Why is vitamin D deficiency on the rise?
Research is pointing to more and more people suffering the consequences of vitamin D deficiency including susceptibility to serious illnesses like MS (Multiple Sclerosis).
Many people are avoiding sun exposure due to fear of ozone layer problems, or because of skin cancer or concern of skin wrinkling. Twenty minutes of sun exposure daily to 6% exposed skin is necessary for maintaining our body’s own production of vitamin D. Some drugs bind fats, including fat soluble Vitamin D and contribute to low vitamin D levels. These drugs include Cholestyramine, a bile acid sequestering medication, and laxatives.
Intake of Olestra and soluble fiber can also potentially reduce vitamin D absorption from food. Statin drugs can cause cholesterol levels to fall lower than ideal which may contribute to vitamin D deficiency. Patients with fat malabsorption, problems with bile production or production of lipase for digesting fats are also susceptible to low vitamin D levels.
Patients with dark skin pigmentation or a dark tan may require up to four times longer sun exposure to absorb the same amount of UVB as light or untanned skin, because melanin blocks UVB. African descent individuals have a much higher incidence of vitamin D deficiency, especially in northern states. Obese individuals can have 50% lower plasma levels of vit D than normal weight people, for the same supplementation levels or sun exposure.
Women with low hormone levels are more susceptible to vitamin D deficiency. Estrogen or progesterone deficiency (amenorrhea, surgical or age-onset menopause) impairs the formation of the active form of vit D. Aging skin has a reduced capacity of vitamin D synthesis. By age 75, vitamin D levels can be 25% lower than levels in younger individuals.