Doctor's Note

Because different families of fruits and vegetables can have entirely different phytonutrient profiles, variety is important. See, for example:

Eating oranges is always better than drinking juice. I'll discuss the difference more in the next video Reducing Muscle Fatigue with Citrus.

Please make sure to rinse your mouth with water after consuming sour fruits to protect your tooth enamel (see Plant-Based Diets: Dental Health).

For more context check out my associated blog post: How Citrus Might Help Keep Your Hands Warm and Citrus to Reduce Muscle Fatigue.

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  • brec

    What are those apparently tiny citrus fruits in the video’s initial picture?

    • Kumquats! I’m so glad you asked–they’re my fave. The skin is so thin, you eat them skin and all so get all those rind phytonutrient goodies. My grandma used to have a kumquat tree that I have fond noshing memories of from my childhood.

      • brec

        The produce guy at my local Whole Foods says that kumquats tend to be available in the winter.

  • JB

    Is there any evidence that eating citrus or taking hesperidin alone may be helpful for those with Raynaud’s phenomenon?

    • That’s exactly what I was thinking JB! Unfortunately, I’m not seeing anything:

      • Bummer!

        I’m excited about this finding. I also get cold hands and feet quiet often (I believe it is related to my Hashi’s). I am hoping that this citrus finding might help me get the blood flowing. However, I did a similar search as yours Dr. G on PubMed and found nada. :(

        Still, I’m going to try chomping on more oranges to see if I can sense a difference.

      • HemoDynamic, M.D.

        Thanks for this interesting study find! Again, deeply appreciated!

    • Thea

      Great question JB. I’ve always had the ridges in my nails, but it wasn’t until I was an adult that the cold started cutting off the circulation in my fingers. The condition has gotten worse as I have gotten older and it adds an element of fear when I consider participating in outdoors events during the winter. (My doctor’s only help (which to be fair may be all that she had to offer) was to wear gloves – which does absolutely nothing for me.)

      I guess I’ll just have to eat a bunch of oranges this winter and see if it helps.

      • JPotter

        Agreed that gloves are little help, sometimes even seem to make Raynaud’s cold fingers worse. Ample mittens, big enough to ball your hands up inside, work much better. My partner’s Raynaud’s used to be big trouble; but he’s had no finger shutdowns in the last few years, since taking to a plant based whole foods no added oil diet.

        • Thea

          JPotter: Thanks for sharing! I’ve been pretty close to whole plant based diet – though I do sometimes have oils in my diet. (Most of the time I modify a recipe to take the oils out.)

          I’ve also found that the best approach is to keep all the fingers together and curled up into a fist if possible. My approach has been to pull my hands inside my sleeves when I can. I often can’t make-due with mittens. I’m usually out with my dog and end up needing to have actual use of my hands/fingers fairly frequently. I can pull my hands in and out of my sleeves pretty easily, but it’s really not a great solution. Too often I still get the “progressive vessel collapse” (as I think of it).

          I’ve tried those hand-warmers with some, minimal, success.

          Thanks again for sharing.

          • I use the curled up fist technique, as well.

            Feet are another animal altogether, though. At night, I try to warm my feet on my partner. He does not appreciate that much. So, sometimes I sleep with socks on.

            If time and circumstance allow, I take a hot bath; that seems to warm me up pretty good. If time and circumstance do not allow, I sometimes warm my hands under warm running water.

          • Thea

            re: unappreciated warming of one’s feet on one’s partner.
            Oh pish-tosh. What are partner’s for?

            re: running water: Yes, a huge help for me. What causes me concern is when I’m at a place like the beach (which gets very cold and windy here) and I can’t guarantee that I will have access to warm water. I worry about that sort of thing a lot. It’s been fine so far. I just worry. Of course, now I could down a few oranges/orange juice – but then I expect to have some bathroom problems. There’s never any pleasing me.

          • “What are partner’s for?” Ha ha! That’s what I tell him. :)

          • LynnCS

            Yes, have to remember that part. Thanks. Going to start with one orange and test it out.

      • LynnCS

        Raynauds is a problem for me to, so hope the oj works too. As far as the ridges in the fingernails, mine have really improved since being on McDougalls. Keepin it preety tight. Whole only. Going for the healthiest possible outcomes.

    • HemoDynamic, M.D.

