Plant-based eating patterns can contribute to healthy ageing. The two dietary patterns most closely linked to longevity – the Mediterranean diet and the Okinawa diet from Japan – are both characterized by an abundance of plant-based foods and low to moderate amounts of fish and lean meat.
Plant-based eating is just as relevant, if not more so, to the ageing population as it is to the population at large. It is associated with a lower incidence of obesity, lower risk of developing cardiovascular disease, Type 2 diabetes and cancer - the main non-communicable diseases associated with premature mortality.
Nutritional concerns for older adults are related to both under- and overconsumption of energy and nutrients. Elderly are especially vulnerable to malnutrition. Particular concerns are ensuring adequate protein intake to reduce risk of muscle weakness (sarcopenia). On the other hand, overweight or obesity is also a concern in older adults and plant-based eating can help maintain a healthy weight.
Micronutrients can be inadequate in the diets of older people and care should be taken to ensure a sufficient intake of calcium, vitamins B12 and vitamin D by consuming a wide range of plant foods. Fibre, in conjunction with adequate fluid intake, can aid laxation (often a problem in elderly) and can help encourage gut microbiotic diversity.
Several long-term studies (both in Europe as in US) have shown that the disease burden among persons who never smoked, maintain a normal BMI, exercise regularly and follow a healthy predominantly plant-based diet is considerably lower than that of those who do not adhere to any of these healthy lifestyle behaviours.
In a Dutch cohort of over 33,000 people it was calculated that higher adherence to plant-based eating patterns (Mediterranean diet or prudent diet) compared to a typical Western diet, particularly when combined with other lifestyle factors (healthy body weight, no smoking and exercise), resulted in a lower disease burden and about two years longer in good health as quantified by Disability-Adjusted Life Years.
The Adventist Health Study 2 (AHS-2) is very large study involving nearly 100,000 North American Seventh-day Adventists, of which approximately 9% are vegan and 31% are lacto-ovo vegetarians. The impact of gradual increase in plant-based eating on health outcomes was investigated in this population group. All-cause mortality in the AHS-2 was about 10% lower in all vegetarians combined than in non-vegetarians. Additionally, it was observed that premature mortality was related to a higher intake of meat protein whereas individuals consuming protein mainly from nuts and seeds, lived longer in good health.
What is sarcopenia
Sarcopenia is the loss of lean muscle mass, strength and importantly muscle quality and function. It is a slow, progressive condition and is part of the natural process of ageing.
Between the ages of 40 and 80 years around 30 to 50% of muscle mass can be lost. After the age of 50, muscle function is estimated to be reduced by 1 to 2% each year, and as much as 3% a year after the age of 60. The decline in muscle mass and function becomes pathological when it is sufficiently severe to lead to falls, frailty, immobility and loss of independence.
It is not entirely clear what causes sarcopenia, although a number of factors associated with ageing appear to play a role. These include: increases in inflammation, lack of physical activity, decreases in levels of hormones such as testosterone and oestrogen, a reduction in nerve cells that control muscle movement and changes in the way the body handles muscle formation versus muscle breakdown.
In addition, older adults, are more prone to a reduction in food intake. This reduction can lead to inadequate amounts of calories and/or protein to maintain a healthy muscle mass.
Importance of a healthy lifestyle
A healthy diet, including sufficient amounts of high-quality protein and vitamin D, and being physically active can help to build and maintain good levels of muscle mass and strength and can reduce the risk of sarcopenia in later life.
A variety of lifestyle factors (both in early and later life) are related to preventing, delaying and managing sarcopenia.
- Regular exercise is essential for preserving and increasing muscle mass. In particular, weight-bearing exercises such as walking and resistance exercises.
- Sufficient amounts of protein is important for building and maintaining muscle mass, strength and function. The daily protein intake recommendation for adults is currently 0.8g of protein/ kg body weight. Elderly may need more protein to maintain proper levels of muscle mass and function. The PROT-AGE recommendations advise that older adults (> 65 years of age) should consume between 1g and 1.2g protein per kg of body weight. In the UK, mean protein intakes for 65-74 year olds and over 75 year old men is in excess of 1g/kg/day which is in line with higher protein recommendations for older adults. However, mean intakes for women over 75 years is below 1g protein/kg/day. Additionally, around 30% of all over 64 year olds are falling within the 2.5th percentile for intakes.
- Spreading dietary protein evenly across the day can optimise muscle protein synthesis. Experimental data indicates that muscle protein synthesis (MPS) plateaus at around 0.25g-0.3g high quality protein/kg body weight per meal. This equates to roughly 20g of protein (~10g essential amino acids) for young individuals. The limited data for older adults suggests a higher threshold of around 25 to 30g protein at each meal. Plant proteins may be required at higher levels.
- Vitamin D may also be useful in maintaining muscle strength and reducing the risk of sarcopenia. Older adults are at increased risk of developing vitamin D insufficiency because, as they age, skin cannot synthesize vitamin D as efficiently, they are likely to spend more time indoors, and they may have inadequate dietary intakes of the vitamin D. The UK government recommends 10mcg of vitamin D dietary supplement daily for older adults.
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