How protein gives us strength to live longer

Protein, whether from plant or dairy sources, helps slow muscle loss and keep us able-bodied and independent,

Foods high in protein help maintain and repair muscle mass, allowing us to stay mobile and strong as we age.  Picture: iStock 

Protein is one of the most debated nutrients, whether on social media, in supermarket aisles, or in GP consulting rooms.

As we begin to understand more about how diet shapes ageing, discussion of protein is moving from the fitness culture into the broader conversation, particularly among women. Protein is a key ingredient in maintaining health, strength, and independence later in life.

For women thinking about long-term health and longevity, two questions arise: How much protein should we eat per day? and what kind of protein are we eating?

Protein plays a vital role in maintaining muscle mass, supporting metabolic health, and preserving physical function. As we age, we lose muscle.

This decline accelerates after menopause, when hormonal changes affect both muscle and bone. Over time, muscle loss can contribute to frailty, falls, and loss of independence.

Dr Aisling Farrell: Protein is one of the most debated nutrients, whether on social media, in supermarket aisles, or in GP consulting rooms.

This change is a common and often under-recognised issue among older women, and I am seeing increasing interest from female patients in how lifestyle choices might help prevent this functional decline.

One of the key areas I discuss during consultations is diet. Adequate protein intake slows muscle loss by providing the building blocks needed to maintain and repair muscle tissue. Data from the Framingham Heart Study Offspring Cohort which followed adults for two decades, found that higher protein intake was associated with preserved physical function, particularly among women.

Maintaining muscle strength is crucial for everyday activities, from climbing stairs and carrying groceries to staying balanced and preventing falls. In this sense, protein intake may influence not only how long we live, but how well we live.

For most adults, general guidance suggests 0.8g of protein per kilogramme of body weight per day. However, emerging research suggests that people aged over 65 may benefit from slightly higher intakes, around 1-1.2 g/kg per day, to help maintain muscle mass and strength.

Plant protein

While adequate protein intake is important, the type of protein may also influence long-term health outcomes. Plant-based protein sources may offer additional benefits.

A systematic review and dose-response meta-analysis, published in the BMJ, found that higher plant protein intake was associated with significantly lower cardiovascular disease mortality.

And for every additional 3% of daily calories from plant protein, the risk of death from any cause fell by 5%. This is particularly relevant for women, as cardiovascular disease remains their leading cause of death globally.

Plant proteins are found in beans, lentils, chickpeas, and nuts. These foods also provide a broader range of nutritional benefits. They are rich in fibre, which is associated with improved cardiovascular health, including lower cholesterol and healthier blood-sugar control.

Research on women provides further insight. Data from the long-running Nurses’ Health Study found that women who consumed more plant protein during midlife were significantly more likely to experience “healthy ageing”, which means reaching older age free from major chronic disease, while maintaining good physical, cognitive, and mental health.

What about dairy?

While much of the discussion around healthy ageing focuses on plant protein, dairy also plays a positive role, and dairy protein has also been associated with better odds of healthy ageing in women.

Dairy foods, such as yogurt, milk, and cheese, are high in protein, but are also an excellent source of calcium, a key nutrient for healthy bones. The risk of osteoporosis increases with age, particularly after menopause, when declining oestrogen accelerates bone loss. Adequate calcium and protein intake can help support bone density and strength as we age.

Protein powders

While whole-food sources of protein should always be the priority, protein powders can be a convenient option, particularly after exercise.

Blending a scoop of protein powder into a smoothie with whole foods like oats, yogurt, honey, and fruit can support recovery after exercise and increase our protein intake quickly.

However, it is important to check labels carefully as some brands can be very high in added sugars.

Strength training

Of course, diet is only one part of healthy ageing. Protein provides the building blocks for muscle, but exercise provides the stimulus for their growth.

Strength training is, therefore, key to maintaining healthy muscle.

I encourage my patients to aim for two to three resistance-based workouts a week, whether that involves weight training, resistance bands, bodyweight exercises, or structured strength classes.

Simple swap

Improving the quantity and type of protein in your diet does not require a dramatic overhaul.

Small, gradual shifts in everyday eating patterns can make a meaningful difference over time. Some examples I encourage my patients to include are lentils in soups and stews, chickpeas or quinoa in salads, or a handful of nuts as a snack.

The key message from the research is simple: Eating enough protein is important for healthy ageing.

For women, in particular, diets richer in plant-based protein are increasingly associated with reduced cardiovascular risk.

Importantly, this does not require a dramatic dietary change. Consider substituting meat for a plant-based alternative once a week, prioritising protein intake at meals, and doing strength training twice a week.

Over time, those small, everyday choices may ultimately shape not just how long we live, but how well we age.