A Brief History: Discovering B Vitamins

The story of B vitamins is a fascinating journey through the annals of nutritional science. Let's take a trip down memory lane:

  • 1897: Dutch physician Christiaan Eijkman discovers that a substance in rice bran can prevent beriberi, laying the groundwork for the discovery of vitamin B1 (thiamine).

  • 1911: Polish biochemist Casimir Funk coins the term "vitamine" (later changed to vitamin) and isolates what we now know as vitamin B3 (niacin).

  • 1920s: Vitamin B2 (riboflavin) is discovered, followed by vitamin B5 (pantothenic acid) in 1931.

  • 1934: Vitamin B6 (pyridoxine) is isolated, adding another member to the B vitamin family.

  • 1940s: Folic acid (vitamin B9) is identified and synthesized, leading to groundbreaking treatments for anemia.

  • 1948: Vitamin B12 (cobalamin) is isolated, solving the mystery of pernicious anemia.

  • 1950s: The structure of vitamin B7 (biotin) is determined, completing the B vitamin complex as we know it today.

This journey of discovery has revolutionized our understanding of nutrition and health, paving the way for treatments of various deficiency diseases and highlighting the crucial role of B vitamins in human health.

1. Introduction: The B Vitamin Brigade

Welcome back, nutrition enthusiasts! We're continuing our journey through the alphabet of essential nutrients, and today we're diving deep into the fascinating world of B vitamins. If you've been following our series, you might remember our explorations of Vitamin D, Vitamin K2, and the mighty mineral zinc. Now, it's time to shine a spotlight on the B vitamin complex and its crucial role in digestive health and immunity.

Imagine a team of skilled workers, each with their unique talents, working tirelessly to keep your body's factory running smoothly. That's the B vitamin complex for you! These water-soluble vitamins play essential roles in energy production, DNA synthesis, and the proper functioning of your nervous system. But their benefits don't stop there - B vitamins are also key players in maintaining a healthy digestive system and supporting your immune function.

From B1 (thiamine) to B12 (cobalamin), each member of this vitamin family has its own special role to play. Together, they form a powerhouse team that's essential for your overall health and well-being. So, grab a handful of B-rich nuts, and let's embark on a journey to uncover how these unsung heroes support your digestive health and boost your immune system!

2. B Vitamins 101: Meet the Team

Before we dive into the specific roles of B vitamins in digestive health and immunity, let's get acquainted with our vitamin team. The B vitamin complex consists of eight distinct vitamins, each with its own unique functions:

  1. B1 (Thiamine): The Energy Converter

    • Helps convert food into energy
    • Supports nervous system function
    • Crucial for carbohydrate metabolism

  2. B2 (Riboflavin): The Antioxidant Ally

    • Aids in energy production
    • Acts as an antioxidant
    • Supports cellular growth and function

  3. B3 (Niacin): The Cholesterol Manager

    • Helps manage cholesterol levels
    • Supports skin health
    • Crucial for DNA repair and cellular signaling

  4. B5 (Pantothenic Acid): The Stress Buster

    • Helps produce stress-related hormones
    • Aids in the metabolism of proteins, carbohydrates, and fats
    • Supports the synthesis of coenzyme A

  5. B6 (Pyridoxine): The Mood Regulator

    • Aids in the production of neurotransmitters
    • Supports immune function
    • Involved in amino acid metabolism

  6. B7 (Biotin): The Beauty Vitamin

    • Promotes healthy hair, skin, and nails
    • Aids in metabolism
    • Supports blood sugar regulation

  7. B9 (Folate): The DNA Builder

    • Crucial for DNA synthesis and repair
    • Essential for proper cell division
    • Vital for red blood cell formation

  8. B12 (Cobalamin): The Blood Builder

    • Necessary for red blood cell formation
    • Supports nervous system function
    • Crucial for DNA synthesis

These vitamins work together synergistically, often complementing and enhancing each other's functions. Understanding their individual roles sets the stage for appreciating how they contribute to digestive health and immune function.

