First, why should you even care about vitamin D? Consider the following effects of having optimal levels:

• Vitamin D increases muscle protein synthesis and the overall capacity to perform both aerobic and anaerobic exercise.
• Vitamin D helps maintain muscle mass during long periods of inactivity.
• Low levels of vitamin D correlate strongly with reduced lung capacity.
• Without proper levels of vitamin D, arteries get stiff.
• Women with optimal levels of vitamin D have higher circulating levels of estradiol, testosterone, FSH, LH, and DHEA, all of which lead to better health and even better orgasms.
• Vitamin D modulates innate and adaptive immune responses.

But even if the average athlete or person was on board with all of that and decided to assume responsibility for their vitamin D status, they'd have several hurdles to overcome.

The best way to fortify vitamin D levels is the natural way, i.e., lying buck naked or virtually buck naked in the sun at least twice a week for 20 minutes. It'd be even better if you could rig up some device to make you spin like a rotisserie chicken, thereby exposing all your bits to the sun.

However, this practice (lying in the sun) has largely fallen by the wayside because of legitimate fears of skin cancer. Even if we do venture out in the sun regularly in varying degrees of nakedness, most of us wear sunscreen, which blocks the skin's ability to convert UVB radiation into vitamin D3.

Besides, many people live at the "wrong" latitudes and only get therapeutic amounts of sunlight a few months out of the year. So scratch that.

What about eating a lot of vitamin-D-rich foods? It's a seemingly logical course of action, but it too has its shortcomings. For one, there aren't that many naturally-rich vitamin D foods. Aside from eggs, cod liver oil, certain fatty fish in general, some algaes, and a few varieties of mushrooms, vitamin D is generally in short supply.

Besides, the total amount of vitamin D (both D2 and D3) found in a food during chemical analyses doesn't reflect its bioavailability. A lot of the vitamin is bound up in the actual food and remains so after you eat it. Lots of things contribute to this: the physiochemical form of the vitamin D, the fatty acids and fibers in the food, the size of the food particles themselves, and the quantity of the vitamin itself.

Interactions between vitamin D and other fat-soluble nutrients might also be a factor, as well as a bunch of host-related issues (age, disease state, fed condition, genetics, obesity, etc.).

Then there's how you might prepare any vitamin-D-containing foods. Heat affects it. Light affects it. Moisture, oxygen exposure, and even storage conditions affect levels of vitamin D. That means that any vitamin-D containing foods that are boiled, pressure-cooked, Insta-Potted, baked, or air fried could end up being vitamin-D compromised.

Unbeknownst to most, vitamin D has a partner of sorts. If its partner isn't around, it doesn't go to work – it won't even get off the couch, let alone brush its teeth and put its pants on.

This partner is the mineral magnesium, which is already largely deficient in the typical American diet. Some surveys have calculated that 85% of Americans are lacking in this super-important mineral.

Athletes generally have it even worse because magnesium hitches a ride on sweat. The more you sweat – as you might in any athletic endeavor – the more magnesium-compromised you are and the less probable it is that your body will transport, synthesize, and activate vitamin D.

Next to the now-declared dangerous practice of lying in the sun, supplementation is generally the most efficient way to up your vitamin D game. The trouble is, vitamin D supplements manufactured in the traditional manner are prone to all the same manufacturing and absorption problems attributed to vitamin-D containing foods – moisture, oxygen exposure, and non-optimal storage conditions.

I've seen the repercussions over and over again – even experienced them personally. You take the initiative and try to elevate your vitamin D levels to optimal blood levels (at or beyond 50 ng/ml or so) and start popping conventional capsules and grimacing down sardines and whatever for weeks or even months, and nothing much happens. Levels don't budge.

Recent technological advances have changed all that, though. The only form of vitamin D3 worth taking is microencapsulated vitamin D3. This form of the vitamin is manufactured by encapsulating vitamin D3 molecules in liposomes or solid lipid nanoparticles.

The vitamin then presents as tiny "beadlets" and is protected from moisture, oxidation, pH, temperature, and mechanical forces. The microencapsulated product is stable, water dispersible, and, most importantly, highly bioavailable.

Studies show that the effects of this form of vitamin D3 remain constant for up to 14 days, making it clearly superior to the conventional vitamin D3 supplements that comprise most of the market. People who use it have reported rapid and impressive increases in blood levels of vitamin D3.

Biotest immediately recognized the value of this form of vitamin D3 and incorporated it into its i-Well™ Immune Support product. Each 3-capsule serving contains 5,000 IU of vitamin D3 (as choleocalciferol), along with 400 mg. of beta-1,3-glucan, 400 mg. of EGCG, and 400 mg. of solid lipid curcumin particles, each with its own immune-boosting properties.

(These latter two substances work together with vitamin D to convey a host of beneficial effects on the human body, mostly in the form of immuno-enhancements.)

Using this form of vitamin D3, in conjunction with adequate dietary or supplemental magnesium (at least 300 to 400 mg. a day) would surely stop this dietary epidemic of low vitamin D levels among athletes and regular folk and stop it fast.

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