Skip to main content

Climate change can cause selenium deficiency in soil and humans (downtoearth,)

Predicting yet another implication of changing climate, a new study has claimed that human diet may be deficient of an essential micronutrient called selenium (Se) in the future. The report, published in journal Proceedings of the National Academy of Sciences, finds that quantity of the element will be depleted in soil, leading to lower uptake by plants and further, its reduction in our diet.

A team of researchers from Eawag, a research institute based in Switzerland, and five other institutes analysed already available data to model selenium concentration distribution globally. A total of 33,241 soil data points from 1980 to 1999 were used to look into the concentration of this micronutrient.

The team predicted the global Se-soil distributions scenario for 2080-2099. The overall effects are reduction of levels in Se in soil in most parts of the world. They also predict that it is likely that 66 per cent croplands will lose 8.7 per cent of their selenium amount.  These effects may be more pronounced in India and Europe. Both change in climate and soil carbon content dictate this forecast, according to researchers.

Two factors influence Se concentration in soil: precipitation and aridity index (denotes parched areas). Selenium gets leached out from soil due to precipitation. High Se concentrations are found in regions with high acidity and moderate precipitations, while low concentrations of the element are found in arid regions with high alkaline soil and low clay content. This was also established in earlier research.

Effects on health

Insufficient selenium intake is estimated to affect one billion people worldwide. Selenium is required to make antioxidants and prevent cellular damage in the body. Other symptoms of its deficiency include hypothyroidism, including extreme fatigue, mental slowing, goiter, mental retardation, and miscarriages. Exposure to high concentration of Se is also said to have detrimental effects to health.

Cases of a deadly heart ailment called Keshan disease, which has been linked to selenium, deficiency, were reported in northeast and southwest China in 1935. The condition was fatal in 40 per cent of the cases in 1940. When Se levels in the region were studied to investigate any link, it was found that Se concentration in maize and vegetables lower in endemic regions than non-endemic regions. The blood and hair samples from endemic population also showed low Se levels. However, researchers think there could be other factors like viral infection at play. Another study highlighted the role of Se in improving cardiac function after six months of treatment in a 15-month-old child from Saudi Arabia.

Selenium additives can be added to animal feed to avoid the ramifications of Se deficiency. Brazil nuts are rich in selenium and their consumption can reverse deficiency of the element.

Comments

Popular posts from this blog

NGT terminates chairmen of pollution control boards in 10 states (downtoearth,)

Cracking the whip on 10 State Pollution Control Boards (SPCBs) for ad-hoc appointments, the National Green Tribunal has ordered the termination of Chairpersons of these regulatory authorities. The concerned states are Himachal Pradesh, Sikkim, Tamil Nadu, Uttarakhand, Kerala, Rajasthan, Telangana, Haryana, Maharashtra and Manipur. The order was given last week by the principal bench of the NGT, chaired by Justice Swatanter Kumar. The recent order of June 8, 2017, comes as a follow-up to an NGT judgment given in August 2016. In that judgment, the NGT had issued directions on appointments of Chairmen and Member Secretaries of the SPCBs, emphasising on crucial roles they have in pollution control and abatement. It then specified required qualifications as well as tenure of the authorities. States were required to act on the orders within three months and frame Rules for appointment [See Box: Highlights of the NGT judgment of 2016 on criteria for SPCB chairperson appointment]. Having

High dose of Vitamin C and B3 can kill colon cancer cells: study (downtoearth)

In a first, a team of researchers has found that high doses of Vitamin C and niacin or Vitamin B3 can kill cancer stem cells. A study published in Cell Biology International showed the opposing effects of low and high dose of vitamin C and vitamin B3 on colon cancer stem cells. Led by Bipasha Bose and Sudheer Shenoy, the team found that while low doses (5-25 micromolar) of Vitamin C and B3 proliferate colon cancer stem cells, high doses (100 to 1,000 micromolar) killed cancer stem cells. Such high doses of vitamins can only be achieved through intravenous injections in colon cancer patients. The third leading cause of cancer deaths worldwide, colon cancer can be prevented by an intake of dietary fibre and lifestyle changes. While the next step of the researchers is to delineate the mechanisms involved in such opposing effects, they also hope to establish a therapeutic dose of Vitamin C and B3 for colon cancer stem cell therapy. “If the therapeutic dose gets validated under in vivo

SC asks Centre to strike a balance on Rohingya issue (.hindu)

Supreme Court orally indicates that the government should not deport Rohingya “now” as the Centre prevails over it to not record any such views in its formal order, citing “international ramifications”. The Supreme Court on Friday came close to ordering the government not to deport the Rohingya. It finally settled on merely observing that a balance should be struck between humanitarian concern for the community and the country's national security and economic interests. The court was hearing a bunch of petitions, one filed by persons within the Rohingya community, against a proposed move to deport over 40,000 Rohingya refugees. A three-judge Bench, led by Chief Justice of India Dipak Misra, began by orally indicating that the government should not deport Rohingya “now”, but the government prevailed on the court to not pass any formal order, citing “international ramifications”. With this, the status quo continues even though the court gave the community liberty to approach i