By: Kim Ross, DCN, CNS, LDN, IFMCP

1. Introduction
2. A Healthy Barrier and Its Functions
3. A Compromised Barrier
4. Factors that Impact GI Integrity and Lead to a Self-Tissue Response
5. Nutrition, Lifestyle and Health Components
6. Nutrient Solutions to Build the Intestinal Barrier
7. Pure Encapsulations Nutrient Solutions
8. Conclusion
9. Resources

Introduction

The intestinal barrier is more than just a digestive checkpoint - it's a key defender against non-beneficial microorganisms, toxins, and antigens while allowing the body to absorb vital nutrients. When this barrier is compromised, it can lead to a cascade of symptoms, including occasional bloating, abdominal discomfort, irregular bowel movements, and nutrient malabsorption.

One common consequence of a weakened barrier includes intestinal concerns, often triggered by self-tissue response. According to the CDC, over 3.1 million Americans experience intestinal immune concerns,¹ which can disrupt nutrient absorption and weaken overall immunity.

This article will explore the essential nutrients that support the mucosal immune system and strengthen the intestinal barrier, offering insights into how dietary interventions can help maintain gut integrity and overall health.

A Healthy Barrier and Its Functions

The intestinal barrier consists of a monolayer of specialized epithelial cells that line the gut lumen, forming a selectively permeable barrier. These epithelial cells are sealed together by tight junction proteins, including occludin, claudin-1, and zonula occludens-1 (ZO-1).^2,3 Tight junctions function as "gatekeepers," determining what substances can pass through the intestinal lining into the bloodstream while preventing the entry of harmful microorganisms, toxins, and antigens.

The intestinal barrier also includes a mucus layer, which provides physical protection by preventing direct contact between microbes and the epithelial cells. It contains antimicrobial peptides and secretory immunoglobulin A (sIgA), which neutralize non-beneficial microorganisms and contribute to immune defense. This layer is rich in immune cells such as macrophages, dendritic cells, and T-cells, which play key roles in maintaining immune homeostasis.³

The primary functions of the gut barrier include:⁴

• absorption of nutrients
• regulation of immune responses
• maintenance of intestinal homeostasis
• prevention of the translocation of harmful substances
• supporting bidirectional communication between the gut microbiota and the immune system

A Compromised Barrier

When the integrity of the gut barrier is compromised, it can lead to increased intestinal permeability, commonly called "leaky gut." Increased permeability allows larger molecules, such as undigested food particles, toxins, and microbes, to enter the bloodstream, potentially triggering an unbalanced state and immune activation. This, in turn, can lead to persistent intestinal distress and self-tissue response in the intestines, further exacerbating symptoms and contributing to systemic changes.

Factors That Impact GI Integrity and Lead to a Self-Tissue Response

The integrity of the intestinal barrier and the development of a self-tissue response in the intestines is rarely a result of one factor. Instead, it is a multifactorial process influenced by numerous factors, including the health of the microbiome, immune and cytokine responses, and nutrition, lifestyle, and health components.

The Health of the Microbiome

The gut microbiome is a complex ecosystem of nearly 100 trillion microorganisms that maintain mucosal health.² Beneficial microbes such as Bifidobacteria, Lactobacilli, enterococcus, and Clostridium produce short-chain fatty acids (SCFAs), which support tight junction integrity and signaling.²

Conversely, a microbial imbalance resulting from low microbial diversity or gastrointestinal infections can increase intestinal permeability and promote an increased immune response. Evidence suggests that individuals with a self-tissue response in the intestines have a reduction of beneficial bacterial species in the gastrointestinal tract.⁵

The Immune and Cytokine Responses in the Gut

The gut-associated lymphoid tissue (GALT) is an integral part of the immune system, responsible for responding to non-beneficial bacteria while maintaining tolerance to dietary antigens and commensal bacteria. Cytokines such as interleukin-10 (IL-10) promote immune tolerance, whereas excessive production of cytokines like IL-6 and TNF-α disrupt mucosal balance. Activation of these cytokines can perpetuate barrier and tissue changes, contributing to systemic immune activation.^6,7

