Most people’s image of the typical acid reflux patient is an overweight, middle-aged man who’s overdone it on burgers or pizza and is complaining of heartburn.

But as an ear, nose and throat doctor, I see patients every day who break the stereotypical mould — for acid damage afflicts people of all ages, including the very young. In fact, more than 7 million Britons suffer from it.

And it doesn’t just manifest itself as heartburn or regurgitation. These aren’t even the most common symptoms — in my practice, most acid reflux patients are more likely to have throat-related complaints, such as a lump-like sensation that causes difficulty swallowing.

Other common symptoms include a chronic cough (that persists longer than eight weeks), frequent throat-clearing, hoarseness and a sore throat. Often, someone with these symptoms won’t realise they have reflux because the oesophageal tissues have likely been exposed to acid for so long, they’ve been numbed to its effects.

These ‘silent’ symptoms mean the condition can be overlooked, which has its own risks: a growing number of people are now succumbing to oesophageal cancer — the most extreme manifestation of acid damage.

But why are so many of us plagued by acid reflux in the first place? The answer, I believe, lies in the food and drink we consume every day.

Doctors used to be concerned about only the acid that came up from the stomach into the oesophagus — now we know the problem is also the acid from certain foods on their way down.

These foods cause problems in two ways: they loosen the valve at the bottom of the oesophagus (the lower oesophageal sphincter), allowing the stomach contents and acid to rise up, or they directly irritate the oesophagus.

Our lifestyles also play a part. Smoking, eating late at night, rushing our food and being overweight can cause inflammation or put pressure on the oesophageal valve (rushing our meals and eating late can lead to bloating and gassiness). Stress is also implicated, as it triggers the release of hormones that can increase production of gastric acid.

Based on my 27 years’ experience treating patients with acid reflux, I’ve devised a plan to tackle this growing problem, which I set out in my new book, The Acid Watcher Diet.

This plan has two stages: a 28-day ‘healing’ phase, where you avoid foods that trigger acid damage, such as citrus fruits, tomatoes, coffee, peppers, seed oils, chocolate and processed food generally, and choose instead those rich in compounds that help repair the damage, some of which are listed in the box below.

This is followed by the maintenance phase, where you reintroduce some banned foods back into the diet. This second phase should last a minimum of two weeks, but you can follow it for life. More than 4,000 of my patients have tested my plan, and all reported relief from the pain and disruption of acid damage.

As well as losing weight, they had more energy and less inflammation in their throats. And many (with the exception of those who have Barrett’s oesophagus, where the cells lining the gullet become precancerous) have been able to stop taking medication such as proton pump inhibitors — which reduce the production of stomach acid to treat acid reflux.

Note: if you have symptoms several times a week, or over-the-counter medication isn’t working, see your GP to rule out other causes.

Before I set out the plan in more detail, let me explain why dietary acid is so damaging.

The key lies in pepsin, an enzyme that’s meant to help break down food in the stomach. Though this is a controversial new area, I am convinced pepsin presents a very real, lurking danger.

In the stomach, pepsin is inactive until woken up by acidic foods.

But once mixed into gastric acid, it can surge up into the oesophagus, chest, vocal cords and throat, where pepsin molecules can attach to pepsin receptors. This is when the real trouble begins. Once pepsin is planted in your oesophagus, it is activated each time you eat or drink something acidic.

As you may recall from your school chemistry lessons, the pH scale runs from 1 to 14 — anything below pH 7 is considered acidic; everything above that is alkaline.

Pepsin becomes most active in an environment with a pH level between 1 and 4.

If there are no food proteins for it to break down (as there are in the stomach), the activated pepsin will eat away at the throat and oesophagus, causing problems from inflammation and heartburn to Barrett’s oesophagus — and possibly oesophageal cancer.

What’s especially worrying is that once pepsin gets into your gullet, it floats through the airways and can end up anywhere, including your lungs, where it can cause inflammation and conditions such as asthma and bronchitis.

Pepsin receptors have been found in the sinuses and middle ears in people with acid reflux. The concern is that, if activated repeatedly, pepsin can spark inflammation throughout the body.

A key feature of the Acid Watcher diet is that it keeps pepsin in your stomach, where it belongs, and prevents the activation of it outside the stomach.

DITCH CANNED SOUP AND VEG

The secret is not letting calories, carbohydrates or fat dictate whether a food is ‘good’ or ‘bad’: make choices based on a food’s acidity or pH value. A general rule is that the more processed a food, the more acidic it is, due to the chemicals used to preserve it.

Dietary acid is found in carbonated drinks (sweetened, fizzy drinks can have a pH of 2.5), commercially produced fruit juices and in products containing high-fructose corn syrup (a sweetener made using sulphuric acid), such as biscuits, cakes and ice cream.

