Doctor's Note

This is the final video in a nine day series on vitamin D. Be sure to check out yesterday’s video-of-the-day Resolving the vitamin D-bate and today's blog:Vitamin D: Shedding some light on the new recommendations. 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.

For some context, please check out my associated blog posts: Vitamin D: Shedding some light on the new recommendationsHow to Enhance Mineral AbsorptionVitamin D from Mushrooms, Sun, or Supplements? , and How Should I Take Probiotics?

  • Michael Greger M.D.

    This is the final video in a nine day series on vitamin D. Be sure to check out yesterday’s video-of-the-day Resolving the vitamin D-bate and today’s blog: Vitamin D: Shedding some light on the new recommendations. 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.

  • kobby

    Dr. Greger,
    Can you do some research on Spirulina and Chlorella? I have been hearing some things about these green algaes and want to know more about before i start taking them.
    thanks again.

  • Jessica

    Dr. Greger, thanks for all the info on vitamin D.

    I posted a question on your vinegar video, but I’m reposting here, since you may not have seen it. Are you familiar with research linking high glycemic foods with incidence of macular degeneration? (NY Times reported on a 7/07 study in The American Journal of Clinical Nutrition.)

    Is there any reason to believe that restricting high glycemic foods, adding in vinegar, or boosting antioxidants by eating lots of leafy greens would help prevent further development of severe macular degeneration?

    Thanks for any insight you can provide!

    • Michael Greger M.D.

      Thanks for your question–sorry it took me so long to get back to you. I’ll reply over on the Is Vinegar Good For You? video.

  • Anthony Zacchino

    Do Vegan Vitamin D supplements have a different absorption rate compared to non vegan Vitamin D supplements?

    • Michael Greger M.D.

      Taken daily at the kind of daily doses I recommend, vitamin D2 (ergocalciferol) and D3 (cholecalciferol) appear bioequivalent (meaning they both work just as well in your body). However if your physician suggests you take large intermittent doses (such as 50,000IU weekly, then D3 is probably superior).

  • jms

    How does this work? How does the body know which is your largest meal of the day, in order to absorb more Vitamin D? Say you take Vitamin D at lunch. How does the body know whether you’re going to eat a larger meal at dinner?

    Also, I’ve heard that oatmeal interferes with Vitamin D absorption. True?

  • chpado

    Yep – Vitamin D deficient and now on 2000IU per day – taking it with the biggest meal!

    I do have an ask the doctor question on an unrelated topic – I have been vegan for 8 years and saw a remarkable shift in my lipid profile that has persisted over the years and shows up in my most recent lipid profile which was 167 total cholesterol with HDL of 101 and LDL of 52, VLDL of 14. I read somewhere that high HDL is not necessarily good news. What’s the complete story on all these DLs?

  • DrDons

    Hi chpado, Congratulations on the improvement in your values. The science is changing all the time and the story is getting more complete but you need to stay tuned as the science changes. As far as LDL goes the lower is better but Dr. Esselstyn and others say that an LDL below 90 is a good target. Some would go below 70 which is where you are with an LDL of 52. HDL is considered a good cholesterol and you have a higher level than most. The target for total cholesterol is often mentioned to be below 150. Total cholesterol is the sum of LDL + HDL + 1/5(triglycerides). Given your high HDL which is good it would be hard for you to get below 150. I would feel great about your current numbers and wouldn’t use them as an “excuse” to consume foods that would raise the level. See for more information.

  • StrayKat

    Dr. Greger,

    You seem to be in favor of a ‘maintenance’ dose of vit D for most people. My OB/GYN discourages it because she insists that in a few more years we’ll be hearing about damage it does to the liver. Why aren’t you concerned about the long term effects on the liver?

    I ask because I am on the fence myself. Unsupplemented, my vit D levels gradually sink down to the single digits (frank osteomalacia), but I’m concerned about taking a high maintenance dose as daily insurance. I’m not sure if it’s better to get my levels up and not take anything for awhile until they drop again, or take 5,000 – 50,000 IU on a daily basis.


  • SaraKay

    Hi Dr. Greger,

    I was recently diagnosed with a vitamin D deficiency with levels in the single digits. This is no surprise considering I was only on 400 IU for most of the winter. Now I’ve switched to 2000 but my doctor wants me to take the weekly megadose for 12 weeks. The supplement she wants to give me contains soy oil which I am sensitive too and also gelatin which I don’t want to eat as I abstain from animal products.

    Do you know of any other product I could use instead? Is there one you recommend for deficiency?

    Thank you for a VERY informative site,

  • Michael Greger M.D.

    For some context, please check out my associated blog post Vitamin D: Shedding Some Light on the New Recommendations!

  • daisy

    vitamin D3 preferred over D2?

    • Valnaples

      Yes, D3 is preferred…my Vit D was 44 two years ago…Doc advised 5000 IUD of D3 daily *with* calcium and/or big meal…! Seems to have helped!

  • Bill Misner

    With all due respect, Dr. Greger…what supplements do you take with your foods, which I presume are from whole plant sources?

  • LynnCS

    Dr. Greger. Thank you for making it so easy to find your videos and blogs. I love surfing your info. Good to find out about taking vit.D with a meal. Thanks.

  • Gurpreet Kaur

    Dr. Greger,

    My mother has asthma for the last 25 years and now when she got her cavities removed and filling done she has severe pain in that whole side of the mouth where filling was done. The dentist says because her eosinophilis level is high i.e. as per latest report it is 18 nad esr is 22 she is having that pain, i will be really thankful if you please answer me this, whether there is any connection between these two problems or the dentist is making us fool and how can the eosinophilis level be reduced to normal.

    Thanks in advance

  • Jsr
  • TETA

    Dear doctor what about anti candida diet???i am confused,i have candida and leaky gut……there are alot of diets….are fruits ok?????is meat ok???please inform me….regards from GREECE!

  • karl

    I remember using “Y2K”. 2k IU is recommended. Take with meals (hoard food for the computer crash). Whatever it takes… kinda funny.