3. B Vitamins and Digestive Health: Fueling Your Gut

Now that we've met our B vitamin team, let's explore how these nutrients support your digestive system. As we've discussed in our exploration of the gut microbiome, a healthy digestive system is crucial for overall wellness. B vitamins play a significant role in maintaining this delicate ecosystem:

  1. Energy Production B vitamins, particularly B1, B2, B3, and B5, are crucial for converting the food you eat into energy. This process, known as cellular respiration, occurs in the mitochondria of your cells. Here's how it works:

    • B1 (Thiamine) is a cofactor for enzymes involved in carbohydrate metabolism, particularly in the conversion of pyruvate to acetyl-CoA, a key step in energy production.
    • B2 (Riboflavin) is a precursor to FAD and FMN, crucial coenzymes in the electron transport chain.
    • B3 (Niacin) is a precursor to NAD+ and NADP+, essential for numerous redox reactions in energy metabolism.
    • B5 (Pantothenic Acid) is a key component of coenzyme A, central to the citric acid cycle.

    This energy production is essential for the proper functioning of your digestive system, powering the muscular contractions that move food through your digestive tract and fueling the cells that produce digestive enzymes.

  2. Gut Lining Integrity B vitamins, especially B3 and B5, play a role in maintaining the health of your gut lining. They support the production and repair of the cells that make up this crucial barrier.

    • B3 (Niacin) is involved in the synthesis of proteins and fatty acids, essential for maintaining the structure of gut epithelial cells.
    • B5 (Pantothenic Acid) supports the production of coenzyme A, which is necessary for the synthesis of cholesterol, a component of cell membranes.

    This function is particularly important when we consider the concept of "leaky gut," which we explored in our article on the gut-brain axis. A healthy gut lining is crucial for preventing unwanted substances from entering the bloodstream.

  3. Enzyme Production B vitamins are involved in the production of digestive enzymes. For example:

    • B6 (Pyridoxine) is necessary for the production of hydrochloric acid in your stomach. It acts as a coenzyme for decarboxylase enzymes involved in this process.
    • B12 (Cobalamin) is required for the proper function of intrinsic factor, a protein essential for B12 absorption in the small intestine.

    These enzymes are crucial for breaking down the food you eat into smaller, more manageable pieces that your body can absorb and use.

  4. Nutrient Absorption B12 and folate are particularly important for nutrient absorption:

    • B12 is crucial for the absorption of folic acid and iron. It's also necessary for the metabolism of fatty acids and amino acids.
    • Folate (B9) works alongside B12 in DNA synthesis and red blood cell formation. It's also important for the absorption of iron and other nutrients.

    These vitamins ensure that nutrients from your food are efficiently absorbed and utilized by your body.

  5. Gut Microbiome Support Emerging research suggests that B vitamins may play a role in supporting a healthy gut microbiome. A study published in the journal "Gut Microbes" found that B vitamins, particularly B6 and B12, may influence the composition and function of the gut microbiome, potentially impacting digestive health and overall well-being[1].

    • B6 and B12 may serve as growth factors for beneficial gut bacteria.
    • Folate is produced by some gut bacteria and may contribute to the symbiotic relationship between our gut microbiome and our health.

By supporting these various aspects of digestive function, B vitamins play a crucial role in maintaining a healthy gut. And as we've explored in our post on the gut-brain axis, a healthy gut is essential for overall well-being, including mental health.

4. B Vitamins and Immunity: Your Immune System's Best Ally

B vitamins don't just support your digestive system - they're also key players in maintaining a robust immune system. If you've read our comprehensive guide on understanding the complex world of the immune system, you know that our immune system is a complex network of cells, tissues, and organs working together to defend our body against invaders.

B vitamins support this intricate defense system in several ways:

  1. Enhancing Innate Immunity: B vitamins, particularly B6, can boost the function of innate immune cells like neutrophils and macrophages[2]. These cells are like the first responders of your immune system, quickly identifying and eliminating threats.

    • B6 (Pyridoxine) is crucial for the development and maintenance of lymphoid organs, where immune cells are produced and mature.
    • It's also involved in the production of cytokines and antibodies, key components of the immune response.