Nutrition, Lifestyle & Health Components

Nutrition: The Standard American Diet (Western Diet) contains a high intake of refined sugars, processed carbohydrates, red or processed meat, omega-6 fatty acids, and alcohol, exacerbating the body's cytokine balance processes. The way of eating is also partially responsible for decreased bacterial diversity in the gut and contributes to inadequate intake of essential vitamins and minerals. Poor nutrient absorption is a common presentation for people with a self-tissue response in the intestines.^8,9

Conversely, a diet rich in fruits and vegetables, fiber, omega-3 fatty acids, fish, grains, and legumes protects and supports a healthy GI barrier. Studies have shown that eliminating some food groups, such as gluten and dairy or other known food allergies or intolerances, may help reduce GI symptoms and support a self-tissue response.⁹ Special attention should be given to replacing vitamins and minerals, such as B vitamins, vitamin D, electrolytes, and omega-3 fatty acids, as indicated.¹⁰

Lifestyle: Perceived stress that is uncontrolled or not well managed is considered a predictor of the exacerbation of GI symptoms and self-tissue response.¹¹ Poor sleep quality is associated with elevated levels of IL-6, TNF-α, nuclear factor-kB (NF-kB), and CRP (C-reactive protein), known markers of the immune system.¹²

Health Components: General health components such as a history of intake of medications, exposure to environmental toxins and genetic predisposition also play a role in the susceptibility to a compromised intestinal barrier and immune response.

Nutrient Solutions to Build the Intestinal Barrier

Glutamine is the most abundant amino acid in the body. It is the primary energy source for enterocytes (the cells that line the small intestine and colon), utilizing about 30% of total glutamine.^13,14 It also helps maintain healthy intestinal integrity by enhancing the intestine's protective mucosal lining and promotes tissue repair from metabolic stress.^14‡

Studies have demonstrated that L-glutamine supplementation reduces intestinal permeability and supports outcomes in patients with compromised barrier integrity.^13‡

Arabinogalactan, a fiber derived from larch trees, is a prebiotic that promotes the growth of beneficial gut bacteria. such as Bacteroidetes, Bifidobacterium, and Faecalibacterium praisnitzii, which are crucial for proper gut-associated lymphoid tissue (GALT) function and development.¹⁵ These bacteria produce SCFAs, including butyrate, which enhance epithelial integrity and modulate cytokine production.^‡

Arabinogalactan also has immunomodulatory properties, supporting the production of natural killer (NK) cells and promoting mucosal immunity.¹⁶ It may also promote healthy production of cytokines, which mediate cell-to-cell communication between cells involved in the immune response. Its dual role as a prebiotic and immune supporter makes it a valuable addition to protocols to restore gut health.^‡

Perilla (Perilla frutescens) is a traditional herb rich in polyphenols and rosmarinic acid. which promote cytokine balance and antioxidant effects. Its active compounds reduce the production of cytokines such as IL-6 and TNF-α, which are implicated in intestinal immune changes.^17‡

In a randomized, controlled trial involving 50 individuals, 150 mg of Benegut^® Perilla frutescens extract twice daily offered significant support for GI comfort.¹⁸ Perilla also stabilizes mast cells, reducing hypersensitivity reactions that can contribute to mucosal damage.^19‡

Additionally, its antioxidant properties help neutralize reactive oxygen species (ROS), protecting the intestinal lining from oxidative stress.²⁰

Astragalus (Astragalus membranaceus) is a well-known adaptogenic herb with a long history of use in Traditional Chinese Medicine (TCM). It promotes immunity by supporting B and T lymphocyte production, balancing Th1/Th2, and modulating cytokine response.²¹ It also protects the intestinal barrier by upregulating tight junction proteins and secretory IgA (sIgA) production. This key immune component coats the intestinal lining and prevents the adherence of non-beneficial microorganisms.²² Its adaptogenic properties further support resilience against stress, a contributing factor to a compromised intestinal barrier.^23‡

Deglycyrrhizinated licorice (DGL) supports the healing of the GI barrier and other mucous membranes by increasing blood supply to mucosa, increasing the production of mucus, which acts as a protective barrier for the intestinal lining and improves the life span of intestinal cells.^24‡

Pure Encapsulations^® Nutrient Solutions

Pure Encapsulations offers expertly crafted supplements made with high-quality, pure ingredients and supported by verifiable scientific research. These products are designed to complement personalized care plans.^‡

Epi-Integrity powder: is a carefully formulated blend of glutamine, prebiotic fiber, and herbal extracts that support the modulation of mucosal immune responses and promote gastrointestinal (G.I.) barrier integrity. It helps maintain a balanced microbiome, provides mucosal protection, and supports epithelial cell health for optimal gut function.^‡

Suggested Use: 1 scoop, 1-2 times daily. Add 1 serving to 8 oz of water or juice. Shake or stir until dissolved.

