With the greatest of respect: there is published science on the differences in both glucose uptake and calcium metabolism in African Americans. A recent 20 year longitudinal study revealed a 2000% increase in early cardiac mortalities in African Americans between the ages of 40 and 50. D3 deficiencies in African American are presumed to be the major causation. It would seem plausible that there is a problematic period in a rapid D3 repletion process where calcium supplementation and elevated parathyroid secretions are responsible for mislaid calcium in smooth muscle tissue. A slower D3 loading process may reduce the parathyroid secretions and reduce this problem.
I’m almost following you, but not quite. Are you saying that blacks diabetics need or don’t need D3?