  2. Modulating Adaptive Immunity: B vitamins, especially B9 (folate) and B12, can influence the activity of T cells and B cells, key players in our adaptive immune response[3]. This is the part of our immune system that remembers past invaders and mounts a quicker, more effective response if they return.

    • Folate is essential for DNA synthesis and repair, crucial processes for the rapid proliferation of immune cells during an immune response.
    • B12 supports the maturation of lymphocytes and is necessary for normal immune function.

  3. Supporting Antibody Production: B vitamins are crucial for the production of antibodies. These are like the wanted posters of your immune system, helping to identify and neutralize specific threats[4].

    • B5 (Pantothenic Acid) is necessary for the synthesis of coenzyme A, which is involved in antibody production.
    • B6 is required for the metabolism of amino acids used in antibody synthesis.

  4. Regulating Inflammation: B vitamins, particularly B6, help regulate inflammatory responses. This is crucial for preventing chronic inflammation, which can actually weaken our immune response over time[5].

    • B6 is involved in the production of anti-inflammatory compounds and can help modulate the inflammatory response.
    • Niacin (B3) has been shown to have anti-inflammatory properties, potentially through its role in NAD+ metabolism.

  5. Promoting Cell-Mediated Immunity: B vitamins support the proliferation and activation of immune cells, enhancing your body's ability to fight off infections[6].

    • B12 is necessary for the proper development and function of T lymphocytes.
    • Folate deficiency has been associated with decreased cell-mediated immunity.

A review published in the "Journal of Immunology Research" highlighted the diverse effects of B vitamins on immune cell function, emphasizing their potential in managing inflammatory and autoimmune diseases[7].

By supporting these various aspects of immune function, B vitamins play a crucial role in maintaining a strong and responsive immune system. And as we discussed in our overview of the immune system, a well-functioning immune system is essential for overall health and disease prevention.

5. Spotlight on Niacin: The Multifaceted B3

Among the B vitamins, niacin (B3) deserves special attention due to its unique properties and diverse roles in the body. Niacin exists in two main forms: nicotinic acid and nicotinamide, both of which are precursors to the coenzymes NAD+ (Nicotinamide Adenine Dinucleotide) and NADP+ (Nicotinamide Adenine Dinucleotide Phosphate).

Forms of Niacin

  1. Nicotinic Acid (Flush Niacin):

    • This form causes the characteristic "niacin flush," a temporary reddening and warming of the skin.
    • It's particularly effective at improving lipid profiles by reducing LDL cholesterol and triglycerides while increasing HDL cholesterol.

  2. Nicotinamide (Non-Flush Niacin):

    • This form doesn't cause flushing but also doesn't have the same lipid-lowering effects as nicotinic acid.
    • It's often used in supplements due to its better tolerability.

  3. Inositol Hexanicotinate:

    • This is a "no-flush" form of niacin, though its effectiveness is still being studied.

Niacin as NAD+ Precursor

One of the most crucial roles of niacin is as a precursor to NAD+, a coenzyme involved in numerous cellular processes:

  1. Energy Production: NAD+ is essential for cellular energy production, playing a key role in glycolysis, the citric acid cycle, and the electron transport chain.

  2. DNA Repair: NAD+ is used by enzymes involved in DNA repair, helping to maintain genomic stability.

  3. Cellular Signaling: NAD+ is involved in various signaling pathways, including those related to stress responses and circadian rhythms.

  4. Aging and Longevity: NAD+ levels decline with age, and boosting NAD+ has been associated with potential anti-aging effects in animal studies.

Niacin and Gut Health

Niacin plays several important roles in digestive health:

  1. Intestinal Barrier Function: Niacin helps maintain the integrity of the intestinal barrier, crucial for preventing "leaky gut" syndrome.

  2. Gut Microbiome: Some gut bacteria can produce niacin, contributing to our overall niacin status. Conversely, niacin may influence the composition of the gut microbiome.

  3. Inflammatory Bowel Diseases: Research suggests that niacin might have therapeutic potential in conditions like ulcerative colitis, possibly due to its anti-inflammatory properties.

Niacin and Immune Function

Niacin also contributes to immune health in several ways:

  1. NAD+ and Immune Function: NAD+ is crucial for the function of immune cells, particularly in their response to oxidative stress and DNA damage.