Conclusion

Restoring intestinal barrier integrity and supporting mucosal immune responses are essential for addressing symptoms associated with self-tissue responses in the gut. Healthcare providers can leverage evidence-based nutritional strategies to address the underlying factors contributing to a compromised barrier. Nutrients such as L-glutamine, arabinogalactan, perilla, Astragalus, and DGL offer targeted support for mucosal repair, cytokine modulation and immune balance.^‡

Resources

Gastrointestinal Self-Tissue Response Protocol: Designed by our scientific and medical advisors to help you deliver the most effective care and support for your patient's intestinal health.^‡

Drug-Nutrient Interaction Checker:  Provides valuable information on potential interactions between your patients' prescriptions, over-the-counter medications and nutritional supplements.

PureInsight^™: Our streamlined platform easily collects patient data and provides valuable recommendations to help achieve their health goals.

Virtual Dispensary: Our Pure Patient Direct program provides account holders FREE access to our virtual dispensary to help simplify patient sales and reduce in-office inventory.

You can also explore Pure Encapsulations^® to find On-Demand Learning, Clinical Protocols and other resources developed with our medical and scientific advisors.

1. Center for Disease Control and Prevention. June 21, 2024. Accessed January 19, 2025. https://www.cdc.gov.
2. Fusco W, Lorenzo MB, Cintoni M, et al. Nutrients. 2023;15(9). doi:10.3390/nu15092211
3. Di Sabatino A, Santacroce G, Rossi CM, Broglio G, Lenti MV. Intern Emerg Med. 2023;18(6). doi:10.1007/s11739-023-03329-1
4. Ghosh S, Whitley CS, Haribabu B, Jala VR. CMGH. 2021;11(5). doi:10.1016/j.jcmgh.2021.02.007
5. Khan I, Ullah N, Zha L, et al. Pathogens. 2019;8(3). doi:10.3390/pathogens8030126
6. Ullah H, Arbab S, Tian Y, et al. Front Immunol. 2024;15:1413485. doi:10.3389/fimmu.2024.1413485
7. Tanoue T, Umesaki Y, Honda K. Gut Microbes. 2010;1(4). doi:10.4161/gmic.1.4.12613
8. De Castro MM, Pascoal LB, Steigleder KM, et al. World J Exp Med. 2021;11(1). doi:10.5493/wjem.v11.i1.1
9. Christensen C, Knudsen A, Arnesen EK, Hatlebakk JG, Sletten IS, Fadnes LT. Advances in Nutrition. 2024;15(5):100219. doi:10.1016/j.advnut.2024.100219
10. Balestrieri P, Ribolsi M, Guarino MPL, Emerenziani S, Altomare A, Cicala M. Nutrients. 2020;12(2). doi:10.3390/nu12020372
11. Edman JS, Greeson JM, Roberts RS, et al. Explore: The Journal of Science and Healing. 2017;13(2). doi:10.1016/j.explore.2016.12.005
12. Irwin MR, Opp MR. Neuropsychopharmacology. 2017;42(1). doi:10.1038/npp.2016.148
13. Abbasi F, Haghighat Lari MM, Khosravi GR, Mansouri E, Payandeh N, Milajerdi A. Amino Acids. 2024;56(1):60. doi:10.1007/s00726-024-03420-7
14. Kim MH, Kim H. Int J Mol Sci. 2017;18(5). doi:10.3390/ijms18051051
15. Cao Y, Shen J, Ran ZH. Gastroenterol Res Pract. 2014;2014. doi:10.1155/2014/872725
16. Dion C, Chappuis E, Ripoll C. Nutr Metab (Lond). 2016;13(1). doi:10.1186/s12986-016-0086-x
17. Pressi G, Rigillo G, Governa P, et al. Pharmaceutics. 2023;15(1). doi:10.3390/pharmaceutics15010240
18. Buchwald-Werner S, Fujii H, Reule C, Schoen C. BMC Complement Altern Med. 2014;14. doi:10.1186/1472-6882-14-173
19. Takano H, Osakabe N, Sanbongi C, et al. Exp Biol Med. 2004;229(3). doi:10.1177/153537020422900305
20. Adam G, Robu S, Flutur MM, et al. Antioxidants. 2023;12(3). doi:10.3390/antiox12030727
21. Wang XY, Wang RC, Qu ZY, Zhu YZ, Li YL. Frontiers in Natural Products. 2022;1. doi:10.3389/fntpr.2022.971679
22. Liang H, Tao S, Wang Y, et al. Front Nutr. 2024;11. doi:10.3389/fnut.2024.1364739
23. Park HJ, Hyun YK, Yoon KH, Kyung SK, Shim I. Korean Journal of Physiology and Pharmacology. 2009;13(4). doi:10.4196/kjpp.2009.13.4.315
24. Murray MT. In:Textbook of Natural Medicine.; 2020. doi:10.1016/b978-0-323-43044-9.00085-6

