Nutrition for healthy ageing: combating sarcopenia and inflammageing

With a rapidly ageing population, more people than ever are becoming at risk of nutritional frailty. Older age is a time when specific nutrient needs can be higher while the ability to meet those needs has greater barriers. In this blog post, I highlight how our nutrition needs change as we age, the factors that make it harder to meet these needs, and the role nutrition plays in promoting healthy ageing and improving the outlook of age-related diseases.

The world’s population is ageing. We’re living longer and because of that comes a host of potential health problems. In Australia alone, older people comprise a considerable proportion of the population with over 1 in 7 people aged 65 and over. Compare that to almost 100 years ago when just 5 people in one hundred made it past 65 years. And future projections put the number of older adults in Australia at more than 1 in 5 in just the next 30 years. You’ll find similar trends in almost all countries.

With ageing and a longer life comes a variety of changes to the body. These include muscle loss, thinner skin and less stomach acid. There are also changes in our nutritional needs. Protein stands out here. It is one of the few nutrients where you see a substantial jump in official recommended intakes once someone hits their senior years – and for good reason. More about that shortly.

Barriers to good nutrition in older age

Having official recommendations for nutrient goals is one thing; achieving them is another. And this is where unique factors related to ageing arise that can compromise meeting nutrient needs – further exacerbating the risk of deficiencies.

First, there are social factors. This can include a change in housing and living situation.. Then there can be the loss of a partner and all the upheaval that can cause. And of course, changes in income going from employment to retirement can all affect someone’s living circumstances. Depression, lack of independence and social isolation are all big factors that can make food less appealing, further contributing to a less-than-ideal diet.

Then there are physiological factors such as a decline in health and the presence of chronic disease. For instance, atrophic gastritis which is common in adults over 50 results in stomach inflammation and a decline in factors needed for vitamin B12 absorption. Mobility issues can affect access to food and even the ability to open jars and food containers or lift heavier things in the kitchen. Poor dentition, swallowing problems and changes in taste and smell all affect the eating experience.

The end result of all this is a greater risk of malnutrition in seniors. Estimates point to 1 in 3 community living older people being malnourished. That number escalates when you look at hospital and institutional settings.

The consequences of poor nutrition in older age are severe. They include a compromised immune system, muscle weakness and decreased bone mass which can lead to falls and fractures, poor wound healing, a higher risk of hospitalisation and earlier mortality.

Nutrients to watch out for

Some nutrients are more of a concern than others for likely not being inadequately consumed in older adults. These include protein, omega-3 fatty acids, fibre, calcium, magnesium, potassium, and the vitamins A, B6, B12, D and E.

Let’s take vitamin D just as one example. Vitamin D is found in only a few foods, so the sun is the major source contributing to about 80 percent of the body’s reserves. Less mobile people such as those in nursing homes are at greater risk of vitamin D deficiency. This is compounded by a decline in kidney function with age as the kidneys are needed for vitamin D activation.

Low levels of vitamin D are associated with lower-extremity muscle weakness, impaired balance and accelerated loss of muscle mass, strength and physical function. That makes vitamin D deficiency an independent predictor of falls in older people.

A systematic review and meta-analysis of 47 randomised-controlled trials designed to reduce falls and fracture risk by vitamin D supplementation concluded that vitamin D supplementation plays an important role in reducing the risk of falls. A benefit of vitamin D on fracture risk reduction though was only seen with vitamin D and calcium supplements combined. A greater benefit with vitamin D was seen at supplement doses above 800 IU per day.

Why a higher body weight is better in older age

Excess body weight gets a big focus throughout the lifespan for its link with chronic disease. But once a person gets into their older years, that link starts to unravel.

Just looking at BMI at a population level in adults over 65 years of age and its link to earlier mortality, there is a clear U shape to the graph. That in itself isn’t so surprising as very low and very high body weight are linked to earlier mortality. What is surprising is that the bottom of that U curve comes in at around a BMI of 28 kg/m². This gives credence to current recommendations on body weight in older age that a ‘healthy’ BMI range should be higher than the normally used range of 20 to 25.

