Can you get vitamin D through a window? Experts reveal the truth
As for food, fortified milk and orange juice, as well as egg yolks and certain types of mushrooms (UV irradiated) contain small amounts (as in virtually obsolete) of vitamin D2 (the much less bioavailable and effective form of the micronutrient). Native dietary sources of vitamin D3 include certain fatty fish, such as salmon, for example.
Even just to reach the basic recommended dietary intake (i.e. 600 IU for healthy adults, according to the national academies) to avoid bone health problems, one would need to drink more than six glasses of milk fortified daily, 12 whole eggs or a 3.5 ounce serving of sockeye salmon, and experts agree that 600 IU is not enough distance from the fat-soluble nutrient to move the needle on vitamin D status in order to achieve (and maintain!) healthy levels.
As mentioned earlier, national rates of frank vitamin D deficiency and insufficiency [i.e., 25(OH)D blood test results less than 20 ng/ml or 30 ng/ml] in adults is 29% and 41%, respectively. But racial inequalities clearly exist, with 82% of black Americans and nearly 70% of Latinos suffering from D deficiency.
If we simply look at the amount of vitamin D we put in our mouths each day, nationally representative research demonstrates that between 93 and 100 percent of the US population does not consume even 400 IU of vitamin D per day.
With this in mind, Holick recommends that all of its clients take a daily vitamin D supplement, regardless of the season. Drake agrees, stating that the Linus Pauling Institute recommends that generally healthy adults take 2,000 IU of supplemental vitamin D each day, but noting that achieving ideal blood levels of vitamin D (that is, i.e. above the 30 ng/ml “danger zone” for insufficiency and within that coveted 50 ng/ml range) may require an even higher supplementation dose.
mbg Vice President of Scientific Affairs, Ashley Jordan Ferira, Ph.D., RDN, breaks down exactly How many vitamin D we need to achieve healthy serum levels: “Pharmacokinetic research shows that it takes 100 IU of vitamin D to increase the serum D levels of a normal weight adult by approximately 10 ng/ml. This means so to reach 50 ng/ml you need 5,000 IU of vitamin D per day.” She elaborates by saying “given that two-thirds of our country is overweight or obese, our daily vitamin D needs as a country are actually higher, but 5,000 IU is a great place to start.”
If you’re trying to do some quick mental math to figure out how many servings of milk, eggs, or fish you’d need to eat to get 5,000 IUs of vitamin D a day, we’ll save you the trouble, that’s a lot. Too much, we’d just be chatting. Simply put, daily vitamin D supplementation is the most effective way to achieve sufficient vitamin D levels and maintain whole-body health.*
(Looking for a really effective D3 supplement that will help you achieve and maintain adequate vitamin D status? Check out our roundup of vitamin D supplements.)