Doctor's Note

Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. And be sure to check out all the videos on juice, particularly Phytochemicals: The nutrition facts missing from the label.

For some context, please check out my associated blog posts: Alzheimer's Disease: Up to half of cases potentially preventableApple Peels Turn On Anticancer GenesThe Science of Acai Berries, and  Which Common Fruit Fights Cancer Better?

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  • Michael Greger M.D.

    Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. And be sure to check out all the videos on juice, particularly Phytochemicals: The nutrition facts missing from the label.

  • Heidi Woodruff

    What about green smoothies? I blend apples, bananas, blueberries and spinach. Is it better to have the whole fruit instead of the juice?

    • Toxins

      Hello Heidi,

      To add on to Nicky’s comment, typically it is best to eat the whole food as you don’t get as full from the smoothie. The fibers are destroyed in the blending process. Its a different story if your juicing a fruit because then you are missing out on 90% of then nutrients!

      • Joel

        Your post is confused. a) A green smoothie DOES use the whole fruits and veges, nothing less than eating them whole but unblended.
        b) What do you mean by “destroyed”?

        • Toxins

          Sorry Joel for the confusion, let me clarify.

          If your trying to get full, when you blend up an apple for example in a smoothie, you will not get as full as you would eating the apple alone because you have now liquified the fibers. If one is trying to get in the greens and fruits for the day then go ahead and liquify, no issues, but if your looking to stay satiated longer, then eating the whole food is best.

          I also added that juicing is a poor alternative to smoothies. I hope my post makes more sense now.

          • A

            Not actually true. There have been some studies (sorry i can’t reference them i saw it on a BBC nutrition documentary) that compared fullness from eating a fruit and drinking a glass of water compared to a smoothie of the same fruit blended with the same amount of water. The smoothie was actually more fulling. This is because unless the water is fully blended with something to give it nutrients and calories it get absorbed very quickly leaving behind the fruit like a sieve. Where as a smoothie the liquid component gets absorbed way slower (along with the fruit) as the body can’t separate them as they are so well blended. This is all despite the fact some of the fibre gets broken down during the blending process. I have a smoothie every day for breakfast and it leaves me incredibly full unit lunch time.

          • Ed

            Interesting. Jeff Novick presented the results of a study that had the exact opposite conclusion from your study. He talks about it here:


    • Michael Greger M.D.

      I’m a huge green smoothie fan! You’re taking the healthiest thing on the planet (dark green leafy vegetables) and releasing all that nutrition (you could never really chew that well). In fact I just wrote the foreword for the Complete Idiot’s Guide to Green Smoothies, which will be out May 2012.

  • NickyC

    Hi Heidi,
    Green smoothies are awesome! Whole fruit is almost always better than the juice. The juice is a highly concentrated source, and therefore provides an abnormal amount of sugar. Furthermore, the whole fruit contains the fibers, which are highly beneficial to your health.

  • Maria Vandervert

    Hi Dr. Greger – What are your thoughts on fresh green juice? Juicing fresh cucumber, pear, kale, ginger,romaine, broccoli.

  • Michael Greger M.D.

    For some context, please check out my associated blog post Alzheimer’s Disease: Up to half of cases potentially preventable!

  • Simon Porteous

    Hi Dr Greger, I’m trying to learn more about the natural anti-inflamatories in foods, in particular te supposed benefits of bromelains from pineapple. Are you able to shed some light on the subject. Thanks.

  • livnat

    hi my name is livnat and i want to know what is the best diet for kids 8 and 9 yr old ty.

  • Superfoods for life

    Doc. What are the best nutrients for an eye disease called karatoconus.

  • Annie

    I read that tart cherry juice is good for arthritic pain and good to drink at night before bed. Is it really?

    • sf_jeff

      Search the site. He has a good video on this.

  • Francis Fong

    What about freshly squeezed raw sugar cane juice? Any studies on the health benefits of drinking it?

  • Kerry

    I wish you would check out the juice of the muscadine grape. There are 88 phenolic compounds in the muscadine grape. Probably better than any of those surveyed in the video, I imagine.

  • jeff swanson

    Hey, Doc. Can you do a video on hydrochloric acid deficiency?
    As it turns out I CAN eat wheat. I just need to take hydrochloric acid before and after eating it. As a matter of fact my joint pain; which has plagued me since high school is gone when I take hydrochloric acid. :)

  • Tamera LeMaster

    I am confused about this. Are you saying that green smoothies are not as good for you as people would have you believe? I think I would find a lot of people who would argue this point.

    • Toxins

      Juices and smoothies are very different things. Smoothies retain the fiber and much of the nutrients.

  • Sweet Tooth

    What about sugarcane juice? Could you possibly do a video on that. From the research I have done, in its natural state the juice is very high in polyphenols, soluable fibre, is brimming with an abundance of vitamins and minerals and has a glycemic index of between 30-40 depending on the variety. That’s lower that a lot of conventional table juices. What’s your thoughts?

  • N It Together

    If you drink grape juice AFTER eating a meal with a lot of fiber does it affect how the grape juice is metabolized?

    • Joseph Gonzales R.D.

      It probably does, as fiber helps slow rises in glucose.

  • Travis

    What about pineapple juice???

    • Joseph Gonzales R.D.

      I think pineapple juice was listed in the video :-)

  • Aisha waseem

    Hi! Can anyone suggest if nestle fruita vitals pomegranate juice is a reliable alternative to home-made juice? I’ve been suggested juices for better skin condition.

  • Dionicio Rivera

    Dr. Greger, there is a “guyabno” fruit that is found in the Philippines, (I am making an assumption that this fruit is found in other tropical countries as well with different name), and the claim is; “it is 1,000 time better to fight cancer than chemotherapy.” What is you take on that? Dionicio Rivera,