VITAMIN A

The quiet nutrient that keeps the body oriented, resilient, and connected.

THE BODY KNOWS

Vitamin A is one of the nutrients the body uses quietly and consistently. Every day, it supports the way we see, the way our skin feels, the way our tissues renew, and the way our immune system stays balanced. Much of this happens behind the scenes — cell by cell, signal by signal — long before we notice any changes.

Because vitamin A is fat-soluble and stored, the body can draw on reserves when life becomes more demanding. But it also means subtle shifts in digestion, protein intake or stress can influence how available it is. Understanding how this nutrient works gives us steadier footing in our own physiology.

Vitamin A helps the body maintain clarity, structure and rhythm — supporting functions that help us feel more connected to ourselves and the world around us.

AT A GLANCE

Signs You’re Not Getting Enough

In Somada’s world, the goal is awareness — not micromanagement. Notice:

1. Changes in how easily your eyes adapt when moving from bright to dim environments [2][9]
2. Dry skin and mucosal surface comfort or moisture (dry skin, eyes, nose, mouth) [2]
3. Feeling less resilient and suspectable to colds/flu [9][11]
4. How you sleep - shifts in daily rhythm or sleep–wake regularity (emerging evidence) [5][7]

These lived cues often reveal more than a single blood value, especially since serum retinol remains stable until stores are significantly depleted.

Common Questions

1. Do plant and animal sources work the same?

They provide vitamin A in different forms, and the body handles each a little differently.

Animal foods supply preformed vitamin A (retinol and retinyl esters), which can be used directly once absorbed. Plant foods supply provitamin A carotenoids (such as beta-carotene), which the body converts to retinol according to need.

Conversion from carotenoids is variable and influenced by genetics, gut health, dietary fat and overall nutrient status. For some people, this means plant sources alone may not reliably meet requirements, while for others they contribute meaningfully. Both forms can play a role in a balanced, wholefood diet. [1][2][10]

2. Should I be concerned about Vitamin A overdose (hypervitaminosis)?

Vitamin A is fat-soluble and stored in the body, so both adequacy and excess matter.

Wholefood sources consumed in reasonable amounts are unlikely to cause excess in healthy adults. For context, a 6-capsule serve of Somada’s Organic Beef Liver provides approximately 44% of the FSANZ RDI, with lower contributions from the Organic Iron Blend.

Preformed vitamin A from supplements and high intakes from animal foods over time can exceed recommended upper levels if not considered carefully. Provitamin A carotenoids from plant foods pose a lower risk of excess, as conversion is regulated by the body.

Upper intake levels exist to guide safety (see Daily Requirements table). Pregnant and breastfeeding women should be particularly mindful of total vitamin A intake, especially from concentrated sources. Seek individual guidance if unsure.

3. Does vitamin A affect immunity?

Vitamin A supports normal immune function, particularly at barrier surfaces such as the eyes, respiratory and GI tracts, where immune cells and epithelial tissues work to protect the body.

Adequate vitamin A helps maintain these surfaces. When intake or availability is low, susceptibility to infections may increase and recovery can be slower, reflecting reduced barrier integrity and immune regulation. Consistent stores over time are more effective than a single immunity “boost”. [3][4][9][11]

Wholefood Sources

Somada centres wholefood nutrition. The richest natural sources include:

Nutrients that support its function

• Dietary fat — assists normal absorption [2]
• Protein — required for RBP synthesis and healthy transport mechanisms [1][2]

Practical ways to include it

• Add a small portion of liver (15g/day) for a concentrated source of preformed vitamin A.
• Include eggs and dairy through the week for steady baseline intake.
• Build meals with colourful vegetables and pair them with healthy fats to support carotenoid absorption.
• Cook leafy greens lightly and serve with fresh olive oil or animal fats to increase availability.

DAILY REQUIREMENTS

(All units µg/day Retinol Equivalents)

Note: FSANZ Recommended Daily Intake (RDIs) are based on the food standards code, which we must comply with legally; while NRVs are provided from eatforhealth.gov. Both are population level guidance only and not necessarily individual targets.

Higher Requirements

Vitamin A requirements increase during pregnancy due to greater physiological demand, and during breastfeeding to support maternal and infant needs. Note the upper limit also reduces.

For those who want to understand the scientific mechanisms further, keep reading.

