Doctor's Note

This is the final installment of my 4-part video series on the latest science on protecting our vision. In Greens vs. Glaucoma I listed the best foods to help prevent glaucoma, and in Dietary Prevention of Age-Related Macular Degeneration I did the same for age-related macular degeneration. Then I addressed the Dietary Treatment of Glaucoma, in which I also mentioned black currants (as well as in Enhanced Athletic Recovery Without Undermining Adaptation).

By using a standing or treadmill desk, we can avoid some of the other adverse health effects of sitting at a computer all day. See my video Standing Up for Your Health. I’m now up to 17 miles a day!

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  • Anon

    “most herbal supplement labels lie” and drugs share a common affiliation.

  • jj

    Do we having any studies that discuss light sensitivity and dilation relative to nutrition. Someone in my family has eye damage and the eye lets in too much light.

    • Guest

      I had viral pinkeye and was left with permanent light sensitivity. I too would like to know what could improve this condition.

      • Kartoffelmao

        A diet low in sugar is a start.

  • guest

    Speaking of supplements, I have never taken nutritional yeast ((and brewers yeast)) but would like to know if these are safe to ingest or are they man-made, factory, machinery produced food derivatives that have no place in the human GI tract? Some doctors online have made claims that these yeasts are MSG in disguise. Is this true? I do not understand the whole free and bound glutamate issue but there are vegans who avoid these nutritional yeast and brewers yeasts like the plague due to this issue. Any help, Dr. Greger?

    • Darryl

      Nutritional yeast is the same species used to leaven bread and brew beer. Its just grown on molasses, dried, and heat sterilized. Glutamate is a non-essential amino acid that when free (not part of a protein) is responsible for the 5th taste, umani or savouryness. In the brain, it also serves as an excitatory neurotransmitter required for memory formation. The concerns about its sodium salt MSG, are addressed in this review. Nutritional yeast is 9% glutamate, but only a fraction of that is free, and importantly, its low in sodium. Autolysed yeast extracts (like Marmite or Vegemite) have a higher free glutamate proportion and high salt content, and became the MSGs replacement of choice in processed foods. I use all three, but too much MSG will make your cooking taste like processed foods, while nutritional yeast and yeast extract offer more a complex, nuanced umani.

      • guest

        Thank you very much.

      • guest

        If it were the same as bread and beer, why don’t bread and beer have the high amounts of vitamins and minerals that are found in nutritional and brewers yeast? Something must be different, no?

        • Darryl

          I’m sure nooch uses yeast selected to express more B-vitamin synthetic enzymes, as well as optimized culture conditions. Beer, particularly unfiltered beer, actually contains significant amounts of B-vitamins, though the alcohol impedes absorption. The yeast makes a lesser contribution to the nutritional profile of bread, perhaps due to limited time during the rise. The minerals in the nutritional yeast are from the molasses in the growth medium.

          • guest

            “B-vitamin synthetic enzymes”?

            I thought the B vitamins were natural in the yeast, no? The product I want to buy says “unfortified” but still has B-vitamin amounts that are extremely high for such a small amount per serving.

          • Darryl

            Yeast has biosynthetic pathways for thiamin (B1), riboflavin (B2), niacin (B3), pantothinate (B5), pyridoxine (B6), biotin and folate. They don’t make cobalamin (B12), which is only produced by bacteria and added to the culture medium in some brands.

            Vitamins comprise only 0.5% of the weight of nutritional yeast – micrograms are tiny.

          • guest


          • DH

            Is there any difference between getting those B-vitamins from a B100 complex tablet versus specifically fortified (supplemented) nooch? i.e. is one healthier than the other?

            The only thing that worries be about my B100 complex is the 400 mcg of folic acid. I already get lots of folate in my diet – being a leaf-eater, naturally of course. The other things in there bring me nicely to my RDA/AI/DV values (except the choline, which at 41 micrograms is miniscule, but I do not want too much choline either…. Hazen’s research findings).
            I had angular stomatitis before I started the B100 complex. The nooch I eat is not specifically fortified with vitamins.

          • Darryl

            The B-complex pills are comparable in price but a bit more more complete for the vitamins. I’ve found them for 4¢ while bulk bin nutritional yeast ran 5¢ for 5 grams (1.8 tsp), which will cover 100% of needs for B1, B2, B3, B6, B9, B12, but not B5 or folate. However, if you eat greens for folate and wheat germ / mushrooms / tomato / sweet peppers etc for the B5, then you’re golden with the yeast. As I recall, when I ran some sample base diets through CRON-O-Meter, the only reason I needed yeast was if I wasn’t supplementing B12.

