I used to think I was really cool because I never spent any time in the sun. If you stopped me on the street to talk to me, I would move our conversation across the street into the shade before continuing. In my mind, this meant I was going to be wrinkle-free forever – it was a super healthy choice, right? Well, for starters, I don’t even want to think of the chemicals that were in the sunless tanners I used. And secondly, as you may know, our bodies need sunlight to make Vitamin D.

Yes, I’m telling you to go tanning.

Let’s pause for a moment to appreciate how cool that is: Vitamin D is the only vitamin our bodies can actually make out of practically nothing. It’s the closest to photosynthesis we’re going to get.

Depending on your coloring, you need about 20 minutes of direct sunlight on your arms and legs (sunscreen-free) to make the amount of vitamin D you need to stay healthy. Even a sunblock with SPF 8 will seriously decrease the amount of the vitamin you’re going to make.

And if you’re like me, and you spend most of your time in an iron jungle like New York City, you probably aren’t even getting those daily 20 minutes of direct sunshine in the summer.

In fact, recent studies show that about 40% of the adult U.S. population has a vitamin D deficiency.

Why vitamin D deficiency is really no bueno…

Most of us know that vitamin D is good for our bones, but it’s also super important for our thyroid. Low vitamin D blocks the production of thyroid hormone. This is obviously bad for our metabolism, but it also throws off multiple parts of the endocrine system. It goes kind of like this:

Basically, this little hormone cascade results in 2 important things:

1. Not enough progesterone. This is a big deal because progesterone is estrogen’s counterpart in a healthy menstrual cycle. Estrogen rules the first half and progesterone rules the second half.
2. A negative feedback loop that keeps the thyroid from functioning properly, which impairs the body’s ability to make enough progesterone, which impairs thyroid function.

What this means for our monthly cycles and our fertility…

Basically, this can be pretty bad for our monthly cycles, and therefore our fertility, and therefore our health (because fertility is synonymous with optimal health). Upsetting the progesterone-estrogen balance can result in all sorts of things like:

• irregular bleeding
• PMS
• weepiness pre-period
• luteal phase defect
• fibroids
• painful periods
• endometriosis

And since progesterone is the pregnancy hormone, this can also mean increased likelihood of infertility or miscarriages.

Low thyroid hormone also comes with its own set of issues like:

• hair loss
• pelvic pain
• abdominal pain
• ovarian cysts

So how do you know if you’re deficient?

Any number of period problems or symptoms of an underactive thyroid can signal a deficiency. The best thing to do is to get tested so you can determine exactly where your vitamin D levels are at. Ask your doctor to for a 25(OH) vitamin D test.

Also be aware that you may not exhibit noticeable symptoms even if you are mildly deficient.

Where to get that D if you can’t get enough sun exposure…

The sun is by far the best way to get bioavailable vitamin D. But, if you can’t get enough sun exposure, and I certainly can’t in January in NYC, then you can get vitamin D from your food and/or from supplements.

• Fatty fish (salmon, cod); mushrooms; parsley; eggs; and nuts are good sources of vitamin D. Opt for these whole foods over fortified foods like processed dairy and cereal products.
• You can also supplement with cod liver oil. This has the benefit of being a food-derived source that comes with other bonuses, like healthy fats. Take as directed on the bottle.
• If you just don’t do well with oil supplementation, you can supplement directly with vitamin D. There is a risk of toxicity with vitamin D supplements so it is best to get your levels tested before supplementing with large amounts. If you are just maintaining your vitamin D levels in the winter (which I do) or warding off against a deficiency and not exhibiting symptoms, then 1,000 IU a few times a week up to daily should suffice. If you have a deficiency you may want to take up to 7,000 IU a day to replenish your nutrient stores. I recommend Thorne Vitamin D 1,000 IU for maintenance and their 5,000 IU for replenishing. (Please consult with your physician first.)

So whether or not you have access to the sun right now, keep this little guy in mind! Your hormones will thank you 🙂