Image Credit: Micheile Henderson / Unsplash. This image has been modified

Vitamin D Supplements for Increasing Aging Muscle Strength

We have known for more than 400 years that muscle weakness is a common presenting symptom of vitamin D deficiency. Bones aren’t the only organs that respond to vitamin D—muscles do, too. However, as we age, our muscles lose vitamin D receptors, perhaps helping to explain the loss in muscle strength as we age. Indeed, vitamin D status does appear to predict the decline in physical performance as we get older, with lower vitamin D levels linked to poorer performance. As I discuss in my video in my video Should Vitamin D Supplements Be Taken to Prevent Falls in the Elderly?, maybe the low vitamin D doesn’t lead to weakness. Rather, maybe the weakness leads to low vitamin D. Vitamin D is the sunshine vitamin, so being too weak to run around outside could explain the correlation with lower levels. To see if it’s cause and effect, you have to put it to the test.

As you can see at 1:01 in my video, about a dozen randomized controlled trials have tested vitamin D supplements versus sugar pills. After putting them all together, we can see that older men and women taking vitamin D get significant protection from falls, especially among those who had started out with relatively low levels. This has led the conservative U.S. Preventive Services Task Force, the official prevention guideline setting body, and the American Geriatric Society to “recommend vitamin D supplementation for persons who are at high risk of falls.”

We’re not quite sure of the mechanism, though. Randomized controlled trials have found that vitamin D boosts global muscle strength, particularly in the quads, which are important for fall prevention, though vitamin D supplements have also been shown to improve balance. So, it may also be a neurological effect or even a cognitive effect. We’ve known for about 20 years that older men and women who stop walking when a conversation starts are at particularly high risk of falling. Over a six-month timeframe, few who could walk and talk at the same time would go on to fall, but 80 percent of those who stopped walking when a conversation was initiated ended up falling, as you can see at 2:14 in my video.

Other high-risk groups who should supplement with vitamin D include those who have already fallen once, are unsteady, or are on a variety of heart, brain, and blood pressure drugs that can increase fall risk. There’s also a test called “Get-Up-and-Go,” which anyone can do at home. Time how long it takes you “to get up from an armchair, walk 10 feet, turn around, walk back, and sit down.” If it takes you longer than ten seconds, you may be at high risk.

So, how much vitamin D should you take? As you can see at 3:00 in my video, it seems we should take at least 700 to 1,000 units a day. The American Geriatric Society (AGS) recommends a total of 4,000 IU a day, though, based on the rationale that this should get about 90 percent of people up to the target vitamin D blood level of 75 nanomoles per liter. Although 1,000 IU should be enough for the majority of people, 51 percent, the AGS recommends 4,000 IU to capture 92 percent of the population. That way, you don’t have to routinely test levels, since 4,000 IU will get most people up to the target level and “is considerably below the proposed upper tolerable intake of 10,000 IU/d.” The AGS does not recommend periodic mega-doses.

Despite the AGS’s recommendation, because it’s hard to get patients to comply with pills, why not just give people one megadose, like 500,000 units, once a year, perhaps when they come in for their flu shot? That way, every year, you can at least guarantee an annual spike in vitamin D levels that lasts a few months, as you can see at 4:00 in my video. It’s unnatural but certainly convenient, for the doctor at least. The problem is that it actually increases fall risk, a 30 percent increase in falls in those first three months of the spike. Similar results were found in other mega-dose trials. It may be a matter of too much of a good thing. See, “vitamin D may improve physical performance, reduce chronic pain, and improve mood” so much that people start moving around more and, thereby, increase fall risk. When you give people a whopping dose of vitamin D, they get a burst in physical, mental, and social functioning, and it may take time for their motor control to catch up to their improved muscle function. It would be like giving someone a sports car when they’ve been used to driving a beater. You’ve got to take it slow.

It’s possible, too, that such unnaturally high doses may actually damage the muscles. The evidence the researchers cite in support is a meat industry study showing you can improve the tenderness of steaks by feeding cattle a few million units of vitamin D. The concern is that such high doses may be over-tenderizing our own muscles, as well. Higher vitamin D levels are associated with a progressive drop in fracture risk, but too much vitamin D may be harmful, as you can see at 5:29 in my video.

The bottom line is that vitamin D supplementation appears to help, but the strongest and most consistent evidence for prevention of serious falls is exercise. If you compare the two, taking vitamin D may lower your fall risk compared to placebo, but strength and balance training with or without vitamin D may be even more powerful, as you can see at 5:41 in my video.

