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What Dose of Vitamin D Is Good?

People respond differently to vitamin D pills, so finding the exact right dose of vitamin D supplements may require some trial and error with monitoring.
Vitamin D supplements

In the early part of the 20th century, when vitamin D was discovered, scientists found that it prevented rickets. Since then, low levels of vitamin D have been implicated in a range of health conditions. Researchers have suggested that supplementation could help prevent osteoporosis (Calcified Tissue International, online Sep. 28, 2019). Supplements have not been shown to prevent other conditions, unless the patients already are deficient in the vitamin. But what dose of vitamin D is appropriate? We heard from a reader on a very high dose.

Is the Prescribed Dose of Vitamin D Too High?

Q. My doctor told me to take 5,000 IU of vitamin D in the morning and 5,000 IU of vitamin D in the evening. Is this dose of vitamin D OK?

A. According to the National Institutes of Health Office of Dietary Supplements, the RDA for vitamin D (ages 1-70) is 600 IUs.  The experts established 800 IUs as the RDA for individuals older than 70. We think that is low, but your intake of 10,000 IUs is very high. According to the experts, the upper limit should be 4,000 IU a day.

Since your doctor prescribed this dose of vitamin D, however, we trust that she or he is monitoring your progress on a regular basis. When you have reached a level of 25 hydroxyvitamin D that is sufficient, presumably your physician will lower the dose. People apparently respond to supplementation in divergent ways, probably due to genetic differences (Journal of Diabetes Research, online Sep. 8, 2019). 

Vitamin D to Boost Your Mood:

Some people have found that too little vitamin D is associated with a low mood. Here is one reader’s story:

Q. During a very cold winter, I began to feel more SAD than usual, as well as fuzzy, forgetful and achy. This worried me enough to send me to the doctor.

All my blood tests were fine except for my vitamin D, which was very low. Some high-dose supplements eventually caught me up, but apparently my ordinary multivitamin hadn’t been working.

Now I am reading that low vitamin D has been linked to breast cancer, immune problems and other conditions as well as seasonal affective disorder. If I couldn’t get enough sun exposure to make vitamin D where I live below the Mason-Dixon line, what about people in the north? Can older people who don’t go outside get enough vitamin D?

How Can You Get Enough Vitamin D?

A. Research links low circulating levels of vitamin D to seasonal affective disorder (SAD) and depression (Psychiatry Research, May 30, 2015; Journal of Postgraduate Medicine, Apr-June 2019). It seems that supplements may boost mood. In addition, you should try to avoid very low levels of this vitamin. Ask your doctor to monitor your blood level of 25-hydroxyvitamin D. The meta-analysis did not specify the best dose of vitamin D to counteract depression, unfortunately.

Vitamin D deficiency has also been associated with conditions such as cancer, hypertension, arthritis, osteoporosis, diabetes and multiple sclerosis (Nutrition Journal, Dec. 8, 2010). Older people with inadequate vitamin D levels may have less hand strength and walk more slowly (PLoS One, Aug. 21, 2018).

You are correct that people in northern states may have difficulty getting enough vitamin D. In fact, the National Health and Nutrition Examination Survey showed that 29 percent of Americans were deficient in vitamin D and another 41 percent had low levels (British Journal of Nutrition, April 28, 2018). An extremely high dose of vitamin D can lead to serious toxicity, however (Multiple Sclerosis, Aug. 2019).

Learn More:

Finally, you can learn more about optimal vitamin D levels to boost your mood and your bone strength, as well as vitamin supplements in our Guide to Vitamin D Deficiency. It provides more information on the pros and cons of this nutrient.

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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies. .
Vitamin D Deficiency

Learn about the symptoms of low Vitamin D and ways to overcome deficiency, for children and adults. Information on avoiding vitamin D overdose and which supplements are best.

Vitamin D Deficiency
  • Sami A & Abrahamsen B, "The latest evidence from vitamin D intervention trials for skeletal and non-skeletal outcomes." Calcified Tissue International, online Sep. 28, 2019. DOI: 10.1007/s00223-019-00616-y
  • Hu Z et al, "The association between polymorphisms of vitamin D metabolic-related genes and vitamin D3 supplementation in type 2 diabetic patients." Journal of Diabetes Research, online Sep. 8, 2019. doi: 10.1155/2019/8289741
  • Kerr DC et al, "Associations between vitamin D levels and depressive symptoms in healthy young adult women." Psychiatry Research, May 30, 2015. DOI: 10.1016/j.psychres.2015.02.016
  • Vellekkatt F & Menon V, "Efficacy of vitamin D supplementation in major depression: A meta-analysis of randomized controlled trials." Journal of Postgraduate Medicine, Apr-June 2019. DOI: 10.4103/jpgm.JPGM_571_17
  • Zhang R and Naughton DP, "Vitamin D in health and disease: current perspectives." Nutrition Journal, Dec. 8, 2010. DOI: 10.1186/1475-2891-9-65
  • Mendes J et al, "Vitamin D status and functional parameters: A cross-sectional study in an older population." PLoS One, Aug. 21, 2018. DOI: 10.1371/journal.pone.0201840
  • Liu X et al, "Vitamin D deficiency and insufficiency among US adults: Prevalence, predictors and clinical implications." British Journal of Nutrition, April 28, 2018. DOI: 10.1017/S0007114518000491
  • Feige J et al, "Life-threatening vitamin D intoxication due to intake of ultra-high doses in multiple sclerosis: A note of caution." Multiple Sclerosis, Aug. 2019. DOI: 10.1177/1352458518807059
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I’m trying to get my vitamin D levels up but the supplements give me acid reflux. Wondering about the vitamin D patch or vitamin D lotion. What about the happy light?

