A healthy diet is the key to a healthy body, and it starts with a balanced gut microbiota. A healthy gut microbiota can help maintain efficient digestion, optimal nutrient absorption, and a strong immune system. With that in mind, here are 5 types of foods to select in order to maintain a healthy, balanced microbiota and promote good intestinal health.
Fruits and vegetables, key foods for a healthy microbiota
The health benefits of a regular consumption of fruits and vegetables are undeniable. They are also beneficial for the gut health. Fruits and vegetables are rich in polyphenols. There are hundreds of known polyphenols: a wide variety is useful for microbial diversity. They are able to interact with dietary fibers and lipids, and to modulate the activity of the gut microbiota (1). Polyphenols can influence the composition and functionality of the intestinal microbiota by modifying the balance between the different bacterial species and increasing the production of beneficial metabolites (2). Up to 95% of the polyphenols we consume undergo a journey to the colon, where they are metabolized. Several gut bacteria, including Lactobacilli and Bifidobacteria have been recognized as key players in metabolism of polyphenols (3). There are many sources of polyphenols:
- fruits (berries, apples, pears, grapes, citrus fruits),
- vegetables (spinach, artichokes, onions, Brussels sprouts, broccoli),
- whole grains,
- tea,
- red wine,
- dark chocolate and
- spices (especially turmeric, ginger and cinnamon).
Besides, a diet rich in fruits and vegetables prevent the proliferation of certain pathogenic bacteria (4). As fruits and vegetables support the growth and diversity of good intestinal bacteria, it is recommended to consume 5 servings per day, varying colors and types to get a full range of nutrients beneficial to our microbiota.
Fiber-rich foods
Fibers are defined as “edible carbohydrate polymers naturally occurring in foods such as fruits, vegetables, legumes, and cereals“(5). The bacteria of the microbiota are able to digest the fibers provided by the diet. This digestion will allow the production of beneficial compounds such as short chain fatty acids (SCFA) like butyrate, acetate and propionate. These SCFAs play a crucial role in maintaining intestinal health by providing energy to the epithelial cells of the intestinal mucosa and regulating inflammation. A good fiber intake helps maintain a good diversity of microbiota and promotes the growth of beneficial gut bacteria, including specific types such as Bifidobacteria (6).
The regular and diversified consumption of foods rich in fiber is therefore fundamental (6).
Sources that can easily be included in recipes include vegetables, legumes, nuts and seeds:
- Spinach, Brussels sprouts, broccoli, carrots, cauliflower and green beans, for example
- Raspberries, pears, apples, strawberries and bananas
- High-fiber legumes include lentils, chickpeas and kidney beans
- Whole-grain cereals and foods (pasta, bread) (6)
Fermented foods, allies for the microbiota
Fermented foods are defined as foods or beverages produced through controlled microbial growth, and the conversion of food components through enzymatic action. The microorganisms present in fermented foods can have probiotic effects and can help restore or maintain the balance of the intestinal flora by stimulating the growth of beneficial bacteria. In addition, they often contain bioactive compounds such as polyphenols and organic acids, which may have antioxidant and anti-inflammatory properties. Regular consumption of fermented foods can also contribute to the diversity of our gut flora by temporarily introducing new microorganisms to the gut (7).
Healthy fermented foods containing live bacteria include:
- yogurt, and Greek yogurt
- kefir,
- skyr,
- cheese
- sauerkraut
- kimchi
- tempeh, …
Yogurt is easy to eat: on its own, with fruit or cereals, or used as an ingredient in various cooked dishes, it can be used in a variety of ways for breakfast and snacks (7).
Probiotics
A probiotic is defined as a « live microorganism which when administered in adequate amounts confers a health benefit on the host (Lactobacillus, Bifidobacterium, Enterococcus) » (8). Probiotics contribute to the maintenance of the epithelial barrier, enhancing its strength and reducing permeability. Additionally, they have been found to modulate immune and inflammatory responses, improve digestion, and regulate appetite and body weight (8).
Foods rich in probiotics include yogurt or fermented milk. Yogurt is probably the best known and most widely consumed probiotic. It contains specific strains of lactic acid bacteria, Lactobacillus delbrueckii subsp, bulgaricus and Streptococcus thermophilus. The European Food Safety Authority (EFSA) issued an official scientific opinion (2020) that claims the consumption of live cultures in yogurt improves digestion of lactose for individuals with lactose maldigestion (9).
Regular consumption of probiotic-rich foods promotes diversity and balance in the intestinal microbiota, thereby contributing to maintaining optimal digestive function and overall health (8).
Prebiotics
Prebiotics are “substrate that is selectively used by host microorganisms, providing a health benefit” (10). They include, for example, fatty acids such as conjugated linoleic acid or omega-3, various types of polyphenols, as well as oligosaccharides such as fructo-oligosaccharides (FOS), inulin, lacto-oligosaccharides (GOS), xylo-oligosaccharides (XOS) and the oligosaccharides contained in breast milk (HMOS) (10).
Prebiotics have a strong connection with the intestinal microbiota. They serve as nourishment and stimulate the growth of beneficial bacteria in the colon, including bifidobacteria and lactobacilli, while inhibiting the growth of potentially harmful bacteria. Prebiotic foods are fermented by these beneficial bacteria, resulting in the production of short-chain fatty acids (SCFAs). (10)
They are naturally present in foods such as grains; vegetables; fruits and legumes; here are some examples of food sources:
- Grains : oats, rye and barley
- Vegetables: artichokes, asparagus, onions, leeks, tomatoes, spinach and Brussels sprouts
- Fruits: bananas, apples, pears, kiwis, nectarines, peaches and berries
- Legumes: lentils, chickpeas, kidney beans and white beans
- Nuts and seeds: almonds, hazelnuts, pistachios, flaxseeds and chia seeds (10)
5 tips to put into practice on a daily basis!
- Regular physical activity helps maintain a healthy microbiota (11)
- Avoid antibiotics unless absolutely necessary, as they can disrupt the balance of the microbiota (12)
- Avoid processed foods high in saturated fat, sugar and salt, which can damage the microbiota. Indeed, these can reduce bacterial diversity in the gut and increase the growth of potentially harmful bacteria (13)
- Limit alcohol consumption: Alcohol can damage the intestinal mucosa and disrupt the balance of the microbiota (14)
- It is recommended to drink enough water throughout the day (1.5 to 2L per day) to maintain good hydration and promote the health of our microbiota. Choose plain water rather than sugary or alcoholic drinks (15)
One watchword: diversity! Diversify your meals by eating different, complementary foods: bread and cereals, fruit and vegetables, pulses, seeds, meat, fish and/or eggs, dairy products, fats.
For more information
- How to support a healthy gut in children?(Infographic)
- The importance of a good gut health in children (infographic)
- Five great-tasting fermented foods to help your health
- Human gut microbiota: meet the bacteria
