If you have paid the least bit of attention to health care coverage in the past few years, you probably have noticed the growing number of studies citing that insufficient levels of vitamin D contribute to elevated disease risk from myriad illnesses ranging from autoimmune disorders, cardiovascular disease, and osteoporosis all the way to cancer and diabetes. So you might be wondering, how much vitamin D do I need each day?
The answer to this question is a bit complicated because there are significant variations in vitamin D needs for some people. First I’ll give a rule of thumb that works reasonably well for most people. Later I’ll add some additional considerations that may significantly affect appropriate dosage.
Basic Guidelines for Vitamin D3
A simple rule of thumb you can use to determine how much vitamin D you should consume each day is based upon the observation that 100 IU of vitamin D3 will raise the blood level of an adult by about 1 ng/mL. Vitamin D researchers are widely recommending blood levels of between 40 to 60 ng/mL (conservative) or 50 to 80 ng/mL (newer recommendation with growing acceptance). For a typical adult getting little vitamin D from food or sun (the common case), supplementing with vitamin D3 at 4000 IU to 8000 IU per day is appropriate depending upon your target for your vitamin D blood test.
In the past couple of years as vitamin D3 dosages recommendations have been raised, 5000 IU vitamin D3 softgels have become very inexpensive. Most such products use tiny softgels that are easy to swallow even for senior citizens. Another reason I like the 5000 IU softgels is that their vitamin D3 is already dissolved in an oily fat. Compared to powders, powder capsules, and tablets, this makes it more likely the active ingredients will be absorbed in the digestive tract.
For adults, 5000 IU per day is a good “rule of thumb” starting point for vitamin D3 supplementation. This 5000 IU per day also applies to teenagers who are roughly adult-sized, typically those around 14 years of age or older.
For teenagers and adults, a suitable inexpensive product that has tiny softgels of 5000 IU each is Swanson Health Care Products High Potency Vitamin D-3 5000 IU that features 250 softgels for $8.99. That’s about as inexpensive as vitamin D3 supplements can be unless you find a good sale. So for around $1 per month with that product, most adults can get enough vitamin D3 via supplementation. A good alternative is NOW Foods Vitamin D3 5000 IU 240 softgels, but this usually runs about $14 per bottle.
Preschool kids need about 1000 IU of vitamin D3 per day. As they are often unable or unwilling to swallow softgels, you may find it easiest to add this to their food via vitamin D3 drops. Customer reviews of Carlson Labs Carlson For Kids Liquid Vitamin D3 Drops, 400 IU, 365 drops 10ml suggest this is a good product for kids because it has no taste and can mix unobtrusively and easily with any drink or food containing some fat. You could easily put a drop of this in the food or drink for each meal to get about 1200 IU of vitamin D3 per day. Some report using these drops successfully directly in the mouth of their kids, also.
School age kids prior to growing to near the size of adults would benefit from around 2000 IU to 3000 IU of vitamin D3 per day, either drops or the usually cheaper softgels if you can get the kids to swallow them. For kids who can’t handle tiny softgels, you might try Carlson Labs D Drops Liquid Vitamin D3 4000 IU every other day or four drops per weeks as they are 4000 IU per drop and are also tasteless.
If your kids will swallow softgels, the high potency 5000 IU softgel products I mentioned should be fine for them simply by taking them less often than every day. For example, for a school age kid prior to teenagers in high school, swallowing three or four of the 5000 IU softgels per week is about right to get around 2000 IU to 3000 IU per day on average. Unless water soluble vitamins (most forms of B and C vitamins in particular), this works because vitamin D3 is fat soluble and the body stores it for future use.
If you have trouble getting your kids or yourself to take vitamin D3 supplements every day, it is fine to take all of them for the week at once with a big meal containing fat for best absorption. Even if you sometimes accidentally give two big doses per week because you forgot when the last dose was, it is unlikely to create any health problem unless you do this often.
Safe Upper Limits for Vitamin D3
According to Dr. John Cannell of the Vitamin D Council, overdose from taking a massive quantity of vitamin D3 during one day is less likely than overdose from water, aspirin, or Tylenol. To further drive this home, there is no known successful suicide attempt using vitamin D. The estimated LD50 (lethal dose for 50% of the patients taking it) for vitamin D3 in humans would be approximately 168 bottles containing 250 capsules of 1000 IU each or about 33 bottles containing 250 softgels of 5000 IU each. Can you imagine taking even one bottle of vitamin D capsules or softgels in one day? If you’re still not convinced that vitamin D is not likely to kill anybody in one or two attempts even if they tried very hard to do themselves in with it, see How Much Vitamin D is Too Much? Take This Vitamin D Quiz to Find Out!.
The main risks for vitamin D are not acute overdose but instead chronic overconsumption risks that show up not via death but by initially mild symptoms that can easily be reversed simply by lowering an overly high vitamin D intake. According to Dr. Michael Holick, the generally safe upper limits for long-term daily vitamin D3 intake for healthy weight people are 10,000 IU per day for adults (and similar size teens), 5000 IU per day for preschool and school age kids, and 2000 IU per day for kids under 1 year old.