Health Tips

Dr. Vliet’s Health Tip: The Vitamin A Advantage: Faster Healing, a Stronger Gut Barrier, and Immunity Booster

Most everyone has heard about Vitamin A’s role in visual acuity and eye health. What doesn’t get nearly enough attention, however, is Vitamin A’s many other critical roles: helping the body heal from injuries, boosting immunity during stress and infection, and increasing the strength and resilience of your gut barrier and microbiome balance. 

When vitamin A levels are too low (have you had yours checked recently?), wound healing drags on, inflammation becomes harder to resolve, and the intestinal lining is more fragile and vulnerable. When Vitamin A levels are optimal, all thee critical systems work together far more smoothly, and are more resistant to damage from stress, inflammation, and infections.

In today’s health tip I will give a brief overview of what vitamin A does on these fronts: wound healing, inflammation, and gut health.  You can check the archive to read my original health tip Vitamin A: Good For More Than just Your Eyes for a more detailed look at vitamin A on other body systems.

What vitamin A is and what it does
Vitamin A is a fat‑soluble family of compounds (retinol, retinal, retinoic acid, and provitamin A carotenoids such as betacarotene) that your body uses to control cell growth, differentiation, and immune function. Vitamin A acts through gene regulation (via retinoic acid binding to nuclear receptors), so its effects are wide‑ranging and subtle—more like changing the “software” of cells than flipping a single on/off switch.  Think of Vitamin A as a master “instruction signal” that tells cells when to grow, repair, or stand down.

Key roles:

  • Vision: Essential for low‑light vision and normal eye function.
  • Skin and mucosal barriers: Helps skin, gut, and airway linings renew and repair.
  • Immune system: Influences how T cells, B cells, and innate immune cells respond, making it central in the balance between defense and over‑reaction.
  • Growth and development: Critical during pregnancy, childhood, and tissue remodeling after injury or surgery.

Vitamin A and Wound Healing
When tissue is injured—whether a cut, a surgical incision, or an internal ulcer—your body moves through hemostasis, inflammation, proliferation, and remodeling/maturation. Vitamin A supports each of these stages.

  • Hemostasis is the process by which the body stops bleeding. It both prevents excessive blood loss at an injury site and preserves vascular integrity so that circulation can continue.
  • Inflammation cleans the wound clearing debris and pathogens and coordinates the early repair response.
  • Proliferation is the phase of rebuilding tissue and restoring the barrier.  Proliferation also makes cells for new capillaries and to restores skin coverage.
  • Remodeling/Maturation is the last step during which new tissue is gradually strengthened, reorganized, and shaped into a more stable scar.

Epithelial repair

  • Vitamin A promotes growth and differentiation of epithelial cells (the cells that line skin and organs), helping wounds close and new, healthy surface tissue form. Vitamin A deficiency slows re‑epithelialization and can lead to fragile, poorly healed surfaces.
  • Fibroblast activity and collagen
    Vitamin A influences the cells that lay down collagen and extracellular matrix (fibroblasts) and supports granulation tissue formation, which is the scaffolding for new tissue. Too little vitamin A means less robust granulation tissue and weaker repairs; balanced amounts help tissues regenerate with stronger and better structure.
  • Angiogenesis (new blood vessels)
    Vitamin A helps regulate signals that guide new capillaries into healing tissue, so oxygen and nutrients reach the area. This is vital for both external wounds and internal surgical sites.
  • Counteracting steroiddelayed healing
    Corticosteroids (like prednisone, dexamethasone) are notorious for slowing wound healing. Experimental models show that vitamin A can partially reverse steroid‑induced delays in repair, restoring tensile strength and wound closure toward more normal levels. That’s why clinicians sometimes consider vitamin A a necessary supplement to support patients on long‑term steroids undergoing surgery or dealing with chronic wounds.

External vs internal and surgical wounds

  • External (skin) wounds
    Adequate vitamin A helps cuts, abrasions, and minor burns heal more quickly and with a stronger, more intact barrier. Its use as a topical agent (retinoid creams) is common in dermatology for scars and photoaging, but you do not want to apply retinoids directly to fresh incisions because they can irritate a fresh wound.  Retinoids are more often considered later, to influence remodeling and lessen scaring. Oral supplementation would be much more appropriate to support immediate healing.
  • Internal and surgical wounds
    After surgery, internal tissues rely on the same vitamin A‑dependent processes: epithelial repair, collagen deposition, and controlled inflammation. Patients who are deficient or malnourished—especially those with GI disease, bariatric surgery, or chronic illness—may heal more slowly and benefit from vitamin A supplementation to correct any deficiency and support healing.

