You Probably Don’t Need a Probiotic—Our RDs Recommend These Supplements Instead

Omega 3s, collagen, vitamin D, and multivitamins all may help support gut health

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Recommended Supplements


We commonly hear how important it is to take probiotic supplements for gut health. But where does this recommendation come from, and is it valid or just another fleeting health fad? As dietitians who love myth-busting, we decided to figure out what the latest science actually says about gut health—and probiotic supplements. 

Having many different types of healthy gut bacteria—also called a diverse microbiome—can, among other things, support digestion and help strengthen our immune systems. Probiotics are the supplement form of these bacteria, so the logic behind taking them makes sense. But there are countless strains of probiotics, making it hard to know which ones to take and in what quantities.

The more experts we talked to and the more research articles we read, the more we began to understand that there is no clear probiotic supplement type and dose that has been shown to promote gut health in healthy people.

At the same time, other nutrients can help encourage the growth of a variety of healthy bacteria in the gut. Fiber provides food for the good bacteria we naturally have and helps them flourish. Eating fermented foods (or foods that naturally contain live probiotics) may plant a variety of new good bacteria in the gut and provide other health benefits. And certain supplements—such as omega 3s, collagen, and vitamin D—may both nourish and support our good bacteria and keep our digestive tracts healthy, especially if you’re not getting enough of these nutrients from food.

Keep in mind that gut health is impacted by a number of things like diet, exercise, stress, and sleep. It’s also important to note that underlying health conditions and medications can have a big impact, and research is ongoing for how supplements can affect gut health. It’s worth remembering that while taking omega 3s, collagen, vitamin D, or a multivitamin that contains a variety of nutrients may be beneficial for some, they are not a silver bullet solution.

Always speak with a healthcare professional before adding a supplement to your routine to ensure that the supplement is appropriate for your individual needs and which dosage to take.

Omega 3s Provide Heart-Healthy Fats and May Support a Healthy Gut  

Nature Made Omega 3 Fish Oil 1200 mg


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Omega 3 fatty acids are heart-healthy fats primarily found in fish and nuts. We need to get these fats from food and supplements, and one of the main benefits omega 3s provide is helping to lower inflammation in the body. 

Research suggests omega 3s may also play a role in gut health by helping to change gut bacteria (also called gut microbiome or gut flora) in a positive way. In other words, omega 3s can help encourage the growth of a variety of good bacteria. The anti-inflammatory effects of omega 3s can also help the gut by keeping the lining of the digestive tract healthy (also known as improved gut permeability).

You can get omega 3s from eating two servings of fatty fish per week—think salmon, mackerel, sardines, herring, black cod, and bluefin tuna. If you don’t eat these fish regularly, you may want to talk to a healthcare provider about adding an omega 3 supplement.

Our omega 3 recommendation is Nature Made Omega 3 Fish Oil. It is third-party tested for ingredient amounts and contaminants from USP—one of our trusted third-party testing organizations. Nature Made purifies their fish oil to make sure harmful contaminants found in fish like PCBs, dioxins, and furans are at safe levels.

The recommended serving size is just one softgel a day which provides 1,200 milligrams of fish oil and 720 milligrams of omega-3s, including 360 milligrams of EPA and 300 milligrams of DHA (the types that have been most researched for health benefits). They are free of gluten, dairy, and have no added colors or flavors, but are not vegan-friendly. For a vegan-friendly alternative, try Deva vegan omega-3.

Collagen Powder Provides Protein and May Support Skin, Joint, and Gut Health

Vital Proteins Collagen Peptides


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Collagen is the most abundant protein in the body and is mainly found in the joints, bones, tendons, ligaments, and skin. It is possible to get collagen from foods, but research has shown some collagen supplements may have benefits for skin and joint health. Some research also suggests collagen may also have a beneficial role in gut health, although more research is needed. If you’re looking for a collagen supplement, we recommend Vital Proteins Collagen Peptides—an added bonus is that it's also a good source of protein.

Collagen contains all essential amino acids and is particularly high in hydroxyproline, glycine, and proline. This could be important for gut health, as hydroxyproline has been shown to help lower inflammation in many areas of the body including the gut.

Another reason collagen supplements can be considered gut-friendly is most supplements already have the collagen proteins broken down to smaller amino acids (peptides). This means there is less work needed for the digestive system to break down and absorb collagen nutrients. 

A 2022 study found a collagen supplement of 20 grams per day for eight weeks helped reduce bloating and improve mild digestive symptoms in healthy females. While larger and longer studies are needed, collagen is generally considered safe, and this study suggests collagen may help with mild digestive discomfort for some healthy people.

We love that Vital Proteins Collagen Peptides is made from grass-fed, pasture-raised cows. It is third-party tested for ingredient amounts and banned substances, as it is NSF-Certified for Sport. A serving provides 20 grams of collagen, and it is free of sweeteners, flavors, gluten, and dairy. It can easily be added many ways including oatmeal, smoothies, cold, or hot beverages.

Note that if you have underlying gastrointestinal (GI) problems, it’s best to talk to a healthcare professional before taking a supplement to make sure it would best suit your needs. GI expert Suzie Finkel, MS, RD, CDN notes a collagen supplement is likely safe for most people but may not play a role in GI disease treatment.

