Robert M. Kerr

Food and Agricultural Products Center

 

By Nurhan Dunford, FAPC Oil/Oilseed Specialist

 

Just recently, I was reading an article about diet and health. I learned the human gastrointestinal tract harbors more than 100 trillion bacteria. You are probably thinking there is a mistake in the previous statement –– so many bacteria in our body? I thought the same thing when I first read it. But, that is correct. More than 100 trillion bacteria reside in our body. And, that’s not all. In addition to bacteria, there are parasites, archae, fungi and viruses in the human gut. Indeed, microorganisms outnumber other cells in our body by 10:1.

 

We are exposed to microorganisms first during delivery in the birth canal and later through breast milk and environmental contacts. Microorganisms in the nasal passages, oral cavities, skin, gastrointestinal tract and urogenital are characterized as human microbiome. Each person has a unique network of microorganisms or microbiota, which consist of both beneficial and potentially harmful microbes.

 

The general perception is microbes are threats to our health. Matter of fact, most of these microorganisms are not only tolerated but also often required for regular body functions. Mounting scientific evidence indicates microbes in our gastrointestinal tract have profound impacts not only on physical health but also on mental health.

 

We peacefully co-exist with microorganisms ­­­–– even the harmful ones (pathogens that promote disease) –– when we are healthy. But, certain diets, illnesses, prolonged use of antibiotics and some medications may disrupt this balance.

 

Research on the role of microbiota on health has been going on for several decades. Changes in the gut microbiota during obesity, diabetes, liver related diseases, cancer and neurodegenerative diseases have been widely reported. Even stool frequency and consistency affect microbiota. Many recent studies have explicitly pointed to the diet as the most important confounding factor affecting microbiota over time.

 

Beneficial bacteria stimulate the immune system, breakdown potentially toxic food components, produce vitamins such as B and K and amino acids, and release enzymes that help with the digestion of complex food components such as starch and fiber. For example, fermentation of fibers by enzymes secreted by gut microorganisms produces short chain fatty acids (SCFA) that are nutrients for the body. SCFA also play important roles in muscle function and possibly the prevention of chronic diseases, including certain cancers and bowel disorders.

 

Interaction between nutrients and gut microbiota might have a major impact on many disorders.  For example, fiber consumption enhances SCFA production, lowering the pH of the colon. Low pH limits the growth of some harmful bacteria like Clostridium difficile, which can cause symptoms like diarrhea and life-threatening inflammation of the colon.

 

Indigestible carbohydrates and fibers, such as inulin, resistant starches, gums, pectins and fructooligosaccharides, enhance SCFA production. These fibers are sometimes called prebiotics because they support a beneficial microbiota. There are prebiotic fibers marketed in the form of dietary supplements, but the best way to get these fibers is by consuming raw fiber rich foods like garlic, onions, leeks, asparagus, Jerusalem artichokes, dandelion greens, bananas and seaweed. Fruits, vegetables, beans and whole grains, including wheat, oats, and barley, also are good sources of prebiotic fibers.

 

Several decades ago, the conventional wisdom was stress or spicy foods triggered stomach inflammation and ulcers, raising the risk of gastric cancer. But, discoveries in the 1980s and 90s revealed bacterium Helicobacter pylori was the real culprit –– not just food or stress.

 

In the early 1900s, Élie Metchnikoff, a Nobel Prize winning Russian scientist, hypothesized toxic bacteria in the gut caused aging and senility. He thought replacing native gut microbes with “host-friendly” microbes could promote health and longevity. These beneficial bacteria found in fermented foods like kefir, yogurt with live active cultures, pickled vegetables, tempeh, kombucha tea, kimchi, miso and sauerkraut are called probiotics. Although lactic acid bacteria comprise majority of the microorganisms in fermented foods, other microorganisms also are present in smaller numbers. Probiotic foods containing beneficial live microorganisms may alter one’s microbiome.

The dietary supplement market, which includes prebiotics and probiotics, is huge. Americans spent about $2.5 billion on supplements in 2018. It is important to keep in mind supplements are not always effective. Some people are called “resisters,” meaning the probiotics they take are expelled from the body without colonizing in the gut. Scientific studies in the field emphasize the importance of personalized approaches to a healthy lifestyle. In fact, “culinary medicine” and “Fresh Food Farmacy” are some of the new approaches and services that combine the art of food and cooking with the science of medicine. These services design food prescriptions for patients with various illnesses.

 

Culinary medicine is based on a multidisciplinary approach that brings physicians, health-care providers, chefs and registered dietitians together to develop personalized diets and hold educational classes to educate community members, including local high school children, athletes, churchgoers and workforce. The goal is to create behavior changes that will lead to a healthier lifestyle.

 

Fresh Food Farmacy is designed to address and reduce food insecurity, which is defined as the inability to afford nutritionally adequate and safe food. The likelihood of a person experiencing food insecurity to develop unhealthy behaviors that could lead to chronic conditions is quite high. To address this issue, Fresh Food Farmacy partners with local food banks to provide healthy food, such as lean meats, whole grains, reduced fat dairy products, fruits and vegetables, to food insecure patients and families. Education and behavioral changes are the main objectives of the program.

 

I’m sure you have heard of the adages, “you are what you eat” and ‘‘let food be thy medicine and medicine be thy food,” by Hippocrates, inferring the association between food and health. But, the mechanisms by which food, gastrointestinal microbiota, genetics, lifestyle, age and chronic malignancies affect disease prevention, treatment or development have been unclear. Recent advancements in science and technology have enhanced our understanding of the latter relationships. Today, nutrigenomics, which refers to the advanced study of the relationship between our genes and diet, provides the opportunity to design personalized dietary prescriptions by taking into account the individual variability in the microbiota, genes and lifestyle, and improve health outcomes.

 

References:

American Journal of Health Promotion, 2019, Vol. 33(5) 820-834

Annu. Rev. Food Sci. Technol. 2018. 9:589–608