Dr Aamer Khan, from Harley Street Skin, says small changes make big difference

Latest research shows only 20% of disease of old age are based on genetics

The doctor says his tips could help you extend your life for up to 15 years

Many people entering their 40s and and 50s would like to look, and feel, younger than they do.

And now, a leading Harley Street doctor has revealed his top tips for slowing down the ageing process and extending your life for up to 15 years.

Dr Aamer Khan, who is the co-founder of Harley Street Skin, believes that small changes to our lifestyle can make a significant difference when it comes to our health later on in life.

In fact, the latest research shows that only 20 per cent of diseases of old age are actually based on genetics, rather than 80 per cent as previously believed.

Here, Dr Khan, who has co-written a new book entitled Turn Back Time, shares with FEMAIL his top tips for staying young...

1. DO A DAILY CROSSWORD

Keeping your brain stimulated is essential when it comes to the later years of your life. Dr Khan recommends doing a daily crossword puzzle, or even learning a new language

Dr Khan says that it's important to make sure you stimulate your brain as you head towards the latter years of your life.

'The brain needs exercising to avoid becoming sluggish so learn a new language, read, learn to play a new instrument or do a daily crossword puzzle,' he explains.

'These last two will help slow the development of dementia and depression.' 

2. TAKE A BRISK WALK

Building exercise into your daily routine - such as taking a brisk walk every day - is vastly important when it comes to slowing down the ageing process.

'Regular exercise helps prevent the arterial ageing that contributes to memory loss, improves muscle mass and makes you look and feel better,' Dr Khan says.

'Even 30 to 45 minutes a day of brisk walking has been shown to grow new brain cells as well as to reduce the risk of heart disease, cancer, diabetes and depression.'

3. TAKE VITAMIN D

Looking after your bones becomes more important later on in life, and Dr Khan recommends taking Vitamin D to help in this area.

'Half of all women and one in five men aged over fifty will break a bone because of osteoporosis,' he says.

'A vitamin D supplement helps promote calcium absorption and bone health. Weight-bearing exercises, such as working out with lightweights, three times a week, can also help keep bones strong.'

4. FIVE MINUTES OF MEDITATION

Dr Khan recommends doing five minutes of meditation a day to combat stress

Stress is a major factor when it comes to the ageing process - meaning you should try your best to combat it.

Dr Khan recommends five minutes of meditation a day in order to relax.

'Stress contributes to every disease, directly or indirectly. It shrinks the brain and increases the waistline,' he explains. 'So deal with it – somehow.

'Make time for mindfulness, or even better, meditation and even a few minutes of relaxed deep breathing.

'With your eyes closed, focus your mind on one object, breathe in deeply over five seconds and then blow away any stresses of the day over five seconds. Wait for a count of five and then repeat.

'Do this for five minutes and then follow with a glass of water.'

5. WEAR SUNCREAM EVERY DAY

We all know about the importance of wearing suncream when on holiday, but Dr Khan says it's important to protect your skin every day, regardless of the weather.

'Forget wrinkle cream - the only skincare product that can truly slow ageing and prevent skin cancer is sunscreen,' he explains.

Dr Khan says that you should always use a broad spectrum cream, which protects you from both UVB rays and UVA rays, which causes skin cancer and skin ageing.

He recommends using a minimum SPF 20 cream to be applied every day, rain or shine, and SPF 50 when on holiday.

6. DON'T FORGET THE DENTIST

Visiting your dentist for a check-up is crucial, as gum disease can be a sign of heart disease

Everyone knows that regular check-ups at the dentist is vital for your oral health - but what you might not know is that they are also essential when it comes to your general well-being.

'Visit your dentist for a check-up at least twice a year to avoid gum disease as people with gum disease are twice as likely to have heart disease,' Dr Khan explains.

He also suggests regular trips to the opticians, which can also pick up on early health warnings, as well as well person checks with your GP as often as they will do it.

7. LAUGH MORE

Being happy is crucial when it comes to staying young, Dr Khan says.

'A positive attitude can boost feel-good hormones so laugh more, socialise with friends and enjoy life,' he says.

'Research shows that a good laugh can help manage stress and prevent the release of damaging hormones in the body.'

8. AVOID CAFFEINE AFTER 5PM

Getting a good night's sleep is essential when it comes to slowing down the ageing process.

Dr Khan suggests avoiding caffeine after 5pm and drinking alcohol in moderation to help with this.

He says should should aim to get seven hours of sleep a night, explaining: 'Sleep deprivation can cause weight gain, weakens the immune system and may accelerate ageing.

'You need two and a half hours before sleep becomes restorative.'

9. CUT BACK ON REFINED CARBOHYDRATES

Dr Khan says cutting back on refined carbohydrates - anything with sugar or white flour - and instead eating plenty of fruit, vegetables, nuts, white meat and fish will help in preventing weight gain and any associated health problems.

'Remember that weight gain is a symptom of something going wrong, so we can screen against it and make changes early to control it,' he says.

'Obesity is when it has become a disease, and gone beyond prevention, and treatment may be the only option.'