Doctor's Note

Plant-based diets may help prevent all four major causes of blindness. I’ll cover the other two, glaucoma and cataracts, in Prevent Glaucoma and See 27 Miles Farther, and Prevent Cataracts with Diet; my next two videos in this three-part series. See also How to Prevent Diabetes, and How to Treat Diabetes. And for an alternative Alternative Healthy Eating Index, see Calculate Your Healthy Eating Score

Also, be sure to check out my associated blog posts: Preserving Vision Through Diet, and Treating Crohn’s Disease With Diet.

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  • Michael Greger M.D.

    Plant-based diets may help prevent all four major causes of blindness. I’ll cover the other two, glaucoma and cataracts, in my next two videos in this three-part series. See also How to Prevent Diabetes and How to Treat Diabetes. And for an alternative Alternative Healthy Eating Index, see Calculate Your Healthy Eating Score. In addition, please help yourself to the hundreds of other videos on more than a thousand subjects.

    • HemoDynamic

      The Bomb you are!!  Without that daily dose of Dr. Gregor’s reviews I would be flailing to keep up with the science and would probably just give up, and go back to eating meat!  Well, not really but I would have resorted to some Tofurkey ;-}

  • guest

    I was surprised to read in the last source you cited that “alcohol consumption of 1.5–2.5 drinks/d as ideal for men and 0.5–1.5 drinks/d as ideal for women.” Aside from you previous comments that alcohol doesn’t help people who practice even a minimally healthy lifestyle, I’d always heard that bad booze makes you go blind. Guess there must be some wine connoisseurs on Harvard’s nutrition board.

    • I thought that what I heard was methanol makes you go blind.

  • This video correctly covers the fact that patients who eat a healthy diet are much less likely to suffer severe vision loss from Macular Degeneration (ARMD).  However, it is also important to NOT smoke and to wear sunglasses to minimize your risk.

    Also, as an eye doctor who has worked with the visually impaired for 20+ years, I have NEVER seen a patient go totally blind from ARMD.  It is a devastating disease that causes loss of central detail vision in the central area of the retina.  But it has no effect on the rest of the retina, and as such most patients are still able to move through the environment without seeing eye dogs, canes for the blind etc.  ARMD takes away all your detail vision however, so reading, driving, watching TV etc are profoundly worsened.  

    For an informative article on ARMD look at this link:

    • Valnaples

      Sorry, now I see in your article the importance of fish oil…thanks! I live in Florida and my eye doctor is also always reminding me about sunglasses too when I go for my routine eye checks…he reminds me about leafy greens too.

    •  Thanks for the information Dr. Henahan.

      I see that fish oil is really beneficial against macular degeneration and of course other things. I’d be getting my omega 3 from a plant source though. It’s about time I get it as I’ve been neglecting it for a long time.

      • Great idea.  I have recently changed to vegetable source EPA/DHA too.  It is more expensive, but I prefer to minimize my animal product intake and I have no worries about residual contamination of fish sourced EPA/DHA.

        • HemoDynamic, M.D.

          Is Flax seed expensive?  Omega 3/Omega 6 ratio of 2:1.  That’s twice as much Omega 3 as Omega 6!  And it’s cheap.  The only other food that comes close is Chia Seed–It tastes discusting (in my opinion) and looks better on my Chia Pet–Just ask Bob Ross.

          • MJ

             How do you eat your chia seed? I put a teaspoon in my smoothies or pancake mix and was thinking about adding it to salads and soups. I haven’t noticed any flavor (good or bad) from the chia. It’s milder than poppyseeds, in my experience. I’d love to sprout it too. Maybe I’ll have to buy a chia pet!

          • HemoDynamic, M.D.

            Maybe it left a bad taste in my mouth after my parents spread chia seeds all over me and made me stand in a corner for a week to grow my own ghillie suit. No not true but it sounded good ;-}
            James R. Bennie, M.D.
            Redding Family Medical Group
            2510 Airpark Dr. Ste., 201
            Redding, CA  96001
            Ph. 530.244.4034

            From: Disqus
            Sent: Wednesday, May 23, 2012 6:51 AM
            Subject: [nutritionfacts] Re: Preventing Macular Degeneration with Diet

            Disqus generic email template

            MJ (unregistered) wrote, in response to HemoDynamic, M.D.:
            How do you eat your chia seed? I put a teaspoon in my smoothies or pancake mix and was thinking about adding it to salads and soups. I haven’t noticed any flavor (good or bad) from the chia. It’s milder than poppyseeds, in my experience. I’d love to sprout it too. Maybe I’ll have to buy a chia pet! Link to comment

          • Marge

            I make Chia Pudding.  Put 2-3 Tablespoons in a bowl, add some chopped nuts, raisens, some natural sweetener,(I add maple syrup), and some Almond Milk.  Put in fridge till it thickens. Add more Almond milk, if needed for pudding-like consistancy. 

          • HemoDynamic, M.D.

            Sounds Delish!  I will give it a try.

