Although we all lose some of our powers of recall with age, there is a lot we can do to make sure our memory remains as razor-sharp as possible.

A good diet is vital in helping delay mental decline and keeping your brain in the best shape possible. Just making sure you eat the right sort of foods can make a huge difference.

It will boost your energy levels, your mood and the levels of neurotransmitters, the brain chemicals that determine how well your brain functions.

Some of the best foods for boosting your neurotransmitters are listed below.

You could also try my simple daily eating program, which ensures you have the right mix of proteins, carbohydrates and fats, essential for optimum brain function.

Within just four weeks you should not only be feeling brighter and sharper, you may well have lost excess pounds (for details of my eating plan, see www.dailymail.co.uk/eatingplan).

But nutrition is just one part of the picture; there are other important factors, too. U.S. research shows that only about 5 percent of memory impairment is due to brain disorders such as Alzheimer's.

Stress, depression, lack of exercise and poor nutrition are far more common causes. The good news is that addressing these can make a big difference to your life.

Exercise
There's a wealth of evidence to show the link between exercise, brain and mood. One recent study from the Journal of Gerontology found that exercise triggers a measurable growth of brain volume in older people. In three months, people who exercised had the brain volume of people three years younger.

Other research found that even three 15-minute sessions of exercise a week can help protect you from dementia later in life.

There are various reasons for this.

Exercise is thought to help boost cerebral blood flow and stimulate the growth of new cells in the brain.

What's more, staying active can help keep you slim, which is another important key to keeping your brain in good condition. Research has found that obesity is linked to a decline in mental ability.

Researchers think this is connected to the hormone leptin, secreted by stored fat. High leptin levels may affect learning and memory. The link between obesity and memory decline doesn't just affect older people; even 30-somethings with high BMIs are thought to be at risk of accelerated mental decline.

There are all sorts of other benefits of regular exercise: It helps elevate mood, boosts your metabolism, can alleviate premenstrual syndrome and period pain, and reduces your risk of heart disease.

Experts recommend three 20-minute sessions of vigorous activity (where you become out of breath) per week, or five weekly 30-minute sessions (such as a gentle walk).

Sleep
Sleep -- or lack of it -- also affects our brains. If you've ever had to concentrate hard or perform at your best the day after a poor night's rest, you'll know all too well how important sleep is for optimal brain power.

Sufficient sleep is vital for maintaining healthy brain cells and it also plays an important role in regulating your mood and sharpening concentration.

As you pass through the stages of sleep, your body produces hormones to repair and regenerate cells. Sleep also enables our mind to process the day's events and activities (dreams facilitate this).

So getting a good night's sleep can boost memory and help newly-formed memories and skills get organized in the brain. Some studies have shown that losing just 1 1/2 hours' sleep for one night can reduce your alertness in the daytime by as much as 32 percent.

Another study showed that people who went to bed six hours later than their normal bedtime performed as badly in attentiveness and reaction tests as those who were drunk!

So, are you getting enough sleep? Research shows the optimum amount for an adult is somewhere between 6 1/2 and 8 1/2 hours a night.

Sleep experts say the best gauge of how much you need is to ask yourself if you're waking up each morning feeling refreshed. Are you able to function at your best? If so, you're probably getting enough.

Try keeping a sleep diary to assess how you're feeling each day.

If you need a stiff coffee to liven you up first thing, then you may need more sleep, and could do well to improve your sleep pattern.

Here are some tips for improving your sleep:

• Take an early-morning stroll (it can boost the body's production of the hormone melatonin, which helps regular sleep).

• Get up at the same time every day -- even weekends.

• Do mind exercises for 30 to 45 minutes during the day.

• Take a warm bath at bedtime.

• Wind down with relaxing music; studies show that listening to soft music 45 minutes before bedtime for three weeks can improve your sleep by 35 percent.

• Try yoga.A U.S. study found that a 20-minute session at bedtime helps reduce insomnia. Patients fell asleep more quickly and slept longer.

• Put your worries aside. Before going to bed, make a list of the things you have to do the following day. This way you'll feel more in control and prepared for the challenges ahead.

• Aim for a clear, cool, uncluttered bedroom decorated in muted colors. Your bedroom should be well ventilated and completely dark (so invest in blackout curtains in summer).

• Neurotransmitters are the brain's messengers; they help determine how well your brain functions, plus your energy levels and mood. Each has a different role and needs a good supply of specific nutrients to work efficiently.

• Seratonin is a feel-good chemical which can make us feel serene, happy and calm. Promotes contentment and sleep. In order for our bodies to manufacture serotonin, we need to eat foods that contain the amino acid tryptophan -- turkey, chicken, fish, dairy products, bananas and eggs.

• Dopamine is responsible for our ability to "get up and go." It's also important for assertiveness and sexual arousal and muscle coordination. We need the amino acid tyrosine to make dopamine. It is found in all proteins (meat, fish, milk products, beans, nuts and soy products).

• Acetylcholine is needed for attention, learning and memory. A deficiency is directly related to impaired thinking. Your body uses choline to produce acetylcholine eggs are a rich source.

• Endorphins and enkephalins make you feel happy and reduce stress. They also reduce pain. Sweet foods, such as chocolate and some junk food, boost the release of endorphins and enkephalins. However, so can a brisk walk.

• Noradrenaline, like adrenaline, livens you up. It's needed to stimulate brain activity, for concentration and the formation of memories. Protein-rich foods are vital for its production.

Adapted from "Eat Yourself Clever" by Carol Vorderman (Virgin Books).

Source: Daily Mail; London (UK). Provided by ProQuest Information and Learning. Powered by YellowBrix.

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