[vixen99]

People with dark skin can experience vitamin D deficiency in northern climates. One of the many symptoms is hypertension. Some estimates are that you need 10 times more sun exposure to produce the same amount of vitamin D as a person with pale skin.

[JulianMorrison]

This does not suggest reducing salt, but rather supplementing vitamin D. It also doesn't rule out stress as a distinct, parallel cause.

[vixen99]

Who says it does?