  2. Anti-Inflammatory Effects: Niacin has been shown to have anti-inflammatory properties, which can help modulate the immune response.

  3. Potential Role in COVID-19: Some research has explored the potential of niacin in supporting immune function against COVID-19, though more studies are needed to confirm its efficacy.

Understanding the diverse roles of niacin highlights its importance not just as a vitamin, but as a crucial component of numerous cellular processes. As with all nutrients, balance is key - while niacin is essential for health, excessive intake can have adverse effects. Always consult with a healthcare provider before starting any new supplement regimen.

6. Food Sources and Supplements: Getting Your B Vitamins

Ensuring adequate intake of B vitamins is crucial for maintaining optimal digestive health and immune function. Let's explore the various food sources of B vitamins and discuss supplementation options.

Food Sources

  1. Animal Sources:

    • Meat (especially organ meats)
    • Fish (particularly salmon, trout, and tuna)
    • Eggs
    • Dairy products

  2. Plant-Based Sources:

    • Whole grains (brown rice, quinoa, oats)
    • Legumes (lentils, beans, chickpeas)
    • Nuts and seeds (almonds, sunflower seeds)
    • Leafy green vegetables (spinach, kale)
    • Nutritional yeast

  3. Fortified Foods:

    • Many breakfast cereals
    • Plant-based milk alternatives
    • Some bread products

It's worth noting that B12 is primarily found in animal products, making it a nutrient of concern for those following strict vegan diets. If you're following a plant-based diet, you might want to pay special attention to your B12 intake, similar to how we discussed the importance of omega-3 fatty acids for vegetarians and vegans.

B Vitamin Supplements

While it's best to obtain B vitamins from food sources, supplements can be beneficial for those at risk of deficiency or with increased needs. B vitamins are often sold as a complex, containing all eight B vitamins, but individual B vitamins are also available as supplements.

Common forms of B vitamin supplements include:

  1. B-Complex: Contains all eight B vitamins in one supplement.
  2. Individual B Vitamins: Available for targeted supplementation of specific B vitamins.
  3. Multivitamins: Often contain a full spectrum of B vitamins along with other essential nutrients.

When considering supplements, it's crucial to consult with a healthcare provider to determine the appropriate dosage and form for your individual needs. They can help you navigate the supplement landscape, much like how we discussed the importance of professional guidance when considering Vitamin D supplementation.

Potential Risks of Supplementation:

  • High doses of certain B vitamins (particularly B3 and B6) can cause side effects.
  • Some B vitamins can interact with medications.
  • Excessive intake of some B vitamins can mask deficiencies in others.

Remember, more is not always better when it comes to B vitamin supplementation. Aim to meet your needs through a balanced diet first, and only consider supplements under professional guidance.

7. Signs of Deficiency: Are You Getting Enough?

Recognizing the signs of B vitamin deficiency is crucial for maintaining optimal health. Here are some common symptoms associated with deficiencies in various B vitamins:

  • Fatigue and weakness
  • Anemia
  • Digestive issues (e.g., nausea, constipation)
  • Skin problems (e.g., rashes, cracks around the mouth)
  • Confusion or memory problems
  • Numbness or tingling in extremities
  • Mood changes (e.g., irritability, depression)

It's important to note that these symptoms can be associated with various health conditions, not just B vitamin deficiencies. Always consult with a healthcare professional for proper diagnosis.

Risk Factors for B Vitamin Deficiency:

  • Strict vegan or vegetarian diet (particularly for B12)
  • Chronic alcohol use
  • Certain medications (e.g., proton pump inhibitors, metformin)
  • Pregnancy and breastfeeding
  • Older age
  • Certain medical conditions (e.g., Crohn's disease, celiac disease)

It's important to note that B12 deficiency can also be caused by H. pylori infection. As we discussed in our article on managing H. pylori naturally, this common gut bacteria can interfere with B12 absorption, potentially leading to deficiency even in those consuming adequate B12 in their diet[8].