          • DGH

            Wow, that’s helpful info, thanks! From, I am marginally deficient in B5, despite taking a tablespoon of wheat germ per day, and tomatos at lunch and dinner as well as sweet bell peppers (red, yellow, orange). So I will continue my B complex therapy and not switch to the fortified noosh (though I continue to enjoy the unfortified variety). I do dislike the extra folate, given my family history of prostate cancer, but no family history of colorectal ca.

          • guest

            So would the folate in an unfortified nutritional yeast be folic acid, or folate? I don’t want to get too much folic acid (synthetic folate), and I assume they are using folic acid in the growth of the product, even though it is not fortified in the end.

          • Darryl

            Ohh, that was a surprise.

            I just looked at a dozen labels for nutritional yeast. Bob’s Red Mill, Bragg, Foods Alive, Frontier, KAL, Now Foods RedStar and TwinLabs products are all fortified with folic acid, as well as other synthetic vitamins, perhaps for better comparisons to multivitamins.

            The Betta Foods, Lewis Labs, and Solgar products were the only ones without. The Solgar label gives a sense of what the nutritional profile of yeast would be without the fortification. Not nearly so impressive. Without the fortification, yeast is pretty expensive as a vitamin source, with it, they’re mostly synthetic B-complex vitamins wearing Birkenstocks to fool rubes like me.

          • HemoDynamic, M.D.

            I wanted to say that I appreciate your time and effort you spend replying to the questions posted on this site. They are informative and helpful and fill a void that I cannot access, and that is ‘time’ for answering the questions. Keep up the great work!

  • Hillary Rettig

    great post, and the night-vision WWII story was fascinating.

    where are people getting these berries?

    • Mike Quinoa

      My Dad, who was in the RAF during World War II in Lancasters, once told me that air crews flying night missions were led blindfolded to their aircraft. That way their pupils would remain dilated and more light-sensitive when they took off in low light (sans blindfolds, of course).

      • Coacervate

        Right on Mike, There was terrific “selective pressure” on those crews. The ones who could see best survived…longer. God bless them everyone.

  • Coacervate

    Thanks, great stuff as usual. i want to point out that saying that all supplements are bad is equivalent to throwing the baby out with the bath water. Like most generalizations it is not true…(a lie then?) and more importantly, a good supplement can provide nutrition that otherwise would not be part of a persons diet. Have you ever eaten billberry? or currants? who eats beetroot every day? Or 3 times a week for that matter? Darn few.

    Few people can/will eat all the top sources of nutrients from day one. They will need years to make the transition. We can encourage with caution or just take an inflexible superior position and score a few points for Team Vegan. Whats the goal here anyway?

    Recently the dreaded FDA has tightened up on these companies who now must provide independent data to register for all New Dietary Ingredient (NDI) status. Some companies make good products that deliver good nutrition.

    So spread your wings you eagle-eyes and fly. time for fledglings to take to the sky…. lets keep our six clear, get the big picture and give em the whole 9 yards. thats how we win this battle of the Bulge (groan).

  • Lee

    There is also the story here in Norway that blueberry jam was used to improve the military recruits night vision.

  • DH

    Thank you, Dr Greger. I am going to try the standing desk idea. I also wonder if you meditate in addition to all other healthy activities? The nice thing about meditation is that you don’t have to sit to do it – in fact, walking meditation is just as powerful as sitting meditation, and for many people, it’s far easier to do (something about that rhythm of footsteps). Do you meditate?

    • Coacervate

      I’d chime in here too. Meditation helps enormously. It helps bring my BP down so much I’m now down to half a beta blocker and a single accupril. I use a “Resperate” breathing pacer and some skills our friend (a buddhist nun!) has taught us…fantastic difference. I’m not pushing (or dissing) buddhism…just that The spousal unit tells me i’m not nearly as bipolar which I don’t miss one bit. Its the alpha waves and higher blood CO2 levels that work the magic.

      • DH

        How does higher blood CO2 levels reduce bipolar … or are you referring to vasodilatation from high blood CO2 (mild respiratory acidosis) lowering your BP?

        • Coacervate

          The second thing, acidosis. I think by breathing deeply and exhaling slowing I become very calm and the co2 rises. When I get anxious, I practice deep breathing and after 15 min I can measure my BP come back say from 160 Sys to 140. I can feel the blood moving back out to my fingertips. It works better for me than many. I think that is because my BP is strongly affected by my mental state. Its a positive feedback loop. I stress about bp, the bp rises, i become more stressed.

