Life Extension Update
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Maintaining optimal zinc levels may help prevent retinal neurodegeneration
Retinitis pigmentosa is a degenerative disease of the retina characterized by misfolding of a light receptor protein called rhodopsin. The disease affects over a million people worldwide, and can lead to blindness before the age of forty. Zinc is an essential component of rhodopsin, and deficiencies of zinc have been associated with retinal neurodegeneration and night blindness. In the current study, Dartmouth Medical School researchers sought to find the location of zinc in rhodopsin and determine whether zinc deficiency can lead to rhodopsin dysfunction.
The team found a cluster of retinitis pigmentosa mutations in the area where zinc is believed to bind with rhodopsin. They experimented with several amounts of zinc to determine the amount that leads to a successful binding and to find what causes the protein to misfold. Assistant professor of pharmacology and toxicology at Dartmouth Medical School, John Hwa, MD, PhD, explained the team’s findings: "We have found if there is not enough zinc in the body or there is a mutation in the zinc binding site, the protein rhodopsin will misfold and break down, triggering cell death, degeneration of the retina and eventually blindness. What is especially exciting about this new direction in our research is that this characteristic of rhodopsin is very similar to other proteins implicated in many neurodegenerative and human diseases. The fact that a trace metal can have such a critical impact on rhodopsin’s ability to function properly may point to significant advances for research in other devastating illnesses as well."
Dr Hwa noted that the average person has 2.3 grams of zinc in their body, making it the second most prevalent trace mineral. When asked how maintaining an adequate level of zinc could help patients with RP, Dr Hwa told Life Extension, “With the defect in the rhodopsin protein created by the inherited mutation the binding to zinc is poorer so increasing the concentration of available zinc would promote zinc binding and thus help stabilize the protein. The disease won't be cured, but an optimal level of zinc could significantly slow down the disease and delay the onset of blindness.”
Zinc is a mineral essential for formation of superoxide dismutase, one of the body’s most important free radical scavengers and one that cannot be directly supplemented. Zinc also promotes wound healing, immune function, taste sensitivity, protein synthesis, insulin production, and reproduction including organ development and sperm motility.
Certain age-related problems common to the eyes are often caused by a breakdown of the circulatory system of the eye. Bilberry extracts have been shown to improve microcapillary circulation. The anthocyanoside content of bilberry may be especially beneficial for night-time visual acuity.(1,2)
1. Altern Med Rev 2001 Apr;6(2):141-66.
More than 28 million Americans over the age of 40 have eye ailments that put them at risk for vision loss and blindness, a number that is expected to rise rapidly as the population ages, according to research published in the Archives of Ophthalmology.
An estimated 20.5 million American adults have cataracts, a figure expected to climb to 30.1 million in the next 20 years.1 Cataracts are the leading cause of blindness worldwide and of poor vision in the US. Like other major causes of blindness and vision loss such as macular degeneration, glaucoma, and diabetic retinopathy, cataracts are strongly linked with aging.
Macular degeneration affects about 1.8 million adults. Another 2.2 million US adults suffer from glaucoma, while 4 million are afflicted with diabetic retinopathy.
This article examines the dangers of excess insulin, the role of insulin in promoting obesity, and a new dietary supplement that has been shown to reduce after-meal insulin release by 40%.
Numerous published studies reveal that excess serum insulin (hyperinsulinemia) is a major health problem. High serum insulin promotes hypertension by impairing sodium balance. Too much insulin harms the kidneys. The vascular system is severely damaged by prolonged exposure to excess insulin. By acting as a catalyst in promoting cell growth, excess insulin increases the risk and progression of certain cancers.
High serum insulin is associated with the development of abdominal obesity and the many health problems induced by abdominal obesity, including atherosclerosis and impotence. Obesity is associated with excess insulin and reduced insulin sensitivity, both risk factors for type II diabetes.
Perhaps the simplest way to evaluate the toxic effects of excess insulin is by examining its effects on human mortality. One study showed that over a 10-year period, the risk of dying was almost twice as great for those with the highest levels of insulin compared to those with the lowest.
The excess elevation of blood sugar after eating wreaks havoc in the body via multiple pathological mechanisms. Elevations in postprandial (after-meal) blood sugar, along with the accompanying insulin surge, are major contributors to the development of diabetic and age-related disorders such as heart disease, as well as diseases of the microvasculature (small blood vessels within the eyes, kidneys, and nerves).
The best fiber sources for reducing after-meal blood sugar-insulin levels, lowering cholesterol levels, and promoting weight loss are those that are rich in water-soluble fibers such as glucomannan, psyllium, guar gum, and pectin.
With the introduction of a new highly viscous fiber blend trademarked under the name PGX™, it may now be possible to achieve the multiple documented benefits of fiber by swallowing only a few capsules before each meal. The longevity potential associated with reducing after-meal glucose and insulin blood levels, lowering total cholesterol and LDL, and losing some weight is enormous.
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