Vitamin D: the Healthy Aging Dose

Vitamin D Confused by all the back and forth in the media about vitamin D?

Don’t be. There’s actually a pretty easy and straightforward approach that most older adults can take.

In this post, I’ll explain what I recommend to most of my older patients, and why.

I’ll also address the following frequently asked questions:

  • Which type of Vitamin D should I take?
  • Do I need to have my vitamin D blood level checked?
  • What should one’s vitamin D level be?
  • Will vitamin D really prevent falls or fractures?
  • Will vitamin D prevent dementia, cancer, and/or premature death?
  • I am outside a lot. Do I need a vitamin D supplement?
  • I heard that a higher level of vitamin D is better for you. How much is too much?

By the way, I’m updating this post in part because I was disappointed by the recent NY Times article “Why Are So Many People Popping Vitamin D?”

Among other things, this article should have had a different headline. The key problem the article describes is that there are too many people being tested for vitamin D. The article does not make the case that too many people are taking vitamin D supplements.

In fact, vitamin D supplementation remains recommended by experts. And as I’ll explain below, there are good reasons to believe that vitamin D supplementation is especially useful for older adults.

Now, I do agree with the article in that many people seem to have unrealistic expectations of what vitamin D can do for them.

I also know that some people are certainly taking more vitamin D than is likely to benefit their health. Sometimes this is because they think it will improve their health. In other cases, it seems to be because their doctors never got around to reducing a higher dose which should’ve only been used for a limited time period. Either way, it’s concerning because taking high doses of vitamin D has been linked to health problems.

Still, if you are an older adult, you probably should be “popping vitamin D.”

But, it should be a sensible dose, you probably don’t need blood tests, and you shouldn’t expect it to work miracles.

Read on to learn how much vitamin D to take, why I recommend taking this vitamin, plus answers to those FAQs.

My Recommended Daily Dose for Vitamin D in Older Adults

For most older adults, I recommend a supplement of vitamin D 1000 IU/day.

I do this because:

  • The American Geriatrics Society (AGS) recommends that clinicians tell older patients to take vitamin D 1000 IU/day, to help prevent fractures.

I also do this because:

  • Many older adults have risk factors for vitamin D deficiency. These include having osteoporosis and spending limited time outdoors.
  • The skin becomes less able to synthesize vitamin D as people get older.
  • Vitamin D seems to be involved in muscle function. Some research has suggested it can help reduce falls, other research hasn’t confirmed this finding. Either way, it seems sensible to avoid frank deficiency.
  • In the vast majority of older people, taking vitamin D 1000 IU as a supplement every day has very low risk of harm.
  • Research suggests that taking vitamin D 1000 IU/day will prevent low vitamin D levels in most older adults.

Other expert groups have provided similar vitamin D guidance. For instance, in 2010 the Institute of Medicine published a report with age-based Recommended Daily Allowances for vitamin D in “normal healthy persons.” For people aged 1-70, they recommended 600 IU/day. For people aged 71+, they recommended 800 IU/day.

Research suggests that low levels of vitamin D are common in older adults who don’t take supplements, but are uncommon in those who do take supplemental vitamin D.

I think either 800 IU/day or 1000 IU/day is fine, but I usually tell people 1000 IU/day, as it’s a nice round number recommended by AGS. I call this the “healthy aging” dose of daily vitamin D.

For people who are already taking a multivitamin or calcium supplement, they should check to see how much vitamin D is already included, as they may already be getting 1000 IU from those supplements.

Frequently Asked Questions about Vitamin D

Which type of Vitamin D should I take? 

Most supplements contain vitamin D3, also known as cholecalciferol. Studies suggest that this increases blood levels a little better than vitamin D2 (ergocalciferol).

Both these versions of vitamin D require processing by the liver and kidneys. People with liver or kidney disease may need to get a special type of supplement from their doctors.

Although Vitamin D supplements are usually taken daily, they also come in higher doses, which may be prescribed for weekly or even monthly dosing. (These are available over-the-counter, but I think it’s best to take these under medical supervision.)

Do I need to have my vitamin D blood level checked?

Probably not. The AGS consensus statement says that testing vitamin D levels should be unnecessary in most older adults, unless some particular symptom or disease warrants it.

The idea is that if people take a daily vitamin D supplement as recommended above, they’ll be highly unlikely to have a vitamin D level that is too low or too high.

On the other hand, if you have been diagnosed with a serious vitamin D deficiency, your doctor will likely recommend a higher dose of vitamin D supplementation. In this case, most experts recommend a repeat vitamin D blood test after 3-4 months of treatment. For most people, the test would be for the 25(OH)D level. People with certain conditions may require a different type of test.

I do end up checking vitamin D levels sometimes in my practice because many of my patients have severe osteoporosis, or sometimes an abnormal blood calcium level.

I find that when I check vitamin D in an older patient who is not taking a supplement, they virtually always have a low level. Probably there are some elderly farmers out there who get enough sun to maintain a good level without taking a supplement. But it seems fairly common for older adults who don’t take a supplement to have low levels.

That said, I agree with those who say that vitamin D testing is often overused. But of all the tests and services to overuse, this one strikes me as fairly minor. If you’re worried about overtesting or overtreatment, it’s far more worthwhile to avoid unnecessary scans, procedures, and medications.

What should one’s vitamin D level be?

This question has been hotly, hotly debated. At this time, it depends on whom you ask.

The Institute of Medicine believes a blood level of 20-40 ng/mL should be adequate. The Endocrine Society, the American Geriatrics Society, and some other expert groups recommend a level of at least 30 ng/mL.

