The definition/level where Vitamin D deficiency is diagnosed has been controversial since 2010 or earlier. The commonly measured 25-D can become fairly low while the active 1, 25-D form is still present within normal or even elevated levels. The lab test to measure 1, 25-D is more expensive and time consuming than simply measuring 25-D and generally only the 25-D form is measured.
A recent review of the issue suggests that the medical community is recognizing that the low levels may not be a risk and that over supplementing can sometimes lead to overdoses. (health.harvard.edu/blog/vitamin-d-whats-right-level)
The review discusses bone fracture risk as a reason to be concerned about vitamin D levels, however supplements of vitamin D and calcium were not found to be reliable for reducing bone fracture risk in post-menopausal women. (jamanetwork.com/2678617) Adequate magnesium, vitamin K, and possibly boron are also needed for maintaining bone density along with vitamin D and calcium. Supplements with all of those nutrients and which also included copper, zinc, and manganese have been found helpful for preserving bone density in post-menopausal women. (lifeextension.com/2017/12/Convenient-Way-To-Maintain-Bone-Health)
Vitamin D also is important for the immune system and reducing the risk of autoimmune disease, infections, and cancer. Having enough is important and too little can be a risk for more than just bone fractures.
The food supply has a good amount of vitamin D fortified foods in dairy products or dairy substitutes and naturally vitamin D rich foods such as salmon, sardines, tuna, and other fatty fish. Egg yolks and mushrooms can also provide small amounts of naturally occurring vitamin D.
Fifteen to thirty minutes of direct sunshine during summer months also can provide vitamin D when the face and arms are exposed and there is adequate cholesterol and the necessary enzymes. Vitamin D is not really a vitamin it is a secosteroid hormone that we can make by slight changes to cholesterol. Excessive levels of active hormone D can cause mood symptoms including anger (similar to steroid abuse- “roid rage“). The enzymes needed to produce vitamin D with sunshine and to activate the vitamin form to the hormone form may be a limiting factor.
It has been theorized that glyphosate from the herbicide Roundup may inhibit the necessary enzymes. Supplementing with the vitamin D3 form would be more active/more likely to bypass a problem with inhibition of the enzymes, having adequate magnesium and omega 3 fatty acids might also help. See links for more info on glyphosate and vitamin D metabolism: (vitamindwiki.com/Vitamin+D+is+suppressed+by+both+Roundup+and+Genes)
Recent update on glyphosate research found reproductive and developmental effects may be possible at the dose that is currently considered safe: (Global Glyphosate Study)
If glyphosate is not safe at the dose that is considered safe in the U.S., then how safe can it be to have in the majority of processed foods? (Glyphosate/Roundup has been banned as an agricultural chemical in a large number of other developed nations.)
Disclaimer: This information is provided for educational purposes within the guidelines of fair use.While I am a Registered Dietitian this information is not intended to provide individual health guidance. Please see a health professional for individual health care purposes.