How Does the Mediterranean Diet Affect Your Gut Microbiome?
The Mediterranean diet is based around the traditional foods eaten by Mediterranean peoples, like the Italians and Greeks, in the 1960s.
This diet places a priority on consuming mostly plant-based foods, but also emphasizes the importance of a holistic, healthy lifestyle. Including engaging in regular physical activity and placing a high priority on social-emotional care.
Compared to those following a Western-style diet, which is full of highly processed foods, those living a Mediterranean lifestyle were exponentially more healthy. Following a Mediterranean diet indicated a decrease in chronic disease development, such as type 2 diabetes and heart disease.
What is the Mediterranean Diet and How Does it Work?
The Mediterranean diet places a high priority on plant-based sources of carbohydrates, fat, and protein. Also, maintaining a relatively low intake of animal foods and byproducts.
This eating pattern places a priority on consuming ample vitamins, minerals, fiber, phytochemicals, and polyunsaturated fatty acids (PUFAs), like omega-3 and omega-6 fatty acids. These micronutrients and beneficial plant compounds are essential for best health and maintaining proper body function, but also linked to reducing risk of disease.
Plant-based foods you’ll prioritize in the Mediterranean diet include:
- Fresh fruits and vegetables
- Nuts and seeds
- Whole grains
- Plant-based fats (extra virgin olive oil, avocadoes, etc.)
- Herbs and spices
Foods you should also include in your Mediterranean diet, but in moderate amounts are:
- Fish and seafood
- Red wine
In addition, the Mediterranean diet suggests red meat to be consumed on occasion and in relatively small amounts. Limiting your intake of red meat is beneficial in reducing your consumption of saturated fat, a leading nutritional component in the development of heart disease.
The Mediterranean diet also eliminates foods that cause disease associated with chronic inflammation, high blood sugar, and weight gain common in the Western diet. Including:
- Added sugars
- Refined grains
- Trans fats
- Refined oils
- Processed meats and foods
The Mediterranean Diet and the Gut Microbiome
Changing your eating patterns according to a new diet always affects the trillions of microorganisms of your gut microbiome. The Mediterranean diet is no exception, having both positive and negative influences over your gut microbiome.
As a diet high in fresh, plant-based foods, the Mediterranean diet contains ample micronutrients, phytochemicals, and fiber. These are essential for key gut microbiome functions and promoting growth of beneficial microbes, like bacteria. Many of these vitamins and minerals also double as antioxidants, protecting the body and intestinal environment from stress that could damage the microbiome.
However, like any diet that promotes the restriction of certain foods, there are also drawbacks of a Mediterranean-style diet. Including enhanced growth of certain pathogenic yeast strains and alterations in the intestinal barrier permeability.
Benefits of the Mediterranean Diet on the Gut Microbiome
Promotes use of the saccarolytic metabolism
The gut microbiota contributes to digestion of macronutrients via two catabolic pathways, saccharolytic or proteolytic. The saccharolytic pathway uses the process of fermentation to breakdown sugars in carbohydrates to produce energy. The proteolytic pathway breaks down protein to produce energy through the process of putrefaction.
Of these two, the proteolytic pathway is known to produce metabolic products that provoke the inflammatory response in the intestines. This also increases intestinal tissue permeability and likelihood of developing leaky gut. This Western Diet is known to promote a shift towards a proteolytic profile, resulting in dysbiosis and disease development.
However, the Mediterranean diet encourages use of the saccharolytic pathway. It also favors the prevalence of saccharolytic microbial species in the gut for healthier catabolism of macronutrients.
Enhanced growth of beneficial bacteria species and metabolite production
The abundance of plant-based micronutrients and phytochemicals in the Mediterranean-style diet, it provides several benefits to the gut and microbiome. This includes an increase in beneficial bacteria colonies, like Bifidobacteria. Bifidobacteria are essential for keeping the gut fortified and immune system strong by assisting to prevent infections.
