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Best Diet to Support Gut Health

The Best Diet to Support Gut Health - And Why it Matters

Reading Time: 9 minutes 15 seconds


DATE: 2019-04-01

Gut health is something we too often take for granted. But did you know that poor digestive health can negatively impact your immune system, mood, energy levels, and even skin health?

What happens in the gastrointestinal tract is crucial for overall health and can help you be well or cause illness and discomfort.

Help your nutrition and fitness client better understand what the gut microbiome is, how they can support it with diet and lifestyle choices, and why all of this matters.

Why is Gut Health Important?

Your gut is your entire gastrointestinal tract, including the mouth, esophagus, stomach, and intestines. Essentially the gut is the passageway for food, from beginning to end. The health of this system impacts almost every other part of the body.

When your gut is in poor health, you will feel the consequences, not just in poor digestion and stomach upset. Gut health has a big impact on other aspects of health:

  • Immunity and the ability to fight infections

  • Energy levels

  • Mood

  • Allergies

  • Skin health and condition

  • Thinking and ability to focus

  • Weight

  • Chronic disease, including diabetes and heart disease, as well as autoimmune disorders

Fitness and maintaining a healthy weight are important, but clearly you can't ignore your gut if you want to maximize all aspects of health.

What is the Human Microbiome?

To really understand the importance of gut health, you need to know what the human microbiome is and how the choices you make impact it. The term microbiome refers to a community of microorganisms, largely bacteria. The human microbiome is the collection of all these microorganisms that live in and on the human body.

Scientists and researchers go further and include the genome of all these bacteria in the definition of the microbiome. A fascinating fact about the human microbiome is that it outnumbers our own human genes by a factor of 100 to one.[1] We are literally overrun by bacteria.

A group of researchers mapped the entire genome of our microbiome and found some interesting facts:[2]

  • We are all living with pathogens that cause disease, but when we're healthy they don't make us sick.

  • There are approximately ten microorganisms for every one cell in the human body.

  • The microbiome is found all over, including on skin, in the gut, and in the nose.

  • The human microbiome accounts for between two and six pounds of an individual's body weight.

  • Bacteria in the gut breaks down much of the carbohydrates, proteins, and fats we eat.

  • We don't have adequate enzymes to break down these compounds and rely on bacteria to do it.

  • When bacteria digest food in the gut, they create vitamins and other beneficial substances.

How a Diet to Support Gut Health Impacts the Microbiome

The research into the human microbiome has also found that the cast of characters is always changing. You need these bacteria in your gut to digest food, but it doesn't always have to be the same bacteria doing the work. In fact, as we age and go through certain life changes, the makeup of the microbiome also changes.

Everyone has a unique microbiome, like we have our own genome. Aging, hormonal changes, environment, and other factors cause shifts in the microbiome population. One of the biggest factors in changing the gut microbiome is diet. What you eat impacts your colony of bacteria.

For instance, researchers have found that diets rich in fat as well as sugar and other simple carbs promotes the growth of certain types of bacteria in the gut that leads to weight gain. A healthier diet encourages the growth of so-called "healthy" bacteria that help us maintain a better weight.[1]

Other Factors that Affect the Microbiome

It's not just the foods we eat that support or damage the gut microbiome, although food is a big part of it. Some of these factors are out of our control. For instance, aging and hormone changes like those that accompany puberty and menopause, influence the microbiome. Our own individual genetics also impact the bacterial makeup of the gut.

But there are other factors that we are able to manage and control that can change the microbiome in the gut. These include hygiene, stress, exercise, and sleep. Essentially, most healthy lifestyle choices support a healthy gut and a varied and "good" microbiome.

Important Signs Your Gut Health is Poor

You can't see your gut microbiome, so how do you know if it's in good shape or not? A good sign that you have good gut health, and a good mix of bacteria in your microbiome, is overall good health. If you don't get sick often, have no chronic diseases, and have plenty of energy and minimal digestive issues, chances are your microbiome is thriving.

