Gut Bites MD

Christopher Damman, Associate Professor of Gastroenterology, School of Medicine, University of Washington. Editor-in-Chief of Gut Bites MD.

Your gut microbiome has grown weak with ultra-processed food. Four “F” Foods can help strengthen it again. Find tips & TOOLS below on foods to cultivate your gut microbiome & health. Bon Appétit from Gut Bites MD!

Self feeding

When we think about food, we tend to focus on the nutrients important for our health but less about the nutrients important for the health of our friends and partners in health, the microbes in our gut. Our microbes are unsung heroes that take undigested food and transform it into vital nutrients not always present in our diet alone.[1,2] 

Modern diets involving ultra-processing and low consumption of whole plant-based foods (e.g. whole grains, beans, nuts, seeds, fruits, and vegetables) have been starving our gut microbes; and in effect, starving ourselves of many nutrients that are critical for our metabolic, immune, and psychological health.[3] How could we have missed this important fact you might ask? What are the nutrients that feed our microbes? What are the nutrients they produce? Read on below!

Modern nutrition

The story of modern nutrition begins over 100 years ago when science first discovered that food can be separated into different components that each have key metabolic roles in our body:  The macronutrients including carbohydrates (sugar and starchy foods), protein (lean portions of meat and beans) and fat (fatty portions of meat and nuts). And the micronutrients including vitamins (B’s, C, A, D, E, K) and minerals (potassium, magnesium, selenium, etc.).[4] 

With the discovery of these nutrients we could label and explain nutrient deficiencies like kwashiorkor (protein deficiency), beriberi (B1/thiamine deficiency), pellagra (B3/niacin deficiency), scurvy (C deficiency), rickets (D deficiency), and so on![4] 

Armed with this knowledge, we emphasized a balanced diet that contained certain portions of carbs, fats, and proteins and fortified foods like bread and baked goods with micronutrients that we may not have received enough of otherwise in the diet. This knowledge allowed for incredible advances forward in addressing nutritional disease.[4]

Rise of ultra-processing:

But at the same time nutrition took a turn for the adverse with the advent of modern processing techniques which with good intentions was aimed at maximizing shelf stability and minimizing cost of goods.[5] They replaced some traditional processing & preserving methods of brining and fermenting that historically augmented rather than diminished the nutritional quality of foods.[6]

Over time ultra-processed foods came to replace many of our whole foods (grains, beans, nuts, seeds, fruits, and vegetables).[7] Processing removed important nutrients like fibers and polyphenols (e.g white flour and rice).[8–10]  It also concentrated simple carbohydrates/sugars (e.g. sodas, juice, corn syrup) and less healthy types of fat (e.g. omega-6’s).[11,12]  

Processed foods delivered on the macro and micronutrient profiles that science defined as important to human health, but missed the key ingredients in our microbiome’s diet.

Microbiome awakening

The last 10 years has seen an awakening to the importance that microbes are playing in our diet and linked them to many chronic health conditions  (e.g. obesity,[13] diabetes,[13] autoimmune disease,[14] depression,[15] Alzheimer’s,[16] etc.).  We are recognizing just how important the gut microbes are and how cultivating them is critical for health. 

If grown right, they produce many nutrients that are well known to us like B vitamins, amino acids, and even neurotransmitters.[1,2] They also produce other molecules that are less commonly known like secondary bile acids and short chain fatty acids (e.g. butyrate).[17,18] Indeed our gut microbiomes are little factories that produce critical nutrients, many of which are simply not present in the diet!

A microbiome diet to grow your garden

OK.  So with a little luck, perhaps I’ve intrigued you with the idea that gut microbes are important to health; but you might ask now, how do we grow them? The public health messaging of eating whole foods that are largely plant based, and embracing medically validated diets like the Mediterranean and Dash diets are all pointing in the right direction. They reintroduce the microbe-fueling nutrients that have largely been missing from our modern ultra-processed diets.[19,20] 

Yet adherence to public health’s and doctors’ good advice remains imperfect and the epidemic of metabolic, inflammatory, and neurologic disease continues to grow.[21] How do we fix this?

Just as the 19^th century saw a flurry of research in the lab that decoded the macro and micronutrients of foods, we are now seeing a similar flurry of research around the nutrients made by our microbes and that are critical for health.[22,23] Butyrate, involved in preventing leaky gut, balancing the immune system, and regulating neurons may be one of the more important molecules produced by our microbiome. (See blog on butyrate) Understanding these processes allow us to shine the light more specifically on which foods to eat in greater abundance and to redesign processed foods that reincorporate these nutrients. 

We are coming to realize that the historical focus on whether too much carbohydrate or too much fat is the source of health problems may have been off base. Instead we need to focus on a healthy balance of the right types of carbohydrates (fibers vs. simple carbohydrates) and types of fats (omega-3’s vs. omega-6’s and saturated) (See Blog on Carbohydrates vs. Fat).[24]  

The four phonetic F’s of food

The fibers and healthy fats of plant-based foods both contain nutrients that healthy gut microbes thrive on. Many plant-based foods also have high polyphenols that serve to balance the gut microbiome. Fiber, healthy fats, and phenols are the so called phonetic F’s of food; but there is one more F to add, fermentation. Just as our microbes in the lower gut can take plant-based foods and transform them into vital nutrients, so too can microbes outside our bodies transform foods into those with greater nutrition.

Getting practical

So what microbiome diet friendly foods to focus on you might ask?  Below are some specific prebiotics to consider that are common to some of the longest lived communities in the world: 

·  Fibers: steel cut oats, beans, brown rice, whole grain breads/pastas/crackers. Focus on the whole grain!

·  Phytonutrients: berries, apples, plums, purple cabbage. Eat the rainbow of fruits and vegetables!

·  Healthy Fats: fatty fish (salmon, tuna, sardines), fatty fruits and their oils (avocado and olive), tree nuts and their butters (almond, cashew, dark chocolate). Focus on omega-3’s!

· Ferments: Olives, pickles, sauerkraut, kimchi, kefir, yogurt, cheese, kombucha. Those in the refrigerated section are key!

In the end, let your healthy eating mantra be Fibers, Healthy Fats, Phytontutrients, and Ferments! Your microbes will thank you, and your body will be healthier for it! Here’s a calculator tool to help choose the highest quality 4F Foods.

More Resources:

Gutbites.org — where you’ll find more practical food & microbiome digests to improve gut and overall health.

Gut Microbiome Nutrition Calculator — to help in gut healthy food choice and meal preparation.

Christopher Damman, Associate Professor of Gastroenterology, School of Medicine, University of Washington. Editor-in-Chief of Gut Bites MD.

MD-authored gut health literature digests & first-in-class food quality calculator to power your microbiome.