The diminished intelligence of children exposed to mercury contamination before birth costs the US economy $8.7 billion a year in lost productivity, according to a study published in a science journal. The study estimates that between 317,000 and 637,000 of the four million children born each year in the United States are exposed in the womb to mercury levels above the Environmental Protection Agency’s safety level.
The IQ loss to children whose mothers’ blood level of mercury was at or above EPA’s safety level was subtle and varied depending on the mother’s exposure, according to the study in Environmental Health Perspectives, a journal published by the National Institutes of Health. The peer-reviewed study was done by paediatricians at the Mount Sinai School of Medicine and the Albert Einstein College of Medicine, both in New York.
Children with mothers whose mercury levels were at or near the safety level suffer an IQ loss of less than one point, while children whose mothers are among the five percent of the population most highly exposed suffer IQ losses ranging from 1.6 points to 3.21 points, the study said. “While this diminution in intelligence is small in comparison with the loss of cognition that can result from other genetic and environmental processes, the loss resulting from (mercury) exposure produces a significant reduction in economic productivity over a lifetime,” the study said.
The estimate of $8.7 billion in annual economic impact from mercury was calculated using methodology employed in previous studies of the economic impact of lead exposure, which also lowers intelligence. The health and societal impacts of mercury “are very analogous to lead,” said Dr. Philip Landrigan, a co-author of the study.
Coal-fired power plants, the single largest source of man-made mercury emissions in the United States, are responsible for $1.3 billion of the economic loss, the study found. Leonard Levin, mercury issue manager for the industry-funded Electric Power Research Institute, said the study relies on limited or flawed data in its calculation of the effect of mercury exposure on fetal intelligence. “There is a huge uncertainty around whether there is any effect or not” on intelligence from low levels of mercury exposure, Levin said. The study also overstates the number of children exposed and exaggerates the contribution of power plants to mercury pollution, Levin said.
Mercury emissions from power plants, incinerators, industrial processes and natural phenomena like volcanoes settle in water bodies. Microbes transform the deposits into methylmercury, the most toxic form of mercury. The contaminant then works its way up the food chain. People are exposed to mercury primarily by eating fish, especially large, predatory species like shark, swordfish and some species of tuna. — Samina Iqbal
Better health with dietary modification
Low Density Lipoproteins or LDL is a component of blood cholesterol. Elevated levels of LDL is a risk factor for heart disease, states a recent issue of the Annals of Internal Medicine.
Dietary modification is considered the first approach to treatment. Recommendations for diet have changed over the years with the guideline that inclusion of certain foods, along with restriction of saturated fats, would prove more effective. Several dietary factors such as soy protein, soy isoflavones, plant sterols, soluble fibre, oats, nuts and garlic have established or potential lipid benefits.
To prove this effect a study was conducted on 120 adults, between the ages of 30 and 65 years, with raised LDL values. Two groups were formed on two different diet patterns. Both diets provided 30% energy from total fat. Diet one had reduced fat cheese, low fat frozen lasagna, and low fat sugar rich snack foods. Diet 2 was Low Fat Plus and contained more vegetables, legumes, whole grains and fruits. This diet was matched with Diet 1 by the addition of modest amount of butter, cheese and eggs. The trial lasted for four weeks and each participant was weighed weekly.
At the end of the four weeks, the 59 adults who consumed high amounts of vegetables, fruits, legumes and whole grains had greater improvement in total and LDL cholesterol levels. The study concluded that the addition of nutrient-dense plant-based foods enhanced the cholesterol lowering effect of a low fat diet. This can be attributed to the high intake of psyllium, plant sterols and soy protein in the prescribed low fat diet. — Fatema Jawad