Self-Tissue Response: Core Immunology and Clinical Strategies

Presented by: Sam Yanuck, DC⁺

Increasing your knowledge of functional immunology can give you a valuable advantage in your practice because much of what is seen in functional medicine practice has an immunological basis. This is especially true in cases involving self-tissue response, where the presence of other common factors like GI function, autonomic function, metabolism, food responses and environmental factors can all play a role. This webinar will explore the underlying immunology of self-tissue response, describe connections to other factors common in these cases and present interventions that can support the immunological health of your patients.

You’ll come away with knowledge of the following key objectives:

• Review the immunological mechanisms that underly all self-tissue response.
• Learn to see complex cases as a map of the patient’s immunological factors.
• Recognize the connections between the immune system and the larger functional medicine picture.
• Identify and address key immunological leverage points to support the health and well- being of your patients.

By: Kim Ross, DCN, CNS, LDN, IFMCP

Positive mood and emotional well-being are essential to overall health, yet low mood affects a significant portion of the global population. According to the World Health Organization, 5% of adults (over 280 million people) worldwide experience some level of low mood or loss of pleasure and interest in activities. In comparison, it is estimated to affect about 10% of all adults in the United States.^1,2 Additionally, it is reported that low moods are 50% more common in women than men.²  

People struggling with low mood experience variable ranges of psychological and physical symptoms. These can include pervasive feelings of sadness or hopelessness, a lack of interest in activities, fatigue and difficulty concentrating. These symptoms are often accompanied by physical manifestations such as changes in appetite, sleep disturbances and decreased energy levels.2 Importantly, underlying immunological processes have been found to play a critical role in regulating mood states, opening avenues for innovative therapeutic approaches.¹

Immune System Activation and the Brain

An area of science called neuroimmunology has highlighted the deep, bidirectional connection and communication between the brain and immune system and its influence on mood regulation.^3–5 Immune cells, including microglia, astrocytes and cytokines, interact directly with neurons, contributing to the modulation of mood and cognitive function.^6,7

Studies suggest that systemic immune activation can affect the nervous system via production of cytokines, including  interleukin-1 beta (IL-1b), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-α), which can cross the blood-brain barrier.¹ Alteration of the immune/brain interaction can affect neurotransmitter balance, affecting the production of serotonin, GABA, dopamine and norepinephrine, which are critical for mood stabilization.⁴

Cytokines and Neurotransmitter Balance

Cytokines can influence neurotransmitter balance by modulating key pathways responsible for serotonin, dopamine and glutamate/GABA synthesis and reuptake. For example, the cytokine interferon-gamma (IFN-g) can activate the enzyme indoleamine 2,3-dioxygenase (IDO), which degrades tryptophan, a precursor to serotonin, into kynurenine. This shift reduces serotonin availability, affecting mood regulation.8 However, some kynurenine metabolites have neuroprotective properties, reinforcing the importance of having a healthy cytokine balance within the body.⁸

Similarly, some cytokines (IL-1b, IL-6, IFN-g, and TNF-α) have been shown to decrease the transport of tyrosine (a non-essential amino acid produced from phenylalanine), which is needed for the synthesis of dopamine and catecholamines.9  Cytokines have also been implicated in increasing glutamate activity through quinolinic acid production.¹⁰