  • Valnaples

    Yes, Dr. Henahan: I have a high school friend who had cataracts before the age of 50! Her eye doctor said it was probably due to the fact that she smokes. Also, I’ve read of fish oil being very important for eye health; do you think it’s important to also include to stave off eye disease especially as we age? Thanks.

  • LisaKSkinner

    I’d love to rely exclusively on diet and flax seed for my Omega3s instead of fish oil DHA capsules. Is there a standard amount of flax seed that’s recommended for daily consumption? Also, does using ground flax seed in baked goods lessen the efficacy of the Omega3s?

    • Toxins

       Fish oil is quite harmful indeed so it is best to stick with the flax seeds.

      Dr. Greger recommends two tablespoons of flax seeds per day.

      Woman need approximately 1.1 grams of omega 3 per day and men need 1.6 grams of omega 3 per day. Two tablespoons of ground flax seeds have approximately 3.1 grams of omega 3.

      Cooking does not degenerate the fats, they remain intact so it is perfectly ok to cook with ground flax seeds as the omega 3 will not be diminished.

      • LisaKSkinner

         Hi Toxins,
        Thanks so much!
        It’s easy to add ground flax seed to baked goods, for example, plus ground flax seeds work well as a substitute for eggs in recipes for muffins and the like.

      • Lawrence

        My understanding is that heat does harm flax seed oil. That is why I use organic, cold pressed flax seed oil.

        • Americium Dream Documents

          cold pressed less harmful to oil than baking?!
          when you pull the oil it is exposed to oxygen;
          baking saves the oil from oxygen by adding
          antioxidant herbs and more oxygen-stable fats
          like monounsaturates or mct oil,
          so that instead of longterm exposure to air,
          we are going straight from the protective seed
          to the fatty antioxidant emulsions .

          • Lawrence

            I no longer use the oil but the meal as the oil within the meal is more stable in this form.

      • David Johnson

        What about risk of ingesting too much cadmium from flax? I have seen no discussion of this point. Perhaps 1 or even 2 Tbls per day would be ok. But I don’t know if that’s true. Also there’s the issue that not much of the plant Omega 3, ALA, is converted to DHA. At least one study has shown vegans have very low DHA levels. To me that’s a good argument for geting DHA/EPA from algae-based supplements.

        • Toxins

          Here are Jeff Novicks comments on Cadmium and flax

          The EPA has determined that exposure to cadmium in drinking water at concentrations of 0.04 ppm for up to 10 days is not expected to cause any adverse effects in a child.

          The EPA has determined that lifetime exposure to 0.005 ppm cadmium is not expected to cause any adverse effects.

          The FDA has determined that the cadmium concentration in bottled drinking water should not exceed 0.005 ppm.

          The Occupational Health and Safety Administration (OSHA) has limited workers’ exposure to an average of 5 μg/m3 for an 8-hour workday, 40-hour workweek.

          However, food is not really the main issue here especially for those following the recommendations here. While low levels are found in all foods the highest levels are found in shellfish, liver, and kidney meats. As with most of these chemicals, eating low on the food chain is important to decreasing exposure.

          In addition, while toxicity has occurred from contaminated water getting into the food supply, human exposure to environmental cadmium is primarily the result of the burning of fossil fuels and municipal wastes. Tobacco smoking is the single most important source of cadmium exposure in the general population. On average, smokers have 4-5 times higher blood cadmium concentrations and 2-3 times higher kidney cadmium concentrations than non-smokers.

          Cadmium content is influenced by the soil and studies have shown no significant change (or difference) in blood cadmium levels after supplementing with flaxseed or flaxseed oil.

          European Journal of Clinical Nutrition (2002) 56, 157-165. DOI: 10.1038/sj/ejcn/1601298 The effect of flaxseed supplementation in processed foods on serum fatty acids and enterolactone

          In regards to ALA conversions,

          This recent study showed that the conversion rate in Vegans is 2x that of a fish-eater.

          “Comparison of the PLLC n23 PUFAs:DALA ratio between dietary-habit groups showed that it was 209% higher in vegan men and 184% higher in vegan women than in fish-eaters, was 14% higher in vegetarian men and 6% higher in vegetarian women than in fish-eaters, and was 17% and 18% higher in male and female meat-eaters, respectively, than in fish-eaters This suggests that the statistically estimated conversion may be higher in non-fish-eaters than in fish-eaters.”

          In addition, another study showed that despite this “theoretical” low conversion rate, there is not evidence of any harm so, the problem may not be in the conversion rate, but in the assumption that it is low.

          “There is no evidence of adverse effects on health or cognitive function with lower DHA intake in vegetarians”

          “In the absence of convincing evidence for the deleterious effects resulting from the lack of DHA from the diet of vegetarians, it must be concluded that needs for omega-3 fatty acids can be met by dietary ALA. ”

          • David Johnson

            Thanks very much for the references!

