Thyroid Hormone Controls the Eye‘s Visual Pigments

Thyroid hormone is crucially involved in controlling which visual pigment is produced in the cones. Previously, it was assumed that the colour sensitivity of the cones is fixed in the adult retina.

Children born with a thyroid hormone deficiency have serious defects of physiological and mental development, hence newborns are routinely checked for thyroid hormone deficiency, and hormone substitution therapy is given when indicated.

Researchers at the Max Planck Institute for Brain Research in Frankfurt/M., together with colleagues at the University of Frankfurt and universities in Vienna, have now been able to show that in mature cones of mice and rats the production of visual pigment is regulated by thyroid hormone. It is assumed that this mechanism exists in all mammals, including humans. If so, the adult-onset of thyroid hormone deficiency would affect colour vision.

Studies in mice have shown that thyroid hormone also plays an important role in the development of the eye and particularly the cone visual cells. In the retina of the eye, the cones are the visual cells responsible for colour vision. Most mammals have two spectral cone types containing either of two visual pigments (opsins), one sensitive to shortwave light (UV/blue opsin), and the other to middle-to-longwave light (green opsin). Cones express a thyroid hormone receptor. Its activation by the hormone suppresses the synthesis of UV/blue opsin and activates the production of green opsin.

6 Nutrients for Veg-Eaters

B12 Complex



A deficiency in B12 can also cause depression, mood issues, vision problems, low blood pressure, and dementia amongst a host of other issues. According to Vegetarian Savvy, besides animal products, many fortified vegan foods and supplements contain this crucial vitamin. Vegetarians can also get their fill from raw cow's milk or organic milk, organic cheese, and organic eggs.


Iron



The daily recommendation is 18 mg of iron a day. Iron intake requirements are 1.8 times higher for vegetarians because nonheme iron is not absorbed as well as heme iron. You can find it in pumpkin seeds, tofu, and sun dried tomatoes, Jerusalem artichokes, pine nuts, and sunflower seeds.


Iodine



Iodine is necessary for the production of a thyroid hormone. A deficiency in iodine can lead to the enlargement of the thyroid gland as well as mental retardation in unborn babies. Iodine can be found in a number of foods including eggs, milk, some breads, iodine salt, ice cream, nori, soy milk, soy sauce, and yogurt.


Omega 3 Fatty Acids



An imbalance in the body's fats with a shortage of essential fatty acids is linked to cancer, asthma, depression, accelerated aging, diabetes, and ADHD to name a few. An adult needs 1.4 to 4.6 grams of Omega 3 per day. Omega 3 can be found in hemp seeds, flax seeds, chia seeds, and algae (spirulina, blue-green algae, and chlorella).


Zinc



Zinc is crucial for growth and immune function. Men require 11 mg/day and women need 8 mg/day). Get zinc from whole grains, beans, yogurt, shiitake mushrooms, and sesame seeds.


Protein

Alzheimer's Prevention in your Pantry

Alzheimer's, the degenerative brain disorder that disrupts memory, thought and behavior, is devastating to both patients and loved ones. According to the Alzheimer's Association, one in eight Americans over the age of 65 suffers from the disease. Now Tel Aviv University has discovered that an everyday spice in your kitchen cupboard could hold the key to Alzheimer's prevention.

An extract found in cinnamon bark, called CEppt, contains properties that can inhibit the development of the disease, according to Prof. Michael Ovadia of the Department of Zoology at Tel Aviv University. After discovering that the cinnamon extract had antiviral properties, Prof. Ovadia empirically tested these properties in both laboratory and animal Alzheimer's models.

The researchers isolated CEppt by grinding cinnamon and extracting the substance into an aqueous buffer solution. They then introduced this solution into the drinking water of mice that had been genetically altered to develop an aggressive form of Alzheimer's disease.

After four months, the researchers discovered that development of the disease had slowed remarkably and the animals' activity levels and longevity were comparable to that of their healthy counterparts.