Our bodies' immune system keeps a track record of every microbe that it has ever encountered and defeated in the memory cells (white blood cells - B- and T-lymphocytes).

Once a microbe enters the body again, it can be easily recognized and defeated before it multiplies and make you feel sick.

The hippocampus - a structure in the brain - controls the brain's ability to learn and form memories of day-to-day facts.

But research found that the activity in the hippocampus steadily declines with age. The memory of subjects in their 50s and 60s weakened as subjects recalled events that were up to 12 years old but reached a plateau during older remembrances.

A favourite of most people across the world, french fries come in many shapes and sizes and are loaded with additives to add that irresistible taste. A regular serving of fries has 500 calories, while the same serving of regular potatoes has about 150.

The average American consumes 29 pounds of french fries in a year, and is home to the famous fast-food query: You want fries with that?

Getting the right nutrients in your body first thing in the morning is hugely beneficial when it comes to maintaining focus throughout the day.

Eating a wide variety of wholegrains, fruits, vegetables, nuts, seeds and legumes throughout the day ensures that blood sugar levels are stable and provides the brain with healthy fats, carbohydrates, protein, antioxidants, vitamins and minerals. These all work synergistically to promote brain health, focus, memory, concentration, and health in general.

• Melancholic depression, as described by Hippocrates, was considered a unique condition that struck people out of the blue.
• It is now known as "endogenous depression" (coming from within) and different from depression in response to external stressors.
• In 1980, depressive disorders were remodeled as a single entity that only varies by degrees of severity.