Other studies in which vitamin D supplements have been put to the test in randomized placebo-controlled studies, effectively proving—or disproving—their efficacy, are featured in videos such as:

That brings up a number of important questions, which I answer in these videos:

Unfortunately, most supplements are useless—or worse. Here are some additional videos on supplements I’ve produced that may be of interest to you:

For more on the benefits of exercise, see Longer Life Within Walking Distance and How Much Should You Exercise?

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

50 responses to “Vitamin D Supplements for Increasing Aging Muscle Strength

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  1. What does “This image has been modified” mean? The elderly people I know wear jeans and sneakers, and have been doing so for the past who knows how many decades. And even shorts, some that go above the knee. I have a couple of skirts I haven’t worn for years.

    I’m a big believer in daily exercise/yoga/rebounding/weight lifting/walking, etc. And of course sunshine when we can get it. Along with a daily multivitamin.

    1. YR,

      That is interesting.

      The elderly people I know are still wearing the same clothing that they wore for the past 50 years.

      None of them wear jeans.

      Their clothing looks very much like what the people in the image are wearing.

    2. YR,

      I like sweatpants, or loose baggy pants. Flannel nightgowns and robes as loungewear in the winter. And muumuus in the summer, anywhere. I hate anything with a waist, or at least a fitted waist. Lowered waistlines are a boon.

      But maybe I’m not old enough to count?

      ps: we had some remodeling work done in our bedroom, so my husband and I cleaned out our closets — and out went all those work clothes (donated). So liberating!! Why were work clothes so constraining and restrictive? To remind us that the workplace is, too? (Especially bras, pantyhose, high heels…yuck! And skirts. Blech!)

      1. Dr J – I’m not retired yet, but moved to a pleasantly informal workplace for my last job before retirement. I took SO much pleasure from weeding every skirt, dress, and pantyhose from my wardrobe!

        Yoga taught me to appreciate clothes that encourage movement. I’m of the jeans generation, but everything I own now has a stretch waistband, and all my bras are stretchy yoga-friendly. It’s amazing how much more natural movement you do when your clothes aren’t unconsciously constraining you. Maybe someday we’ll start talking about the evils of American Standard Fashion.

        1. I hate jeans. They are stiff and uncomfortable. And for the very life of me I cannot understand why a person would buy jeans that are already torn up.

      2. Dr. J., you mentioned flannel nightgowns. I slop around in nothing but them during the day hours and sleep in the nude at night. Like Marilyn Monroe claimed to do. Let the air flow in, nothing constricting. Comfort first.

        I live alone, of course. But when my husband was alive, it seems I did the nightgown thing then too. When we had company I’d force myself to put something more presentable on, and then look forward to when they left..

        During the summertime I wear a large-size man’s T-shirt around the apartment. Barely covers my butt. :-)

        This may or may not be “the truth” about MM:

      3. Thank goodness times have changed! I don’t wear high heels, pantyhose, or skirts to work, and only wear bralettes, not even a real bra. I wear jeans and T-shirts and converse. I wouldn’t be able to think in pantyhose and high heels!

    3. Myself, and the people that are around me, are either in stretchy jeans or spandex running/cycling/yoga gear and some wear shorts year round…fairly action oriented group, but do bring out the dresses for shopping in town or appointments or dinner out.

      I am like you YR. I get in a few sessions of exercise daily plus walk the dogs. I found also that I feel better if I exercise for at least an hour outside daily, rain or shine.

  2. The sports car analogy is one to think about.

    Listening to the Rich Roll’s interview, the “How Not To Age” concept sounds interesting.

    The interview really helps to understand the process here.

    In that respect, it was one of the best interviews with Dr. Greger I have heard to date. Seriously worth the listen. It isn’t a rehash. It is the hash itself.

    1. If you put the cursor over the line that represents how far you are in the video, he gives every topic.

      That is so useful.

      I can go back to that interview and click right on the part where Dr. Greger talks about the next books he is writing.

      Is that always on videos and I haven’t noticed?

    1. I recommend posting that interview on the site. It explains the process here.

      It also is Dr. Greger in his authentic personality.

      Win. Win.

    2. I really enjoy listening to Rich Roll interviews… he’s very professional and has the most interesting guests.

      Dr Greger is of course terrific. I enjoyed hearing his comments about How Not to Diet. Have you downloaded the app yet Deb? I have a print out taped to the fridge to remind me, though I prepare my daily dozen fare by memory these days.

      Eating early in the day, not eating past 6pm, and adding another half hour exercise has made all the difference. Thanks Dr Greger!