WHAT VITAMIN A DOES IN THE BODY

Role in the Body

• Supports normal vision and dark adaptation through the retinal–opsin system [1]. The body converts dietary vitamin A into 11-cis-retinal, which binds to opsin proteins in photoreceptor cells. Reduced availability of retinal may slow regeneration of photopigments after bleaching caused by light exposure, impairing dark adaptation or night vision.
• Helps maintain the normal structure of epithelial and mucosal surfaces such as skin, the eye surface, mouth and respiratory and gastrointestinal tissues [1][9]. The biologically active derivative, all-trans retinoic acid (RA), binds to nuclear receptors to regulate gene transcription for cell differentiation, proliferation, and maintenance. Suboptimal vitamin A may lead to subtle changes such as reduced mucous or tear secretion (dryness),
• Contributes to the normal function of the immune system. RA produced by dendritic cells in the gut promotes the differentiation of gut-homing lymphocytes (T and B cells), supports IgA-producing plasma cells, and modulates the balance between regulatory T-cells (T_regs) and pro-inflammatory Th17 cells. [3][4]
• Supports normal cellular differentiation, growth and tissue maintenance. RA acts as a ligand to nuclear RAR/RXR receptors, which bind DNA and modulate transcription of hundreds of genes involved in cellular growth, differentiation, and morphogenesis, thereby influencing development, maintenance and repair of multiple tissue types (epithelial tissues, mucosa, possibly bone and reproductive tissues). [5][6]
• May play a role in normal circadian rhythm regulation (emerging evidence). RA signalling affects gene expression in brain regions such as the suprachiasmatic nucleus, modulating intracellular pathways linked to circadian rhythms and other neuronal regulatory systems. Though data in humans remain limited, inadequate vitamin A could theoretically perturb circadian regulation or neuronal homeostasis — possibly affecting sleep–wake cycles or other rhythm-dependent neurophysiological processes [7].

Absorption & Utilisation

Vitamin A is absorbed primarily in the small intestine. Preformed vitamin A (retinol and retinyl esters) from animal-derived foods is hydrolyzed to retinol, incorporated into micelles with dietary lipids and bile salts, and taken up by enterocytes. Provitamin A carotenoids (e.g., β-carotene) from plant foods are also absorbed in micelles and then enzymatically cleaved to generate retinol. [1][2][10]

Once absorbed, retinol is esterified (retinyl esters) and transported to the liver, where most vitamin A is stored in hepatic stellate cells. When needed, retinol is mobilized into the bloodstream bound to retinol-binding protein (RBP), often in complex with transthyretin (TTR), which stabilizes RBP and prevents renal loss. [2]

In marginal inadequacy, liver stores may decline gradually but serum retinol remains within “normal” range, masking deficiency in standard blood testing — yet functional impairments (vision under low light, mucosal/epithelial integrity, immune resilience) may begin to emerge [9].

RESEARCH SPOTLIGHT

Study 1 — McEldrew et al., 2023 [1]

• Clinical review describing absorption, storage, transport and deficiency states.
• Describes forms of vitamin A (retinol, retinyl esters, provitamin carotenoids), absorption, storage, transport (RBP-TTR), roles in vision, epithelial integrity, immune function, gene regulation; outlines deficiency and toxicity contexts — foundational clinical summary.

Study 2 — Carazo et al., 2021 [2]

• Detailed review of vitamin A forms, metabolism, conversion and detection.
• Helps clarify differences between preformed vitamin A and carotenoids, and how the body uses each. Useful for understanding homeostasis and bioavailability.

BRINGING IT ALL TOGETHER

Vitamin A is one of the nutrients that anchors the body’s sense of steadiness. It helps us see clearly, maintain resilient surfaces, and keep immune function balanced. Modern life — with shifting diets, digestive stress and irregular routines — can influence how available it feels in the body.

Wholefood sources offer a grounded, practical way to stay nourished. As always, it’s less about perfection and more about returning to the foods and rhythms the body recognises.

This article provides general nutrition information only and is not intended as medical advice.

References

[1] E. P. McEldrew et al., “Vitamin A,” StatPearls, 2023. Link

[2] A. Carazo et al., “Vitamin A Update: Forms, Sources, Kinetics, Detection …,” Nutrients, vol. 13, no. 5, 2021. Link

[3] B. Cassani, E. J. Villablanca, J. De Calisto, S. Wang, and J. R. Mora, “Vitamin A and immune regulation: Role of retinoic acid in gut-associated dendritic cells, immune protection and tolerance,” J. Immunol., 2012. Link

[4] L. de Mendonça Oliveira et al., “Impact of retinoic acid on immune cells and inflammatory diseases,” Mediators of Inflammation, 2018. Link

[5] M. Menezes & C. Almeida (2024), “Structural, functional, nutritional and clinical aspects of vitamin A: A review” Link

[6] H. Debelo et al., (2017) “Vitamin A”, Link

[7] X. Guo et al., “Impacts of vitamin A deficiency on biological rhythms,” Frontiers in Nutrition, 2022. Link

[8] National Academies / FAO/WHO–cited reviews: “Role of vitamin A in human metabolic processes,” FAO/WHO monograph. Link

[9] P. Marzeda & J Luszczki, (2019), “Role of Vitamin A in health and illness”, Link

[10] (Various historical & clinical-overview sources including “Vitamin A – in health and illness,” classic nutritional/physiological reviews.) Link

[11] J. O. Amimo et al., “Immune impairment associated with vitamin A deficiency: insights from clinical studies and animal models,” Nutrients, 2022. Link

[12] S. Gattu et al., “Epithelial retinoic acid receptor β regulates systemic amyloid A synthesis and ensures steady-state retinol transport,” PNAS, 2019. Link