Doctors Explain How Diet, Less Stress Can Restore Heart, Brain and Gut

In an excerpt from a pioneering new book, we yesterday explored how modern life can harm the 37 trillion cells responsible for keeping the body powered. Today, the authors share science-backed ways to help restore cellular health and slow the effects of ageing…

What you eat is important, but stress can be just as influential at a cellular level. Even the healthiest diet may struggle to restore a body that remains in a constant state of alarm.

The relentless demands of modern life can weaken the mitochondria — the microscopic ‘power stations’ within cells that convert food into usable energy.

Stress can also trigger inflammation in cell membranes and interfere with the messages cells send one another. As a result, hormones may become unbalanced, immune defences can slow and concentration may suffer.

Evidence suggests that persistent, low-level pressure — caused by juggling too many tasks, taking on excessive commitments, sleeping badly or carrying emotional strain — can disrupt the communication networks cells need to function properly.

The problem is that the body’s stress-response system remains permanently activated. Kept in this heightened state, it can become overly reactive and promote inflammation.

In the long term, stress does more than leave you feeling exhausted. It can speed up biological ageing and create conditions linked to illness.

A 2022 review published in the journal Frontiers in Immunology reported that prolonged psychological stress can disturb hormone regulation, with possible implications for the development of autoimmune conditions and the progression of cancer.

For many people, emotional and psychological strain represents the greatest drain on cellular energy. Reducing the pressure to remain constantly busy is therefore a powerful place to begin.

Our bodies were not built for an endless stream of stimulation. Each alert, message or work email can activate neural pathways similar to those our ancestors relied on when fleeing danger.

When the nervous system stays on high alert, the body redirects energy away from detoxification, balanced hormone activity and immune protection — all essential processes for repair and renewal.

One straightforward strategy is to set aside a day each week when you do not chase achievements or productivity, but give yourself permission simply to pause and exist.

Making time for activities that genuinely lift your mood can help, too. Laughter encourages the release of nitric oxide, helping blood vessels relax, while socialising with a friend can increase oxytocin and endorphins. These ‘feel-good’ chemicals may help ease cellular inflammation and support the body’s natural repair processes.

Spending time outdoors may offer another form of support. A landmark 2019 study published in Science Advances found that exposure to nature can strengthen immune function, lower blood pressure, improve thinking and reduce stress. Box breathing is another easy technique for calming the stress response: breathe in for four seconds, hold for four, breathe out for four, then hold again for four.

Want to know whether stress could be ageing your heart, brain and gut faster than it should? Take our test to discover which lifestyle and dietary changes may be worth making now.

FOODS TO BOOST THE HEALTH OF YOUR CELLS

A nutritious diet supplies cells with the essential building blocks they need to maintain themselves and carry out effective repair.

Healthy fats

Each of the body’s trillions of cells is enclosed by a protective membrane made from phospholipids — specialised fats that include omega-3 and omega-6 essential fatty acids. Because the body cannot produce these fats on its own, they must come from food.

Omega-3 fats are abundant in wild-caught oily fish, including salmon, sardines, anchovies and mackerel. They can help reduce inflammation and maintain the flexibility of cell membranes, allowing cells to communicate more effectively. This is especially important for the brain, which is made up of almost 60 per cent fat.

Omega-3s can also help lower blood pressure, prevent arterial plaque and are linked to a lower risk of cognitive decline and depression.

Food rich in omega-3 includes grass-fed meat, pasture-raised eggs, walnuts, chia seeds and cod liver oil.

A second ‘nearly essential’ tier of fats also protects cells. These include olive oil and coconut oil which is rich in ketones, an alternative energy source that also aids immune defence.

Clean protein

Protein, built from amino acids, is used to create neurotransmitters, fuel mitochondria, repair tissues and balance the immune system.

There are 20 amino acids in total, nine dubbed ‘essential’ because you need to get them from food. But the whole ‘symphony’ of amino acids is needed to keep cells strong and slow organ ageing.

Source matters too, since the quality of animal protein depends on the quality

of the animal’s life, which is why grass-fed meat is worth prioritising.

Offal is especially valuable, supplying vitamin B12, zinc and choline, which amplify the regenerative power of amino acids.

Powerhouse fruits

Berries and pomegranates are rich in polyphenols, powerful plant compounds that calm inflammation, repair DNA and fuel mitochondria.

Berries, such as raspberries and blueberries, contain anthocyanins, which guard cell membranes against oxidative stress.

In the major US Nurses’ Health Study, women who ate two or more servings of blueberries a week had slower cognitive decline.

The best veg

Vegetables offer gut-friendly fibre and phytochemicals along with vitamins and minerals.

Leafy greens such as chard, kale and spinach are rich in vitamin K, magnesium and folate, which support methylation (chemical control of which genes are switched on), bone health and blood vessel flexibility, and are linked with slower cognitive ageing.

Cruciferous vegetables such as broccoli and cabbage are anti-inflammatories that may reduce cancer risk. Starchy vegetables such as carrots, pumpkin and sweet potato provide slow-release resistant starch, plus antioxidants such as beta carotene, lutein and zeaxanthin, critical for immunity, eye health and skin repair.

Cooked vegetables are often more beneficial than raw. This is true for tomatoes (higher levels of lycopene when cooked), carrots and sweet potatoes (beta carotene is better absorbed if cooked with healthy fats) and cruciferous vegetables (lightly steamed are easier to digest).

Mushrooms varieties including reishi, maitake, shiitake and turkey tail sharpen immune surveillance and may offer anti-cancer protection.

Grains and legumes

Foods such as quinoa, millet, rice, and fermented rye and barley retain their bran and germ, preserving fibre, minerals and protective plant compounds.