BOTTOM LINE: Vitamin A is not a magic woundhealing vitamin, but is  an essential cofactor. If your vitamin A levels are low, wounds of all kinds (external, surgical, internal) heal slower and are more fragile.

Vitamin A and Inflammation
I have read many articles that call vitamin A “anti‑inflammatory,” but that’s only part of the story. It’s more accurate to say that vitamin A helps your immune system respond appropriately: strong enough to deal with threats yet restrained enough to avoid chronic damage.

Modulation of inflammation

  • Tcell balance
    Retinoic acid helps promote regulatory T cells that keep the immune response in check and influences the cells that drive more aggressive inflammation. Vitamin A deficiency shifts the balance toward a more chaotic, often over‑reactive pattern, which can result in autoimmune conditions.
  • Barrier vs systemic inflammation
    Adequate vitamin A strengthens epithelial barriers and mucosal immunity (especially in the gut and airways). Stronger barriers mean fewer microbes and toxins leaking into circulation, which helps reduce low‑grade, systemic inflammation over time. We see this play out especially in the gut, where new research is pointing to endotoxins escaping through leaky gut barrier and wreaking havoc throughout the body.
  • Contextdependent effects
    In Vitamin A deficiency or infection‑heavy settings, supplementation tends to reduce harmful inflammation and improve outcomes. In healthy non-deficient adults, however, high‑dose vitamin A may actually raise inflammatory blood markers like CRP.  This is an example of why indiscriminate high‑dose use is not recommended unless you check blood level of Vitamin A.

BOTTOM LINE: Vitamin A supports the regulation and resolution of inflammation by strengthening barriers and modulating activity of  immune cells. Vitamin A is helpful when low or in acute or specific inflammatory conditions, but not a generalized “natural antiinflammatory pill” for everyone.

Vitamin A and Gut Health: Barrier resilience, microbiome diversity, and host–microbe signaling
The gut is where vitamin A’s effects really shine. Here, it supports the physical barrier, trains immune tolerance, and works in partnership with the microbiome.

Barrier integrity and “leaky gut”

  • Epithelial lining and villi
    Vitamin A helps intestinal epithelial cells develop and renew properly. Deficiency can lead to villous atrophy (thinning of the absorptive surface) and weaker lining, making it easier for irritants and microbes to cross into the body.
  • Goblet cells and mucus
    It supports goblet cells that produce mucin, the main component of the mucus layer protecting your gut wall. Low vitamin A often means a thinner, patchier mucus barrier, increasing exposure of the epithelium to the contents of the gut and contributing to increased permeability.
  • Tight junctions and permeability
    Adequate vitamin A is associated with better expression of tight‑junction proteins which keep the cells lining the gut sealed together. When vitamin A is low, permeability (“leaky gut”) tends to increase, allowing bacterial fragments (like LPS-lipopolysaccaride a known endotoxin) to reach the bloodstream and fuel systemic inflammation.

Immune Modulation in the Gut: Mucosal immunity and tolerance
A large portion of the immune system resides in the gut-associated lymphoid tissue (GALT). Vitamin A is essential here:

  • Immunoglobulin (IgA) and guthoming lymphocytes
    Retinoic acid (RA) instructs T and B cells to “home” to the gut via receptors like α4β7 and CCR9, and supports class‑switching to IgA, the antibody that patrols mucosal surfaces and neutralizes pathogens without causing excessive inflammation This helps the immune system distinguish between friendly microbes and pathogens at the barrier. This balanced response reduces chronic inflammation and supports recovery from gastrointestinal infections or disruptions.
  • Regulatory T cells and oral tolerance
    Vitamin A promotes regulatory T cells (T-regs) and innate lymphoid cells that produce anti-inflammatory signals like IL-22 in the intestinal environment. This helps maintain tolerance to food and commensal bacteria while fighting invaders. These cells are key to oral tolerance—your ability to encounter food antigens and friendly microbes without overreacting. Deficiency is linked to more reactive, less tolerogenic immune profiles in the gut and potentially leading to irritable gut syndromes (IBS).

