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Vitamin D production from UV radiation: The effects of total cholesterol and skin pigmentation

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Our body naturally produces as much as 10,000 IU of vitamin D based on a few minutes of sun exposure when the sun is high. Getting that much vitamin D from dietary sources is very difficult, even after “fortification”. The above refers to pre-sunburn exposure. Sunburn is not associated with increased vitamin D production; it is associated with skin damage and cancer. Solar ultraviolet (UV) radiation is generally divided into two main types: UVB (wavelength: 280–320 nm) and UVA (320–400 nm). Vitamin D is produced primarily based on UVB radiation. Nevertheless, UVA is much more abundant, amounting to about 90 percent of the sun’s UV radiation. UVA seems to cause the most skin damage, although there is some debate on this. If this is correct, one would expect skin pigmentation to be our body’s defense primarily against UVA radiation, not UVB radiation. If so, one’s ability to produce vitamin D based on UVB should not go down significantly as one’s skin becomes darker. Also, vitamin D ...

Is there a link between telomeres and dietary fiber?

New evidence published in Archives of Internal Medicine has it that eating more dietary fiber, particularly from whole grains, could lead to a longer life. The large study found a high-fiber diet reduced risk of heart disease and cancer, as well as infectious and respiratory illnesses. This is great news for those eating diets high in fiber. What’s also interesting is that another reason why dietary fiber is protective to health is because of its influence on telomeres. Telomeres are the protective caps at the end of chromosomes, and their length is considered the closest way to measure lifespan in humans. As reported in a prospective cohort study published in the March 2010 issue of American Journal of Clinical Nutrition (AJCN), telomere length is positively associated with higher fiber intake in women. Dietary fiber from whole grains appears to provide the strongest benefit. In addition, in the AJCN study, the researchers found telomere length was negatively associated with inc...