Your guide to the gut-immune connection

Highlights

• Gut health issues are incredibly common and are linked to imbalances in the immune system

• The gut microbiome and the immune system have a close relationship that influences our health

• Your gut immune health is a critical part of your gut health

• A few simple dietary changes may help improve your gut health and immune balance

What is “gut health”?

These days, “gut health” is a popular topic in health discussions. But what does that actually mean? While there are many ways people define “gut health,” the term really refers to the function of the gastrointestinal (GI) system which runs from our mouth to our large intestine. It also incorporates the health of our gut microbiome, the trillions of microorganisms that live along our GI tract. But here’s something most people don’t know: the health of the gut immune system plays a key role in overall gut health.

How common are gut issues?

Gut problems are incredibly common and may be on the rise. In the United States it is reported that there may be between 60 and 70 million people suffering from digestive issues. Common signs of gut health issues include bloating, nausea or issues and trouble with consistent bowel movements. These are all issues linked to imbalances in the gut immune system.

What’s the link between the gut and the immune system?

First off, it’s critical to understand that our immune system does a whole lot more than simply defend us against microbes. In fact, our immune cells and signals are major ways data from the outside world gets translated into information that can be used by the cells in our body. With this in mind, it’s no surprise that the majority (around 70%) of our immune cells reside in and around the gut.

Immune cells in the gut play a key role in our health because they have direct contact with our food, our microbiome and all the other molecules and signals floating around in the GI tract. Strong connections between health concerns and gut immune health have been shown in recent research.

How does the gut microbiome factor in?

One of the biggest transfers of data in our bodies is from the gut microbiome (a collection of trillions of tiny organisms including 300-500 different species of bacteria that live in our GI tract) to the gut immune system. The gut microbiome is an absolutely massive source of information, containing over 100 times the number of genes that humans do. Your microbiome is influencing your immune system (especially the immune cells in the gut), and your gut immune cells also influence the makeup of your gut microbiome. Issues with the diversity and the numbers of certain types of gut bacteria have been linked to a variety of immune-related issues.

How do you know your gut immunity needs help?

If you have issues with gut health, you very likely have issues with your gut-immune health. To this end, some indicators that you may have problems with your gut immunity include:

• Upset stomach
• Digestive issues
• Nausea
• Bloating
• Trouble with consistent bowel movements
• Energy issues

What can you do for your gut immunity today?

Since your gut immune system is directly tethered to your gut, one of the best ways to care for your gut immunity is through the nutrients you consume. So what are some of the top tips for foods and nutrients for gut immune wellness?

Get more polyphenols

One great reason to eat more fruits and vegetables is their polyphenols. Polyphenols are plant molecules that may impact a number of pathways in the human body. There are more than 8000 known polyphenols, and they include molecules like quercetin, rutin and curcumin. These molecules help protect plants from microbes and from other stressors, so they’re really a part of a plant’s immune system. Some research suggests that people who eat more polyphenols tend to have better immune balance, including gut-immune balance.

Some great sources of polyphenols are:

• Herbs and spices (e.g. cloves, turmeric and cinnamon)
• Teas and coffee
• Colorful fruits and vegetables
• Dark leafy greens
• Stress-resilient plants like Himalayan Tartary Buckwheat

Prioritize dietary fiber (and especially prebiotic fiber!)

Many popular diets tend to villainize carbohydrates (carbs), portraying this entire family of macronutrients as something we should always avoid. But this is a great example of “throwing out the baby with the bathwater,” since dietary fiber is actually carbohydrate that may have significant benefits to our health and especially our gut-immune health. Right now most people in the United States consume significantly less than the recommended daily fiber intake. Luckily, a number of great tasting foods that are also rich in fiber.

Some examples of fiber-rich foods include

• Berries
• Artichokes
• Peas
• Broccoli
• Lentils
• Dandelion greens
• Garlic
• Onions
• Oats
• Whole grains
• Beans
• Apples
• Himalayan Tartary Buckwheat

Wait, what about prebiotics?

When people talk about fiber, they sometimes also mention the term “prebiotic.” Prebiotics are defined as compounds in our food that are thought to promote a healthy microbiome. Most research on prebiotics focuses on certain types of dietary fiber that may be especially good for our microbiome. There are a number of different fibers in our foods that can act as prebiotics. One interesting example is beta-glucans. Beta-glucans are a type of fiber found in cereals, bacteria, fungi and some algae. 

In addition to beta-glucans, a number of other types of prebiotic fibers have been identified.

Some foods rich in prebiotic fibers include:

• Chicory root
• Jerusalem artichoke
• Leeks
• Asparagus
• Oats
• Apples
• Garlic
• Dandelion greens
• Onions
• Garlic

Consider additional probiotic sources

While “prebiotics” are substances that feed a healthy gut microbiome, “probiotics,” are healthy microbes themselves. Research over the last decades has indicated that the relative number, type and diversity of the bacteria in our gut may have a role to play in our health. These microbes appear to have an especially close connection to our gut immune system, where there is a powerful and constant two-way communication between bacteria and our immune cells.

Probiotics can be consumed in the form of foods, or in supplements that contain certain microbes (usually bacteria). Some bacteria that are at the top of the list for studied potential benefits to human health include lactobacillus and bifidobacterium, and these can often be found in probiotic foods as well as in supplements.

What foods contain probiotics?

When foods are fermented, their sugars are broken down by yeast or bacteria. When you eat fermented foods, you then consume millions or billions of live microbes!

Some examples of fermented foods to try include:

• Kefir – Kefir is a tart, tangy drink made of fermented milk. Consumption of kefir has been linked to improved gut immune balance
• Kimchi – Kimchi is a dish found in traditional Korean cooking made from fermented vegetables (usually cabbage). Kimchi goes great on top of salads and as a condiment on sandwiches and other meals. Eating kimchi has been linked to a number of markers of immune and gut-immune health.
• Sauerkraut – Sauerkraut popular fermented food across the world. Made from fermented cabbage, this food is rich in probiotics as well as vitamins and minerals.
• Tempeh – Tempeh is a popular meat-substitute made from fermented soybeans. It has a nutty taste and chewy texture and is rich in protein
• Yogurt—likely the most popular fermented food consumed in the USA, yogurt is a rich source of probiotics. Yogurt is usually made from milk, but creative food producers have started making it out of alternatives like coconut and almonds. Be on the lookout however, as yogurts often contains tons of added sugar. When possible, opt for the unsweetened options with no sugar added.

Avoid added sugar

In the modern day, the majority of our foods are ultraprocessed and contain added sugar. For example, a troubling 2016 study found that 74% of food and beverage products in the US food supply contained added sweeteners. Why does this matter? Added sugar has been linked to worse metabolic, immune and general health. As it relates to the gut-immune connection, eating or drinking excess sugars may be of particular concern. Sugar-sweetened beverage consumption has been linked to changes in the gut microbiome. It’s also thought that sugar-related changes in these gut microbes may lead to alterations in our gut immune system. To date, there’s been a bit of research looking at how different artificial and non-caloric sugars may impact the microbiome, but there are not yet well-defined answers for which of these is best for those trying to avoid sugar.

Some simple swaps to help decrease added sugar include

• Switch out sugary sodas for flavored sparkling water
• Switch out your salad dressings for versions without added sugar
• Purchase ketchup and other condiments without added sugar
• Try unsweetened teas and coffees in place of sweetened alternatives.