Why Folate Matters for Vision — And Why Nutravision Uses Quatrefolic®

When it comes to our vision, most people think of antioxidants like vitamin C, lutein, omega-3s, or bilberry. But there’s another nutrient that plays a surprisingly foundational role in vision health but is often overlooked: folate, also known as vitamin B9.

Folate is essential for optic nerve function, DNA synthesis, cellular repair, and vascular integrity, all of which are critical for maintaining healthy vision. It isn’t just a pregnancy vitamin; low folate levels have been linked to low mood, cognitive decline, stroke and heart disease. 

And yet, many people aren’t getting enough of it. Folate deficiency is increasingly common with age, and even when if you take supplements, it is often a form of folate that your body may not be able to use efficiently. 

In this article, we’ll explore the science behind folate and vision and why Nutravision features Quatrefolic®, the most advanced, bioavailable form of folate available today.

Why Folate Matters for Vision

Folate is vital for the production of DNA and RNA, the building blocks of every cell in the body, including those in the retina and optic nerve. It also supports the formation of red blood cells and helps regulate homocysteine, an amino acid that, when elevated, is associated with increased risk of damage to blood vessels.

This is particularly relevant for the eyes. Research has linked low folate levels and elevated homocysteine to a higher risk of retinal vascular diseases, including age-related macular degeneration, diabetic retinopathy, and retinal vein occlusion. These conditions often involve damage to the tiny blood vessels that nourish the retina.

Moreover, folate deficiency has been associated with visual disturbances, including blurred vision, optic neuropathy, and even increased risk of neurodegenerative conditions that can affect visual processing.

Multiple studies have linked higher folate levels to better ocular outcomes:

• A 1994 case series published in J Neuro-Ophthalmology documented visual acuity improvements in those with optic neuropathy after folate supplementation.
• A 2014 national prospective cohort study in JAMA Ophthalmology found that individuals with the highest folate intake (≥654 μg/day) had a 25% lower risk of exfoliation glaucoma.
• A 2016 study in American Journal of Clinical Nutrition showed that higher folate intake reduced the risk of progression to geographic atrophy, an advanced form of dry macular degeneration, by 57% in genetically protected individuals. 
• A 2024 population-based, cross-sectional study in Investigative Ophthalmology & Visual Science found that people with the highest blood folate levels had a 53% lower prevalence of glaucoma. Among women, the reduction was 81%.

The Problem with Folic Acid

While folate is naturally found in leafy greens, legumes, and citrus fruits, it’s notoriously unstable. Folate degrades quickly during storage and cooking, which is why many supplements and fortified foods use folic acid, a synthetic form of folate. But there’s a catch.

Folic acid is not biologically active. It must be converted in the body through a multi-step enzymatic process into 5-methyltetrahydrofolate (5-MTHF), the usable form of folate. 

However, up to 40% of people carry a genetic variation in the MTHFR enzyme that slows or impairs this conversion. That means even if you’re taking folic acid, your body may not be getting the active folate it needs. Worse still, unmetabolised folic acid (UMFA) accumulate in the bloodstream, potentially interfering with immune function and masking signs of vitamin B12 deficiency.

 

Methylfolate vs. Folic Acid

Unlike synthetic folic acid, methylfolate is the bioactive form of folate your cells actually use. It bypasses the MTHFR bottleneck, supports homocysteine regulation, and delivers immediate biological benefit.

In other words, methylfolate delivers active folate direct to your cells without relying on inefficient conversion pathways.

Methylfolate also crosses the blood-brain barrier, allowing it to directly support neurological function, optic nerve health, and cognitive clarity. Folic acid, by contrast, remains largely confined to peripheral circulation and must undergo multiple conversions before becoming usable; this is a process that’s inefficient and genetically limited for many individuals.

