“The reason there is not one mentioned how Vitamin D strengthens bones as well as help your immune system, because vitamin D is not directly involved in bones.
If what you mean by “strengthen bones” is the opposite of bone mineral loss, a little called Osteopenia, preferably known as “low bone mass” or “low bone density” that can progress to Osteoporosis, a disease where so much bone minerals are lost that bone weakening increases the risk of a broken bone.
Vitamin D is not directly involved in returning calcium into bones.
What needs to be appreciated is the principal function of vitamin D in calcium homeostasis (balance) is to increase calcium absorption from the intestine. Calcium is absorbed by both an active transcellular pathway, which is ATP energy dependent, and by a passive paracellular pathway through tight junctions.
Then, when there is calcium in the blood, or calcium deposits in arteries, veins, joints or organs (that came out of bones) it is Vitamin K2 that activates proteins that play a role in calcium metabolism and heart health. One of its most important functions is to regulate calcium deposition. In other words, it promotes the calcification of bones and prevents the calcification of blood vessels and kidneys.
The best source of vitamin K2 (menaquinone) is natto, fermented soy beans.
So, optimizing bone health isn’t as simple as getting enough dietary calcium.
Beyond the obvious importance of this mineral, other factors, such as vitamin D3 and magnesium intake, identifying and eliminating low-grade systemic inflammation (mostly from mandible infections), weight-bearing exercise, and intestinal health, also impact bone mineral density, and vitamin K2 should be added to the list.”
Written by Carlos M. Viana OMD CCN