          • David Johnson

            Unfortunately the article at


            is not free so I could not read it. I did read the other one. Some neurological disorders could take decades to manifest. It seems to me that the effetcs of extremely low DHA over decades has not been satisfactorily addressed. The brain/nervous system has lots of DHA, so I’m still concerned.

            Please note that Fuhrman recommends DHA supplementation based on his experience with older male vegans. Here’s a quote from Fuhrman’s website:

            “Omega-3 fatty acids and Parkinson’s disease (PD): A number of animal studies have shown that DHA has preventive and/or therapeutic effects against PD.20-22 I have seen PD in a surprising number of elderly men that eat healthy vegan diets, and I have also observed that all these men were DHA-deficient. Since men convert ALA to DHA less efficiently than women, prevention of Parkinson’s disease with DHA supplementation may be important for non-fish eating men.”

            On the other hand, Fuhrman’s experience is not a scientific study, let alone a consensus based on many studies.

            Norris, based on Furhman’s experience, also recommends supplementation. Here’s a link to Norris’ opinion:


            If you find more articles relevant to this topic, I’d appreciate a heads up. For now, since I see no drawback to taking an algae-based Omega 3, I prefer to err on the side of caution and supplement directly.

            Thanks again for your informative response to my original query.

          • Toxins

            Remember that DHA is created in the body. The elderly generally have poor conversion rates of many things including vitamin D and b12 probably due to aging rather then dietary deficiencies. In these cases it may be necessary to supplement if a deficiency is present. Taking an algae supplement will cause no harm either way

    • Paul3917

       You can also get long-chain omega-3’s from algae oil capsules which of course, are vegan, but they’re a bit expensive.Whether vegans need too   supplement with long-chain omega-3 or whether flax seed is good enough is uncertain. Dr. Fuhrman is at present running clinical trials to answer that question. Until we know the results, I think I’ll continue to take my algae oil just to be on the safe side. 

  • Ak42

    These videos are great! You get to the point and support it. I have shared these with friends who are checking out all your videos. I have been trying to tell them that plant-based is the way to go. You make it concise and easy to comprehend. Thank you.

    Ann K

  • Freedomcallyuri

    hello doctor greger.

    i really enjoy your videos , i think you are a great speaker and you connect with the crowd very well . in relation to this video i have a question , do you know of any studys which looked at retinitis pigmentosa and diet ? 

    • Jacquie RN

      Thank you for the kind words. It appears as though little research has been done on this subject so no definitive conclusions can be made. However, it has been suggested by some research that vitamin A may have a beneficial effect for people with RP. One study was recently published in June 2012 in the Archives of Ophthalmology: ω-3 Intake and Visual Acuity in Patients With Retinitis Pigmentosa Receiving Vitamin A (Arch Ophthalmol. 2012;130(6):707-711). The study calculated dietary intake from questionnaires completed annually by 357 adult patients from 3 randomized trials who were all receiving vitamin A, 15 000 IU/d, for 4 to 6 years. The researchers concluded that ʺmean annual rates of decline in distance and retinal visual acuities in adults with retinitis pigmentosa receiving vitamin A, 15 000 IU/d,are slower over 4 to 6 years among those consuming a diet rich in ω-3 fatty acids. To our knowledge, this is the first report that nutritional intake can modify the rate of decline of visual acuity in retinitis pigmentosa.ʺ

  • Erin

    It just blows me away that most people still don’t seem to know that diet and lifestyle choices largely predict health and disease status :(

  • Jason Strong

    I really appreciate this! I’ve just recently heard about this, and have been looking for someone who knows how to work with macular degeneration in Danville IL, and this gave us some insight for what to look for when choosing one. Thanks for sharing!

  • jamesKelly

    I keep reading references to a studies that showed an increase in
    maculardegeneration in people who took flaxseed daily. Thus getting your
    omega3 from animal source is recommended in people at risk or having
    early signs of amacular degeneration
    But i can never fine the actual research
    I think they are referring to ALA causing an increase risk for macular degeneration
    I was wondering if anone eslse has found the actual research

    Example of where I have found this reference

    University of Maryland Medical Center
    “Although studies have found that eating fish, which includes omega-3
    fatty acids, regularly may reduce the risk of macular degeneration, a
    recent study of two large groups of men and women found that diets rich
    in ALA may increase the risk of macular degeneration. Talk to your
    health care provider.”

    Its confusing

    • garret leahey

      Pls post the source of your quote with as much detail as possible. Thanks in advance for your help.

  • Is there any way to *reverse* the effects of AMD with diet? My Mom is practically blind. Wish I had seen your videos years ago.

  • Pamela Cornely Coyle

    what about AREDS and AREDS 2 supplementation for moderate dry macular degeneration? Is that supplement likely to interfere with the antioxidants in a Whole Food Plant Based (no sugar, minimal oil) diet?
    Pamela Coyle, M.D. (retired radiologist
    P.S. The ophthalmologist recommended it, but the studies as I understood them showed benefit only for wet advanced macular degeneration.