With regard to the "natural vs supplement" argument, some people are very pale and susceptible to skin cancer. It may not be safe for everyone to get enough Vitamin D through natural means alone.
A very pale person may burn in 5 minutes. It doesn't make sense that your body would speed up the synthesis of cholesterol just because your skin has less melanin or is more sensitive to UV radiation. Also keep in mind that no matter how much is synthesized it's up to the liver and kidney to make it into a useful hormone.
http://essays.backintyme.com/item/4
> The lightness adaptation enhances calciferol (vitamin D) synthesis. Too much epidermal melanin for the latitude blocks UV penetration essential to the dermal synthesis of calciferol or vitamin D.
If you have less melanin then more sunlight reaches the lower layers of skin which increases vit D synthesis.
What cause most Vitamin D issues today is that people are NOT enough in the sun...
I personally dislike the sun and used to avoid it a lot (because I am more or less white and it burns me fast), now I have a really bad Vitamin D deficiency and was obliged by the medics to take supplements.
I stopped avoiding the sun... But it is still not really enough (I am programmer... I wake up in a dark room, walk to work in the sun, but the walk is 5 minutes, and then I stay indoors until night, when I walk back home, without any sun, thus my total sun daily is 5 minutes :/)
Excess dietary calcium is stored in the bone bank and withdrawn when one of the 100+ crucial human biochemical reactions requiring calcium lowers the blood availability.
Perhaps there are ways of maximizing the effect of one of our most important and most used nutrients, but nothing can replace the Ca element and it's widespread, fundamental usage in our body.
I wish I could watch your video (I don't speak German) but I want to stress that Ca is absolutely a requirement for healthy bones, and is the #1 requirement. Without calcium intake, there cannot be bone for long.
"For example, some of the proteins produced in response to calcitriol in the intestine help transport calcium across the intestine and into the bloodstream, greatly increasing the absorption of calcium from the diet. The vitamin D receptor is found in several cells that are critical for controlling the metabolism of calcium, phosphorus, and bone: intestinal cells, bone cells, kidney cells, and parathyroid gland cells."
http://www.dummies.com/how-to/content/what-is-vitamin-d-and-...
"Vitamin D’s best-known role is to keep bones healthy by increasing the intestinal absorption of calcium. Without enough vitamin D, the body can only absorb 10% to 15% of dietary calcium, but 30% to 40% absorption is the rule when vitamin reserves are normal." ... "Low levels of vitamin D lead to low bone calcium stores, increasing the risk of fractures." ... "In the intestines, the receptors capture vitamin D, enabling efficient calcium absorption. But similar receptors are also present in many other organs, from the prostate to the heart, blood vessels, muscles, and endocrine glands."
http://www.health.harvard.edu/newsweek/vitamin-d-and-your-he...
Video Translation 01:55 min.: Dr. Feil: "The basil, we use today much much [sic] more herbs, because we see, that herbs stabilize the bones. In the past, it was always said, 'bones and calcium', today we say, the sportsperson needs herbs, to have a strong bone structure". And at 04:31 Dr. Feil: "We recommed today, to eat two handful of nuts every day, that makes the bones strong. ..." [a few seconds later, he recommends walnuts, slightly roasted as the best option]
edit: at 15:21 Dr. Feil: "The Red wine has ... much more boric, the micronutrient boric is good for the bones, ...", he recommends to drink 5 glasses per week (not a whole bottle)