I read studies showing that vit.D3 cannot be properly absorbed without vit.K2 present; so I take a combo sublingual. I also experimented with tanning bed (the mgr said this bed was “most like the sun”) since my D level was tested to be low. After 2 months of 3-minute sessions twice a week, my level doubled to over 50. I plan to start up the tanning bed sessions again now that the weather is cooling down. I got NO tanning effect from those sessions.

As you are no doubt aware, dermatologists frown upon tanning beds because they increase the risk of skin cancer just as sun exposure does.

Our body systems are like an amazing dance hall. Certain partners are necessary to pair up to present a fabulous show. Dr. Steven Lin’s book The Dental Diet, speaks about the balance necessary of many vitamins to create optimal conditions. He writes that the fat soluble vitamins A, D & K along with calcium are in a careful dance with each other. While there certainly must be absolute min/max values for each, they also must be in balance to help each other function. It is simplistic to think just increasing one will always make everything else better. I suspect this is why each vitamin fad fades under scrutiny. No single one can be the answer. Science is still plodding along trying to understand the wonders of our bodies!
BTW, there is no test for vitamin K.

My doc found my D level too low and started me on a huge dose ( I can’t recall, but it was multiple tens of thousands of units) for the first couple days, reverting to a maintenance dose after that.

Well, that initial super-high dose had me so constipated (a problem I never have), that I feared I would have a heart attack or rupture something (I believe I did rupture a blood vessel in my eye, if memory serves). It was horrible. Be forewarned there is a risk in that approach. (No problem once I went on the maintenance dose.)

When tested a number of years ago, my Vitamin D level was what my endocrinologist said was too low (about 27). He preferred I be in the 50-60 range. He put me on 5000 units a day. Since then, my Vitamin D levels are in his preferred range – 55-65. Last time I was tested, my bone level indicated start of osteopenia, however. Since reading posts on the People’s Pharmacy lately, about recent studies showing too high a supplement of Vit D can cause other problems I think I’ll revisit this with my PCP.

In addition — Consumer Lab reports (based on research that they monitor and report on) that there is a 25-D level that is optimal (around 40). Above that level — there appears to be an INCREASE in problems. Neither of my 2 doctors were aware of this research, and only monitored whether D levels were too low. More research may refute this notion, but it’s like low-dose aspirin. Doctors were telling all patients above a certain age to take it daily or several times a week, and now it seems that it can cause problems in people that have not already had a heart event.

Actually, some official medical organizations treat a reading of 29 or less as deficient and below 20 as really bad, and some physicians are telling their patients that they should be at 50.

My Vit D levels are very low. I’ve taken different types of Vit D supplements (sublingual & tablets). Both types cause severe sweating for me. This is an awful side effect for me. My dr said it would help with my fatigue and depression as well. My mother and my grandmother had osteoporosis so I need to do something now before I’m next. Any suggestions?

Fifteen years ago when I was 70 years old my dr., after reviewing my blood tests, prescribed 2,000 IU of D3 per day. I noticed immediately that my previous normal three colds a year reduced immediately to about one cold every two or three years. That has held true whether I wintered here in Western OR, or in southern AZ. I finally reduced that amount to no D3 in summers when I was out in the sunshine almost daily and to 1,000 in late Spring and early Fall — with my doctor’s approval. If I get a sneezing or running nose spell when not taking D3, I take one tablet, and that usually cures it. I have talked to others, including much younger folks, and they have usually had the same results with D3.

If 4,000 IU daily is the established maximum dose, is it okay to take 10,000 IU every 3 days? I ask because I have a very large bottle of chewable tablets in this dosage, and that’s what I’ve been doing.

That should be reasonably safe. Sometimes when scientists do studies on vitamin D supplements, they give a large dose once a month. It is not clear whether those work as well as daily supplements, but you seem to have found a compromise.

My doctor put me on Fosamax years ago because I had osteopenia. I reacted very badly to fosamax (my jaw started locking) and stopped taking it. I changed doctors, and my vitamin D level was tested, and the results were in the severely deficient range. the doctor recommended that I take 5000iu of D3 in a.m and 5000iu’s in p.m. When my D level was tested a year later, it had gone up to the mid-normal range. In addition, my DEXA showed an IMPROVEMENT in my osteopenia. In other word, SOME people definitely benefit from taking high doses of vitamin D3, but it is essential to keep it monitored.

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