Several recent studies have confirmed the benefits of methylfolate in supporting retinal perfusion, reducing vascular stress, and improving visual outcomes:

• A 2019 case series in Eye and Vision (London) documented improvements in microaneurysms, exudates, and retinal edema in patients with diabetic and hypertensive retinopathy after taking supplements containing methylfolate and vitamin D. All patients had MTHFR polymorphisms.
• A 2020 pilot study in Molecular Vision found that three months of methylfolate supplementation significantly reduced homocysteine levels in diabetic patients and showed a trend toward increased retinal blood flow.
• A 2021 study reported that supplementing with methylfolate reduced homocysteine levels and retinal venous pressure in those with glaucoma.
• A 2022 prospective study in Clinical Ophthalmology showed that methylfolate improved retinal microcirculation and visual acuity in patients with mild diabetic retinopathy and MTHFR polymorphisms.
• A 2025 case-control study in Advanced Ophthalmology Practice & Research found that adding methylfolate to anti-VEGF therapy in those with macular degeneration significantly reduced homocysteine and retinal venous pressure, improved retinal fluid clearance, and allowed longer intervals between injections.

These studies support the use of methylfolate as a proactive nutrient for vision support, especially in individuals with vascular risk or genetic conversion issues.

Feature	Folic Acid	Methylfolate (5-MTHF)
Form	Synthetic, inactive	Active, bioavailable
Conversion Needed	Yes	No
Absorption	Variable	High
Genetic Compatibility	Limited	Universal
Risk of Accumulation	Yes	No
Stability	Moderate	High
Cross Blood-Brain Barrier	No	Yes

I Eat Leafy Greens. Do I Still Need Methylfolate Supplements?

Folate is naturally found in foods like spinach, leafy greens, broccoli, legumes, and citrus fruits. But folate deficiency is relatively frequent with age. Several factors can affect how much folate your body actually absorbs and uses:

• Age: As we age, absorption efficiency declines, and homocysteine levels tend to rise.
• Genetics: MTHFR polymorphisms can impair folic acid conversion.
• Diet: Many diets lack consistent sources of natural folate. Furthermore, dolate degrades quickly during storage and cooking
• Medications: Certain drugs (e.g., methotrexate, anticonvulsants) can interfere with folate metabolism.
• Health conditions: Digestive disorders like coeliac or Crohn’s disease can reduce folate absorption.

That’s why methylfolate, or 'active' folate is often recommended in supplement form, particularly for those over 50 or with elevated homocysteine levels.

Why Nutravision Uses Quatrefolic®

Most supplements that contain methylfolate use it in the form of calcium methylfolate. While this form is biologically active and superior to folic acid, it has some limitations in terms of solubility and stability, especially in complex formulations.

That’s where Quatrefolic® comes in.

Quatrefolic® is a patented glucosamine methylfolate. It delivers the same active methylfolate, but in a form that’s more water-soluble, more chemically stable, and more bioavailable than calcium methylfolate.

“The high solubility of glucosamine methylfolate makes it immediately and completely bioavailable.” Prof. Luca Tiano, Polytechnic University of Marche

In a pharmacokinetic study published in Minerva Ginecologica, Quatrefolic® was shown to:

• Reach 1.8x higher peak plasma levels than calcium methylfolate
• Deliver 12% greater total absorption over 8 hours
• Outperform folic acid by 9.7x in total bioavailability

This matters because bioavailability determines how much folate your cells actually receive. For people with MTHFR polymorphisms or vascular risk, that difference can be the tipping point between protection and progression.

That’s why Nutravision uses not just any methylfolate, but the most advanced, bioavailable form — Quatrefolic®.

To Conclude

To summarise, methylfolate plays a vital role in vision health by regulating homocysteine, supporting red blood cell formation, and protecting the vascular and neurological systems that underpin the eye-nerve-brain axis.

When selecting an eye multivitamin supplement, whether as a supplement for optic nerve function, macular health, or general vision support, consider one that contains methylfolate for its distinct advantages.

Nutravision is a next-generation vision vitamin supplement built on the pioneering NP-10 System™, enriched with the methylfolate form of folate, the methylcobalamin form of vitamin B12, the nicotinamide form of vitamin B3, and powerful natural antioxidants such as ginkgo biloba, lutein and saffron.

By including Quatrefolic® in its formulation, Nutravision sets itself apart from other eye supplements, making it the perfect choice for those looking to support and maintain their eye-nerve-brain vision ecosystem over the long term.