Quinoa alone supplies all nine essential amino acids plus the polyphenol quercetin.

Legumes add resistant starch, fibre and protein as well as spermidine, which triggers autophagy (cellular clean-up) and is linked to lower mortality.

Fermented foods

Foods like kimchi, sauerkraut, miso and kefir can help convert carbohydrates into compounds that calm inflammation and support gut-brain communication.

Spoonful of honey

Unprocessed and raw honey contains polyphenols and enzymes that lower inflammation and improve cholesterol and wound healing.

Royal jelly is the nutrient-rich secretion from worker bees, and its unique fatty acid supports tissue repair and longevity pathways.

ARE YOUR ORGANS AGEING TOO QUICKLY?

This simple questionnaire can help you take some targeted first steps towards restoring your cellular health. Always consult your doctor before beginning any new diet, exercise or other regimen.

For each question, answer yes or no, based on the last 90 days. If unsure, answer no.

Add five years for every ‘yes’ to an ageing factor. Subtract five for every ‘yes’ to a protective factor. Then add or subtract the total from your actual age to give the organ’s age, and see where you need to take action:

-10 to 0 years: This organ is biologically younger than your chronological age. Keep doing what you are doing!

+5 to +10 years: Early signs of accelerated ageing. Start supporting this system now.

+15 to +20 years: Significant organ ageing. Make this system your top priority.

Test your digestive and metabolic age

• Do you often feel bloated or fatigued after meals? (+5)
• Do you have insulin resistance, prediabetes or type 2 diabetes? (+5)
• Are you overweight (especially around the middle) or crave sugar and carbs daily? (+5)
• Do you frequently suffer from constipation, diarrhoea or IBS‑type symptoms? (+5)
• Do you eat at least 25-30 grams of fibre daily? (–5)
• Do you regularly include fermented or probiotic‑rich foods? (–5)

What your score means

Improving your digestion is your first step back to cellular health. When digestion weakens, food is only partially broken down leading to bloating, fatigue after meals, inflammation and a slower metabolism; over time, insulin resistance, obesity or autoimmune conditions can develop.

One of the main reasons the digestive system ages is damage to the gut microbiome – when ‘bad’ bacteria dominate, it can lead to inflammation and damage to the immune system.

Habits to improve it

• Drink a cup of bone broth – rich in amino acids – to rebuild a strong gut lining, preventing inflammation and nutrient loss. You’ll find recipes online.

• Add cinnamon and ginger to one meal. Both are anti-inflammatories; ginger may speed up sluggish stomach emptying.

• Lift weights for 20-30 minutes, three times a week. Weight training is very effective in helping reduce insulin resistance as working muscles soak up more glucose.

• Eat slowly and chew thoroughly. Mindful eating calms the nervous system and improves nutrient absorption.

Test your brain and mood age

• Do you often feel foggy or struggle with focus or short‑term memory? (+5)
• Have you battled anxiety, depression or mood swings in the past year? (+5)
• Do you eat fatty fish, olive oil or other foods rich in healthy fats fewer than three times a week? (+5)
• Do you have trouble falling or staying asleep or wake up unrefreshed? (+5)
• Do you regularly challenge your brain with new learning, reading or puzzles? (–5)
• Do you make intentional time for stillness to calm your mind? (–5)

What your score means

With its 86 billion cells, the body’s command centre is its hungriest organ. Neurons are powered by mitochondria – when these are damaged, the brain slows, leading to fatigue, poor memory and brain fog. The brain’s immune and clean-up cells can be over-activated by a poor diet or chronic stress, causing inflammation that can harm brain connections, contributing to mood disorders and possibly dementia.

Habits to improve it

• Eat two pasture-raised eggs, which contain choline – good for mood and memory.

• Take 500mg lion’s mane mushrooms with breakfast; these may support nerve-growth pathways.

• Go for a brisk 20-minute walk.

• Write down three things you are grateful for before going to sleep to lift your mood.

Test your heart age

• Do you have high blood pressure, high cholesterol or a family history of heart disease? (+5)
• Do you experience low energy or shortness of breath with mild exertion? (+5)
• Do you spend long hours sitting and get less than 150 minutes of exercise weekly? (+5)
• Do you often eat processed meats, fried foods or refined carbohydrates? (+5)
• Do you do exercise at least three times per week? (–5)
• Do you regularly consume heart-healthy foods such as leafy greens, berries and olive oil? (–5)

What your score means

Your heart is the hardest-working muscle in your body. Each cardiac cell contains thousands of mitochondria generating the enormous energy you need to keep blood pumping around the body.

Cellular ageing of the cardiovascular system is one of the main drivers of disease, with heart disease responsible for roughly one in three deaths.

With age, the heart’s energy-producing mitochondria become damaged while inflammation and oxidised cholesterol damage blood vessels and cause plaque build-up. The body also makes less nitric oxide, the molecule that keeps blood vessels flexible and dilated. This results in a less efficient heart and stiffer arteries.

Habits to improve it

• Take 100mg supplement of CoQ10 (Coenzyme Q10, ubiquinol) to support heart cells by helping mitochondria produce energy – particularly important for anyone on statins, which deplete CoQ10.

• Eat two generous handfuls of leafy greens, containing natural nitrates to help blood vessels relax.

• Walk briskly for 30 minutes.

Adapted from Heal Your Cells by Josh Axe and Will Cole (Transworld, £22). © Josh Axe and Will Cole 2026. To order a copy for £19.80 (offer valid to 24/10/26; UK P&P free on orders over £25) go to mailshop.co.uk/books or call 020 3176 2937. 

Missed part one? Read it here.