The Sunshine Vitamin, Part 2: Choosing the Right Vitamin D Supplement
Vitamin D supplementation is all the rage these days. In Part 1 of this series, we addressed the discrepancies amongst intake recommendations, with some experts criticizing the widespread use of vitamin D and others recommending far more than the RDA of 600-800 IU daily. If you haven’t read that piece, we highly encourage you to start there for background.
Today’s goal is to help you wade through the noise to find a supplement that works for you – in the correct dosage, at the right frequency, and from the right source to meet your goals.
But first, we have a little more background to cover.
How do you typically get Vitamin D?
It’s worth quickly describing the process by which your body produces Vitamin D because it’s critical in understanding why Vitamin D supplementation is essential for some people.
Uniquely amongst nutrients, Vitamin D production in the body relies primarily on sunlight exposure rather than food sources. When UV-B radiation from the sun reaches your skin, it causes structural changes to a natural form of cholesterol produced in the skin layer called 7-dehydrocholesterol. This conversion sets up the precursor to what will eventually become active Vitamin D in the blood after further modification by the liver and kidneys.
Several common variables can impair your ability to produce adequate levels of Vitamin D:
- Darker skin pigmentation, which is more effective at blocking UV radiation – and consequently, reduces vitamin D production.
- Living north of the 37th parallel, the line bisecting the U.S. from Richmond to San Francisco. Above this line, solar radiation is not strong enough to adequately convert skin cholesterol to Vitamin D during winter.
- Spending most of your time indoors or using high SPF sunscreen anytime you’re in the sun. Please note that we are NOT advocating against using sunscreen.
- Aging (even gracefully) hinders the skin’s ability to produce vitamin D. Older adults often struggle to maintain sufficient levels.
How much Vitamin D should you be taking from supplements?
The “ideal” dose of Vitamin D is still hotly debated. Guidelines from expert groups vary widely, from 600 IU/day set by the Institute of Medicine to 1500-2000 IU/day from The Endocrine Society. However, in many cases, this does not account for individuals who are already below adequate levels, and doses up to 4000 IU/day are deemed safe, with some researchers arguing for even higher thresholds.
Routine blood testing can diagnose Vitamin D deficiency. Some experts recommend 2000-3000 IUs per day from all sources (diet, sun exposure, and supplements) to maintain blood levels in an “adequate” range. During the winter months in New England (November – April), most of this must come from supplements. Because the correct supplement dosage largely depends on your current vitamin D status, the following chart can help select a starting point:
|Vitamin D Status
|Blood Level (ng/mL)
|Daily Dosage (Especially Nov-Apr)
|2000-3000 IUs (maintenance)
|If you aren’t sure
|2000 IU/day is a safe bet to start
***NOTE: as a general rule, every 1000 IU may raise blood vitamin D levels by around 5-10 ng/mL though individual results can vary.
Despite the recommendations above ranging from 600 – 4000 IUs/day, the two most common supplement doses are 1000 IU and 5000 IU, presenting a quandary: how do you hit your desired daily dose without taking four separate pills for one supplement?
Because Vitamin D is fat-soluble and able to be stored by the body, we recommend choosing a 5000 IU supplement for ease and adhering to one of the following dosing schedules:
- 5000 IU taken once a week = 700 IU daily average.
- 5000 IU taken on weekends only = 1400 IU daily average.
- 5000 IU taken M/W/F = 2150 IU daily average.
- 5000 IU taken on week days only = 3570 IU daily average.
- Finally, take daily for 5000 IUs on average.
***NOTE: Because vitamin D is fat-soluble, you will absorb the supplement much better in the presence of food. If taking it with a meal isn’t possible, a ½ spoonful of peanut butter should do the trick.
What’s the difference between Vitamin D2 and D3?
When choosing a vitamin D supplement, check the label for the form of the nutrient included, D2 vs. D3.
D2 is plant-based and is often the form of Vitamin D used to fortify foods. It is sourced mainly from fungi (such as mushrooms) and yeast by exposing them to UV-B radiation. It is the ideal form if you are looking for a vegetarian/vegan supplement.
However, studies demonstrate the superiority of D3 from fatty fish in boosting activated vitamin D levels in the blood. If you choose to utilize a vitamin D2 supplement instead, be mindful that a higher dose will likely be necessary to raise your blood levels a comparable amount.
Can I get my vitamin D from a tanning bed?
Unfortunately, the claim that tanning beds provide a solution to low Vitamin D during the winter isn’t accurate. As the American Academy of Dermatology points out, the form of radiation emitted by tanning beds (UV-A) is not the right type to stimulate skin production of vitamin D (UV-B).
Do you have Vitamin D supplement recommendations?
Absolutely. It should come as no surprise that we’re willing to back our in-house vitamin D supplement, produced in partnership with Xymogen, against any product on the market. It contains a potent 5000 IU of vitamin D3 with added vitamin K2, which helps ensure calcium in the blood gets shuttled into the bone. This action helps to prevent long-term calcification of the arteries.
However, if you’re going to shop online, remember this: unlike food or drug products, supplements are unregulated. With few exceptions, supplement makers do not have to prove the accuracy of health claims on their products. Supplements are rarely third-party-tested to ensure they contain the active ingredients and amounts reported on the label. So, whenever you shop for a supplement, look for a product engaging in third-party testing for purity. A few of our favorite “seals of approval” include USP, NSF, and Informed Choice.
Do you have further supplement questions? We’re here to help. For more information on our supplements at Men’s Health Boston, click here. For a deeper conversation with our in-house dietitian and nutrition expert Zach Wehmeyer, RDN, call our office or request an appointment online today.