Figure 2SAA proteins deliver retinol to intestinal myeloid cells through LRP1 to promote adaptive immunity. SAAs are retinol-binding proteins induced in intestinal epithelial cells by the microbiota and vitamin A. SAAs deliver retinol to retinoic acid-producing myeloid cells by binding to the endocytic receptor LRP1. LRP1 and SAAs promote development of vitamin A–dependent adaptive immunity in the intestine and enhance resistance to enteric infection (Bang, et al., 2021).
Microbiome diversity and dysbiosis
Vitamin A status strongly influences the composition and resilience of the gut microbiome.

  • Diversity and composition
    In animal and pediatric studies, vitamin A deficiency reliably reduces microbial diversity and leads to a more dysbiotic profile, with fewer beneficial Lactobacillus and butyrate‑producing organisms and more opportunistic organisms that thrive in a stressed environment that can cause disease or dysbiosis.
  • Bacteria as retinoid “factories”
    Certain friendly gut microbes—especially anaerobic bacteria like some Clostridia and Lactobacillus species—can convert dietary vitamin A into active retinoids (retinol, all‑trans‑retinoic acid, 13‑cis‑retinoic acid) directly in the gut lumen. When these bacteria are depleted (from antibiotics or dysbiosis), local retinoid production drops, even if dietary intake is okay.
  • Dysbiosis and impaired retinoid conversion
    Dysbiosis disrupts both:

    • The presence of Retinoic acid‑producing bacteria, and
    • The normal microbial signals that calibrate epithelial RA synthesis and transport.
  • This leads to lower Retinoic acid availability at the mucosa and weaker RAdependent immune programming which can contribute to colitis‑like, inflammatory traits.

SUMMARY: Vitamin A is a central coordinator of gut barrier function and host–microbe interactions. Adequate levels supports a diverse, resilient microbiome and a lowpermeability, tolerant gut environment. Deficiency, on the other hand, nudges the system toward leaky barriers, dysbiosis, and chronic inflammation.

THE BOTTOM LINE:  VITAMIN A IS OUR MASTER ARCHITECT OF REPAIR and RESILIENCE

Good sources of vitamin A and how to get enough
Vitamin A comes in two main forms in the diet:

  • Preformed vitamin A (retinol and retinyl esters)
    Found in animal foods. The body can use these directly.
  • Provitamin A carotenoids (like beta‑carotene)
    Found in plant foods. The body converts them to vitamin A as needed.

Food sources

Animal sources (preformed vitamin A):

  1. Liver (beef, chicken, cod) – extremely rich; small amounts go a long way.  Definitely check blood levels if you take cod liver oil daily!
  2. Egg yolks
  3. Full‑fat dairy (milk, cheese, butter)
  4. Cod liver oil (traditionally used but needs careful dosing to avoid toxic levels building up).

Plant sources (provitamin A carotenoids):

  1. Orange and yellow vegetables: carrots, sweet potatoes, pumpkin, winter squash.
  2. Dark green leafy vegetables: spinach, kale, collard greens, Swiss chard.
  3. Orange fruits: mango, cantaloupe, apricots.

Your body is good at converting carotenoids and can up‑ or down‑regulate conversion depending on need, which makes plant sources generally safer with respect to toxicity.

Daily needs and adequacy for most adults: usually met through a mix of animal and plant foods in a varied diet.

  • Men: about 900 micrograms RAE (retinol activity equivalents) per day.
  • Women: about 700 micrograms RAE per day (higher in pregnancy and breastfeeding, but needs careful monitoring to avoid overdose; safety constraints to avoid excess for developing baby).

People at risk of low intake are those who:

  • Eat very low‑fat diets or avoid animal products entirely.
  • Have chronic GI disease (Crohn’s, celiac, chronic diarrhea).
  • Have malabsorption (bariatric surgery, pancreatic insufficiency, bile acid loss).
  • Live with chronic, severe malnutrition due to inadequate food supply

Supplements: multivitamins vs standalone vitamin A

  • A typical multivitamin may contain 700–1500 micrograms RAE (approximately 2,300–5,000 IU), often as a mix of retinol and beta‑carotene. For most people, this plus diet is enough.
  • Stand‑alone vitamin A supplements can range from 1,500 IU up to 10,000–25,000 IU or more. High‑dose retinol should be used cautiously and under professional guidance. I generally do not recommend those higher doses due to risk of toxicity.  I suggest starting with the safer dosing of 3000 mcg.

