Introduction
Plant-based diets have become popular worldwide due to health and environmental benefits. Vegetarianism is most prevalent, with an estimated one-fifth of the Asian population and 1.5 billion followers globally. Many people in American households have started plant-based diets, including meat and dairy products, especially after the COVID-19 pandemic. Several studies have been conducted that have identified the association between plant-based diets and the reduced risk of developing obesity, gastrointestinal, cardiovascular diseases, or other health issues. Gut microbiota plays an important role in transforming dietary nutrients into bioactive metabolites and helps maintain gastrointestinal homeostasis.
What Are Plant-Derived Nutrients?
Plant-based diets predominantly include vegetables, fruits, legumes, grains, nuts, and seeds, and nutrients derived from these sources contribute to the overall health of the individual. It does not include processed foods and animal products and mainly emphasizes natural and wholesome foods. According to the United States Department of Agriculture (USDA), American Institute for Cancer Research (AICR), and American Heart Association (AHA), half a plate of a meal must consist of fruits and vegetables, which provides an adequate intake of fiber, and nutrients such as vitamins and minerals like iron, potassium, folate, magnesium.
What Is the Relationship Between Gut Microbiome and Diseases?
Gut microbiota refers to the microorganisms present in the digestive tract of humans and animals. Colonization of microbes in the human gut (gut microbiome) begins at birth; the gut bacteria produce vitamins, synthesize different amino acids, and also carry out the biotransformation of bile. In a healthy state, the gut microbiome has positive functions such as protecting the host from pathologic conditions, energy production from non-digestible food components, and immune system modulation.
However, in a dysbiotic state (imbalance), the gut microbiome is considered to be a causative element to conditions such as Crohn’s disease, type 2 diabetes, irritable bowel syndrome (IBS), several types of cancer, obesity, and mental health conditions such as anxiety and depression. Studies have demonstrated that this imbalance or an alteration in the composition of the intestinal microflora can lead to the systemic manifestations of various diseases.
How Do Plant-Derived Nutrients Affect the Gut Microbiome?
According to research, plant-based diets are known to be beneficial for human health as they promote the growth of stable and diverse microbial systems in the body. Plant-based diets are known to support sustainable weight management by reducing high-risk conditions such as obesity, hyperlipidemia (high cholesterol), hyperglycemia (increased glucose levels), hypertension, ischemic heart disease, etc. Plant-derived nutrients can influence the gut microbiome in several ways, which include;
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Dietary Fiber: Plants such as onions, artichokes, leeks, chicory, wheat, and bananas contain indigestible fibers that favor the growth and development of healthy bacteria, which in turn improves gut health.
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Phytonutrients: Various phytonutrients such as carotenoids and flavonoids present in plants such as carrots, oranges, peaches, beans, peas, and green leafy vegetables, which have antioxidant and anti-inflammatory properties that modulate the gut microbiome and indirectly support the health of the digestive system.
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Prebiotic Fibers: Plant-based foods are rich in non-digestible compounds or prebiotic fibers such as inulin, pectin, and oligofructose, which are present in onions, garlic, artichokes, fruits, etc, that serve as food for beneficial gut microbes. Therefore, they promote the growth of helpful bacteria such as Lactobacilli and Bifidobacteria, further improving gut health.
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Immune System: Plant-derived nutrients can contribute to a well-regulated and balanced immune response due to the growth of beneficial microbes, thus playing a vital role in regulating the immune system.
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Polyphenols: Plant-derived foods contain compounds such as polyphenols, which positively influence the gut microbiome by reducing the growth of harmful microbes and increasing the growth of beneficial bacteria, thus improving gut health.
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Short-Chain Fatty Acids (SCFAs): When plant fibers get fermented by gut bacteria, they produce short-chain fatty acids such as butyrate, acetate, and propionate. These nutrients are essential to decrease inflammation and maintain the integrity of the gut lining, thus improving the overall health of the digestive system.
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Anti-microbial Properties: Plants such as ginger, garlic, cinnamon, basil, and other herbs have antimicrobial properties that help to prevent the growth of pathogenic microbes (harmful bacteria), thus reducing the potential for infections in the digestive system.
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Weight Management: Plant-based foods are rich in fiber, which causes a feeling of fullness after the meal and also supports a balanced metabolism. This, in turn, improves gut health and helps in weight management.
What Are Some Potential Drawbacks of Plant-Derived Nutrients on Gut Microbiome?
Although plant-derived nutrients have numerous benefits for the gut microbiome, some potential drawbacks must also be considered, which include:
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Digestive Problems: As plant-based diets have high fiber content, they may cause gastric issues such as bloating, indigestion, abdominal pain, and discomfort in some individuals. Hence, it is necessary to gradually increase the fiber content in the diet to allow the gut to adapt.
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Nutritional Deficiencies: Plant-based diets can lead to a deficiency of nutrients like calcium, vitamin B12, omega-3 fatty acids, etc. Moreover, plant-based foods often lack essential amino acids and fats. Therefore, it may be necessary to consult a doctor or a certified dietician to plan a diet consisting of all the vital nutrients.
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Gluten-Allergy: Some people may be allergic to gluten (a protein found in some grains like wheat, barley, rye, etc), which can cause stomach cramps, nausea, vomiting, diarrhea, or abdominal discomfort.
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Specific Variations: It may be challenging for sports persons or athletes who have high-energy requirements or for people living in certain extreme environments to adapt to a plant-based diet, which can cause acidity, gastric problems, fatigue, headache, and weakness.
Conclusion
Nutrition is the main determinant in the composition of the gut microbiome. It is always necessary to consume a balanced diet as it provides a broad spectrum of nutrients to support gut health. Recent studies indicate that switching to plant-based diets can result in the growth of healthy bacteria in the gut. However, more research is required due to their complexity and individual variations. Therefore, a healthcare professional or a certified nutritionist must be consulted, which helps to overcome the drawbacks and also creates a personalized and safe diet plan.