      1. Barb,

        It’s interesting how different people experience different degrees of difficulty in losing weight. I wonder why?

        For me, it wasn’t too hard: about 21 years ago, as a vegetarian, I started practicing portion control, but more importantly, making healthier choices (eg: eat a banana instead of a pastry with my morning coffee, etc). I’d already been exercising for over a year from home, and though I’d lost no weight (or gained any), I was much more fit). And I lost about 25 pounds over about 18 months. In fact, it was so gradual that I was surprised when my pants wouldn’t stay up without a belt!

        Then, a few years ago, I switched to whole plant foods eating, and cutting back on processed and prepared foods as well as added oil, salt, and sugar, and I gradually lost another 10 lbs without trying to. And both times, I’ve kept it off; but I didn’t go back to eating the way I was, which was how I gained the weight in the first place. (There’s a lot of processed junk food that’s vegetarian, and even vegan.)

        But I “graze” all day long. Both my husband (who has lost a total of about 55 pounds since he met me 12 years ago) and I feel as though we’ve “shrunk” our stomachs: we can’t eat too much at one sitting. We eat small meals, and small snacks. But we only stop eating for about 9 – 10 hours at night. (And we are night owls; or at least my husband is, and I’m turning into one: late to bed and late to rise.). And we are only moderately active. (Maybe all those stairs help?) And though we “sit around” a fair bit, it’s interrupted frequently by chores and little activities.

        1. Awesome Dr J! I have always eaten well, but when I finally left the last vestiges of milk, yogurt, cottage cheese behind my weight plummeted… too low. I lost over 25% of my body weight and I was slim to start with. I did recover slowly by adding in 2 or 3 slices of bread per day to go with our soup or salad.

          With the lockdown I found myself eating out of boredom and my usual exercise hangouts were closed. Very depressing. But changing things around to eating an hour earlier, walking more, drinking carbonated water at night, and the few pounds came off easily. When I go back to my regular forms of exercise I will have to add another meal or snacks in a day.

          I have always been interested in diet plans and nutrition. I have origional Pritikin and Ornish books around here somewhere, but interesting that those are the only diets that I thought were good….maybe the early weight watchers and Back to Eden By Kloss, the SDA.

          I never bought the fad diet books – wasn’t interested in nutritionally poor schemes. I didn’t need to lose weight, just made it my life mission not to gain any!

    3. Deb,

      I started watching the Dr. Greger interview video you posted the link to — and I had to chuckle at the comment: You mean you eat this way because of something you read in a magazine at the check-out line in the grocery store?

      Yes, that’s exactly right!! Because that’s what happened to me! I was leafing through a Reader’s Digest (I like to look at these magazines for entertainment, though I rarely buy them) when something caught my eye: a description of “Change One,” a book about how to lose weight by changing one meal at a time — by, you guessed it, practicing portion control and making healthier choices. The article made sense to me (I’d read college level course nutrition textbooks), so I bought the Reader’s Digest issue — and I ordered the book that night. But I started to change the way I ate the next day based on the article alone (which nicely summarized the concepts of the book).

      It wasn’t written for vegetarians, which I was, but the ideas of eat as many veggie servings a day you want, the more the better, eat fruit (but the book suggested a limit of 3 servings a day, worried about the added sugar, I think), cook your meals at home, don’t buy and eat processed food, etc. seemed absolutely correct to me. The book was simple, easy to understand, with lovely photos, even meal suggestions and some recipes. The best part were the graphic illustrations of serving sizes on the inside of the front and back covers: eg, 1/4 cup is about golf ball size, 1/2 cup a tennis ball, 1 cup a softball, a 4 oz serving of meat is the size of a deck of playing cards, etc. It was very visceral! I realized that when eating out, a “single serving” was actually the size of a family-style dinner serving platter! My daughter and I could together eat at least 2 and often 3 meals from one restaurant meal serving. Saved a lot of money, taking home left-overs.

      Anyway, that article changed my life. I even gave a copy of the new and revised edition of “Change One” (it included more information about exercise and eating out) to my husband when we first met, because he wanted to lose weight — and it worked for him, too.

      I guess that there are exceptions that prove the rule.

      1. Dr. J.,

        That is a fabulous story!

        I have found wonderful tidbits in the supermarket checkout lanes and, honestly, pre-the-internet, that, historically, was the most likely place to see something other than the 6 O’Clock news.

        Still is, for those of us who actually GO to Whole Foods.

