Should you Take Vitamin D in the Summer?
During the summer months, do you set aside your Vitamin D supplement, figuring you’ll get enough from the sun? Many of my patients tell me they do, even sometimes as early as spring.
In Seattle, this is not necessarily a good idea. While it’s true that sunshine is the best way for your body to increase its Vitamin D stores, you may want or need to continue taking that Vitamin D supplement even during the summer. First, we Seattleites need to define “sunshine.” And “summer.”
In normal Seattle summers, I tell patients to assume they’re only making vitamin D in July and August, which is generally the only time the sun is strong enough to be doing you any favors. This is not about heat; it’s about the angle of the sun at our northern latitude.
While this summer in Seattle has been unseasonably hot, you still may or may not be making enough Vitamin D from the sun.
Why not? When you hide in the shade or indoors by a fan (or in front of an air conditioner if you’re lucky), you don’t make any Vitamin D. If you’re outside but slathered with sunscreen, you probably don’t either.
So, should you keep taking your Vitamin D supplement? That depends on 3 things:
- your current Vitamin D status;
- whether you’re outside at the right time, in the right conditions (meaning, without sunscreen, in sunshine that could produce a sunburn were you to stay out too long — but don’t stay out long enough to burn!), often enough;
- how efficiently you personally convert sunshine to Vitamin D, or Vitamin D supplements to Vitamin D stores, which varies.
A quick reminder on why we care:
- Vitamin D deficiency is associated with cancer, cardiovascular disease, hypertension, stroke, diabetes, multiple sclerosis, rheumatoid arthritis, inflammatory bowel disease, periodontal disease, macular degeneration, mental illness, influenza, propensity to fall, chronic pain, and more.
- Every day it seems, the list grows longer as to what conditions researchers have found to have a connection with low Vitamin D, or which cells have been found to have a Vitamin D receptor. A meta-analysis of 18 studies indicated that vitamin D supplementation, even in relatively low doses, reduces total mortality.
- Vitamin D deficiency is endemic. Even more importantly the definition of “deficient” is suspect. The official bottom end of the normal range is in the low 30’s (in ng/ml).
- However, that is not at all an ideal or optimal level. Meta-analyses on the topic indicate that we should be aiming for at least 55 ng/ml or higher, to get us over the deficiencies that are correlated with the above-mentioned disease conditions.
Back to the original question: should you keep taking your Vitamin D dose in the summertime? IF your Vitamin D stores are greater than 55 ng/ml, then I usually find that the following dosing works for maintenance:
- 1000iu/day that you’re not outside at the “right time” (see above), which in Seattle usually counts only in July & August, and
- 2000iu/day outside of July & August.
- And note that if you’re dark-skinned, your skin might not convert sunlight to Vitamin D terribly efficiently.
- If you’re not above 55 ng/ml, you may need to dose higher.
However, there’s no perfect generalized guidance, since I’ve found that people add to their stores at their own unique rate. The best way to figure that out is for us to get a baseline test of your current level; then (if you’re my patient) I will give you personalized dosing guidance (or you can ask your own doctor). Then we’ll re-measure in about 3 months to see what’s gone on under the covers.
Now remember, don’t take this post as license to dose your Vitamin D willy-nilly (and, as a reminder, never take any blog post as medical advice). Some practitioners like to dose Vitamin D quite high. I don’t like to, for 2 reasons:
- One is that it can compete for absorption with other fat-soluble vitamins, so dosing too high could cause a relative deficiency in certain other vitamins.
- The second is that Vitamin D acts as a hormone in your body, and prefer to be conservative with hormones. I’d rather not try to control and manipulate what your body should do. I prefer to feed and nourish, and let your own Vital Force use the raw materials as it sees fit.
If you don’t know your level of Vitamin D or we haven’t tested lately, let’s make an appointment so we can do so. In the meantime, may you enjoy the summer in luminous good health, Dr. Deborah