A new study has found that higher levels of mercury in the blood are linked to a greater chance of developing the eye disease glaucoma. Additionally, low levels of manganese (a chemical element) were associated with lower incidence of glaucoma.
This cross-sectional population-based study was published online on August 6th 2015 in JAMA Ophthalmology. The researchers looked a blood or urine metallic element levels, as well as eye disease in 2,680 Korean adults.
While levels of manganese and the heavy metal mercury correlated with glaucoma rates, no link was found between glaucoma and cadmium, lead, or arsenic.
The researchers called for more research on whether trace metals in the body are correlated with glaucoma using prospective studies.
Study: “Association Between Body Levels of Trace Metals and Glaucoma Prevalence.” Shuai-Chun Lin, Kuldev Singh, Shan C. Lin. JAMA Ophthalmol. August, 2015
Fish
Fish are the largest proven source of mercury in the US and most fish do have trace amounts of mercury. High levels of mercury are found in some species, especially the larger fish such as king mackerel, marlin, orange roughy, shark, swordfish and tilefish. While salmon and other mid-sized fish are lauded for their high omega-3 content, it is true that these larger fish do contain higher levels of mercury compared to smaller fish, such as herring and sardines which are low on the food chain. High levels of mercury have been found, for example in the fat of northern grizzly bears which have a diet high in salmon.
The fish which are recommended for consumption for their omega-3 content are US-raised shrimp, canned light tuna, salmon, pollock, and catfish (although remember that catfish are a bottom-feeding fish and catfish coming from polluted rivers may well contain any number of contaminants.)
High Fructose Corn Syrup
This frequently used sweetener in processed foods finds small amounts mercury in 9 out of 20 samples. This poses an increased risk especially for children and pregnant women.1
Rice
In China rice has been contaminated by mercury where it is grown near industrial areas. One study found that 7% of residents of Wanshan province had excessive levels of mercury. The ‘variety’ of mercury is known as methylmercury, having been converted to this more dangerous form by bacteria which naturally live in rice paddies.2
Animal Products
Even back in 1975 researchers evaluating soils, human hair and animal products including, milk, eggs, beef, pork in North Dakota found that they all contained various low levels of mercury. The range was 4 to 50 ppb for foods, and 1708 ppb for hair (higher because mercury accumulates in the body.)3 According to the EPA, maximum contamination levels are currently considered to be 2 ppb.
Drinking Water
If your water comes from a household well you should have it tested to be sure that it is not contaminated by mercury from cropland, industrial and landfill runoff.
Alzheimer’s Disease Note
It should be noted that a number of studies have evaluated mercury levels in Alzheimer’s patients and a connection apparently exists there as well.4, 5
Next: Nutritional support, diet, & lifestyle tips for glaucoma.
You are at risk for glaucoma if:
- You use certain medications
- You are myopic and use the computer a lot
- Have low thyroid
- Have had surgery to remove your ovaries before menopause
Footnotes:
- Renee Dufault, et al, Mercury from chlor-alkali plants: measured concentrations in food product sugar, Environmental Health, January, 2009.
- Barrett, Julia R., Rice Is a Significant Source of Methylmercury: Research in China Assesses Exposures, Environmental Health Perspectives, September, 2010.
- J.L. Sell, et al, Concentration of mercury in animal products and soils of North Dakota., Archives of Environmental Contamination and Toxicology, 1975
- J. Mutter, Does inorganic mercury play a role in Alzheimer’s disease? A systematic review and an integrated molecular mechanism, Journal of Alzheimer’s Disease, Vol. 22, 2010.
- M. Chin-Chan, Environmental pollutants as risk factors for neurodegenerative disorders: Alzheimer and Parkinson diseases., Frontiers in Cellular Neuroscience, April, 2015.