Few educated non-racists would likely deny that, with all else equal, the darker your skin color the more likely you would get vit D deficiency as the link between skin type and vit D production in the skin is well known.
Any non-moron would understand merely acknowledging a biological fact isn't ever racism even if that fact just happens to involve race or color. Any non-moron would understand racism isn't merely about just mentioning the word 'race' or 'color' in a statement.
Very few if any people would claim a guy is a racist merely for blaming vitamin D deficiency on skin color; If its a biological fact, which in this case it is, its very obviously not racism.
People with dark skin
Larger amounts of the pigment melanin in the epidermal layer result in darker skin and reduce the skin's ability to produce vitamin D from sunlight. It is not sure that lower levels of 25(OH)D for persons with dark skin have significant health consequences. Intake of RDA levels of vitamin D from foods and/or supplements will provide adequate amounts of this nutrient to these individuals.
Race was identified as a significant risk factor, with African-American adults having the highest prevalence rate of vitamin D deficiency (82.1%, 95% CI, 76.5%-86.5😵 followed by Hispanic adults (62.9%; 95% CI, 53.2%-71.7😵