Circadian (11): Don’t Sail Your Ship Without an Anchor

Today we are going to dive deep into how midday sets the time for all of our cells that cannot see light like the SCN can. Time, as far as the cells are concerned, really is the activation and then the deactivation of CLOCK and BMAL1 proteins in the nucleus. Activation of these proteins is the cell’s daytime, and their deactivation is its nighttime.

The biggest influencer of it all is, of course, vitamin D. Midday sun contains the only key (UVB) which can unlock vitamin D production in our skin. After activation, vitamin D goes to every cell in the body and occupies its docking station. This activates the BMAL1 and CLOCK genes to produce their respective proteins.

This is how the midday light message can be ‘seen’ by the whole body, even though UVB does not penetrate the skin more than 0.06mm. If you take out the red blood cells, virtually all of the rest of the body has receptors for vitamin D. This is important, because you want the whole body to work in sync. When vitamin D is present, the time for the different organs is calibrated and resynchronised. It matters not if you are a surface organ like the skin or a deep one like the liver. Even the pineal gland has vitamin D receptors. The eyes are not left out either, despite their more immediate access to natural light and, therefore, time.

Imagine this process repeating itself millions of times during our species’ existence. The genes have been entrained, and the whole body is anchored to this phenomenal period we now take for granted. Suddenly, we came along and consistently avoided midday exposure at safe doses, on top of all the other circadian disruptions we have allowed to happen. We see plummeting vitamin D levels, and guess how we try to sort it out? Vitamin D supplements, of course.

Now, that is dangerous for many reasons. First, most people take supplements in the morning. If our body sees midday in the morning, you have just created a false time for the body to operate on. Second, we don’t always take supplements at the same time every day. I have met people who take vitamin D at any time of the day or night when they remember to do so. You can imagine how disruptive that will be to their circadian rhythm. Third, our digestive system doesn’t always behave the same even if we keep the dose timing consistent. If you are taking vitamin D supplements, it is quite likely that you are taking them because you are deficient in the first place, meaning your digestive system probably doesn’t have the right clock to know what to do when. Fourth, most of the active vitamin D we supplement with will go straight to the liver first due to our enterohepatic circulation. This doesn’t just mean that the liver will metabolise a large part of it to waste; more crucially, our bodies have never seen an uneven distribution of this time-controlling vitamin at this scale. This is especially true because supplemented vitamin D is fat soluble, whilst skin-produced vitamin D swims freely in the bloodstream to reach wherever your vascular network reaches.

It is one thing to sail your ship without an anchor, but it is another to do it with multiple anchors that confuse the whole deck crew. I say keep to the anchor we have been familiar with forever: the sun. Your consistent midday sun exposure will line up all of your cells’ activities. No one part of the body will be doing something completely different from the rest. They will all work in the same time zone. When your midday is every cell’s midday, your midnight will be every cell’s midnight too, because they all run out of BMAL1/CLOCK at the same time.

Beyond that, there are other reasons why supplementation won’t work. We don’t only get vitamin D from midday sun exposure. The sun at midday has the highest amount of infrared, which stimulates a low-inflammation environment via TGF-Beta. This protects the BMAL1 and CLOCK proteins from early degradation, ensuring they last longer.

At safe doses, the midday sun's UVB hits the skin to stimulate alpha-MSH. Alpha-MSH has many functions, the most famous of which is tanning. Perhaps we will talk more about alpha-MSH in the future, but for now, keeping to the subject at hand, it also upregulates BMAL1.

Of course, I am not recommending anyone bake in the midday sun. Too much midday sun, especially when your skin has little melanin (tan) from long-term sun avoidance, is going to be detrimental to you and your body clock. The UVB can stimulate too much alpha-MSH if you are out for too long. At higher concentrations, alpha-MSH turns BMAL1 off as it wakes the PER and CRY proteins. Remember, these proteins silence BMAL1 and CLOCK. If your BMAL1/CLOCK are silenced before nighttime, your biological clock turns faster. Instead of the expected 24-hour cycle, your BMAL1/CLOCK vs. PER/CRY activity might complete its cycle in 23–23.5 hours. Your body might register 30 days—or gene cycles—after an actual 28 days of the earth’s rotation. This means that you age quicker. This is the environment where cancer thrives. Cancer cells love not being governed by time genes like BMAL1 and CLOCK.

Is it any wonder then that most cancers are associated with vitamin D deficiency one way or another? And I emphasise—that includes melanoma too.