Vitamin D: What's Your Optimum Daily Dose?

Patient Expert

Health claims for vitamin D have rocketed over the past decade, with studies showing evidence that sufficient vitamin D in your daily diet can do everything from increase cardiovascular health to reduce cancer risk. Not all vitamin D health claims are legitimate; many have yet to be proven over time. But one thing we know: vitamin D is an important element in bone strength. Are you getting enough?

A healthy diet is critical to your overall health; we all know that. Study after study has shown that people who eat more fruits and vegetables, more fiber, more healthy fats and a moderate level of protein and carbohydrates will be healthier than those consuming inordinate amounts of processed foods, sugar, saturated fat, and empty carbs. In other words, the Twinkie Diet is NOT a good health choice.

Along with tracking the foods we eat, it's also important to understand the components of those foods most important to our individual health. If you're a breast cancer survivor, you might want to eat lower-calorie foods, in order to maintain a healthy weight. At risk for a heart attack? Definitely avoid those artery-blocking saturated fats.

And if you're at risk for osteoporosis? Keep tabs on your daily calcium and vitamin D consumption. Because those two elements - one a mineral, one a vitamin - are critical to maintaining bone strength, particularly as you age.

As an older woman, you probably know that your calcium goal is 1,200mg-1,500mg daily. And that amount of calcium is fairly easily attainable, between the foods you commonly eat, and supplements.

But what about vitamin D? Well, that's a bit more complicated.

We obtain Vitamin D through three main sources: food; supplements, and sunlight. So right off the bat, understanding your daily vitamin D intake has an extra variable - sunlight - compared to calcium.

In addition, there's disagreement in the medical community around optimum blood levels of vitamin D, and how to reach those levels. Some doctors recommend supplementation of up to 50,000 IU vitamin D a week (about 7,143 IU/day); while the government's Food and Nutrition Board (FNB) believes the daily cap should be 4,000 IU.

The Institutes of Medicine, a division of the National Academies, says that individuals with a vitamin D blood level of over 50 nmol/l are considered healthy; some in the medical community say that 75 nmol/l should be the lowest acceptable level.

Finally, unlike calcium, many if not most Americans find themselves deficient in vitamin D.

So how do you approach your vitamin D intake?** First, find out what your vitamin D blood level is.** Your doctor can administer a simple baseline test that will easily tell you what you need to know. Beware, though - not all insurance plans cover vitamin D testing without pre-approval, so check with your insurer before you ask for the test.

If your vitamin D level falls within the acceptable range of 50-125 nmol/l range, congratulations -  continue what you've been doing, as far as diet, supplementation, and sun exposure.** But if your Vitamin D level is below 50 nmol/l, speak with your doctor about the best way to raise it.** S/he may suggest additional exposure to sunlight, if that's a possibility. The National Institutes of Health, via its Office of Dietary Supplements, recommends 10 to 15 minutes of sun exposure twice a week, between mid-morning and mid-afternoon. This is outdoor sun (not through a window); and without sunscreen.

Your doctor may also recommend tweaking your diet to include more vitamin D-rich foods. These might include fatty fish (tuna, mackerel, sardines, salmon); eggs yolks (whole eggs, not egg substitutes); beef liver, cheese, and vitamin D-fortified milk, as well as D-fortified cereal, margarine, and orange juice. (Hamel, 2011)

And finally, you might decide to increase your daily vitamin D supplementation. While those whose vitamin D level is within the normal range are fine with supplements of 600 IU-800 IU daily, those wishing to raise their vitamin D blood level need more - but how much more?

You might think, "Let's get this done - the more the better." But studies have shown that "megadosing" with vitamin D is ineffective - and may actually be harmful. The FNB has set the Tolerable Upper Intake Level (e.g., the maximum amount you should take daily) at 4,000 IU for vitamin D. So don"�t pop those 1,000 IU vitamin D gummies with abandon.

Discuss with your doctor where on the supplementation spectrum, from normal 600 IU-800 IU to upper-limit 4,000 IU, your goal should be. And then follow up with a blood test to check your progress after a suitable interval, determined by your doctor.

Want to know more about vitamin D? Read Vitamin D: Answers to Common Questions.


Hamel, P. (2011, August 23). Vitamin D: Does Megadosing Help? Retrieved January 4, 2015, from

Hamel, P. (2011, September 22). Vitamin D: Answers to Common Questions. Retrieved January 4, 2015, from

Vitamin D. (2014, November 10). Retrieved January 4, 2015, from