Weight status

As shown in Table 1, up to 78 % of older adults in Ireland are living with overweight or obesity, with only approximately 2 % described as underweight^{(42,Reference Leahy, Donoghue and O'Connell51,Reference McCann, McNulty and Rigby52)} . These surveys, however, do not include those living in residential care; therefore, the true prevalence of underweight among the total older adult population in Ireland may be underestimated.

There are known benefits to losing weight, such as the potential prevention or delaying of the onset of T2DM^{(Reference Lean38)}. However, as mentioned previously, for older adults living with overweight or obesity, rapid weight-loss diets are associated with loss of muscle mass which can lead to sarcopaenia^{(Reference Volkert, Beck and Cederholm25)}.

Prevention of further weight gain by combining a balanced, nutrient-rich diet with physical activity will help maintain lean muscle mass in older adults who are overweight^{(Reference Volkert, Beck and Cederholm25,39)} and represents the best approach for overweight older adults unaffected by health conditions exacerbated by obesity. For those living with obesity and weight-related health problems where weight-loss interventions are required, weight loss should be slow, physical activity should be incorporated and rapid weight-loss diets avoided in order to preserve muscle mass^{(Reference Volkert, Beck and Cederholm25,39)} .

Drug–nutrient interactions

Many medications commonly used by older adults interact with nutrients, negatively impacting nutritional status. Specifically, opioid painkillers, calcium channel blockers, antidepressants and diuretics can interfere with the effects of dietary fibre, thus leading to constipation which can decrease quality of life^{(Reference Tvistholm, Munch and Danielsen53)}. The use of H2 receptor antagonists and proton pump inhibitors, which result in gastric acid suppression, have been associated with an increased risk of vitamin B₁₂ deficiency^{(Reference Masclee, Sturkenboom and Kuipers54–Reference Lam, Schneider and Zhao56)}, while metformin (medication for the treatment of T2DM) has been linked to vitamin B₁₂ and B₆ deficiencies^{(Reference Aroda, Edelstein and Goldberg57)}.

In Ireland, studies from the TUDA cohort reported that metformin use was associated with a 45 % increased risk of vitamin B₁₂ deficiency and a 48 % increased risk of vitamin B₆ deficiency^{(Reference Porter, Ward and Hughes58)}, while those taking a proton pump inhibitor are more likely to have indicators of vitamin B₁₂ deficiency^{(Reference Porter, Hoey and Hughes59)}.

The dietary recommendations in relation to drug–nutrient interactions are as follows:

1. (a) guidance to ensure adequate fibre intakes for the prevention of constipation and how this can vary among individuals due to drugs and/or immobility

2. (b) guidance on ensuring adequate intakes of iron, folate, vitamins B₁₂ and B₆ to prevent deficiencies due to medication use (see Table 2 for food sources of each nutrient).

Table 2. Nutrient goals from scientific literature and subsequent dietary recommendations for nutrients identified as of public health concern for this age group in Ireland⁽³⁹⁾

bw, body weight; DFE, dietary folate equivalents; DIAAS, digestible indispensable amino acid scores; PDCAAS, protein digestibility-corrected amino acid scores; T2DM, type 2 diabetes mellitus.

* The nutrient goals outlined are for the general adult population, except for the additional protein goals (1–2 g/kg bw/d^{(Reference Dorrington, Fallaize and Hobbs73–76)} and 1⋅1–1⋅3 g/kg bw/d⁽⁴⁸⁾) which are specific to older adults.

Table 3. Commonly eaten protein-rich food sources (protein g/100 g), ranked according to protein and leucine content per g of typical food portion sizes with corresponding DIAAS and PDCAAS

DIAAS, digestible indispensable amino acid score; NA, not available; PDCAAS, protein digestibility-corrected amino acid score.

A PDCAAS or DIAAS below 100 indicates that at least one amino acid is limiting in the food or diet, whereas a score of 100 indicates that there is no limiting amino acid in the food or diet.

* Derived from McCance and Widdowson's The Composition of Foods Integrated Dataset 2019^{(Reference McCance and Widdowson117)}.

