Are Your Vitamin D Supplements Working? Probably Not (Here’s Why & How To Fix It)

Most people over a certain age know the importance of maintaining good vitamin D levels, especially in the context of bone health (as vitamin D is instrumental in how the body processes calcium).

Most people don’t know that you also need a good amount of vitamin K, or else that calcium is going to get stuck in your arteries instead of getting to your bones.

You can read about that, here: Vitamin K2 And The Calcium Paradox

There are other popular misconceptions about vitamin D, which you can read about here: Debunking the vitamin D fad

And yes, you can still overdo it: Vit D + Calcium: Too Much Of A Good Thing?

And there are even more ways to mess it up! See: How Taking Vitamin D Supplements Can Sabotage Your Vitamin D Levels

Which latter is mostly because of people making mistakes in the category of: Vitamin D2 vs Vitamin D3: What You Would Benefit From Knowing

0mg!

In the US, many people rely on milk for calcium. Some notes about that to get us started:

• Milk is a rich source of calcium, which is useless to the body if you don’t also have good levels of vitamin D and magnesium.
• People’s vitamin D levels tend to directly correlate to the level of sun where they live, if supplementation isn’t undertaken.
• Plant-based milks are usually fortified with vitamin D (and calcium), by the way.
• Most Americans* are deficient in magnesium, because green leafy things don’t form as big a part of most people’s diets as they should.

*magnesium deficiency is very common, and around 80% of people in the US do not meet the RDA for magnesium, despite widespread attention to vitamin D insufficiency.

Learn more: An update on magnesium and bone health

Now, with this in mind, researchers (Dr. Xiangzhu Zhu et al.) investigated the relationship between magnesium (Mg) levels and vitamin D synthesis and vitamin D metabolism.

That latter is important, because your body can be full to the brim with vitamin D, but if you can’t metabolize it, it’s useless to you.

What Dr. Zhu and her team found is that magnesium is seen to regulate vitamin D like a thermostat—raising levels when they are low and lowering them when they are high, which suggests an explanation for why vitamin D supplements do not work consistently across people.

In a randomized, placebo-controlled trial with 239 adults, tailoring magnesium doses to participants’ usual dietary intake, and found that magnesium supplementation increased vitamin D in participants who were deficient but reduced vitamin D in those who already had high levels, suggesting an optimizing rather than a purely boosting effect.

You can read the paper in full, here: Magnesium treatment increases gut microbiome synthesizing vitamin D and inhibiting colorectal cancer: results from a double-blind precision-based randomized placebo-controlled trial

If you prefer to get your nutrients from food rather than supplements, then magnesium intake at recommended levels can usually be enjoyed through foods such as dark leafy greens, beans, whole grains, nuts, avocados, and even dark chocolate.

If you prefer to supplement for convenience or “just to be sure”, then do check out: Which Magnesium? (And: When?)

Want to learn more?

As for why you might want to favor getting it from food if you can, then while the title says “vitamins”, this book discusses an assortment of vitamins, minerals, and other nutrients; the “other nutrients” category including amino acids (branched chain and essential), prebiotics and probiotics, and triglycerides of various kinds:

Eat Your Vitamins – by Mascha Davis, RDN ← see our review, here

Take care!