BOTTOM LINE:  First focus on getting Vitamin A from a variety of foods:  animal sources include beef liver, eggs, dairy and fish; plant sources include carrot juice which contains 40,000 IU for one cup and the dark yellow vegetables.  Then if you are still deficient in Vitamin A, take a supplement as appropriate and under the care of your physician.

When Vitamin A Supplementation Can be Helpful
Vitamin A supplementation is most appropriate when there is clear or likely deficiency. Vitamin A deficiency can be measured by plasma retinol level, a simple blood test that your physician can order or you can order for yourself (cash-pay from national laboratories – Quest Diagnostics/LabCorp, or several online companies)

Vitamin A deficiency is defined as a level of 20 mcg/dL or less.  If your level is below 10 mcg/dL, it indicates severe vitamin A deficiency.  Although rare in the developed world, serious deficiency of vitamin A symptoms include:

  • Dry eyes
  • Night blindness or difficulty driving at night
  • Diarrhea
  • Skin problems
  • Higher risk of respiratory disease (pneumonia), infections (measles, diarrhea), and can cause anemia

People at risk of vitamin A deficiency include

  • Premature infants
  • People from developing countries
  • People after gastric by-pass surgery, or those with irritable bowel disease, ulcerative colitis, Crohn disease, and celiac disease because they may have a hard time absorbing all the nutrients their bodies need.

Vitamin A deficiency can also occur when particular conditions impair healing and mucosal function.

These are additional situations where vitamin A support is often considered:

  1. Malnutrition and chronic GI disease

Undernourished individuals, those with chronic diarrhea, intestinal resections, celiac, Crohn’s affecting the small bowel, or pancreatic/bile acid issues commonly have reduced fatsoluble vitamin absorption and may struggle with wound healing, infections, and gut barrier issues.

  1. Chronic steroid use with surgery or wounds

Persons on long‑term corticosteroids facing surgery or chronic wounds because steroids delay wound healing and research has shown the ability of vitamin A to partially normalize healing in steroid‑treated models.

  1. Postchemo or radiation mucosal injury (gut and oral lining)

Oncology patients recovering from treatments that damage mucosal surfaces because Vitamin A is central to epithelial repair and mucosal immune balance.

  1. Populations with high infection burden

Children and adults in settings with high rates of measles, diarrheal disease, and undernutrition. Vitamin A supplementation programs have reduced morbidity and mortality by correcting widespread deficiency.

I encourage you to consider our high quality certified GMP supplement, TruVitamin A™, available at the Truth for Health Store.   Our Vitamin A reduces the risk of taking an excessive amount because it contains the safer upper limit of 3000 mcg of retinyl palmitate, the preferred supplemental source of vitamin A with an absorption rate of 70%-90%. 

You will also get some vitamin A from our TruMultiV™ and TruMultiV™ with Iron both 1,120 mcg of vitamin A, 75% as natural beta-carotene and 25% as retinyl palmitate. And remember, since vitamin A is a fat-soluble vitamin it should be taken with foods containing some fat.

Cod Liver oil contains high doses of Vitamin A, and also contains vitamin D, also a fat-soluble vitamin that can build up over time).  If you are taking Cod Liver oil every day, be sure to check your Vitamin A AND vitamin D blood levels to be sure you are not getting too much, especially if you have symptoms such as I mentioned above.

Caution:  Vitamin A is a fat-soluble vitamin, and can build up in fat tissue over time, leading to excessively high levels and toxicity.

Symptoms of Vitamin A toxicity can include nausea, vomiting, headache, dizziness, blurred vision, coordination issues, bone pain, and dryness of lips, eyes, and skin. 

Vitamin A toxicity can be either acute, when someone takes a markedly excessive dose in a short time, or chronic, when taking more than needed to maintain optimal levels and the level builds up to a toxic range over time.  NOTE:  Food sources of beta-carotene do not have the problem of toxicity from eating too many fruits and vegetables.

It is important to check Vitamin A blood levels periodically and to avoid taking high doses.