        In the checkouts, there is always a copy of Forks Over Knives. Yes, there is also a copy of a Keto magazine or two and a few other healthy eating magazines. Prevention was always one that caused me to think 30 seconds about my health when I went to the grocery store all of my life. And I will say that when the lines were long, I would open the ones that had a titillating title about how to rev up their metabolism or the food to eat to make the thyroid work better.

        Lots of tidbits.

      2. When I wait in line….at my 6-feet-distance marked off yellow line….I usually choose one of the rags (National Enquirer, Globe, etc.) and glance at the probably made-up articles.

        I ain’t got no couth.

        1. YR, regarding your comment: “I ain’t got no couth.”

          I haven’t heard that word used in ages! Glad it’s still in someone’s vocabulary besides mine :-)

  3. Can vitamin D deficiency be an explanation for susceptibility of nursing home patients to adverse Covid-19 outcomes?

    1. Henry, it is most likely the cholesterol rich food. Viruses love cholesterol rich environment. That helps them to enter into the cells.

      Importance of Cholesterol-Rich Membrane Microdomains in the Interaction of the S Protein of SARS-coronavirus With the Cellular Receptor Angiotensin-Converting Enzyme 2

    2. Henry,

      Quite a few people do believe that Vitamin D deficiency is an explanation.

      The trouble is that people also have co-morbidities.

      But people in countries where they supplemented enough to have better Vitamin D levels have fared better during this pandemic and people with darker skin color have fared worse. Part of it is co-morbidities and part of it may well be Vitamin D. Dr. Greger has videos on how supplementing improved other conditions such as the flu and respiratory infections. Those videos came before COVID-19.

      Some of the interesting things to me that I have seen were that the progressively darker the skin color the worse the outcomes and that countries where the people didn’t supplement, even though they are countries known for sunshine, had more in trouble. (Italy, Spain, etc.)

      1. Deb, Thanks for your reply.
        I am sure nursing home patients who did not die had their share of comorbidities as well. It would seem fairly easy assemble mountains of retrospective data assessing vitamin D levels vs. outcome in otherwise-matched nursing home patients. Unrelated to vitamin D, one could also look for an effect of premorbid mobility, which would seem a likely factor with regard to baseline cardiopulmonary and cognitive function, by level of care – independent vs. varying degrees of assisted. I have not seen mention of such studies. Perhaps they are ongoing. I was hoping Dr. Greger’s staff had come across something in their literature reviews.

        As I understand it, the predominant area of Italy that was affected was northern which is mountainous and closer to central Europe in climate. Can’t speak for Spain.

        1. Hank, I did read something along those lines and I have been back searching for where I might have read it. Probably on bbc at some point.

          Leg strength has a lot to do a person’s ability to survive I recall reading. It is similar to what Dr Greger describes in his article today with the rise from a chair and walk ten feet test.
          Until I find the reference again I will be doing my deep knee bends, walking, and balance exercises!

          1. Thanks Barb. Leg strength and balance are well known correlates of longer survival as people age. I don’t know whether there is a special relationship wrt Covid 19 infection outcome, but it would be an interesting study.

    3. Although susceptibility for COVID19 is probably caused by many factors, your thought that Vit D deficiency could certainly contribute makes sense and we know that nursing home residents are often low in Vit D. (High Prevalence of Vitamin D Deficiency in Elderly Nursing Home Patients Despite Vitamin Supplements
      Your thought that Vitamin D deficiency can contribute to COVID19 risk makes sense, and there have been many studies demonstrating that Vit D supplementation can improve health outcomes in various diseases, it seems that COVID19 is too new and there are not yet actual studies confirming that. Here is one article with a promising title: “Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths”
      ( but concludes based on many earlier studies that use of Vitamin D could be helpful. ”
      “…available evidence indicates that supplementation with multiple micronutrients with immune-supporting roles may modulate immune function and reduce the risk of infection. Micronutrients with the strongest evidence for immune support are vitamins C and D and zinc.”

  4. As an active WFPB senior and yoga teacher, wearing comfortable and attractive clothing is easy. Sunshine, exercise and plants are the magic. B12 and very few supplements, if any and my muscles are great. Why not focus on healthy seniors?

  5. This post says: “We have known for more than 400 years that muscle weakness is a common presenting symptom of vitamin D deficiency” Since vitamins weren’t discovered until the 20th Century, what was it that was being referred to over 400 years ago? Did that discussion include any dietary recommendations?

    1. Mary,

      They were talking about rickets back then.