Why could a higher BMI be better in older age? It can be a sign of better nutrition and hence less risk of malnutrition. And that extra body fat can give some real-world padding to the body to help protect it against falls. What all of this means is that less focus should be given to excess body weight as someone gets older. There are other more important things to be concerned about: such as nutrition frailty and sarcopenia.

Sarcopenia in older adults

Nutrition frailty is a state commonly seen in older adults. It is characterised by significant loss of weight, muscle mass and strength – making the person susceptible to disability. This is all impacted by chronic undernutrition, the presence of disease, hormonal changes and decreased physical activity. Which then leads to sarcopenia.

Sarcopenia is a syndrome characterised by progressive and generalised loss of muscle mass and strength. It is tightly correlated with physical disability, poor quality of life and earlier death. Ageing is a major cause of sarcopenia.

Sarcopenia is compounded by a decline in physical activity, a decrease in motor neuron recruitment needed to make muscles work, and a decline in anabolic hormones. All of this is underpinned by chronic inflammation.

The causes of sarcopenia are the absolute key reason why both resistance exercise and a high-protein diet are the cornerstones of its management and prevention. Protein recommendations of up to 1.5 grams per kilogram of body weight in older age are common now when overt sarcopenia is present. Combining that higher protein intake with resistance exercise can help to preserve and build back valuable muscle mass.

Inflammation + Ageing = Inflammageing

The combination of chronic disease and sarcopenia in older age gives rise to a unique descriptor of the underlying problem: and that’s a term called inflammageing.

Ageing itself is characterised by chronic low-grade inflammation. Chronic inflammation increases platelet activation and blood clotting. It can also deplete the reserve of internal antioxidants, generate free radicals and amplify oxidative stress. And it will even delay wound healing and tissue regeneration and promote cell ageing and premature cell death. I’ve already done a detailed blog post on the topic of inflammation so check that out for a much wider view.

There is now growing evidence linking a dietary pattern ranking high in its proinflammatory potential (and here, think of a typical Western diet high in highly processed foods and low in fibre) and a greater risk of the presence of inflammation, low muscle mass, low muscle function and sarcopenia. One piece of research done on older Australians found that a high dietary inflammatory index score was directly associated with lower lean body mass and less mobility. Mobility was assessed by a timed up-and-go test where a person from a sitting position has to stand up, walk 3 metres, turn around and walk back again. The longer it takes, the more it says about your mobility, strength and balance.

Combatting inflammation

Diet and lifestyle choices can go a long way to treating inflammation. And for diet, what is widely considered an ‘anti-inflammatory diet’ is one high in fruits, vegetables, healthy fats, legumes, and whole grains. A Mediterranean-style diet would be one such variation of this, especially when you add in fish and olive oil.

But it doesn’t stop there. Exercise is also a potent force against chronic inflammation with a negative association between physical activity levels and CRP which is a blood marker for inflammation. So exercise in older age not only helps fight sarcopenia but aids in blunting inflammation – it’s all related.

And then we have dietary fibre. Fibre is a top-rated fuel for our gut microbiome which is a big player in chronic inflammation, especially when you consider our gut is the home to most of our immune activity. When certain beneficial bacteria ferment fibre, they produce butyric acid. Butyric acid helps mediate the immune response, lower circulating inflammatory markers and improve the integrity of the gut barrier. Beneficial microbes also help fight off more inflammatory, gut-damaging microbes directly by suppressing their growth.

Simply put: the more fibre (which means more plant foods) a person eats in their diet, the lower their blood markers of inflammation are likely to be.

Cognitive decline: what role for nutrition?

Of all the diseases linked with ageing, it would be those of cognitive decline such as Alzheimer’s disease that are the most devastating for the person and their family. There is no single cause of dementia, but one factor that is considered a culprit is oxidative stress and inflammation – yet again.

So can antioxidants and other types of nutritional supplements help in addressing oxidative stress? There is very mixed and inconsistent evidence that nutritional supplements such as vitamins B6, B12, C, or E; folate; or omega-3 polyunsaturated fats play a protective role when given in isolation. Yet observational evidence points to a diet containing foods high in phytonutrients offering some degree of protection.

