Oral supplements and oral vitamin B12 are also effective methods of supplementation
It is not addressed here, as it is out-of-scope for this methodology update
The IOMs safe upper limit for daily vitamin D intake is 4,000 IU
The cardiovascular and respiratory side effects include chest pain, tachycardia (increased heart rate), heart palpitations, low blood pressure, and chest tightness, cough with or without production of pink frothy sputum, wheezing and difficulty breathing
This is ideal for people with impaired absorption
This NAD+ elevation activates sirtuins, particularly SIRT1 in adipocytes and hepatocytes, which deacetylates and activates numerous metabolic regulatory proteins including PGC-1, a master regulator of mitochondrial biogenesis, oxidative metabolism, and thermogenesis