Eye Health

Greens and Glaucoma—What You Should Eat To Reduce Risk By 20-30%

Imagine losing your eyesight gradually over time.  Your peripheral vision begins to go, but you barely even notice the change until damage is already done.  That’s what individuals with Primary Open-angle Glaucoma, (POAG) experience as their disease slowly steals the ability to see.  Without pain or debilitating symptoms, glaucoma can lead to permanent blindness.

Based on evidence that nitrates, (precursors for nitric oxide) help stimulate blood flow, researchers from Brigham & Women’s Hospital and Harvard Medical School, Boston set out to determine if certain foods (high in nitrates or nitrites) could aid in the prevention of POAG, which results from progressive optic nerve damage.

With the understanding that intraocular pressure and optic nerve blood flow are responsible for Primary Open-Angle Glaucoma, scientist, Jae H. Kang, Sc.D. and colleagues followed up on more than 100,000 study participants, aged 40 and over for a period of 26+ years.  These individuals were free of POAG at the onset of studies and were divided into five groups based on dietary nitrate intake.  The group with the highest nitrate intake ate about one and one-half servings of leafy green vegetables per day, while the lowest group ate only one serving every three days.

Through regular eye examinations and questionnaires researchers found that approximately 1500 participants developed glaucoma.  Individuals who had the highest intake of nitrates and green leafy vegetables however, were found to have a 20-30 % lower risk of developing POAG in their lifetime.  According to the authors, “These results, if confirmed in observational and intervention studies, could have important public health implications…Nitric oxide signaling is important for maintaining optimal blood flow, and some evidence suggests that it may also be important for keeping eye pressure low,” added lead author, Kang.

Findings were published in the January 2016 edition of JAMA Ophthalmology.


The Connection—What To Eat

While scientists aren’t completely sure of the reasons for the connection between leafy green vegetables and glaucoma, they do know this.  Glaucoma results in part, from restricted blood flow to the optic nerve, and the eyes produce nitric oxide naturally that helps regulate blood circulation.  Leafy green vegetables such as kale, romaine lettuce, collard greens, and spinach contain nitrates.  These nitrates convert to nitric oxide in the bloodstream and help maintain the proper function of blood flow through the eyes. 

What Is Glaucoma?

Found to be the leading cause of blindness in individuals, there are several types of glaucoma disease that cause damage to the optic nerve.  The retina uses this nerve pathway to transport images to the brain once captured.  Eye pressure permanently damages the delicate nerve fibers causing blind spots, and eventually loss of vision altogether. 

Open-Angle Glaucoma is a specific type of glaucoma where the angle in the eye (where the iris touches the cornea) is the proper aperture.  Clogged drainage canals cause an increase in pressure in the eye however, which damages the optic nerve.  This is the most common type of glaucoma currently, affecting about four million Americans.  Sadly, many cases go undiagnosed for years.


What Are The Warning Signs?

While glaucoma does its damage long before most symptoms occur, there are signs that indicate it’s time to see an eye doctor.

  • Difficulty with adjustment to dark rooms
  • Trouble with focus on objects near or far
  • Squinting from unusual light or glare
  • Iris color changes
  • Swollen lids, or red-rimmed, encrusted eyelids
  • Persistent eye pain
  • Double vision
  • Dark spot in center of field of vision
  • Outlines seem wavy or distorted
  • Persistent watery eyes
  • Itching or burning eyes in addition to dry eyes
  • Seeing ghostlike images or spots
  • The following conditions may require emergency medical treatment:
  • Sudden vision loss in one eye
  • Sudden hazy/blurred vision
  • Seeing flashing lights or black spots
  • Seeing rainbows or halos around light

Who’s At Risk?

Risk factors include:

  • Age
  • Eye pressure elevated
  • African ancestry
  • Corneas are thin
  • History of glaucoma in family
  • Nearsighted
  • Preexisting injuries to the eyes
  • Use of steroids
  • A history of shock or anemia that is severe

Individuals may also have an increased risk of Open-Angle Glaucoma if they are diabetic, or suffer from hypertension, according to the University of Michigan Kellogg Eye Center.


Prevention and Protection

Early detection is the key to protection from irreversible damage to eyes.  Because Open-Angle Glaucoma occurs without warning, it is important to get eye exams on a regular basis.  While there is no “cure” for glaucoma, the disease can be prevented or managed very effectively with one or more treatment measures.  A combination of eye drops, prescription medications, laser procedures, surgical procedures, or dietary changes may either prevent, or slow further damage from occurring.

Other conditions that can affect eyesight include, cataracts, macular degeneration, and diabetic retinopathy.

For healthy eyes it is critical to limit exposure to:

  • Smoke
  • Sunlight
  • Environmental toxins

The following may help prevent certain age-related eye diseases and conditions:

  • Omega-3 fatty acids
  • Lutein
  • Zeaxanthin
  • Vitamin C
  • Vitamin E
  • Zinc
  • Copper
  • Vitamin B complex with folic acid

Foods including the following may promote eye health:

  • Spinach
  • Kale
  • Collard greens
  • Brightly colored fruits
  • Fish
  • Walnuts
  • Seafood
  • Canola oil
  • Flaxseed oil

Nutritional Support Through Natural Supplements

Natural dietary supplements containing vitamins, minerals and herbal extracts may aid in the prevention or management of certain ocular conditions.


Offers support for eyes, lungs and arteries in a purified formula, derived from marigolds.  Helps protect eyes from free radical damage.


Contains lutein, antioxidants, vitamins and minerals to protect eyes from oxidation and damaging free radicals.


Helps extend the life of antioxidants through alpha-lipoic acid, as well as fight free radicals both within and outside cells.

Getting the right nutritional support to meet the body’s needs for healthy eyes is critical.  While some conditions may not be cured through current treatment modalities, they may be prevented altogether through changes in diet and supplementation.

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