As noted above, the party line — which I consider reasonable — is that most people don’t need their vitamin D level checked. In the absence of certain health problems, a low vitamin D level is unlikely in someone who takes a daily supplement.

Will vitamin D really prevent falls or fractures?

Good question. Some studies have suggested that vitamin D reduces the chance of these serious health events, but these results have been questioned by later studies.

The US Preventive Services Task Force used to recommend Vitamin D to help reduce fall risk. But in 2018, they changed their recommendation. (They also said that their new recommendation doesn’t apply to people with osteoporosis or vitamin D deficiency.)

My current take is that vitamin D might help with falls and fracture risk, especially for certain older adults. Since it has a low chance of harm and possibly helps some people a least a little, I recommend it.

However, I usually tell people to not have overly optimistic expectations of vitamin D’s effects. In most older adults, problems such as pain, fatigue, and/or falls are due to multiple underlying causes, so there’s often no easy fix available.

Will vitamin D prevent dementia, cancer, and/or premature death?

Several studies have identified an association between vitamin D deficiency and diagnoses such as Alzheimer’s disease and cancer. In other words, people with these conditions tend to have low vitamin D blood levels.

But an association isn’t the same thing as causation, so it’s not yet known whether vitamin D deficiency causes these diseases. It’s also not yet known whether taking vitamin D supplements will reduce one’s chance of developing these diseases.

To date, most randomized studies of vitamin D to improve health outcomes have been negative. (Meaning, the group receiving vitamin D supplementation did not appear to do better.)

Although it’s possible that low vitamin D levels might be a factor in developing certain diseases, it’s probably a small effect. Cancer and Alzheimer’s, after all, generally seem to be the result of lots of little factors — genetics, epigenetics, stress, immune function, nutrition, inflammation, toxins — interacting over time.

In 2010, the Institute of Medicine concluded: “This thorough review found that information about the health benefits of vitamin D supplementation beyond bone health—benefits often reported in the media—were from studies that provided often mixed and inconclusive results and could not be considered reliable.”

2014 Cochrane review of vitamin D supplementation to prevent mortality concluded that “Vitamin D3 seemed to decrease mortality in elderly people living independently or in institutional care. “

My take: although the ongoing research on vitamin D is very interesting, it’s unlikely to make practical changes to my current approach.

A daily dose of vitamin D 1000 IU should prevent very low vitamin D levels, and should be sufficient to help most aging adults get the benefit — whatever it may be — of vitamin D.  Furthermore, vitamin D 1000 IU/day is highly unlikely to cause harm to most older adults.

Over the past ten years, no research I’ve heard of has indicated that I need to change this approach.

The bottom line is this: Avoiding low vitamin D levels is probably beneficial to health, but there’s no solid evidence suggesting that high vitamin D levels are particularly beneficial to health.

I am outside a lot. Do I need a vitamin D supplement?

Hard to say without checking your levels. In general, I recommend people take a daily vitamin D supplement no matter how much time they spend outside.

To begin with, it’s usually a good idea to wear sunscreen if you are going to be exposed to UV radiation, because skin cancer is very common!

Also, for your skin to synthesize vitamin D, you need to be exposed to UVB radiation. This type of solar radiation gets scattered by the atmosphere, so exposure will be affected by season, latitude, and the time of day. (You probably won’t get much UVB radiation to synthesize vitamin D if you are out in the early morning or later afternoon.)

Furthermore, even if you are getting enough vitamin D through sunlight or diet, taking a supplement of 1000 IU is unlikely to raise your vitamin D levels to a problematic range.

In my view, people of all ages usually have plenty they can and should do for their health and their lives. Is it really a good use of your valuable time to spend it figuring out vitamin D you might be getting through sunlight and/or your food?

I say it’s better for you to take whatever vitamin D supplement is recommended for your age (or by your doctor), and focus your energies on getting enough exercise, implementing other healthy habits, taking care of those who need you, and managing any chronic conditions you have.

I’ve heard that a higher level of vitamin D is better for you. How much is too much?

Again, this depends on who you ask. The American Geriatrics Society says for most people, total vitamin D (from supplements and food) shouldn’t exceed 4000 IU/day.

Research into the risks of too much vitamin D is ongoing. A study of very high vitamin D supplementation (500,000 IU once a year) increased falls and fractures in older adults, so clearly it’s possible to have too much of a good thing.

Vitamin D also promotes calcium absorption, and high levels of vitamin D can cause high levels of blood calcium.

I have also personally encountered a few patients with high blood calcium levels, who were taking high doses of vitamin D supplements and had fairly high blood levels of vitamin D.  One of them went on to have a heart attack a few months later; his blood level of vitamin D had been about 70 ng/mL. This is a single case, but some research does suggest that high levels of vitamin D may be associated with coronary artery calcifications, especially in men. It is certainly possible that future research may find links between high vitamin D blood levels and increased heart attack risk.

My own practice is to caution patients if they are taking daily vitamin D supplements of more than 2000 IU/day in the absence of documented deficiency. I also discuss a reduction in vitamin D supplementation if a patient has a blood level greater than 50 ng/mL.

I know that some health providers recommend substantially higher vitamin D levels, but as best I can tell, there is no high-quality research evidence to support this.

Useful Links

For more information on vitamin D, here are some useful articles:

So remember, don’t let the media hype confuse you.

Pop that vitamin D. But ask questions if your doctors want to test you, especially if you’ve already been taking vitamin D supplements.

And if for some reason you are taking a higher dose of vitamin D — such as 50,000 IU per week — be careful about continuing it indefinitely.  For most people, higher doses should only be used for a few months, and then a lower maintenance dose should be possible.