If your goal is to build muscle, you better make sure you have enough vitamin D in your body. One of the primary functions of vitamin D is muscle growth. Believe it or not, taking a shower every day can actually lead to a vitamin D deficiency — which may result in muscle loss, weakness, and ultimately, a slower metabolism. It’s true!

I learned this valuable lesson from Dr. Peter Osborne, author of No Grain, No Pain, who gave an excellent talk on the subject at The Diabetes Summit. Here are some of the key highlights from that discussion:

• One of the main reasons for vitamin D deficiency involves over-hygienic habits — constantly washing your hands and showering too often. Even people who live in sunny climates can be severely deficient if they wash too frequently.
• You won’t get much vitamin D from your diet. Liver and mushrooms are among the best sources, but beyond that, there’s not much available in food. Even fortified foods often contain the nonactive form of vitamin D (D2), which has little hormonal impact. And the dosages are usually so low that it’s like “trying to spit on a forest fire” — it won’t do much!
• We make vitamin D primarily through sun exposure. There’s a form of cholesterol that sits as an oil on your skin. When UV light hits that oil, it converts it into vitamin D.
• The vitamin D formed on your skin can take up to 16 hours to fully absorb into the bloodstream. After that, it must travel to the liver and kidneys to be converted into its active form. That means your liver and kidneys need to be functioning well for the whole process to work efficiently.
• Showering daily — especially with soap — removes that oil from your skin, taking some of the vitamin D with it. So even with plenty of sun exposure, frequent showering can compromise vitamin D absorption.
• The germ theory of disease has made people so afraid of germs that many have forgotten about balance. You don’t need to scrub your entire body with soap every day. Over-washing may actually contribute to disease, particularly autoimmune conditions.
• Vitamin D plays a crucial role in regulating your immune system. It helps keep immune cells in check — like parents keeping teenagers under control at a house party. Without enough vitamin D, those immune cells can run wild, causing internal damage much like a ransacked home!

Take-Home Message:

Shower every other day when possible. If you must shower daily, soap only the “stinky” parts and allow the natural oils on your skin — especially the areas exposed to sunlight — to remain and absorb. Ideally, shower in the morning before sun exposure, not at night. Give your body the extra time it needs to absorb vitamin D while you sleep.

P.S. Here’s my challenge to any health-care practitioner who prescribes vitamin D supplements to their (non-infant) patients or clients: https://theelitetrainer.com/my-vitamin-d-challenge/