There are, of course, signs of poor health that may point to your gut as the problem. Many of these may not seem related to the gut at all. Because the microbiome impacts so many areas of health, many seemingly unconnected issues can be traced back to the digestive tract:

  • Stubborn acne and other skin conditions, like dermatitis or psoriasis

  • Asthma and allergies

  • Fatigue and lack of energy, in spite of getting enough sleep

  • A foggy brain, struggling to think clearly or focus

  • A lot of dental cavities

  • Depression or anxiety

  • Difficulty sleeping

Of course, literal signs of poor gut health can also indicate that your microbiome could use some support: indigestion, inflammatory bowel conditions like Crohn's disease, ulcers, diarrhea or constipation, gas and bloating.

A Diet to Support Gut Health

An overall healthy lifestyle that includes getting enough sleep, managing mood and stress, and regular exercise supports a healthy gut. But, changing how you eat is one of the biggest, most important things you can do to promote gut health.

Diversify Your Diet

One of the simplest things you can do for better gut health is to eat a variety of foods. Your gut microbiome is populated by a wide variety of types of bacteria. These different species have different nutritional requirements. By eating a greater diversity of foods, you cover all the bases and promote a diverse microbiome.

Eat a Variety of Whole Foods

The typical western diet is unfortunately not very diverse, but it is also made up of too much fat, sugar, and processed foods. Diversity in your diet should begin with whole fruits and vegetables and also include nuts, seeds, legumes, and whole grains.

Not only do these foods provide a variety of nutrients for your gut bacteria, but they are also rich in fiber. Fiber is a substance that we humans cannot digest, but which is essential for some bacterial species. Vegan and vegetarian diets promote the microbiome in the gut, probably because of the abundance of fiber.

One particular type of gut bacterium important for reducing inflammation and improving gut health has been found in studies to benefit especially from almonds, pistachios, blueberries, apples, and artichokes.[3] Make these a regular part of your diet for a happy gut.

Eat More Fermented Foods

Fermented foods are those that have been prepared with microbes, usually bacteria or yeast. Yogurt, sauerkraut, kimchi, tempeh, kombucha, and kefir are examples. They include active, live bacteria. When you eat or drink these foods they add bacteria to the gut microbiome. Just watch out for sugar. Yogurt, for instance, can be very high in sugar. Choose plain varieties and add fruit for natural sugar.

Include Polyphenols

Compounds in plants known as polyphenols have important health benefits, but when we eat them we don't digest them all. Those that make it into the intestines support the growth of bacteria. Some foods and drinks that are rich in polyphenols are dark chocolate, red grapes and red wine, almonds, broccoli, blueberries, onions, and green tea.

Eat Leafy Greens

Leafy green vegetables have long been known to be nutritionally dense. But there is also evidence that these veggies support gut bacteria. They contain a substance called sugar sulfoquinovose, which the healthy bacteria in the gut use as an energy source. Furthermore, research indicates that this has the added bonus of squeezing out harmful bacteria in the gut.[4]

Supplements for Gut Health

Supplements to support your gut microbiome may be useful. Check with your doctor before you start using one. There are two main types:

  • Prebiotics. A prebiotic supplement is anything that the bacteria in your gut feeds on and ferments. They are compounds that you cannot digest. With a healthy, whole food diet, you should get adequate fiber to act as prebiotics, but there are also supplements available.

  • Probiotics. Probiotic supplements are actual live microorganisms. Yogurt, sauerkraut, and other fermented foods contain probiotics, but some people benefit from supplements with live cultures. For instance, if you went through a course of antibiotics for an infection, it may have wiped out a lot of the beneficial bacteria in the gut. Your doctor may recommend a probiotic supplement to rebuild it.

Avoid or Limit These Foods for Good Gut Health

Eating the right foods is important for supporting your gut microbiome and for good digestive health. Perhaps equally important is avoiding foods that are detrimental to gut health. If you have a client who seems to have chronic digestive issues, be sure they see a doctor. They may have a treatable condition, like colitis, or an allergy or intolerance to gluten, lactose, or certain foods.

Read more about the Whole 30 diet and how it may help your client determine foods that cause them digestive issues and other problems. Check out the ISSA blog post on this topic.

