Introduction: The Tell-Tale Sign
The first sign of a vitamin A deficiency typically manifests as Nyctalopia.
Often misheard and misunderstood, nyctalopia simply means night blindness.
What is Nyctalopia?
Inability to see well in low light or darkness.
Common examples include:
Difficulty driving at night, especially in the rain.
Struggling to read a book or see in a dimly lit room.
This is often mistaken for a simple need for glasses when the underlying issue may be a nutritional deficiency.
A Modern Cause of Eye Strain: Digital Screens
Prolonged screen time (phones, computers) causes eye muscles to go into spasm.
This spasm affects your ability to see and can lead to prescriptions for glasses.
Recommendation: To counter this, spend at least one hour outside daily.
Focus on looking into the distance and at various objects to relax the eye muscles and improve vision.
The Science Behind Vitamin A and Vision
Retinol: The Active Form of Vitamin A
The active form is called Retinol, named for the retina in the back of the eye.
Retinol is crucial for creating Rhodopsin (or "visual purple").
This is a protein in the eye that converts light into electrical signals for the brain.
Rhodopsin is found in the rods of your eyes, which are responsible for:
Vision in low-light conditions.
The Problem with Beta-Carotene (The Precursor)
Beta-carotene is a "pre-vitamin A" that must be converted into active retinol by the body.
This conversion is highly inefficient.
To get the same amount of retinol found in 3 oz of beef liver, you would need to consume:
40 pounds of raw carrots, or
454 cups of raw kale.
Relying solely on plant-based beta-carotene often does not provide sufficient active vitamin A.
Best Dietary Sources of Active Vitamin A (Retinol)
Grass-fed beef liver (the richest source)
Egg yolks
Cod liver oil (also provides Vitamin D and Omega-3s)
Raw cheese (especially from sheep's milk)
Raw cream and raw butter
Important Note: Pasteurization destroys vitamin A. Pasteurized dairy products (milk, cheese, butter) are not good sources.
Other Key Roles of Vitamin A in the Body
Prevents dry eyes and helps the eye focus (accommodation reflex).
Prevents dry, rough, and scaly skin by aiding skin cell differentiation.
Crucial for the immune system by maintaining the health of all mucous membranes (sinuses, throat, lungs, digestive tract).
Vital for proper childhood development.
Why Are People Deficient? Key Reasons
High Demand: Pregnant and breastfeeding women have significantly increased needs.
Misunderstanding Beta-Carotene: Believing plant sources provide enough active retinol.
Genetic Factors (Polymorphism): A common genetic mutation can impair the body's ability to convert beta-carotene into retinol.
Bile & Gallbladder Issues: Vitamin A is fat-soluble and requires bile for absorption. Deficiency can be caused by:
Gallstones, gallbladder removal, or a fatty liver.
Low-fat diets.
Statin medications (which block cholesterol, a precursor to bile).
Gut Microbiome: Antibiotics can kill gut microbes that help produce bile.
Destroyed by Heat: Pasteurization and overcooking destroy vitamin A in dairy and beta-carotene in vegetables.
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