Linus Pauling Institute Fall, 2009 Newsletter
This newsletter is remarkable, and available for free if you fill out the LPI form here. I recommend you subscribe to this newsletter, full of outstanding nutrition information based on the latest research from this institute. Here's a few highlights worth noting. LPI is designated by NIH as a Center for Excellence for Research on Complementary and Alternative Medicine.
a. Zinc is Crucial for DNA Integrity and Prostate Health - Yang Song, PhD
The connection between zinc deficiency and cancer has been suggested by several large epidemiological studies. These observational cohort studies found that low zinc status is associated with increased cancer incidence. Zinc deficiency impairs DNA integrity and, thus, increases the cell susceptibility to abnormal growth.
At least two mechanisms are likely involved in the effect of zinc deficiency on DNA damage. First, zinc deficiency compromises the functions of the zinc-containing antioxidant enzyme, copper-zinc superoxide dismutase, and increases oxidative stress. Increased oxidative stress causes oxidative DNA damage directly. Second, zinc deficiency impairs DNA repair functions by interfering with the activities and expression of DNA repair proteins. Altogether, zinc-deficient cells take a double hit-DNA damage is increased and the ability to repair that damage is compromised.
b. Vitamin D - Vitamin D deficiency is the most common micronutrient deficiency in the world, occurring in over 50% of people in the US, Europe, China, India, and elsewhere. Vitamin D deficiency is linked to an increased risk for cancer, diabetes, autoimmune disease, bone disease, multiple sclerosis, rheumatoid arthritis, infectious illnesses, upper respiratory tract infections, tuberculosis, and the risk of dying from cancer or heart disease. Dr. Holick noted that the highest intake of vitamin D correlates with the least incidence of cancer. Antimicrobial activities of vitamin D may also improve resistance to influenza.
To achieve satisfactory vitamin D status in infants, Dr. Holick recommends 4,000 IU/day for lactating mothers to ensure adequate vitamin D status in nursing infants. Compounding the problem of vitamin D insufficiency, virtually no vitamin D is synthesized in the skin in latitudes north of Atlanta, Georgia in the winter. He recommends at least 400 IU daily for children and 1,400-2,000 for adolescents and adults. Toxicity is very rare and does not occur until at least 10,0000 IU have been consumed daily for at least five months.
Also published: Frei B, Lawson S., Vitamin C and cancer revisited PNAS 2008 105:11037-1103
Recent work at NIH has elucidated how very high concentrations of vitamin C attained only by IV administration generate hydrogen peroxide around cancer cells that then kills them. This mechanistic explanation should stimulate better-designed clinical trials using IV vitamin C.