Limit Sugar and Processed Foods

Our digestive systems are really good at absorbing sugar without the help of intestinal bacteria. When you eat too much sugar you are essentially starving the microbiome. It's not just sugar, though. Refined, white carbs, like those in white bread, white rice, and pasta, are also easily digested and absorbed, bypassing the microbiome.

Stay Away from Artificial Sweeteners

While it's tempting to just replace sugar with artificial, non-nutritive sweeteners, it turns out these aren't good for your gut bacteria either. Research[5] indicates that these sweeteners can actually change the composition of the microbiome of the gut, and not in good ways. The changes promote the growth of harmful bacteria, raise blood sugar levels, and trigger glucose intolerance.

Cut Back on Alcohol

There's no reason to teetotal, but alcohol is a toxin and essentially empty calories. Limit drinking to moderate amounts for overall health and also to support gut health. Excess alcohol will impact the composition of microorganisms in the gut, causing an imbalance between good, healthy bacteria and harmful bacteria. For the best gut health, stick with an occasional glass of red wine for the polyphenols.

Other Tips to Optimize Gut Health

Good gut health is not limited to your food choices. There are other lifestyle choices and changes you can make that have a positive impact on digestion, gut health, and the microbiome:

  • Manage or limit stress, which can harm the body in so many ways. Too much stress can change your gut microbiome and actually reduce its diversity of species.

  • A great way to minimize stress is to get enough sleep. Irregular sleep patterns, poor quality sleep, and simply not enough sleep have a negative impact on gut bacteria.

  • It hardly needs to be said here, but exercise is crucial for good gut health and not getting adequate activity can reduce bacterial diversity.

  • Avoid unnecessary use of antibiotics. Of course there are times when you need antibiotics, which can be life-saving. But, we tend to overuse them. For instance, antibiotics will not cure viral infections like the flu or a cold, but they will kill off a lot of the bacteria in your gut.

  • Breastfeed your baby if possible. If you or your client is a new mother, breastfeeding is an important way to provide an infant with a healthy gut microbiome. A mother's milk nourishes gut bacteria.

A diet to support gut health doesn't have to be difficult. As long as you eat a variety of whole foods, with plenty of plant-based choices, and you limit processed, sugary, junk food, good gut health is simple.

Learn more in-depth information about nutrition and how food choices impact overall health. Check out the ISSA's comprehensive course on Nutrition Coaching.

Best Diet for Healthy Gut Handout

Click HERE to download this handout and share with your clients!


[1]University of Utah. (n.d.) Genetic Science Learning Center. Retrieved from https://learn.genetics.utah.edu/content/microbiome/

[2]National Institutes of Health. (2012, June 13). NIH Human Microbiome Project Defines Normal Bacterial Makeup of the Body. Retrieved from https://www.nih.gov/news-events/news-releases/nih-human-microbiome-project-defines-normal-bacterial-makeup-body

[3]Shinohara, K., Ohashi, Y., Kawasumi, K., Terada, A., and Fujisawa, T. (2010). Effect of Apple Intake on Fecal Microbiota and Metabolites in Humans. Anaerobe,16(5), 510-5. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/20304079

[4]Speciale, G., Jin, Y., Davies, G.J., Williams, S.J., and Goddard-Borger, E.D. (2016). YihQ is a sulfoquinovosidase that cleaves sulfoquinovosyl diacylglyceride sulfolipids. Nature Chemical Biology,12, 215-17. Retrieved from https://www.nature.com/articles/nchembio.2023

[5]Suez, J., Korem, T., Zeevi, D., Silberman-Schapira, G., Thaiss, C.A., Maza, O., Israeli, D., Zmora, N., Gilad, S., Weinberger, A., Kuperman, Y., Harmelin, A., Kolodkin-Gal, I., Shapiro, H., Halpern, Z., Segal, E., and Elinav, E. (2014). Artificial Sweeteners Induce Glucose Intolerance by Altering the Gut Microbia. Nature,514, 181-6. Retrieved from https://www.nature.com/articles/nature13793

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