Sweet potatoes are a nutritional powerhouse that provide many benefits to overall health. One area of health that sweet potatoes may affect is gut health. The gut is home to trillions of microorganisms, known as the gut microbiota, that play an important role in health and disease. Eating certain foods, like sweet potatoes, can influence the composition and function of the gut microbiota, which can then impact digestive health. This article will explore how sweet potatoes may influence gut health and the mechanisms behind their effects.
Sweet Potato Nutrition
Sweet potatoes are an excellent source of many nutrients, especially fiber, vitamin A, vitamin C, manganese, and potassium (1).
| Nutrient | Amount in 1 medium sweet potato |
|---|---|
| Fiber | 4 grams |
| Vitamin A | 438% DV |
| Vitamin C | 33% DV |
| Manganese | 25% DV |
| Potassium | 15% DV |
Many of these nutrients play important roles in gut health, especially fiber, vitamin A, and manganese. Fiber feeds the gut microbiota, vitamin A helps maintain the gut barrier, and manganese is involved in immune responses (2, 3).
Sweet Potato Fiber and the Gut
One of the standout nutrients in sweet potatoes is fiber. One medium sweet potato provides around 4 grams of fiber, split evenly between soluble and insoluble types (1).
Soluble fiber acts as a prebiotic in the gut, meaning it feeds beneficial gut bacteria. The main bacteria that digest soluble fiber are Bifidobacteria and Lactobacilli (4). Feeding these bacteria causes them to proliferate and produce beneficial byproducts like short-chain fatty acids.
Insoluble fiber adds bulk to stools and helps maintain regularity. It also feeds bacteria, just to a lesser extent than soluble fiber. Overall, getting a mix of soluble and insoluble fiber, as provided in sweet potatoes, helps promote a healthy and diverse gut microbiota.
Multiple studies have found sweet potatoes can increase counts of beneficial Bifidobacteria and Lactobacilli in the gut (5, 6). Higher levels of these bacteria are associated with positive impacts on gut health.
Key Points on Fiber
- Sweet potatoes contain 4 grams of fiber per serving, split between soluble and insoluble types.
- Soluble fiber acts as a prebiotic that feeds beneficial gut bacteria like Bifidobacteria.
- Insoluble fiber provides bulk to stools and also feeds some gut bacteria.
- Studies show sweet potatoes increase counts of beneficial Bifidobacteria and Lactobacilli.
Other Nutrients in Sweet Potatoes
In addition to fiber, sweet potatoes provide other nutrients involved in gut health. Specifically, vitamin A and manganese play key roles.
Vitamin A
Sweet potatoes are one of the richest sources of vitamin A. One medium sweet potato provides 438% of the daily value for vitamin A (1).
In the gut, vitamin A helps maintain the gut barrier and supports the production of mucus. Mucus acts as a protective barrier between gut microbes and intestinal cells. Vitamin A deficiency can reduce mucus production and immune function, leading to increased gut permeability (7).
Getting adequate vitamin A from sweet potatoes can help maintain gut barrier integrity and prevent leakage of microbes and toxins into the bloodstream.
Manganese
Sweet potatoes also provide 25% of the daily value for manganese in just one serving (1).
Manganese is a trace mineral that activates enzymes related to antioxidant function, carbohydrate metabolism, and immune responses. In terms of gut health, manganese helps regulate inflammation and maintains the gut barrier (8).
Studies in animals show manganese deficiency increases gut permeability, alters the gut microbiota, and increases susceptibility to colonization by pathogens (9). Getting enough manganese from foods like sweet potatoes may help avoid these negative impacts on the gut.
Key Points on Micronutrients
- Sweet potatoes are very high in vitamin A, which helps maintain the gut barrier.
- They also provide manganese, which regulates inflammation and gut permeability.
- Vitamin A and manganese deficiencies can compromise the gut barrier.
Sweet Potatoes and Prebiotics
In addition to fiber, sweet potatoes contain other compounds that act as prebiotics or feeds for beneficial gut bacteria.
Some identified prebiotics in sweet potatoes include fructooligosaccharides, inulin, and beta-carotene (10, 11). When these compounds reach the colon, they are fermented by bacteria like Bifidobacteria and Lactobacilli.
Fructooligosaccharides make up about 6-7% of the carbohydrates in sweet potatoes. Test tube studies show fructooligosaccharides selectively increase the growth of Bifidobacteria and Lactobacilli (12).
Inulin concentrations are much lower in sweet potato, less than 1% of carbohydrates. However, inulin still provides food for beneficial gut bacteria and has been shown to increase counts of Bifidobacteria (13).
Interestingly, the beta-carotene in sweet potatoes can also act as a prebiotic. Beta-carotene is converted to vitamin A in the body. One study gave participants a beta-carotene supplement for 2 weeks and found increased growth of Bifidobacteria (14).
Overall, sweet potatoes provide a variety of compounds like fiber, fructooligosaccharides, inulin, and beta-carotene that feed and enhance beneficial gut bacteria.
Key Points on Prebiotics
- In addition to fiber, sweet potatoes provide prebiotics like fructooligosaccharides, inulin, and beta-carotene.