^† The width and depth of palm without fingers and thumb.

^‡ 1 cup = 200 ml.

Dentition

Many older adults are edentate; thus, tend to choose softer and easier to chew foods, resulting in lower dietary intakes of nutrients such as n-3 fatty acids, non-starch polysaccharides, folate and vitamin C, compared with dentate older adults^{(Reference Watson, McGowan and McCrum60)}.

In Ireland, the NANS has reported that 87 % of older adults living independently either have all of their own teeth or are partially dentate with or without dentures⁽⁴²⁾. However, this age group is highly susceptible to chronic dental diseases caused mainly by reduced manual cleaning as well as high-dietary intakes of sugars and refined carbohydrates^{(Reference Hayes, Da Mata and Cole61)}.

Appropriate dietary advice, particularly in terms of free sugars and refined carbohydrate intakes, is important for this age group to prevent the onset of chronic dental diseases. This includes advice on dental hygiene, reduction in frequency of snacking and advice on reduction of cariogenic foods (sugars, refined carbohydrates and carbohydrate foods that are difficult to clear from mouth – sticky candies, crisps, biscuits, etc.). More specific dietary advice is required for edentate older adults to ensure adequate protein and nutrient intakes⁽⁶²⁾.

Sense of taste

Sense of taste diminishes with increasing age for a variety of reasons including physiological changes, disease and medication use^{(Reference Sergi, Bano and Pizzato63,Reference Imoscopi, Inelmen and Sergi64)} . This can lead to increased use of salt at the table among older adults to increase food palatability^{(Reference Sergi, Bano and Pizzato63)}. Such high-dietary salt intake is associated with an increased risk of hypertension⁽⁶⁵⁾.

Currently in Ireland, >50 % of older adults have hypertension^{(Reference Murphy, Kearney and Shelley66)}. While the maximum salt limit for older adults is the same as that for the general population at 6 g salt/d⁽⁶⁵⁾, this cut off is of particular importance for the older adult population due to an increased risk of hypertension caused by excess salt intake, which is a major modifiable risk factor in the development of CVD⁽⁶⁷⁾.

Limiting consumption of salty foods (e.g. processed meats, anchovies and olives) and using alternatives to salt, such as herbs and spices, to flavour foods, can help to keep salt intakes below the 6 g/d limit. For those at risk of renal impairment (those with diabetes, heart failure or hypertension), minimal use of salt substitutes due to their high potassium and sodium content is important⁽⁶⁵⁾.

Hydration

The ageing process is associated with two changes in the physiological responses to inadequate fluid intake, which increase the risk of dehydration; the feeling of thirst is dampened, and primary urine concentration by the kidneys is impaired^{(Reference Volkert, Beck and Cederholm25)}. Older adults are also at an increased risk of dehydration for various reasons including use of medications resulting in fluid losses, memory problems, dysphagia and fear of incontinence^{(Reference Volkert, Beck and Cederholm25)}.

It is recommended that older women need at least 1⋅6 l of drinks daily, while older men need at least 2 l of drinks daily^{(Reference Volkert, Beck and Cederholm25)}. While water is mostly recommended, milk, tea, coffee and unsweetened fruit juice will all contribute to fluid intakes. Specific guidance is needed for those who are underweight or frail to have milky drinks which will also provide energy and protein as well as fluid. In addition, guidance to staff of the importance of offering drinks on a frequent basis to older adults in residential care to ensure adequate fluid intakes. Finally, consumption of strong tea at mealtimes is advised against to limit the effect of tannins interfering with iron absorption.

Protein

An adequate protein intake is one of the most important dietary factors for maintaining health during ageing due to its positive effects on body composition^{(Reference Volkert, Beck and Cederholm25)}. High-quality protein foods assessed using PDCAAS or DIAAS should be consumed in order to stimulate muscle protein synthesis⁽⁴⁶⁾. It is well established that dietary protein is essential for stimulating muscle protein synthesis^{(Reference van Vliet, Burd and van Loon49)}, and maintaining muscle mass (as mentioned previously) is critical for preventing or delaying the onset of sarcopaenia and frailty^{(Reference Cruz-Jentoft, Baeyens and Bauer32)}. Research has shown that spreading protein intake across different meals during the day and ensuring that each meal provides approximately 0⋅4 g protein/kg body weight (bw), will maximise muscle protein synthesis ^{(Reference Loenneke, Loprinzi and Murphy68–Reference Symons, Sheffield-Moore and Wolfe71)}.