      JB I will let you know if it works because my son (13 yo) has this problem of Reynauds phenomenon. It’s always worse when he eats dairy, or gets dehydrated which happens when he is playing basketball. So even though it will be anecdotal we are going to try and control the variables [eliminate all dairy (which he almost always does) and stays hydrated] and see if it (the orange) works for him.

      • Plantstrongdoc M.D.

        Your son eats dairy !?
        Is he smoking too !!!?

        • HemoDynamic, M.D.

          It’s rather a funny story. He doesn’t eat dairy a lot but we went camping last week and instead of camp grub we decided to go to a local Mexican food restaurant and get some food. So (in his infinite wisdom–at 13 yo) he decided to order a Cheese Quesadilla which he never eats and happened to be packed with cheese. He even stated to me, “Hey Dad look at this (pointing to the huge amount of stringy mucus–cheese) on his quesadilla and proceeded to eat all that cheese.
          Then after we went back to the camp he went with his friend down to the store which sold Soft-serve ice-cream about 20cm tall!!!
          He told me the next morning it was the worst night of his life! He woke up about 1am and had to run to the bathroom and had explosive diarrhea (visual in effect) that lasted about 20 minutes and for three more times that night.
          The next day his stomach was so upset that Pepto Bismol helped but he said I am never going to eat that crap again.
          Letting kids do what they want is the best lesson of all, rather than “brain-washing” them to believe what “we” already know!
          No, he’s not smoking–yet! ;-(
          At least that I know of.

  • Gb0138

    Interesting. I use orange essential oil in hand lotion on my feet on cold nights. I swear it keeps my feet warmer. Is that possible?

  • Nelson

    Dr G, when is your show on Dr Oz going to air?

  • How many oranges would one have to eat to equal 2 cups of OJ?

    • Darryl

      Less than you might imagine. Hesperidin (and other citrus polyphenol) concentrations are highest in the peel, not the juice.

      Nogata, Yoichi, et al. “Flavonoid composition of fruit tissues of citrus species.”Bioscience, biotechnology, and biochemistry 70.1 (2006): 178-192.

      Take a look at table 3 (peel concentrations) and table 4 (juice vesicle concentrations) and you’ll note hesperidin levels are higher by roughly 30-40 fold in the peel.

      • BPCveg

        Hi Darryl,
        I really appreciate your thoughtful and scholarly posts. Including orange peel in the diet is intriguing.

        I guess when comparing OJ with whole oranges on the basis of nutrient content, another potentially important variable is the fullness factor. Say OJ gives you half as much of an important nutrient than the equivalent amount of whole fruit but you can consume four times more OJ without feeling as full, then aren’t you still better off going with the OJ?

      • Lawrence

        Be careful with consuming citrus peel as it contains aromatic oils which can upset your tummy.

        • LynnCS

          We use orange and lemon “essence”…peel in foods all the time and the pith is where the bioflavanoids are. I have eaten it since I was a kid. Always liked it. Funny what some of us throw out as garbage.

  • APM

    Is taking vitamin C supples as effective as eating or drinking the citrus?

  • Why does blood flow increase? Caldwell Esselstyn describes blood flow and the role of nitric oxide. Any connection, do you think?

  • I can vouch for this. I had a long history of cold hands and feet, even in the summer. When I went “raw”, I no longer suffered from bad circulation. When winter came and I ate some cooked lentil soup, my hands and feet got cold again. I thought to myself, “Deer live outdoors all winter…” so I went back to eating raw – especially dark green leafy vegetables – and my hands and feet grew warm again. Green leaves contain chlorophyll, which is only one ion different from hemoglobin. The structure of a leaf reflects the veins and vessels, capillaries in our bloodstream.

  • David Pollock

    Does grapefruit also have at least reasonable levels of hesperidin?

    • Katrina

      Naringin is the flavonoid found in grapefruit, not hesperidin. While there are amounts of hesperidin in grapefruit, the amount is not as well absorbed by the small intestine. Naringin is the best absorbed flavonoid in the grapefruit. The fact that hesperidin is not absorbed through grapefruit does not make grapefruit not as healthy- it only means it has a different flavonoid make up.

