Medically reviewed by Andrea C Robbins, BSN RN

For seniors, keeping a healthy gut is a priority to living a healthy, active life and feeling well. A healthy gut helps not only to digest food but fight off sickness and promote healing. Fermented foods and probiotics are types of foods that contribute to building a healthy microbiome in the colon. If you’re new to these food types, let’s take a closer look at how they support senior digestion.

Why is gut health important for seniors?

As we get older, our bodies don't digest food as well. This can cause problems like:

• Vitamins and mineral deficiency: It's harder to get the nutritional parts from food.
• Discomfort: Like bloating, gas, and constipation.
• Weaker immune systems: Most of the immune system is in the digestive track.

Probiotics and fermented foods can help with these problems by breaking down food, helping the body better absorb the nutritional elements, increasing the gut’s ability to fight disease and boost immunity, and regulating the body to avoid constipation.

What's the difference between fermented foods and probiotics?

Sometimes people use these words as if they are the same, but they're a little different in how they behave.¹

Fermentation

Fermentation is when tiny microorganisms, like bacteria, change sugar into something else, like alcohol or acid. Examples include things like wine, beer, sauerkraut, bread, yogurt, kefir, and cheese. These foods often have labels with the description "contain live active cultures." Fermented foods might have living microorganisms, but not always. Scientists are still learning about how they help us, but they can still be part of a healthy diet.

Probiotics

Probiotics are live microorganisms that, when you eat enough of them, make you healthier. Yogurt is a probiotic food because it has good bacteria in it, like Lactobacillus bulgaricus and Streptococcus thermophilus. These bacteria help us digest lactose, which is the sugar in milk. Some yogurts have a "live and active culture" seal on the package. This means that the bacteria are still alive after the fermentation process. Companies aren’t required to use the seal, so some yogurts might have enough good bacteria even if the label doesn’t reflect it.²

You might hear that probiotics help your gut microbiome by adding good microorganisms. But that's not entirely true. Probiotics don't usually stay in your gut microbiome for a long time. Instead, they create a better place for good bacteria to live, helping the beneficial bacteria grow and thrive.³

Another similar sounding word is prebiotic. Prebiotics are parts of food that your body can't digest, but they feed good microorganisms. They help the good bacteria grow in your gut and are found in foods with lots of fiber.

Foods with probiotics

Finding probiotics or prebiotics may sound like work, but they are present in many tasty foods that are easily found in most communities. Here are a few ideas to get you started:

Foods with probiotics

• Yogurt: Yogurts with "live and active cultures."
• Kefir: A milk drink like yogurt, but thinner.
• Sauerkraut: Fermented cabbage.
• Kimchi: A Korean side dish made from fermented veggies.
• Miso: A Japanese seasoning made from fermented soybeans.
• Tempeh: A fermented soybean food that's firm.
• Kombucha: A fermented tea drink.
  

Prebiotic-rich foods

These prebiotic foods feed the good bacteria in your gut and are easily found in most grocery stores.

• Dried beans and other legumes
• Garlic
• Asparagus
• Onions
• Leeks
• Certain artichokes
• Green bananas
• Wheat
  

What to look for in a probiotic

If you have spoken to your healthcare provider or primary care doctor, and they agree that it's reasonable that you try a probiotic, here are common guidelines to keep in mind as you shop:

Colony-forming units (CFUs): This is the number of bacterial cells you get in each probiotic dose. 

A well-researched strain: Look for the names Lactobacillus, Bifidobacterium, or Bacillus, which are some of the most recognizable strains.

Storage information: Be sure to refrigerate probiotics since heat can kill bacteria. Also, watch the expiration date as probiotic efficacy declines over time.

Prebiotics: These are forms of soluble fiber, like inulin, that probiotics feed off. 

Capsules: Capsules are better than other forms like powders or gummies.

Name brands: Choose a name brand that has clinical research behind it. Probiotics aren't regulated by the FDA because they are sold as supplements.

What are the best probiotic strains for older adults?

Not all probiotics are the same. Each probiotic strain has a specific job to do in the gut or for health in general. For instance, if you’re wondering what the best probiotic for senior women is, consider that different strains are designed to target certain conditions like recurrent vaginal infections. 

Here are common probiotics for seniors and the strains that may be best for your symptoms or condition.⁴

• Constipation - Lactobacillus reuteri DSM 17938
• IBS – Lactobacillus, Bifidobacterium and Streptococcus strains. While research indicates some improvement, the debate continues as to using probiotics for IBS.
• Vaginal infections - Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14.
• High cholesterol - Lactobacillus reuteri NCIMB 30242

What are the risks and benefits of probiotics for seniors?

Probiotics are usually safe for seniors, but it's smart to speak with your primary care doctor before making changes to your diet. The risks may be higher for some seniors, depending on their overall health. Some symptoms to watch for:

• Upset stomach: Some people might get gas or bloating when they start taking probiotics.
• Medication interaction: Talk to your primary care doctor if you take any medicine, because probiotics could cause problems like allergic reactions or digestive issues.
• Infections: Rarely, probiotics can cause infections in people with weak immune systems.

Benefits of probiotics for seniors

In addition to generally helping with gut health, probiotics offer other benefits for seniors and the elderly. General benefits you may see include:

• Better management of diarrhea and symptoms
• Improvement of lactose intolerance
• Reduced vaginal inflammation due to bacteria
• Helps with bad breath

Fermented foods and probiotics can help you keep your gut healthy as you get older. Eating these foods and thinking about taking probiotics can help your digestion, make your immune system stronger, and promote better health. While fermented foods and probiotics offer benefits, it’s important to visit with your doctor about any risks to your health. If you are searching for a doctor who specializes in senior healthcare, find a CenterWell senior primary care doctor near you and learn about CenterWell’s services.

Disclaimers:

Content contained on this page is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider before starting any new fitness or dietary plan. References are provided for informational purposes only and do not imply endorsement of any website or other sources. For any health-related questions, contact your healthcare provider.

Sources:

• “What’s The Difference Between Probiotic And Fermented Foods?”, Undeniably Dairy, last accessed on July 16, 2025, https://www.usdairy.com/news-articles/ask-dr-dairy-whats-the-difference-between-fermented-and-probiotic-foods#:~:text=What%20is%20a%20fermented%20food,these%20foods%20could%20impact%20health.
• “Fermenting the Facts: A Science-Based Guide to Fermented Foods,” Stanford Medicine, last accessed July 15, 2025, https://med.stanford.edu/nutrition/education/Resources/Fermenting-the-Facts.html
• “Probiotics: The Science Of What They Are And How They Work,” ISAPP, last accessed July 16 2025, https://isappscience.org/for-consumers/learn/probiotics/
• “How to Buy Probiotics That Work,” AARP, last accessed July 16, 2025
  https://www.aarp.org/health/drugs-supplements/how-to-buy-probiotics-that-work/