Vitamin D is Essential for Overall Health and May Play a Crucial Role in Protecting Your Gut

Thorne Vitamin D 1,000


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Vitamin D is an important vitamin important for bone health, muscle strength, and immune system function. Similar to omega 3s, some research has shown vitamin D can also positively affect gut bacteria and lower gut inflammation. Studies have also shown vitamin D can play a role in supporting the health of the intestinal wall and promoting gut-related immunity.

Vitamin D can be found in foods like fatty fish and dairy products, and your body can also make it from sunlight. But there’s a good chance that you’re not getting enough vitamin D from the sun or from your diet. Thorne Vitamin D-1,000 provides 1,000 International Units (IUs) of vitamin D in an easy-to-take capsule from a brand we trust.

Experts note more research is needed including dosing recommendations for vitamin D and gut health. In fact, some people may have a genetic predisposition to have a stronger gut health response to a vitamin D supplement.

Before taking a vitamin D supplement, it is important to get your blood levels checked. A healthcare professional can then guide what is the best dosage for you depending on your needs. If you are deficient in vitamin D, taking a supplement to get blood levels within normal range will likely provide the most health benefit compared to if your blood levels are already at a healthy range.

If a healthcare professional recommends a vitamin D supplement, we suggest Thorne Vitamin D 1,000. One capsule provides 1,000 IU (International Units) or 125% of your daily needs, and it comes in the more absorbable form as vitamin D3. We like that Thorne has extensive in-house testing for ingredient quality, purity, and they collaborate with organizations like the National Institutes of Health (NIH) for clinical research of their supplement ingredients. 

If a higher dose of vitamin D is recommended, Thorne also has a 5,000 IU vitamin D supplement. This higher dose is NSF certified for sport which means additional testing has been done to ensure the supplement contains what it says it contains with no potentially harmful contaminants, including ingredients banned for athletes. This dose may be more appropriate for someone needing to correct a deficiency under the guidance of a healthcare professional.

Multivitamins Provide a Variety of Vitamins and Minerals to Fill Nutrient Gaps

Nature Made Multivitamin Tablets


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All vitamins and minerals have numerous important functions in the body, and how they impact gut health is a growing field of research. Studies have shown the minerals selenium, zinc, and iron can play an important role in promoting a diverse and healthy gut microbiome.

It’s important to know these minerals can be found in foods such as nuts, seeds, legumes, seafood, and meat. A healthcare professional or a registered dietitian can help determine if supplementing these nutrients would be beneficial or if your diet is adequate in these (and other) nutrients.   

If a multivitamin is appropriate for you, we suggest Nature Made Multivitamin Tablets. This multivitamin is budget-friendly, third-party tested for ingredient amounts and contaminants from USP, and the single tablet serving is smaller and easier to take than other options.

While it does not contain omega 3s or collagen, this multivitamin can replace the need for a vitamin D supplement for most people, as it contains 1,000 IU of vitamin D3. It provides 100% of your daily needs for iron, 136% of your daily needs of zinc, and 127% of your daily needs for selenium. This multi also provides around 100% or more of your daily needs for most other vitamins and minerals aside from calcium or magnesium. 

Note that if you take other vitamin or mineral supplements, there is a potential to get too much zinc, selenium, and iron. A healthcare professional can check all supplement labels to ensure your levels are safe for these nutrients.

Are Probiotics Ever Beneficial?

Something important to know about probiotics is there are thousands of different types (or strains). Therefore, the research that has shown a benefit of one specific type of probiotic cannot be applied to another type of probiotic—or even a combination of probiotic strains.

Research has identified health benefits from specific probiotic strains for a few conditions such as pouchitis or antibiotic associated diarrhea. More research is needed before making probiotic recommendations for other conditions or for the general population.

Foods for Gut Health

Gut health supplements are just one small piece of overall gut health. Diet is one of the strongest influences for overall gut health, as foods can promote a variety of healthy gut bacteria.

Fiber from plant foods such as fruits, vegetables, whole grains, and legumes aid with digestion, act as fuel for probiotics, and play a crucial role in overall health.

Fermented foods are natural sources of a variety of probiotics and play a role in supporting gut health. More research is needed to determine if they are functional foods, or foods that promote added health benefits beyond meeting basic nutrition needs.

If you are trying to get more fermented foods in your diet, here are some dietitian-approved suggestions.

Madge’s Food Company Kimchi: Kimchi is a traditional Korean favorite condiment that is made from fermented vegetables. Madge’s Food Company’s kimchi is fermented in small batches to ensure a quality product, and it does not add any extra sugar or animal-based ingredients. Kimchi can be added to most savory dishes such as eggs, stews, or fried rice.

Lifeway Plain Kefir: Kefir is a fermented dairy product that is a good source of probiotics, protein, calcium, and vitamin D. Kefir can be easily added to smoothies or used as a base to make your own dressing. Plain kefir doesn’t have added sugar or artificial sweeteners, and blending it with fruit and a touch of honey can add sweetness.

Health-Ade Kombucha: Kombucha is a fermented tea drink that can be a source of probiotics, although the amount and type can vary. Like other sweetened beverages, it is a source of added sugar, but kombucha is lower in sugar than most other sweetened drinks like soda or juice.

Note that kombucha can have trace amounts of alcohol from the fermentation process. Therefore, if you are completely avoiding alcohol, or are pregnant, breast feeding, or on medications, you should consult a healthcare professional before drinking.

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