Why Vitamin D3 Supplements May Not Replace Sunshine

Heather Dessinger

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vitamin d supplements

So, the other day I was talking with this senior researcher at MIT. Man, I can’t believe I finally got to say that! It’s been #184 on my unofficial bucket list for, like, ever. Now to cross off #185  . . . does anybody know where I can find a cranberry bog? 

Back to the subject at hand, though. I contacted Dr. Stephanie Seneff after hearing her speak on Nutrition and Metabolism at the Wise Traditions conference last year. Dr. Seneff is a Senior Research Scientist at the MIT Computer Science and Artificial Intelligence Laboratory. She holds a B.S. degree in Biophysics, M.S. and E.E. degrees in Electrical Engineering, and a Ph.D in Electrical Engineering and Computer Science, all from MIT.

Anyway, during her presentation Micah and I were in a rather rowdy toddler room with the sound piped in, but I thought I heard her say that Vitamin D3 supplements may have all of the same benefits associated with sunlight. But she couldn’t have said that, right? Vitamin D supplements are sunshine in a bottle!

Maybe not. 

Dr. Seneff recently confirmed via email that she doesn’t believe Vitamin D supplements convey the same benefits as sun exposure. According to her, it’s what happens right before our bodies make vitamin D that makes all the difference: the oxidation of cholesterol and sulfur on our skin. (Before we jump in, please keep in mind that I am not a doctor or a nutritionist and this site does not provide medical advice. Please see my full disclaimer here. Okay, back to the post!)

Both cholesterol and sulfur afford protection in the skin from radiation damage to the cell’s DNA, the kind of damage that can lead to skin cancer. Cholesterol and sulfur become oxidized upon exposure to the high frequency rays in sunlight, thus acting as antioxidants to ‘take the heat,’ so to speak. Oxidation of cholesterol is the first step in the process by which cholesterol transforms itself into vitamin D3.” (source)

This process yields Vitamin D sulfate, which according to Dr. Seneff is vastly different than plant-based Vitamin D2 and animal-based Vitamin D3.

Upon exposure to the sun, the skin synthesizes vitamin D3 Sulfate, a form of vitamin D that, unlike unsulfated vitamin D3, is water soluble. As a consequence, it can travel freely in the blood stream rather than encapsulated inside LDL (the so-called ‘bad’ cholesterol) for transport. The form of vitamin D that is present in both human milk and raw cow’s milk is vitamin D3 sulfate (pasteurization destroys it in cow’s milk).” (emphasis mine, source)

The transformation of sulfur into sulfate is essential to good health because “it populates the extracellular matrix proteins of all the cells and keeps them healthy,” says Seneff. “It’s especially important in the blood for keeping microbes at bay  . . . which is why it appears that vitamin D builds a stronger immune system (I don’t think this is correct –I think it’s the sulfate that gets produced in the skin upon sunlight exposure that protects the immune system, and the vitamin D is just an indirect measure of sunlight exposure — that is, unless you get your vitamin D predominantly from supplements).” (emphasis mine, source)

But, Surely . . .

The body can convert D3 supplements into D3 sulfate, right? Unfortunately, though our bodies are genius chemists that does not appear to be possible. Synthesis of cholesterol into D3 and sulfur into sulfate occur simultaneously, like mixing eggs and flour/salt/water to bake a cake. You can’t put the eggs in the oven, bake at 350F for 45 minutes and then pull out the pan and add the flour, right? Same thing here.

Interestingly, Vitamin D3 and Vitamin D3 sulfate are each beneficial in their own way. For example, plain old D3 is amazing at transporting calcium through the body, whereas:

The sulfated form of vitamin D does not work for calcium transport . . . [However] it’s the sulfated form of vitamin D that offers the protection from cancer. It strengthens your immune system. It protects you from cardiovascular disease. It’s good for your brain. It helps depression. I think all of those effects of vitamin D are effects of vitamin D sulfate.”

Sounds pretty good, except if you’re like me you want the calcium transport, too! No worries, after Vitamin D sulfate does its thing it converts back to Vitamin D3 and gets to work on bone health. Or, as Dr. Seneff put it “vitamin D3 sulfate parks its sulfate somewhere among the extracellular matrix proteins, helping the blood to stay healthy. Having done that, it becomes vitamin D3 and can then transport calcium.”

What About Cod Liver Oil?

No discussion of D3 supplements is complete without talking about one of the most popular supplements in the real food community, cod liver oil. It contains Vitamin D3 instead of D3 sulfate, but both Dr. Seneff and I still recommend it. I can’t speak to all of her reasons, but I can tell you mine:

Dr. Weston A. Price has firmly established the benefits of consuming fat soluble vitamins A, D, E , and K. Unlike D3 drops which isolate one component, cod liver oil is a delicate balance of beneficial co-factors, essential fatty acids, antioxidants and micronutrients. Specifically, Vitamin D works with Vitamin A to utilize calcium and phosphorous in the body. Contrary to what we have heard, carrots contain betacarotene, which is a precursor to Vitamin A and not true Vitamin A. Not all of us are able to efficiently convert betacarotene to Vitamin A, which is why it’s preferable to consume preformed Vitamin A as well. (source)

So, isn’t consuming cod liver oil a form Vitamin D supplementation? Yes . . . yes it is.

The fact is our bodies don’t make much Vitamin D during the winter, and it makes sense to seek out additional vitamin D from whole food sources. But we still need sunshine to synthesize sulfate! According to Dr. Seneff, even in winter our skin can do this by synthesizing another compound, cholesterol sulfate – just add sunlight!

Is it a good idea to consume Vitamin D rich foods during the winter? Or even D3 drops if that is not available? Though I deeply respect Dr. Seneff’s research, I think so. As Kristen of Food Renegade said in the comments:

The ideal is to eat enough cholesterol from good animal sources and get enough sunshine so that Vitamin D levels are never a problem. The next best thing is to eat superfoods high in Vitamin D and other complimentary nutrients — like fermented cod liver oil. Perhaps the next best thing is to have quality, whole food based supplements that may mimic the synergistic nature of a superfood (I’m thinking of brands like Standard Process and their various Cataplex suplements). And finally, although it may be useless for some things, like the creation of sulfate, there’s the intake of a straight up isolated Vitamin D3 supplement which still has measurable benefits as study after study has proven. (And of course the BAD option would be to take no supplements and eat a Standard American Diet and expose yourself regularly to environmental toxins while not having a healthy enough body to eliminate them.)

Sometimes, we can’t let the good be the enemy of the ideal. And, of course, that means we should know what the ideal *is*.”

So what’s my takeaway from all this? I still focus on feeding my family nutrient-dense foods which contain lots of fat-soluble vitamins, but I don’t rely on them exclusively to meet our Vitamin D needs. Just like exercise and good quality sleep, I consider responsible sun exposure to be beneficial both for Vitamin D production and the regulation of our circadian rhythm.

This article was medically reviewed by Madiha Saeed, MD, a board certified family physician. As always, this is not personal medical advice and we recommend that you talk with your doctor.

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About HEATHER

Heather is a holistic health educator, herbalist, DIYer, Lyme and mold warrior. Since founding Mommypotamus.com in 2009, Heather has been taking complicated health research and making it easy to understand. She shares tested natural recipes and herbal remedies with millions of naturally minded mamas around the world.