Dell Stanford, a senior dietitian at the British Heart Foundation, adds: “Consuming two or three cups of coffee a day may be linked to lower risk of cardiovascular disease compared to drinking no coffee. However, drinking more than four or five cups of coffee per day will probably raise your caffeine intake to above the recommended daily maximum of 400mg (4-5 cups).

“Generally, the effects of too much caffeine may include temporarily increased blood pressure and heart rate, palpitations, anxiety, agitation, nausea, headache and sleep disturbance.”

Can coffee substitute regular exercise?

Suresh thinks not. “Coffee complements, it shouldn’t replace exercise,” she says. “Regular physical activity will directly improve strength, endurance and the body’s ability to function well. While the caffeine in coffee might give you a performance boost and delay fatigue, it’s there as a support tool.”

What other foods might help with frailty?

Antioxidants, like polyphenols, help to neutralise free radicals, protecting cells, including muscle and brain cells, from damage. Nichola Ludlam-Raine, a dietitian and the author of How Not to Eat Ultra-Processed, says: “Yes, coffee is a major source of polyphenols, but similar compounds are found in berries, dark chocolate, olive oil, green tea and many vegetables. Once consumed, they’re absorbed in the gut (though bioavailability varies), metabolised mainly in the liver, and act throughout the body.

“Protein-rich foods (like eggs, dairy, legumes, tofu, fish and lean meat) are important for muscle preservation, in addition to foods rich in omega-3 fatty acids (like oily fish, flaxseed and walnuts), and those containing vitamin D and calcium are also key (think eggs and dairy) for bone strength.

“Fermented foods are also important for gut health (which supports immunity), and colourful fruits and veg for their antioxidant content, which all contribute to preventing frailty.”

What type of coffee is best?

The general thinking is that a straight, black, filtered coffee (ones that have been through a paper or metal filter such as an AeroPress or filter coffee machine) is the healthiest.

Adding milk to your brew will provide certain essential vitamins, protein and calcium, but if you get into the cappuccino and latte territory you will also be totting up the calories. Data from a Scandinavian study (the Tromso Heart Study) found that drinking filtered coffee was associated with lower mortality, while non-filtered coffee contributed to increased cholesterol and cardiovascular risk.

Choosing a high-quality bean will mean it’s rich in polyphenols. Medium-roast coffee provides a balance of antioxidants. And, although processed, decaffeinated coffee isn’t necessarily bad – it still contains all the benefits, just perhaps at slightly lower levels.

Are there downsides to drinking four or more cups of coffee daily?

Not everyone’s tolerance to coffee is the same, but generally, an overload of caffeine can have health repercussions. Ludlam-Raine says: “Yes, there could be potential issues, including disturbed sleep, especially if consumed after midday.

“You could also experience increased heart rate, anxiety and raised blood pressure. Anyone who struggles with acid reflux or [irritable bowel syndrome] might find too much coffee causes digestive problems. It’s also worth noting that caffeine can interfere with calcium absorption – so older adults should balance intake with good sources of calcium and vitamin D elsewhere in their daily diet.”

The Telegraph, London

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