It’s even in canned soups and vegetables — especially if they’ve been pickled or fermented. If the label includes citric or ascorbic acid, this suggests the product is acidic.

And there are other foods you may be more surprised to learn are bad for an Acid Watcher — take the Mediterranean-style diet, for example. It protects against inflammation, cardiovascular disease, obesity and insulin-resistance — a precursor to type 2 diabetes — but some of its staples are high-acid foods that must be avoided.

These include wine, tomatoes, vinegar, lemon, onion and garlic (the latter two play a role in bloating, indigestion and heart-burn by putting pressure on the oesophageal valve).

Of these, wine is the most detrimental — not only is it highly acidic, but all alcohol is a carminative, which means it loosens the oesophageal valve.

Other carminatives include chocolate, caffeine, fresh and dried mint and peppermint tea, so these should be avoided. However, some components of the Mediterranean diet are good for you, and the high-fibre content is important because it sweeps waste from your stomach, aiding healthy digestion and protecting your oesophagus.

So if acidic foods are bad, does that mean alkaline diets are good?

Some of these diets claim that, by curtailing acidic foods, you can help restore the pH balance of your blood, but this is impossible and complete rubbish: you cannot change or ‘balance’ your blood pH through dietary measures (it’s actually regulated by the kidneys).

Another major misconception is that eliminating ‘acidic’ food groups — such as meat, it’s claimed — will reduce your acidic overload and make you healthier.

Again, rubbish. Cutting out food groups is the last thing you need, as some can aid healing from long-term acid exposure.

Similarly misguided is the ‘alkaline ash’ theory, which claims that some acidic food leaves an alkaline residue in the body.

Lemon is said to be one, and lemon water is touted as a home remedy for heartburn, but really, it activates pepsin in the throat. Such misinformation is downright dangerous.

You really must quit — here’s why: 100 per cent of smokers have acid reflux disease.

If you smoke, you are guaranteed to develop it throughout the length of your aerodigestive tract, from your throat to your oesophageal valve — that’s because cigarette smoke and nicotine delay stomach emptying, which puts pressure on the oesophageal valve.

The first phase of the diet — the 28-day healing phase — is based on eight principles that will help you eliminate or reduce inflammation and tissue damage. These are:

1. Eliminate acid triggers.

2. Rein in your reflux-generating habits — quit smoking completely and cut out processed food.

3. Avoid fried food — it loosens the oesophageal valve.

4. Eat three meals, and two mini-meals, at regular intervals between 7am and 7.30pm. This ensures you don’t overeat and allows the stomach three hours to digest before lying down, avoiding night-time reflux.

5. Practise the rule of five: you can eat foods with a pH value of 5 and higher, while pH 4 foods can be introduced in the maintenance phase. These foods will help heal the damage to your oesophagus by keeping pepsin in check.

6. Introduce more fibre into your diet — it keeps your digestion healthy, reducing reflux. Eat a daily minimum of 450g of vegetables above pH 5 (for example, five medium-sized carrots) — half of which should be raw — and a daily minimum of 225g raw fruit (a handful of cubed cantaloupe with a banana).

One meal a day should be vegetarian to maximise fibre intake.

7. Drink only water.

8. Avoid seed oils. These — rapeseed, sunflower, sesame oils — have a borderline pH, but are essentially acidic because their extraction process involves chemicals. Instead, use extra virgin olive oil.

Other borderline foods are peppers, berries and honey, as these stimulate pepsin production. (However, berries are permitted in both phases of the diet if you balance them with an acid neutraliser, such as almond milk, in a smoothie for example. Similarly, honey can be eaten if combined with a nut butter.)

Spices such as chilli are also not recommended during the healing phase, as they can loosen the oesophageal valve.

REGULAR exercise helps to accelerate weight loss, reducing pressure on the oesophageal valve.

But the type of exercise you do is important. Heavy weight-lifting, sit-ups and crunches, excessive jumping (such as in high-impact aerobics), competitive cycling and advanced yoga should all be avoided, as these can encourage gastric acid to flow upwards.

However, gentle yoga can be beneficial because its emphasis on deep-breathing can help reduce stress hormones that increase acid production (but be careful with the ‘downward dog’ pose, where the head is positioned below the waist, as this may trigger symptoms).

Reflux-safe exercises include cycling on a stationary bike (or one that doesn’t require you to crouch) and light weight training.

AFTER 28 days, you should notice your reflux is much improved.

Next is the maintenance phase, where you can introduce foods with a pH of 4 or above — including red, yellow or green bell peppers, some varieties of apples and soft cheeses including feta and cottage cheese.

This phase should last for two weeks, after which you can eat normally again.

If your symptoms return, or to protect yourself long-term, you can choose to stick to this stage for life.