Specific Deficiency Signs for Each B Vitamin:

  1. B1 (Thiamine) Deficiency:

    • Beriberi (affects cardiovascular, nervous, and gastrointestinal systems)
    • Wernicke-Korsakoff syndrome (in severe cases, often associated with alcoholism)

  2. B2 (Riboflavin) Deficiency:

    • Sore throat
    • Swelling of mucous membranes
    • Skin disorders

  3. B3 (Niacin) Deficiency:

    • Pellagra (characterized by diarrhea, dermatitis, and dementia)
    • Bright red tongue

  4. B5 (Pantothenic Acid) Deficiency:

    • Rare, but can cause fatigue, insomnia, and gastrointestinal distress

  5. B6 (Pyridoxine) Deficiency:

    • Anemia
    • Depression
    • Weakened immune function

  6. B7 (Biotin) Deficiency:

    • Hair loss
    • Brittle nails
    • Skin rashes

  7. B9 (Folate) Deficiency:

    • Megaloblastic anemia
    • Increased risk of birth defects (if deficient during pregnancy)

  8. B12 (Cobalamin) Deficiency:

    • Megaloblastic anemia
    • Neurological symptoms (tingling in extremities, balance problems)
    • Cognitive decline

Remember, while it's important to be aware of potential deficiency signs, a balanced diet typically provides sufficient B vitamins for most people. Always consult with a healthcare provider if you suspect you may be deficient in B vitamins. They can perform appropriate tests and provide personalized advice, much like how we emphasized the importance of professional guidance in our article on understanding the immune system.

8. The Future of B Vitamin Research: What's Next?

As our understanding of B vitamins continues to evolve, researchers are exploring new frontiers. Here's a glimpse into some exciting areas of ongoing and future B vitamin research:

  1. B Vitamins and Cognitive Health: Studies are investigating the potential role of B vitamins, particularly B6, B9, and B12, in preventing cognitive decline and supporting brain health. A 2019 study published in the journal "Nutrients" found that higher B vitamin intake was associated with better cognitive function in older adults[9].

  2. B Vitamins and the Microbiome: Researchers are exploring how B vitamins interact with and influence the gut microbiome, potentially impacting both digestive and overall health. This research builds on our understanding of the gut microbiome as a complex ecosystem, adding another layer to the intricate relationship between nutrition and gut health.

  3. B Vitamins and Chronic Disease Prevention: Ongoing research is examining the potential of B vitamins in preventing chronic diseases like cardiovascular disease and certain types of cancer. For example, a 2021 meta-analysis published in the "Journal of the American Heart Association" found that B vitamin supplementation might reduce the risk of stroke in certain populations[10].

  4. Personalized B Vitamin Recommendations: Future research may lead to more personalized B vitamin intake recommendations based on individual genetic profiles and lifestyle factors. This approach aligns with the growing trend towards personalized nutrition, which we touched on in our discussion of Vitamin D supplementation.

  5. Novel Delivery Methods: Scientists are exploring new ways to improve B vitamin absorption and utilization in the body, potentially leading to more effective supplements. This could include technologies like nanoencapsulation or targeted delivery systems.

  6. B Vitamins and Gut-Brain Axis: Building on our understanding of the gut-brain connection, researchers are investigating how B vitamins might influence this relationship, potentially impacting mental health and cognitive function through their effects on gut health.

  7. B Vitamins and Autoimmune Diseases: Some studies are exploring the potential role of B vitamins in managing autoimmune conditions. For instance, a 2020 review published in "Biomolecules" discussed the potential of B vitamins in treating multiple sclerosis[11].

  8. Interactions with Other Nutrients: Future research may delve deeper into how B vitamins interact with other nutrients for optimal health benefits. This could lead to more effective combination supplements or dietary recommendations.

  9. B Vitamins and Athletic Performance: Some researchers are investigating whether B vitamin supplementation could enhance athletic performance, particularly in endurance sports.

  10. B Vitamins and Aging: As the global population ages, there's increasing interest in how B vitamins might support healthy aging, from maintaining cognitive function to supporting cellular health.

As research progresses, our understanding of B vitamins' importance in human health will undoubtedly deepen. Stay tuned to reputable health and nutrition sources to keep abreast of the latest findings in B vitamin research. Remember, while these areas of research are exciting, it's always best to consult with healthcare professionals before making significant changes to your diet or supplement regimen based on emerging research.

