Ilamabad-Scientists at the University of Edinburgh have shed new light on how stress can contribute to memory loss in old age. The study could aid research into treatments for age-related memory disorders.

Many believe that stress is bad for our brains especially as we get older. Now, researchers have shown how two receptors in older brains react to a stress hormone called cortisol. While we know that stress hormones affect memory, this research explains how the receptors they engage with can switch good memory to poorly-functioning memory in old age. The study found that one receptor was activated by low levels of cortisol, which helped memory.

However, once levels of this stress hormone were too high they spilled over onto a second receptor. This activated brain processes that contribute to memory impairment.

The study found that high levels of the stress hormone in aged mice made them less able to remember how to navigate a maze.

The memory recall problem was reversed when the receptor linked to poor memory was blocked. The research helps explain why too much stress over a prolonged period interferes with the normal processes in storing everyday memories.

This is despite the fact that a little bit of stress can help us better remember emotional memories. We now know that lowering the levels of these stress hormones will prevent them from activating a receptor in the brain that is bad for memory. Understanding the mechanisms in the brain, which affect memory as we age, will help us to find ways to combat conditions linked to memory loss. We know that too much sugar is bad for our waistlines and our heart health, but now there’s mounting evidence that high levels of sugar consumption can also have a negative effect on brain health – from cognitive function to psychological wellbeing.

While sugar is nothing to be too concerned about in small quantities, most of us are simply eating too much of it. The sweet stuff – which also goes by names like glucose, fructose, honey and corn syrup – is found in 74 per cent of packaged foods in our supermarkets. And while the World Health Organisation recommends that only 5 per cent of daily caloric intake come from sugar, the typical American diet is comprised of 13 per cent calories from sugar.

It’s easy to see how we can get hooked on sugar. However, we should be aware of the risks that a high-sugar diet poses for brain function and mental well-being. Here’s what you need to know about how overconsumption of sugar could wreak havoc on your brain.

It creates a vicious cycle of intense cravings.

When a person consumes sugar, just like any food, it activates the tongue’s taste receptors. Then, signals are sent to the brain, lighting up reward pathways and causing a surge of feel-good hormones, like dopamine, to be released. Sugar “hijacks the brain’s reward pathway”, neuroscientist Jordan Gaines Lewis explained. And while stimulating the brain’s reward system with a piece of chocolate now and then is pleasurable and probably harmless, when the reward system is activated too much and too frequently, we start to run into problems.

“Over-activating this reward system kick starts a series of unfortunate events – loss of control, craving, and increased tolerance to sugar,” neuroscientist Nicole Avena explained in a TED-Ed video. In fact, research has shown that the brains of obese children actually light up differently when they taste sugar, reflecting an elevated “food reward” response. This suggests that their brain circuitry may predispose these children to a lifetime of intense sugar cravings. Heavy sugar intake caused the rats to develop a resistance to insulin – a hormone that controls blood sugar levels and also regulates the function of brain cells. Insulin strengthens the synaptic connections between brain cells, helping them to communicate better and thereby form stronger memories. So when insulin levels in the brain are lowered as the result of excess sugar consumption, cognition can be impaired.

 “Insulin is important in the body for controlling blood sugar, but it may play a different role in the brain,” Dr Fernando Gomez-Pinilla, the study’s lead author, said in a statement. “Our study shows that a high-fructose diet harms the brain as well as the body. This is something new.” It may cause or contribute to depression and anxiety.

 If you’ve ever experienced a sugar crash, then you know that sudden peaks and drops in blood sugar levels can cause you to experience symptoms like irritability, mood swings, brain fog and fatigue. That’s because eating a sugar-laden donut or drinking a soda causes blood sugar levels to spike upon consumption and then plummet. When your blood sugar inevitably dips back down, you may find yourself feeling anxious, moody or depressed.