Fuelling the brain for memory and concentration

How does sugar affect memory and concentration?

Consuming sugary drinks and starchy foods might give us a quick burst of energy, but soon we feel sluggish and tired. Children also get a ‘sugar rush’ after drinking sugary beverages or eating cookies and candy bars, only to feel grumpy when it wears off.

Consuming large amounts of sugary foods can cause a spike in blood sugar levels that increases insulin output. The insulin surge then triggers a drop in blood glucose levels, making us hungry again quickly and causing a dip in energy that makes it hard to concentrate.

The problem increases as we age. Insulin resistance can impair the glucose supply to the hippocampus, which controls memory function in the brain.

This is where Dr Coy’s thinking comes in. Glucose travels around the body in the blood, but it cannot simply walk into a cell on its own. It needs insulin. Insulin is the signal that tells a cell to open up and take the glucose in, so without it the glucose stays in the bloodstream and the cell goes without. Insulin resistance means the cells have stopped responding properly to that signal. There is plenty of glucose in the blood, and the brain still cannot get at it. Eating less sugar does not fix this, and nor does eating more. That is why Dr Coy concluded that the useful thing is a fuel the brain can take in without insulin, alongside a diet that does not keep pushing the insulin system harder and harder.

Keeping blood sugar levels stable

Foods that raise blood sugar sharply don’t help our concentration. Better to choose food and drink that keeps blood sugar levels steady. When it comes to the brain, Dr Coy’s research points to a handful of things working together: his sugars, omega-3 fatty acids, B vitamins, minerals and plant compounds such as polyphenols. Here is the part each one plays:

Galactose:

Galactose, one of Dr Coy’s sugars, gets into the brain without needing insulin, and it causes very little insulin to be released in the first place. That is what interests him. The hippocampus can take up galactose and use it as fuel even when insulin resistance has developed, because galactose does not need the door that insulin opens… continue reading

Other areas of nutrition research that have been studied in relation to memory and brain metabolism include:

• Medium chain triglyceride (MCT) oils and coconut oils, which are involved in the formation of ketone bodies, an alternative fuel for the brain. MCT oils are commonly used alongside Dr Coy’s sugars as part of a ketogenic way of eating.
• B vitamins, in particular vitamin B1 in the form of benfotiamine, which have been studied in relation to nerve cell development and brain metabolism. In his book Dr Coy puts the daily amount at 100mg.
• Lithium is a trace element found naturally in some mineral waters and in food supplements. Population studies have examined whether lithium levels in drinking water are associated with rates of dementia and with mood. The findings are mixed and further research is needed.
• Polyphenols which have been studied in relation to the formation of new nerve cells in the brain (neurogenesis). They are found in berries, green tea, grape seeds and other plants. Dr Coy puts the daily amount at 500 to 750mg.
• Combining his sugars. Dr Coy’s approach is to use galactose, trehalose and isomaltulose together rather than relying on any one of them, so the brain gets a steady supply of energy from more than one route. Tagatose, which is lower in calories, can be added to bring the calorie content down without losing sweetness.