The Mediterranean diet also promotes the production and release of essential metabolites and vitamins from microbes living in the gut. These metabolites, like short- and branched-chain fatty acids, are an important energy source for cellular metabolism of cells in the colon, promoting intestinal barrier integrity and modulation of immune cell response.
Reduction in intestinal inflammation
Priority foods and health lifestyle routines, like participating in regular physical activity, suggested in the Mediterranean diet reduces inflammation in the intestines. Studies have should a reduction in key biomarkers of inflammation, C-reactive protein, within 6 weeks of following a Mediterranean-style diet
From this reduction in inflammation seen in the Mediterranean diet, there has also been a correlation between a reduction in the development of chronic disease associated with inflammation and a weak microbiome. Including Crohn's disease, ulcerative colitis (UC), and irritable bowel syndrome (IBS).
Negative Effects of the Mediterranean Diet on the Gut Microbiome
Increased gut activity and discomfort
Because the Mediterranean diet is composed of high-fiber foods as well as plant-based PUFAs, it is known to increase gastrointestinal activity. Most commonly, more frequent stools with a higher moisture content.
Increasing intake of insoluble dietary fiber, found in a majority of plant-based foods, stimulates saccharolytic fermentation in the gut as part of macronutrient breakdown. In addition, these indigestible fibers also attract water and stimulate gastrointestinal production of mucus, which is to be expelled from the body, providing a ‘bulking-effect’ to stools.
Also, the increased consumption of foods with a high content of PUFA lipids, like extra virgin olive oil, nut-based oils, and avocados, exerts a lubricant effect and stimulates bile acid excretion in the gut and colon. This enhances bowel movement frequency.
Increased growth of pathogenic microbes
The Mediterranean diet has also been shown to increase colonization of certain pathogenic microbes in the gut, including the most prolific yeast, known as Candida.
Increases in this pathogenic yeast, specifically the strain C. albicans, grow in the gut. This strain is responsible for many yeast infections throughout the body, including oral thrush, vaginal yeast infections, and infections of the gut.
This connection could be attributed to ingestion of dietary elements that are carriers of yeasts, like fruits and fermented food products.
Is the Mediterranean Diet a Good Idea for Your Gut Health?
Overall, a Mediterranean-style diet could improve your overall health without providing many drawbacks to the health of your gut and microbiome.
However, it’s important to carefully consider all positive and negative consequences of a new diet before adopting it into your lifestyle. Whenever shifting your intake patterns, it’s a good idea to be proactive in readying your microbiome for the transition.
Consider fortifying your intestinal ecosystem by adding high-quality supplements into your daily routine. Great options that fit with the plant-based priorities of the Mediterranean diet are BIOHM's Super Greens or Super Reds powders, but a staple Prebiotic or Probiotic, but could be the right choice for you, especially one like BIOHM's that balances the entire gut.
These can help to keep your microbiome rich, diversified, and the your bacteria functioning efficiently to keep your gut in the best health as you shift into a Mediterranean lifestyle.
About the Authors:
Dr Mahmoud Ghannoum, Ph.D, EMBA, FAAM, FIDSA is widely considered the leading microbiome researcher in the world. He is the scientist who named the mycobiome, and is the founder of BIOHM, the first company to engineer products and tests to address the total microbiome of both bacteria and fungi, allowing consumers to maintain total digestive health. Ghannoum is responsible for making the breakthrough discovery that bad bacteria and bad fungus work together to create digestive plaque (a discovery covered globally by outlets such as CBS News, Scientific American, Forbes and USA Today). During his career, he has published several books on fungus and over 400 peer-reviewed scientific papers. His work has been cited almost 24,000 times by other scientists, and Stanford University named him as one of the top 0.1% of most cited scientists over the last decade.
Allison Lansman, RDN, LD is a freelance writer and owner of The Freelance RD Nutrition Writing Services. She is passionate about creating exciting, research-based nutrition blog posts with her professional background as a dietitian. Allie prioritizes creating articles all readers can understand and incorporate into their daily lives.