Health Current Affairs

Stress may hamper memory: Research

As per a study conducted by researchers from the University of Exeter (U.K.) and the University of Calgary (Canada), high levels of stress can block memory processes.

What was the study?

Researchers performed experiments on pond snails (Lymnaea stagnalis) which have easily observable behaviors linked to memory and large neurons in the brain and they also respond to stressful events in a similar way to mammals, making them a useful model species to study learning and memory.

Pond snails generally breathe underwater through skin and if the water has low oxygen levels the snails emerge and inhale air using a basic lung opened to the air via a breathing hole. In the experiment, the pond snails were trained to reduce how often they breathed outside water. To train the snails not to breathe air they were placed in poorly oxygenated water and their breathing holes were gently poked every time they emerged to breathe. Snail memory was tested by observing how many times the snails attempted to breathe air after they had received their training. Memory was considered to be present if there was a decrease in the number of times they opened their breathing holes. Their memory was also assessed by monitoring neural activity in their brain.

Just before training, the snails were subjected to two different stressful situations, low calcium — which is stressful as calcium is necessary for healthy shells — and overcrowding by other pond snails.

What was found?

It was found that when snails faced with the stressors individually, their ability to form long term memory declined, although they were still able to learn and form short and intermediate term memory. However, when they were exposed to both stressors simultaneously, it made an additive impact on the snails’ ability to form memory and all learning and memory processes were blocked. It was found that when they were exposed to multiple stressful events they were unable to remember what they had learned.


U.S. food authority to ban trans fat

The US Food and Drug Administration (FDA) has decided to ban the heart-clogging trans fats. As per FDA, although manufacturers already have eliminated many trans fats, the average American still eats around a gram of trans fat a day eliminating which could prevent 20,000 heart attacks and 7,000 deaths each year. Keeping this in mind, the FDA would determine a phase-out timetable in a few months.

What is Trans Fat?

Trans-isomer fatty acids, or trans fats, are a type of unsaturated fat, which is uncommon in nature but can be easily created artificially. These trans-isomer (E-isomer) fatty acids are sometimes mono-unsaturated or polyunsaturated due to the presence of  a double carbon–carbon bond, but they are never saturated.

How they are formed?

Trans fats are formed during the processing of polyunsaturated fatty acids in food manufacturing. The fats are created when hydrogen is added to vegetable oil to make it more solid, which is why they are often called partially hydrogenated oils. In plants and animals, fatty acids generally have cis (as opposed to trans) unsaturations.

Trans fats are used both in processed food and in restaurants, often to improve the texture, shelf life or flavour. The fats are found in some baked goods such as pie crusts and biscuits and in ready-to-eat frostings.

Why trans fat is harmful to our health?

In humans, consumption of trans fats increases the risk of coronary heart disease by raising levels of the lipoprotein LDL (“bad cholesterol”) and lowering levels of the lipoprotein HDL (“good cholesterol”).