  • Ronald Chavin

    Because (1)orange juice contains just as much of the flavanone polyphenol, hesperidin, and the carotenoid, beta-cryptoxanthin, as whole oranges and (2)drinking orange juice has been shown in studies to be substantially less beneficial to our overall health in many ways compared to eating whole oranges, we can conclude that the flavanone polyphenols and the carotenoids in citrus fruits aren’t anywhere near as wonderful as the phytochemicals found in allium vegetables, cruciferous vegetables, legumes, mushrooms, white tea, triphala, Korean red ginseng, psyllium, and wheat bran:

  • Mmr

    Does the study mention whether the core gets colder as a result of the increased blood flow to the extremities? Since as you said, our bodies decrease the blood flow to our extremities to conserve heat, I worry that this might have an unwanted effect in that respect.

    • LynnCS

      I’m no expert, just a Raynaud’s sufferer. I have read that the extremities won’t warm up till the core is warmed up sufficiently. That answered my question about why, when I get this blanching or darkening, I have to turn all the heaters on and am completely frozen till I get warmed up “inside” and then and only then, will my fingers return to normal and then I can see why everybody else is saying “It’s hot in here.” Sowwy!

  • Very cool and smart post.

  • Dan Lundeen

    Has hesperiden been studied for cold urticaria (allergic reaction to cold)?

  • LynnCS

    Dr Greger..Thank yolu so much…So interesting. You didn’t mention whole oranges but, I can only imagine that it would be good. Less juice to the serving, of course. I have raynauds and this sounds like something I could use. For some reason I have stopped drinking oj and less whole oranges too. I think it is the fruit sugar/triglyceride/belly fat issue. Also I have a realated question that I’ve been wondering for a long time. Many people have told me not to eat the skins of oranges. Considering they are clean, I don’t understand that. I thought the best source of bioflavanoids is the pith of the orange. I have always liked it. Aaaand don’t we zest the skin of the orange for lots of uses? Can you direct me to some info? I’m trying my best to use whole foods and not rely in supplements which I don’t really think are good for us. Any info would be appreciated. Thank you, Dr. Greger for these great video’s and blogs. Much appreciated. Lynn

  • Lloyd

    I get cold so easy, especially in my fingers and toes. Wow, this is just what I need. Citrus it is!

  • Baardmans

    I have been diagnosed with Raynaud’s some years ago and have been eating entirely plant-based for six months now. I feel much better in general, but while the Raynaud’s situation has not gotten any worse, it didn’t improve either.

    I tried taking a lot of citrus for a certain period, but it doesn’t seem to help much. I couldn’t find any more information specific to Raynaud’s on the website. I did some research for myself, and found that buckwheat is also a good source of quercetin, which supposedly helps, but alas, I have been eating it for a while but notice no improvements. I also found that caffeine has been believed to have a strong vasoconstrictive effect on the extremities. I also found that theanine, present in tea, ‘counteracts’ the caffeine. Yet I could not find any good information related to Raynaud’s or vasoconstricting/vasodilating effects of tea.

    Could you maybe point me in the right direction? The questions I have are:
    1. Does caffeine / coffee indeed restricts blood flow to the hands?
    2. Is this the same for (green) tea, or does the theanine counteract the caffeine (maybe there is even a small vasodilative effect due to the warmth that needs to be dissipated?)?
    3. Did you maybe come across some more research that might help with Raynaud’s ?

    Thanks in advance!

  • Peter

    Any alternative treatments for Raynaud’s phenomenon (primary) worth trying?
    I’ve been following a healthy whole-foods plant based diets for around 5 years, but still experiencing cold hands and feet – even in the summer time.

    What do think about Magnesium supplements for this cause? Is it worth trying out? Are there any side-effects? Or perhaps there are some other supplements that might help out?

  • Roberto Patera

    Hi, I’ve read that Hesperidin is mainly concentrated in Citrus peel and albedo, hence I wonder if orange juice has, instead, a low concentration of such Flavonoid…

  • James

    Hmmm, since it increases blood flow, can citrus be a healthy version of Viagra??

  • Shlomi

    Since this is the only video mentioning nutrigenomics, I’ll try to ask my question here-
    I’m going to apply for college this year, and I’ve been wondering what profession/courses I should take in order to be able to:
    a. do what Dr. Michael Greger does- examining and researching the way food cures illnesses.
    b. Make my own Researches in the area of nutrigenomics and nutrigenetics.
    Thank you :)