The disconnect here is that antioxidants are not just one molecule; they represent a property that is part of many vitamins and minerals. And there are thousands of other chemicals that have some potential antioxidant activity and these compounds are called polyphenols. There are over 8,000 different types of polyphenols found in fruits, vegetables, grains, legumes, tea and coffee.

A brief reading about polyphenols on the Internet will bring up article after article highlighting that polyphenols are antioxidants and that explains their health benefits. Nutrition science though has well-and-truly moved on from using such simplistic language and concepts to describe how these thousands of polyphenols found in food work. They are much more than antioxidants. Focusing only on antioxidants or a single phytonutrient is like zeroing in on a section of a painting and seeing only the dots. You need to step back and see the bigger picture. It should instead be about polyphenols and their multitude of benefits and actions in the body such as:

• Regulating cell growth and death
• Slowing down cancer cell proliferation
• Altering glucose responses and insulin sensitivity
• Increasing activity of enzymes involved in removing harmful substances from the body
• Decreasing inflammation.

Taken together, it strongly advocates for a food-first approach if nutrition is to have a role in halting cognitive decline, rather than taking nutrient supplements in isolation.

The MIND diet

This leads me to just what are the characteristics of a diet that could be linked to reducing the risk of dementia. And here we have what has been termed the MIND diet which has been developed over many years out of research. And by diet here, I mean ‘way of eating’ not ‘weight loss’. MIND is an acronym for Mediterranean-DASH diet Intervention for Neurodegenerative Delay. It combines characteristics of a Mediterranean-style diet with the DASH diet where DASH stands for Dietary Approaches to Stop Hypertension. The DASH diet can lower high blood pressure which is a risk factor for Alzheimer’s disease. And on top of this, the MIND diet also includes foods specifically relevant to brain health.

Here is what a MIND diet looks like:

• Lots of leafy green vegetables and other kinds of vegetables
• Berries eaten at least twice a week
• Wholegrains eaten each day
• Fish and poultry
• Legumes
• Nuts
• And to round out the Mediterranean flavour, olive oil and if you’re partial to it, some red wine.

The diet also limits how much red meat and highly processed discretionary foods like sweets and fast food are eaten.

So far there is good observational evidence to link this type of dietary pattern with reducing the risk of cognitive decline. For example, an Australian study of 1,220 adults aged 60 years and over without dementia who were followed for 12 years found a 19 percent reduced odds of developing mild cognitive impairment or dementia for those people adhering closely to what a MIND diet advocates for. And this benefit was much greater than what was seen in people just following the principles of a Mediterranean-style diet alone.

Intervention studies with a MIND diet are now beginning to be published. Positive results were seen in a trial of cognitive performance and brain structure in healthy women who were obese. However, a more recent longer-term study that ran for 3 years in healthy adults with a family history of dementia failed to show a difference on cognition or brain structure in those who followed the MIND diet compared to a control group. However, in that last study, a key aspect was that the diets of both groups were designed to provide a mild level of calorie restriction meaning weight loss was seen in both groups. This could have masked direct benefits from the diet itself as both groups actually saw similar improvements in cognition over the study.

And final mention goes to our gut microbiota which, as you can probably guess, changes with older age, especially over the age of 80 where diet, lifestyle and other factors have the biggest impact on health. The ageing microbiota, like the ageing person, suffers from reduced resilience. And there is now some research to show that there could also be a healthy microbiome fingerprint linked to improved health and longevity, though this is certainly a very nascent area.

What it all means

Some aspects of ageing may be inevitable, but the risk of specific age-related diseases and disability may, in part, be modified by dietary choices. This means that nutrition becomes even more important in older age when you consider how many barriers can arise to eating well.

Two of the most important aspects of ageing well come from regular resistance exercise and meeting a higher goal for protein which together can help fight against age-related loss of muscle mass. Furthermore, increasing evidence suggests that a variant around the theme of a Mediterranean-style diet that is high in fruit (especially berries), nuts, legumes, fish and vegetables may reduce the risk of both mild cognitive impairment and dementia along with improving gut microbiota health. The theme of this style of eating can be adapted to any person’s dietary preferences or cultural background and is not a way of eating that should be changed to in older age, but instead to be adopted earlier in life.