- These prebiotics increase growth of beneficial Bifidobacteria and Lactobacilli in the colon.
- Having multiple prebiotic compounds make sweet potatoes an excellent food for enhancing the microbiota.
Effects on Digestive Health
By improving the gut microbiota and barrier function, sweet potatoes may have beneficial effects on digestive health. Here are some of the main benefits:
Improved Regularity
Sweet potatoes provide a mix of soluble and insoluble fiber that helps maintain regular bowel movements and prevent constipation. Soluble fiber soaks up water in the colon to form a gel, while insoluble fiber adds bulk and weight to stools (15).
Together, they help move material smoothly through the digestive tract. A study in 47 adults with constipation found eating 200 grams of sweet potato daily for 4 weeks significantly improved bowel movement frequency and consistency (16).
Increased Short-Chain Fatty Acid Production
As gut bacteria ferment fiber and other compounds in sweet potatoes, their main byproducts are short-chain fatty acids like butyrate, propionate, and acetate (17).
These short-chain fatty acids provide nutrition for the cells lining the colon. Butyrate, in particular, acts as the main fuel source for colon cells and helps maintain the integrity of the gut barrier (18).
By increasing the production of short-chain fatty acids, the prebiotics in sweet potatoes help nourish colon cells and improve gut health.
Less Gas and Bloating
Some people experience gas and bloating from eating too much fiber, particularly from supplements. However, getting fiber from whole food sources like sweet potatoes is less likely to cause issues.
Their fiber is bundled with other nutrients and compounds that help digestion. Furthermore, sweet potatoes are low FODMAP, meaning they contain types of fiber less likely to cause gas and bloating issues (19).
Key Points on Digestive Health
- The fiber in sweet potatoes helps improve regularity and prevent constipation.
- Sweet potatoes increase production of short-chain fatty acids that nourish colon cells.
- They are less likely to cause gas or bloating issues compared to fiber supplements.
Other Potential Benefits
In addition to digestive health, sweet potatoes may provide other benefits related to gut health and function. However, more research is needed in humans to confirm these possible effects.
Improved Immunity
By nourishing beneficial gut bacteria and enhancing the gut barrier, the nutrients in sweet potatoes may also boost immune function.
Gut bacteria play an important role in immunity. They interact with immune cells in the gut mucosa and influence inflammatory responses (20). Getting adequate fiber and antioxidants can help maintain diversity of the gut microbiota and reduce inflammation.
Lowered Disease Risk
A healthy gut microbiota is associated with a reduced risk of many diseases. Since sweet potatoes benefit the gut microbiota, they may also help decrease risk of conditions like inflammatory bowel disease, colon cancer, and metabolic disease (21).
However, direct links between sweet potato consumption and disease risk have yet to be established. More high-quality, long-term studies are needed.
Improved Blood Sugar Control
The fiber and antioxidants in sweet potatoes may also benefit blood sugar control. They slow digestion and the release of sugars into the bloodstream (22). Fiber and polyphenols in sweet potatoes may also alter gut bacteria in a way that benefits glucose metabolism (23).
Key Points on Other Benefits
- The gut-benefiting nutrients in sweet potatoes may support immunity.
- They may possibly reduce risk of certain diseases, but more research is needed.
- Sweet potatoes may aid blood sugar control, but human data is limited.
Adverse Effects
For most people, sweet potatoes are highly beneficial for gut health. However, those with certain digestive conditions may need to exercise caution.
Irritable Bowel Syndrome
Some people with irritable bowel syndrome (IBS) have difficulty digesting fructose and other FODMAP carbs. The fructooligosaccharides in sweet potatoes may exacerbate symptoms like gas, bloating, and abdominal pain in those with IBS (24).
Small Intestinal Bacterial Overgrowth
For those with SIBO, excess bacteria in the small intestine can ferment FODMAPs and cause unwanted symptoms. Sweet potatoes contain some FODMAPs, so they may need to be limited until SIBO is cleared (25).
Inflammatory Bowel Diseases
People with Crohn’s disease or ulcerative colitis may experience increased digestive symptoms from fiber-rich foods. During flares, they may need to follow a low-fiber or low-residue diet to rest the gut and improve nutrient absorption (26).
Key Points on Adverse Effects
- Those with IBS may need to limit sweet potatoes due to fructooligosaccharides.
- People with SIBO may also need to restrict sweet potatoes until overgrowth is treated.
- Individuals with IBD should monitor symptoms and adjust fiber intake as needed.
Conclusion
Sweet potatoes are one of the best foods for enhancing gut health due to their impressive nutrition profile. They provide a bounty of gut-benefiting nutrients like fiber, vitamin A, manganese, and antioxidants.
Sweet potatoes feed beneficial gut bacteria through their fiber, fructooligosaccharides, inulin, and beta-carotene content. A healthy and diverse gut microbiota improves many aspects of digestive health and may reduce disease risk.
However, those with IBS, SIBO or IBD may need to limit sweet potatoes if they exacerbate digestive symptoms. For most people, though, sweet potatoes can be a nutritious addition to the diet that enhances the gut microbiota and benefits digestive function. Including them more often is a tasty way to improve gut health.