News related to Science, Technology, Environment, Agriculture and Medicine in India


7 November 2017

Salt Intake in India

Evil additive or essential for health?

Salt is used extensively in the Indian cuisine. Intake of excess salt can lead to high blood pressure – a leading cause of cardiovascular diseases, accounting for 23% of all deaths in India between 2010 and 2013. Even a modest reduction in dietary salt could substantially reduce cardiovascular events and medical costs and should be a public health target in the present scenario of the nation.

Measuring and monitoring salt consumption is an important step in salt reduction strategies. But that is not an easy task. There is significant day-to-day variation in the dietary intake of individuals. And between individuals there are variable factors that influence sodium absorption, metabolism, and excretion. So how do we measure it easily so that salt as a public health problem can be evaluated?

Indian researchers from the Public Health Foundation of India, Centre for Chronic Disease Control and the All India Institute of Medical Sciences, New Delhi, collaborated with researchers from Australia and Britain to analyse the salt intake of Indians. They selected participants from slum, urban and rural communities in North and in South India. Participants provided 24-h urine collections. From the volume of urine and the concentrations of sodium and creatinine, salt excretion can be measured accurately.

The research team then conducted random morning spot urine samples. There are three distinct ways to estimates salt intake from spot samples: the Kawasaki, Tanaka and Mage equations. The scientists used all three and compared the results with the results from 24h urine collections. Thus they could establish that Kawasaki and Tanaka equations tend to overestimate the intake. The values of salt intake estimated by Mage equations from spot urine are closer to real values.

Collecting and analysing urine over 24 hours consumes time and costs. The spot urine based method, with adequate corrections, on the other hand, may be used as a reasonably good proxy.

In the process of assessing and evaluating the various equations that help estimate salt intake, the researchers also generated data on salt intake – while the recommended intake is about 2g, salt intake recorded in Delhi and Haryana was more than 8. It was more than 9 g/day in Andhra Pradesh.

Journal of Hypertension, 35 (11): 2207-2213 (2017)

Mahadeva swamy H M

Tea Safety

Heavy metal contamination

Tea from Camellia sinensis L. is a popular non-alcoholic beverage. Ideally, such a drink should be free from contaminants. However, the chemical fertilizers used to enhance production leach heavy metals into tea growing soils.

Recently, Tanmoy Karak from the Tea Research Association, Assam along with researchers from the ISRI, New Delhi and the CIMAP, Lucknow characterized selected heavy metals in the tea growing soils of upper Assam. They also assessed the heavy metal absorption ability of tea plants from soil under organic and inorganic amendments after two years of growth.

The team examined environmental risks posed by six heavy metals using ten pollution indices. The risk of contamination inferred from several indices differed significantly. Therefore, they had to generate a new index through a statistical approach. They proposed the Tea Research Association Heavy Metal Contamination Index which can provide essential guidance for the monitoring and regulation of heavy metals in tea growing soils.

The index provides relevant risk assessment and can be correlated with almost all existing indices. It also addresses discrepancies among metal contamination indices in tea growing soils amended with different doses of fertilizers.

Karak and team’s index can be optimised and extended to different tea growing regions worldwide. The findings will help evolve regulatory standards and individual as well as public health recommendations.

Journal of Hazardous Materials, 338: 250-264 (2017)

Saurabh Dewan

A Better Way to Preserve Food

In this fast-paced, grab-a-meal age, foods with preservatives are becoming a part of our life. Preservatives are important to ensure a food safe from various pathogens. However, they have side-effects and could lead to allergies or even be carcinogenic.

A team of Indian scientists from Chandigarh probed the question of whether the quantity of preservatives could be reduced. It seems they have a possible solution according to a paper published in the Journal of Materials Science, July 2017.

The scientists worked with sodium benzoate, a well-known food preservative. While it is popular, it is sometimes used in high quantities, with possible side effects. The scientists used this in combination with silver nanoparticles, which have good antimicrobial properties. They tested the synthesized combination for various foodborne pathogens, showing effective results. It was effective against Salmonella typhimurium type 2, Shiga-toxin producing Escherichia coli, Bacillus cereus as well as Staphylococcus aureus.

The Department of Biotechnology, Govt. of India, supported this study. The significance of this research is that it reduces the quantity of food preservative needed and uses an environment friendly procedure. The nanoparticles were active at very low concentrations making them much more effective preservatives.   This is the first reported research of this synthesis and could reduce risks associated with the overuse of preservatives, while keeping food safe. A better food preservative, it seems, is at hand.

 Journal of Materials Science, 52 (14): 8568-8575 (2017)

B Jayashree

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