Nutrition: Diet plays a critical role in immune and mood regulation. A nutrient and polyphenol-dense Mediterranean diet is rich in vegetables, fruits, omega-3 fatty acids and fiber. It has been shown to modulate cytokine levels and promote mental well-being.^11,12 

Exercise: Regular, moderate-intensity physical activity has been shown to promote cytokine balance. Exercise also helps to reduce stress and provides neuroprotection through the antioxidant system.¹³

Sleep: Poor sleep quality is associated with elevated levels of IL-6, TNF-α, nuclear factor-kB (NF-kB), and CRP (C-reactive protein), important markers of the immune system.¹⁴ Prioritizing sleep hygiene and achieving 7 to 9 hours of restorative sleep can help restore immune balance and positively influence mood.

Mind-Body Practices: Yoga, meditation and mindfulness practices can reduce stress, improve sleep and promote a balanced immune response, including the modulation of cytokines.¹⁵

Polyphenols, including flavonoids, curcumin, epigallocatechin gallate (EGCG) and oligomeric proanthocyanidins (OPCs), are found in a variety of plant-based foods, such as vegetables, berries, green tea and dark chocolate.¹⁶

Curcumin, the active compound in turmeric, exerts its mood benefits by regulating cytokine activity, mainly by reducing levels of TNF-α and IL-6. By maintaining a healthy cytokine response, curcumin supports neurotransmitter balance, especially the monoamines, serotonin, norepinephrine and dopamine.¹⁷ Further, preclinical data suggest that curcumin may bind to NMDA receptors to balance glutamate/GABA signaling.^18‡

Green tea extract contains a high concentration of EGCG, a compound known for its antioxidant and cytokine-modulating properties. The catechins in green tea also help boost dopamine levels, while theanine modulates glutamate, GABA, serotonin and dopamine levels, enhancing a sense of calm and providing cytokine balance.19,20 Green tea extract also supports neurogenesis and promotes the release of brain-derived neurotrophic factor (BDNF), which plays a critical role in mood regulation.^19‡

Pycnogenol, derived from the bark of the French maritime pine tree, is another potent immunomodulator that shows promising cognitive-enhancing effects by reducing oxidative stress and enhancing neurotransmitter activity.²¹ Over 450 articles have been published highlighting the plethora of benefits of this compound in multiple areas of health.^22‡

Pure Encapsulations^® provides uniquely formulated products made with high-quality, pure ingredients backed by verifiable science to complement your plan of care and support healthy aging in your patients.^‡

CurcumaSorb Mind offers support for mental alertness, relaxation and occasional stress. Promotes emotional wellness by supporting healthy levels of serotonin and dopamine.^‡

Suggested Use: Take 2 capsules, 1-2 times daily, with meals.  

Pycnogenol^® 100 mg supports cognitive function and cardiovascular health^‡

Suggested Use: Take 1 capsule, 1-2 times daily, with or between meals.

Green Tea extract (decaffeinated) supports neurocognitive, cardiovascular and cellular health. Provides optimal cellular function and antioxidant protection^‡

Suggested Use: Take 1 capsule, 1-4 times daily, with meals.

The intricate relationship between the immune system and mood highlights the importance of cytokine modulation in mental health. By targeting key cytokines involved in mood regulation, it is possible to influence neurotransmitter pathways and foster positive emotional states.  Making lifestyle changes and using immune-modulating ingredients like pycnogenol and polyphenols offers a holistic approach to supporting mental well-being.

Positive Mood Protocol‡: Designed by our clinician partners to help you deliver the most effective care and support for your patient's mood.

Drug-Nutrient Interaction Checker:  Provides valuable information on potential interactions between your patients' prescriptions, over-the-counter medications and nutritional supplements.

PureInsight™: Our streamlined platform easily collects patient data and provides valuable recommendations to help achieve their health goals.

Virtual Dispensary: Our Pure Patient Direct program provides account holders FREE access to our virtual dispensary to help simplify patient sales and reduce in-office inventory.

You can also explore Pure Encapsulations^® to find On-Demand Learning, Clinical Protocols and other resources developed with our medical and scientific advisors.