      Interestingly, one of the early writers said that rickets was a disease of the infants and toddlers of the wealthy people back then. (Because the wealthy children didn’t go outdoors.) That writer did suspect that it was nutritional, but I lost the page and can’t remember what he thought it was.

      I remember smiling and I think he had the wrong answer, but it was a good try.

      Once poor people moved into urban areas, it switched to being seen with malnutrition, and eventually, they found that cod liver oil or whole milk or butterfat healed it.

      After that, they discovered the sun part of the equation.

      And, after that, UV lights and that you could irradiate feces and it would help rats with rickets because they would eat it.

      1. Oh, that’s right, the guy who was figuring things out thought it was related to eating too much. Because apparently the rich people fed their infants more and kept them inside.

        The fact that obesity eventually did contribute to Vitamin D deficiency, maybe he should get a round of applause for his efforts.

        1. … and eventually someone figured out *what* they were eating too much of. Thank goodness for Dr. G, keeping us informed about all of this.

      2. Thanks, Deb—interesting info. I do think changing the wording of that sentence to clarify what was actually known back then, as you have done so well here, would reduce any possibility of confusion.

      1. Thanks, spring03. Can the original post be edited to clarify that fact? My first impression was that the post was implying knowledge of Vit. D centuries before it was discovered.

    1. George,

      I looked at a study and it wasn’t a study where they gave supplements. They looked at Vitamin D levels and the people who had high levels did have an increased risk of first onset a-fib. Normal levels didn’t.

      I say that because there are dietary factors like meat-eating and drinking milk that can contribute to higher levels.

      They always point to vegans being lower in it.

      Being deficient is also linked to heart problems.

  6. My Vitamin D levels have always been about 14. I know that low levels are associated with Multiple Sclerosis. I wonder if it is a good thing to take Vitamin D to keep my levels higher. I am now taking 5,000 IU, 124 mcg daily to try to correct my levels. Is Vitamin D helpful for MS. I find that my health continues to improve on a whole food, plants only, no oil diet.

  7. The evidence suggests that low vitamin D levels is associated with a higher risk for MS (and many other diseases) and that supplementation in patients with MS reduces the number of exacerbations (and reduces disease risk in many other diseases). We also know that naturally occurring vitamin D from sunlight is significantly more beneficial than supplements. I get my vitamin D by laying out in the sun almost every day for a few minutes and get my vitamin D levels tested. My kids don’t get outside much, so we supplement them with vitamin D.

    As an aside, please keep in mind that a whole food plant based diet, by definition, excludes oil as oil is not a whole food. Its kind of like saying “I’m a non-smoker that does not smoke”

  8. The words “over tenderizing our muscles” describes my situation.

    I’ve been taking VitaShine Vegan Vitamin D3 2500iu tablets daily for more than a year. I had a friend bring D3 and B12 from the UK since neither one is sold in Buenos Aires. My thigh muscles feel like water balloons. They feel tender when squeezed with my hand . Not normal at all for me. Is there an association between taking D3 for the first time at age 71 and over tenderizing the muscles? It is so strange having “sore” muscles when I get out of bed after a good night’s rest for 9 hours.

    Today I did a combination of yoga/pilates/ballet barre.workout at home for 40 minutes and walked outdoors on for an hour. I also use a Bollinger rubber rope for arm exercises. I am determined to maintain muscle strength.

  9. Hi, Janis Kenyon in Buenos Aires! If muscle soreness began after you started taking vitamin D3 supplements, you may be taking too much. Muscle pain can be a symptom of vitamin D excess or toxicity. 2500IU is a high dose for daily use. If you cannot reduce the dose, maybe take it less often. You might be interested in this, in case you have not already seen it: I hope that helps!

    1. Thanks for your quick response to my question. I never would have made the connection with sore muscles and taking vitamin D3 without this valuable post by Dr. Greger.

      I need to be very cautious about sun exposure in Buenos Aires. Fifty years with vitiligo resulted in no pigmentation in my very white skin. I burn easily, wear long-sleeved shirts during the spring/summer months (Nov to April) and discontinued using sunblock this year to avoid all the chemicals. This is why I opted for a daily D3 and go outdoors later in the day when the rays are not as strong.

      I can take half of the tablet instead of a whole one. I can reduce the number of tablets each week. When I go for a walk on a sunny day and get exposure, I won’t take a D3 that day.

      The link doesn’t take into consideration the southern hemisphere, but I can figure out what seems best for me now that I know that excess D3 isn’t doing my muscles any good with toxicity. I am happy to know the solution was so simple.

      Thank you! Thank you! Thank you! Muchisimas gracias!

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