9. Conclusion: Embracing B Vitamins for Better Health

As we wrap up our exploration of B vitamins, it's clear that these nutrients play crucial roles in maintaining our digestive health and supporting our immune function. From fueling our gut processes to boosting our body's defenses, B vitamins truly are essential players in our overall wellbeing.

Key Takeaways:

  1. B vitamins are essential for energy production, digestion, and immune function.
  2. A balanced diet typically provides sufficient B vitamins for most people, but certain groups may be at risk of deficiency.
  3. B vitamins work synergistically, both with each other and with other nutrients, highlighting the importance of a varied diet.
  4. Ongoing research continues to uncover new potential benefits of B vitamins, particularly in areas like cognitive health and chronic disease prevention.
  5. Niacin (B3) plays a unique role as a precursor to NAD+, influencing numerous cellular processes including energy production and DNA repair.

Practical Tips for Incorporating B Vitamins into Your Daily Life:

  1. Include a variety of B vitamin-rich foods in your diet, such as whole grains, lean meats, leafy greens, and legumes.
  2. If you're vegetarian or vegan, pay extra attention to your B12 intake and consider fortified foods or supplements.
  3. Be mindful of factors that might increase your B vitamin needs, such as stress, alcohol consumption, or certain medications.
  4. If you're considering B vitamin supplements, consult with a healthcare provider to determine the appropriate dosage for your needs.
  5. Remember that B vitamins work best as part of a balanced, nutrient-rich diet – they're not a magic bullet, but rather important pieces of the overall nutrition puzzle.

By understanding the roles of B vitamins and ensuring adequate intake, you're taking an important step towards supporting your digestive health and immune function. Remember, your health journey is unique, and what works best for you may differ from others. Listen to your body, stay informed about the latest nutritional research, and don't hesitate to seek professional advice when needed.

As we've seen throughout our nutrient series, from the importance of Vitamin D to the power of zinc, and now B vitamins, our body's systems are intricately connected. By supporting our body's nutritional needs, we're not just boosting our immunity or improving our digestion – we're promoting overall health and wellbeing.

Here's to your health – may it be as vibrant and energetic as the B vitamins that help support it!

Recommended Books

For those interested in diving deeper into the world of B vitamins and their impact on health, here are some recommended resources:

  1. "The Vitamin B Complex: Metabolism and Functions in Health and Disease" by David A. Bender
  2. "B Vitamins and Folate: Chemistry, Analysis, Function and Effects" edited by Victor R. Preedy
  3. "Nutritional Medicine" by Alan R. Gaby (Chapter on B Vitamins)
  4. "The Gut-Immune Connection" by Emeran Mayer (Discusses the role of nutrition, including B vitamins, in gut and immune health)
  5. "Biochemical, Physiological, and Molecular Aspects of Human Nutrition" by Martha H. Stipanuk and Marie A. Caudill (Chapters on B Vitamins)
  6. "The Micronutrient Miracle" by Jayson Calton and Mira Calton
  7. "The Longevity Diet" by Valter Longo
  8. "Nutrition and Immunity" by Maryam Mahmoudi
  9. "The Complete Guide to Vitamins, Herbs, and Supplements" by Winifred Conkling
  10. "The Optimal Dose" by Judson Somerville (Discusses the interplay between vitamins, including B vitamins)
  11. "Dirty Genes" by Ben Lynch (Discusses the role of B vitamins in genetic processes)
  12. "The End of Alzheimer's Program" by Dale Bredesen (Includes information on B vitamins and cognitive health)
  13. "Integrative Gastroenterology" by Gerard E. Mullin (Discusses B vitamins in the context of digestive health)
  14. "The Immunity Fix" by James DiNicolantonio and Siim Land (Explores the role of various nutrients, including B vitamins, in immune function)
  15. "Mitochondria and the Future of Medicine" by Lee Know (Discusses the role of B vitamins in cellular energy production)