1. Miller AH, Raison CL. Nat Rev Immunol. 2016;16(1). doi:10.1038/nri.2015.5
2. World Health Organization (WHO). Accessed June 29, 2024. https://www.who.int/news-room/fact-sheets/detail/depression
3. Zhou L, Foster JA. Neuropsychiatr Dis Treat. Published online 2015. doi:10.2147/NDT.S61997
4. Ross K. Explore. Published online 2023. doi:10.1016/j.explore.2023.02.007
5. Nutma E, Willison H, Martino G, Amor S. Clin Exp Immunol. 2019;197(3). doi:10.1111/cei.13279
6. Dantzer R.  Physiol Rev. 2018;98(1). doi:10.1152/physrev.00039.2016
7. Daëron M. Front Immunol. 2022;13. doi:10.3389/fimmu.2022.984678
8. Tsuji A, Ikeda Y, Yoshikawa S, et al.  Int J Mol Sci. 2023;24(6). doi:10.3390/ijms24065742
9. Mancini M, Natoli S, Gardoni F, Di Luca M, Pisani A.  Int J Mol Sci. 2023;24(6). doi:10.3390/ijms24065618
10. Ho TC, Teresi GI, Segarra JR, et al.  Front Psychiatry. 2021;12. doi:10.3389/fpsyt.2021.642976
11. Koelman L, Egea Rodrigues C, Aleksandrova K. Advances in Nutrition. 2022;13(1). doi:10.1093/advances/nmab086
12. Ventriglio A, Sancassiani F, Contu MP, et al. Clinical Practice & Epidemiology in Mental Health. Published online 2020. doi:10.2174/1745017902016010156
13. Docherty S, Harley R, McAuley JJ, et al. BMC Sports Sci Med Rehabil. 2022;14(1). doi:10.1186/s13102-022-00397-2
14. Irwin MR, Opp MR. Neuropsychopharmacology. 2017;42(1). doi:10.1038/npp.2016.148
15. Black DS, Slavich GM. Ann N Y Acad Sci. 2016;1373(1). doi:10.1111/nyas.12998
16. Winiarska-Mieczan A, Kwiecień M, Jachimowicz-Rogowska K, Donaldson J, Tomaszewska E, Baranowska-Wójcik E. Int J Mol Sci. 2023;24(3). doi:10.3390/ijms24032258
17. Peng Y, Ao M, Dong B, et al. Drug Des Devel Ther. 2021;15. doi:10.2147/DDDT.S327378
18. Ramaholimihaso T, Bouazzaoui F, Kaladjian A.  Front Psychiatry. 2020;11. doi:10.3389/fpsyt.2020.572533
19. Afzal O, Dalhat MH, Altamimi ASA, et al. Molecules. 2022;27(21). doi:10.3390/molecules27217604
20. Shamabadi A, Kafi F, Arab Bafrani M, Asadigandomani H, A. Basti F, Akhondzadeh S.  J Affect Disord. 2023;333. doi:10.1016/j.jad.2023.04.029
21. Simpson T, Kure C, Stough C. Front Pharmacol. 2019;10. doi:10.3389/fphar.2019.00694
22. Weichmann F, Rohdewald P.  Front Nutr. 2024;11. doi:10.3389/fnut.2024.1389374

The GI Immunology Roadmap: The Immune System as a Portal to Gut Health

Presented by: Samuel Yanuck, DC⁺

Join us for an enlightening session on the complex and fascinating relationship between the immune system and the gastrointestinal (GI) tract. This webinar is designed for healthcare professionals interested in understanding the intricate connections that shape our health and well-being.

Learning objectives:

• Review T helper cells and the STAT3-NFkB axis and their significance within the immune system


• Discover how immune responses local to the GI tract contribute to global immune regulation


• Recognize key clinical factors in leaky gut and strategies to turn your GI cases around

Common T Cell Patterns: Recognition & Intervention

Presented by: Samuel F. Yanuck, DC, FACFN, FIAMA⁺

T cells are a type of immune cell that play an important role in the adaptive immune response and have meaningful implications in a variety of health conditions. In this webinar, immunology thought-leader, Dr. Sam Yanuck, will demystify T cells, explain how they contribute to a wide array of symptoms, and reveal how to leverage these insights for more precise and personalized care plans.

Learn how to:

• Recognize immune-related clues in lab work


• Match immunologic patterns to appropriate interventions


• Identify these patterns in patients you’re already seeing