  • Daily “background” intake
    • Most adults should aim to meet needs through food and a standard multivitamin that doesn’t exceed about 5,000 IU (~1,500 micrograms RAE) daily. For many, this is more than enough.
  • Shortterm, supervised “therapeutic” dosing
    • In clear deficiency or specific high‑risk scenarios (severe malabsorption, certain steroid‑treated wounds), a clinician may use doses in the 5,000–25,000 IU/day range for a defined, short period.
    • This must be balanced against liver health, pregnancy status, existing retinoid medications, and other risk factors.
  • Longterm high doses
    • Chronic intake above about 10,000 IU/day significantly increases risk of toxicity (liver damage, bone loss, intracranial pressure, teratogenicity) and is not appropriate for routine use.

Some medications can affect vitamin A absorption.  For example, absorption of Vitamin A is reduced by the weight loss medication Orlistat, while medications to treat psoriasis (such as Soriatane and Targretin made from vitamin A) can lead to Vitamin A toxicity when you add vitamin A supplements with these medicines.

Who should not use high‑dose vitamin A without medical oversight:

  • Pregnant or potentially pregnant individuals (teratogenic risk).
  • People with significant liver disease or heavy alcohol use.
  • Individuals already on retinoid medications (e.g., isotretinoin, acitretin).
  • Those with known bone density problems (excess vitamin A can worsen these).

YOUR ROADMAP: Putting it All Together

  1. Start with food.
  • Include some combination of liver (sparingly), eggs, and full‑fat dairy if you use animal products.
  • Add daily portions of orange vegetables and dark leafy greens.
  1. Use a balanced multivitamin to provide minimal levels such as our TruMultiV or TruMultiV with Iron.
  • This is often enough to cover gaps without risking excess.
  1. Look for risk factors.
  • Chronic gut disease, malabsorption, undernutrition, long‑term steroids, frequent infections.
  • If these apply, talk with your physician about assessing vitamin A status and correct deficiencies.
  1. Support the gut and microbiome.
  • Combine vitamin A adequacy from and/or supplements with fiber, prebiotics, and (in many cases) probiotics such our TruProbiotic™ Complete or TruProbiotic™ Daily to rebuild RA-supportive, barrier‑friendly communities in the gut.
  1. Supplement with TruVitamin A™ for clear medical reasons.
  • Use time‑limited, supervised courses when deficiency, difficult wounds, or complex medical issues arise.
  1. Read more: see my original health tip on TruVitamin A™ Vitamin A: Good For More Than just Your Eyes

As you put all the pieces together that I have described today, I encourage you to consider our other natural medicines with our top quality, cGMP-compliant professional formulas: TruMitochondrial™ Boost,  TruNAC™, Tru BioD3, Tru B™ Complex Full Spectrum, TruZinc™, TruC with BioFlavonoids  (Natural sourced Vitamin C with complete Bioflavonoids), and TruProBiotic™ Daily to replenish critical bifidobacteria depleted by COVID shots, viral illnesses, and antibiotic therapy.

All Truth for Health Foundation Products Meet or Exceed cGMP Quality Standards, the highest quality standard for supplements sold in the USA. For more information, references from studies are listed in the Product Data Sheets for each product, available on our website.
Check us out at www.TruthforHealth.org Click on tab for Store.
OR www.shopTruthforHealth.com

CAUTION: As always, we urge you to avoid supplements without checking knowledgeable sources to evaluate your medical situation, proper lab tests to verify what is needed, and to make sure to avoid adverse interactions with prescription medicines and other supplements you take.  Under medical practice regulations, we are unable to answer individual medical questions or make specific individual supplement recommendations for people who are not established patients of Dr. Vliet’s independent medical practice (www.ViveLifeCenter.com).

FINAL THOUGHTS: THINK OF VITAMIN A AS OUR MASTER ARCHITECT OF REPAIR AND RESILIENCE.
Incorporating Vitamin A-rich foods as part of a balanced diet is a natural way to nurture your gut barrier, immunity, and overall digestive wellness.  Vitamin A is NOT just another vitamin to “take more of”—you need to make informed choices based on current blood levels to know accurately when you need to support healing, lower inappropriate inflammation, and protect gut integrity in a safer, more sustainable way using a supplement. Vitamin A is another important addition to your natural healing tool kit.

To Your good health and improving resilience!
Elizabeth Lee Vliet, MD

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