2021), https://doi.org/10.1038/s41575-020-00375-4.

12. Bo Cheng et al., “The Mutual Effect of Dietary Fiber and Polyphenol on Gut Microbiota: Implications for the Metabolic and Microbial Modulation and Associated Health Benefits,” Carbohydrate Polymers 358 (2025), https://doi.org/10.1016/j.carbpol.2025.123541.

13. Zhi-Wei Guan et al., “Soluble Dietary Fiber, One of the Most Important Nutrients for the Gut Microbiota,” Molecules 26, no. 22 (2021), https://doi.org/10.3390/molecules26226802.

14. Yang Cai et al., “Microbiota-Dependent and -Independent Effects of Dietary Fibre on Human Health,” British Journal of Pharmacology 177, no. 6 (2020), https://doi.org/10.1111/bph.14871.

15. Kedar N. Prasad and Stephen C. Bondy, “Dietary Fibers and Their Fermented Short-Chain Fatty Acids in Prevention of Human Diseases,” Mechanisms of Ageing and Development (2018), https://doi.org/10.1016/j.mad.2018.10.003.

16. Junying Bai et al., “Comparison of Different Soluble Dietary Fibers During the In Vitro Fermentation Process,” Journal of Agricultural and Food Chemistry 69, no. 26 (2021), https://doi.org/10.1021/acs.jafc.1c00237.

17. Khalid A. Abdelhalim, “Short-Chain Fatty Acids (SCFAs) from Gastrointestinal Disorders, Metabolism, Epigenetics, Central Nervous System to Cancer: A Mini-Review,” Chemico-Biological Interactions 388 (2024), https://doi.org/10.1016/j.cbi.2023.110851.

18. Neeraja Recharla et al., “Gut Microbial Metabolite Butyrate and Its Therapeutic Role in Inflammatory Bowel Disease: A Literature Review,” Nutrients 15, no. 10 (2023), https://doi.org/10.3390/nu15102275.

19. Daniela Parada Venegas et al., “Short Chain Fatty Acids (SCFAs)-Mediated Gut Epithelial and Immune Regulation and Its Relevance for Inflammatory Bowel Diseases,” Frontiers in Immunology 10 (2019) https://doi.org/10.3389/fimmu.2019.00277. Erratum in: Frontiers in Immunology 10 (2019), https://doi.org/10.3389/fimmu.2019.01486.

20. Elizabeth R. Mann et al., “Short-Chain Fatty Acids: Linking Diet, the Microbiome and Immunity,” Nature Reviews Immunology 24, no. 8 (2024), https://doi.org/10.1038/s41577-024-01014-8.

21. Arda Erkan Kalkan et al., “Beyond the Gut: Unveiling Butyrate’s Global Health Impact Through Gut Health and Dysbiosis-Related Conditions: A Narrative Review,” Nutrients 17, no. 8 (2025), https://doi.org/10.3390/nu17081305.

22. Kallie E. Hays et al., “The Interplay Between Gut Microbiota, Short-Chain Fatty Acids, and Implications for Host Health and Disease,” Gut Microbes 16, no. 1 (2024),  https://doi.org/10.1080/19490976.2024.2393270.

23. Vineet Singh et al., “Butyrate Producers, ‘The Sentinel of Gut’: Their Intestinal Significance With and Beyond Butyrate, and Prospective Use as Microbial Therapeutics,” Frontiers in Microbiology 13 (2023), https://doi.org/10.3389/fmicb.2022.1103836.