Prebiotics: One of the Three Important Functional “P-Foods”

Prebiotic is one of the three important functional foods that start with the letter, “P”. The three important functional foods are prebiotics, probiotics, and polyphenols.

Prebiotics Defined

Glenn Gibson and Marcel Roberfroid in 1995 introduced the prebiotic concept, and defined it as “a nondigestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number bacterial species already resident in the colon, and thus attempt to improve host health.”¹

There’re several other definitions of prebiotics following this first definition, but the common factor among them is the health benefits of prebiotics to the consumer².

For a non-digestible carbohydrate to be considered as prebiotic, it should have the following properties³:

• Resistance to gastric acidity and mammalian enzymes
• Easily fermentable by gut bacteria, and
• Ability to enhance the viability and/or activity of beneficial microorganisms

There are 10¹⁰ – 10¹² microbes in every one gram of human digestive tract (which include stomach, small, and large intestines)⁴. And these microbes depend mainly on what we feed them to survive and function. When we feed the good microbes in our guts with good foods, like prebiotics, they thrive over the pathogenic ones and ensure the optimal health of guts and entire body.

Prebiotics nourish the beneficial bacteria in the gut. These bacteria break down prebiotics into short-chain fatty acids that enter the bloodstream which positively impact both the digestive system and other organs of the body.

Types of Prebiotics

The most commonly studied and consumed types of prebiotics include:

1. Inulin and Oligofructose

• Food sources: Chicory root, garlic, onions, leeks, asparagus, bananas, wheat, and barley.

2. Fructooligosaccharides (FOS)

• Food sources: Chicory root, bananas, onions, garlic, asparagus, and some dairy products.

3. Galactooligosaccharides (GOS)

• Food sources: Human breast milk, soybeans, and some dairy products.

4. Resistant Starch

• Food sources: Green bananas, potatoes, legumes, and whole grains.

5. Other Prebiotics

• Food sources: Various fruits, vegetables, whole grains, and legumes.

Although prebiotics are mainly found in plant-based foods, a randomized clinical trial showed that omega-3 fatty acid supplement has a potential prebiotic property by altering the microbiome of participants⁵. Prebiotics are also found in breast milk.

Some Health Benefits of Prebiotics^3,6,7

Prebiotics offer a wide range of health benefits including the following:

• Improved Gut Health: They promote the growth of beneficial bacteria, enhancing digestion and nutrient absorption.
• Boosted Immune System: A healthy gut microbiome supports a strong immune system.
• Weight Management: Prebiotics may aid in weight control by influencing appetite and metabolism.
• Reduced Inflammation: They contribute to a reduction in inflammation throughout the body.
• Bone Health: Prebiotics may enhance calcium absorption and bone density.
• Cancer Risk Reduction: They can decrease genotoxic activity of nitro reductase enzyme.
• Improved Mental Health and Psychological Functions: Prebiotics together with probiotics would lead to improvement in depression, anxiety, alzheimer, and autism spectrum diseases.

Prebiotics vs. Probiotics

It’s important to distinguish between prebiotics and probiotics:

• Prebiotics: Non-digestible food components that nourish beneficial bacteria.
• Probiotics: Live microorganisms that confer health benefits when consumed in adequate amounts.

How to Incorporate Prebiotics into Your Diet

Focus on Plant-Based Foods:

• Increase your fiber intake: Aim for a diet rich in fruits, vegetables, legumes, and whole grains. These foods are natural sources of prebiotics.
• Prioritize variety: Different foods contain different types of prebiotics. A varied diet ensures a diverse gut microbiome.
• Cook smart: High heat cooking methods can reduce prebiotic content. Opt for raw, steamed, or lightly cooked vegetables whenever possible.
• Experiment with new foods: Don’t be afraid to try new fruits, vegetables, and whole grains. You might discover new prebiotic-rich favorites.

Specific Food Recommendations

• Allium family: Garlic, onions, leeks, and shallots are excellent prebiotic sources.
• Leafy greens: Kale, spinach, pumpkin leaf, water leaf, and collard greens are rich in prebiotics.
• Legumes: Lentils, chickpeas, and kidney beans are great options.
• Whole grains: Oats, barley, and brown rice are good choices.
• Fruits: Apples, bananas, and berries are also rich in prebiotics.

Tips for Success

• Gradual increase: Introduce prebiotic-rich foods gradually to allow your gut microbiome to adjust.
• Stay hydrated: Adequate water intake is essential for fiber digestion.

Summary

Prebiotics are essential for cultivating a thriving gut microbiome. By consuming prebiotic-rich foods, you can improve digestion, boost immunity, support weight management, and enhance overall well-being.

Remember: While prebiotics offer numerous benefits, individual responses may vary. It’s, therefore, essential to consult with a healthcare professional for personalized advice.

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References

1.         Gibson, Y. & Roberfroid, M. B. Dietary Modulation of the Human Colonie Microbiota: Introducing the Concept of Prebiotics. J. Nutr vol. 125 https://academic.oup.com/jn/article-abstract/125/6/1401/4730723 (1995).

2.         Hutkins, R. W. et al. Prebiotics: Why definitions matter. Current Opinion in Biotechnology vol. 37 1–7 Preprint at https://doi.org/10.1016/j.copbio.2015.09.001 (2016).

3.         Al-Sheraji, S. H. et al. Prebiotics as functional foods: A review. Journal of Functional Foods vol. 5 1542–1553 Preprint at https://doi.org/10.1016/j.jff.2013.08.009 (2013).

4.         Davani-Davari, D. et al. Prebiotics: Definition, types, sources, mechanisms, and clinical applications. Foods vol. 8 Preprint at https://doi.org/10.3390/foods8030092 (2019).

5.         Vijay, A., Astbury, S., Le Roy, C., Spector, T. D. & Valdes, A. M. The prebiotic effects of omega-3 fatty acid supplementation: A six-week randomised intervention trial. Gut Microbes 13, 1–11 (2021).

6.         Sanders, M. E., Merenstein, D. J., Reid, G., Gibson, G. R. & Rastall, R. A. Probiotics and prebiotics in intestinal health and disease: from biology to the clinic. Nature Reviews Gastroenterology and Hepatology vol. 16 605–616 Preprint at https://doi.org/10.1038/s41575-019-0173-3 (2019).

7.         Kazemi, A., Noorbala, A. A., Azam, K., Eskandari, M. H. & Djafarian, K. Effect of probiotic and prebiotic vs placebo on psychological outcomes in patients with major depressive disorder: A randomized clinical trial. Clinical Nutrition 38, 522–528 (2019).