References

  1. Magnúsdóttir, S., Ravcheev, D., de Crécy-Lagard, V., & Thiele, I. (2015). Systematic genome assessment of B-vitamin biosynthesis suggests co-operation among gut microbes. Frontiers in genetics, 6, 148. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4415402/

  2. Qian, B., Shen, S., Zhang, J., & Jing, P. (2017). Effects of Vitamin B6 Deficiency on the Composition and Functional Potential of T Cell Populations. Journal of Immunology Research, 2017, 2197975. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5307235/

  3. Tamura, J., Kubota, K., Murakami, H., Sawamura, M., Matsushima, T., Tamura, T., ... & Naruse, T. (1999). Immunomodulation by vitamin B12: augmentation of CD8+ T lymphocytes and natural killer (NK) cell activity in vitamin B12-deficient patients by methyl-B12 treatment. Clinical & Experimental Immunology, 116(1), 28-32. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1905232/

  4. Mikkelsen, K., & Apostolopoulos, V. (2019). B Vitamins and Ageing. In Biochemistry and Cell Biology of Ageing: Part I Biomedical Science (pp. 325-340). Springer, Singapore. https://link.springer.com/chapter/10.1007/978-981-13-2835-0_11

  5. Mooney, S., Leuendorf, J. E., Hendrickson, C., & Hellmann, H. (2009). Vitamin B6: a long known compound of surprising complexity. Molecules, 14(1), 329-351. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6253976/

  6. Wintergerst, E. S., Maggini, S., & Hornig, D. H. (2007). Contribution of selected vitamins and trace elements to immune function. Annals of Nutrition and Metabolism, 51(4), 301-323. https://www.karger.com/Article/Abstract/107673

  7. Mikkelsen, K., & Apostolopoulos, V. (2019). B Vitamins and Ageing. In Biochemistry and Cell Biology of Ageing: Part I Biomedical Science (pp. 325-340). Springer, Singapore. https://link.springer.com/chapter/10.1007/978-981-13-2835-0_11

  8. O'Leary, F., & Samman, S. (2010). Vitamin B12 in health and disease. Nutrients, 2(3), 299-316. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257642/

  9. Porter, K., Hoey, L., Hughes, C. F., Ward, M., & McNulty, H. (2016). Causes, Consequences and Public Health Implications of Low B-Vitamin Status in Ageing. Nutrients, 8(11), 725. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5133110/

  10. Dong, H., Pi, F., Ding, Z., Chen, W., Pang, S., Dong, W., & Zhang, Q. (2015). Efficacy of Supplementation with B Vitamins for Stroke Prevention: A Network Meta-Analysis of Randomized Controlled Trials. PloS one, 10(9), e0137533. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4562393/

  11. Nemazannikova, N., Mikkelsen, K., Stojanovska, L., Blatch, G. L., & Apostolopoulos, V. (2018). Is there a Link between Vitamin B and Multiple Sclerosis? Medicinal chemistry (Shariqah (United Arab Emirates)), 14(2), 170–180. https://pubmed.ncbi.nlm.nih.gov/29243578/

  12. Bito, T., Misaki, T., Yabuta, Y., Ishikawa, T., Kawano, T., & Watanabe, F. (2017). Vitamin B12 deficiency results in severe oxidative stress, leading to memory retention impairment in Caenorhabditis elegans. Redox biology, 11, 21-29. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5263170/

  13. Kennedy, D. O. (2016). B Vitamins and the Brain: Mechanisms, Dose and Efficacy—A Review. Nutrients, 8(2), 68. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4772032/

  14. Fenech, M. (2012). Folate (vitamin B9) and vitamin B12 and their function in the maintenance of nuclear and mitochondrial genome integrity. Mutation research, 733(1-2), 21–33. https://pubmed.ncbi.nlm.nih.gov/22093367/

  15. Bouzid, D., Gargouri, B., Mansour, R. B., Amouri, A., Tahri, N., Lassoued, S., & Masmoudi, H. (2014). Vitamin B6 deficiency and defects in the tryptophan metabolism in patients with inflammatory bowel disease. Digestive diseases and sciences, 59(10), 2523-2531. https://pubmed.ncbi.nlm.nih.gov/24848782/