          And you know, fewer drugs…got to be better. BP meds make me dizzy and i even blank out. If I stand up too quickly I find myself in a heap. Like those fainting goats I guess.

  • Plantstrongdoc M.D.

    Sometimes I get a craving after dinner for something sweet – many people probably know what I mean. Sometimes it takes willpower to resist. But I have found a solution. Frozen berries! It tastes great, it is convenient, healthy and obviously good for the eyes. Win win.

  • Thanks for the tips. I guess many of us should give our eyes some extra tlc in this computer age. We actually used some dried bilberries for a while. Timely video for us as I am thinking of getting something else for vision support. God bless! :)

  • Very interesting! I feel for your plight in making nutritional videos – darn those tips on looking away from the screen, anyway! :-) Can we buy authentic black currants anymore?

    • tedster

      They are not easy to find. I posted a similar question on the previous day’s video (Dietary Treatment of Glaucoma – Jan. 1) and “Darryl” had a helpful response.

  • Andrew

    So, if literal black currants are banned in the US, does that mean we cannot take advantage of this research by eating the champagne black grapes that pass for currants?

  • Carmen Feconi

    Dr Greger, Thank you for efforts to provide support and knowledge from the primary literature to help us live a better life. I am a forest pathologist and I would like to comment on a statement that was made in this video about the black currant. While it is true that a tremendous effort has been made to eradicate the genus Ribes, the genus containing black currant, because of its role in the life cycle of the fungal pathogen Cronartium ribicola, and it is true that that fewer Sugar pines (Pinus lambertiana) are being harvested now, it is important to recognize that the extant populations are still threatened and destroyed by the disease white pine blister rust. More important than the effect on the harvest is the fact that these trees are large, old, and significant components of the forest’s and the earth’s biodiversity. Furthermore, “white pine” is a common name given to all five-needle pines which includes some amazing organisms like the ancient bristlecone pines (many members of this species are <4,000 y.o.!). White pine blister rust, a non-native or introduced plant disease, threatens all five-needled pines. I want to mentioned this because the video gives the impression that we can't grow black currant because of early 20th century timber industry interests. That is not completely true. I'm not trying to be contentious, but others in my cohort noticed the statement and I thought you would want to be made aware. Let me know if you ever make it out to California and I'll give you the tour of the white pines and we can eat wild ribes with our lunch.

    • Thea

      Carmen: Thank you for taking the time to write the information about black currents. I found it very interesting and helpful.

  • Yum

    The study on bilberries was in Japanese! LOL

  • Mary

    Can you do a video on nutrition’s effect on myopia? I’m curious if there are things people could be doing to prevent or slow worsening eyesight.

  • jamie

    here’s a great source for black currants grown in new york state. i’ve tried the concentrate, and it’s great.

  • andries

    I have floaters in my eyes. Is there a solution for reducing floaters ??

  • George Reichel

    What about blue light blocking glasses?

  • Protein Deficient

    How can i naturally reverse myopia ?
    It’s very hard to be cool with glasses.
    Does eating only sweet potatoes for a year may reverse it?

    Also, i thought all studies must be written in English according the to science community rules.

  • sretchko

    I saw a video from Dr. Mercola saying that LED light bulbs are very damaging to our eyes. Does any body have any more info on LED lights?
    I went into home depot to buy some light bulbs yesterday and they are re;placing almost all of their home use light bulbs with LED’s. The salesperson told me that they were phasing out all of their Incandescent and Fluorescent light bulbs with LED’s.

    You can see the article here

    • Thea

      sretchko: I read the following article and was left at the end of the article feeling unconcerned about LEDs: The nice thing about that article is that it has a section at the end with advice on how to keep your eyes healthy given the world we live in.

      For this case, I don’t know if Mercola is right or if the very first article I found (linked to above) is right. I do know that Mercola has proven unreliable in the past. He sells meat for goodness sake… So, I personally would not take his word for just about anything. I would recommend doing outside research.

  • Sam

    LEDs have a flicker rate /effect, almost all do, but we rarely “see” it, or rather perceive it, in contrast to a regular incandescent /halogen light bulb, which have a filament/spiral that glows, flicker less often. Constant flickering on/off does affect people, some more then the others.

    Here is some in-depth view of these light sources.