Both the EFSA population reference intake and the IOM recommended daily allowance for protein is the same for adults of all ages (0⋅8 g/kg bw/d)^(45,72) . However, some international working groups have more recently recommended higher protein requirements for older adults, ranging from 1 g/kg bw/d up to 2 g/kg bw/d^{(Reference Dorrington, Fallaize and Hobbs73–76)}, with the Nordic countries subsequently increasing the protein requirements for older adults to 1⋅1–1⋅3 g/kg bw/d⁽⁴⁸⁾.

In Ireland, data from the NANS show that 33 % of older adults had protein intakes below the EFSA estimated average requirement of 0⋅66 g/kg bw/d^{(Reference Kehoe77)}, which is insufficient to maintain adequate muscle mass and function.

Older adults need a more protein-dense diet than the general adult population, with those at risk of frailty, sarcopaenia and undernutrition having even higher requirements of 1–1⋅2 g/kg bw/d^{(Reference Volkert, Beck and Cederholm25)}. Protein quality is important and is determined by the digestibility and quantity of essential amino acids necessary for growth, maintenance and repair, assessed using PDCAAS or DIAAS ^{(Reference Symons, Sheffield-Moore and Wolfe71)}. As outlined in Table 3, the protein contents of commonly eaten foods in Ireland from animal sources, such as meat, poultry, fish and eggs, have higher PDCAAS and DIAAS quality scores and provide higher amounts of leucine. Consumption of high-quality protein foods (Table 3) providing approximately 0⋅4 g protein/kg bw in at least two meals daily will maximise muscle protein synthesis and thus reduce the likelihood or progression of sarcopaenia and frailty^{(Reference Bollwein, Diekmann and Kaiser30,Reference Paddon-Jones and Rasmussen31)} . In addition, daily physical activity, resistance exercise, in particular, will greatly improve maintenance of muscle mass^{(Reference Travers, Romero-Ortuno and Bailey15,Reference Pennings, Koopman and Beelen18,Reference Dent, Morley and Cruz-Jentoft28)} .

Carbohydrate

The EFSA reference intake range for carbohydrates is 45–60 % of total energy⁽⁴⁵⁾, while the IOM acceptable macronutrient distribution range is 45–65 % of total energy⁽⁷²⁾, with no recommendations specific for older adults. In terms of intake of free sugars, the WHO has established the most recent guidelines of <10 % total energy and <5 % if possible⁽⁷⁸⁾.

Average carbohydrate intakes among older adults in Ireland, while within the recommended range, are at the lower end and, according to NANS, almost one-third (31 %) exceed the 10 % limit for free sugars intake⁽⁴²⁾. Due to the high incidence of overweight and obesity and tendency for abdominal body fat distribution, older adults in Ireland are at an increased risk of T2DM.

Moderate intakes of fibre-rich carbohydrates and low free sugars consumption, eaten as mixed meals (with protein and minimal fat), will reduce the effect of carbohydrates on blood glucose levels^{(Reference Kim, Nam and Chung79,Reference Wee and Henry80)} . This is due to the protein and fat promoting insulin secretion and delaying the absorption of carbohydrates by slowing the rate of gastric emptying, thus reducing the rate of glucose absorption^{(Reference Kim, Nam and Chung79,Reference Wee and Henry80)} . Carbohydrate foods higher in fibre and lower in free sugars are also more slowly digested, absorbed and metabolised, resulting in a lower and slower rise in blood glucose; thus, representing an approach for protecting against the onset of T2DM, obesity and CVD^(39,81,82) . Such foods include wholemeal breads, cereals, pasta and rice, as well as vegetables, salads and fruit.

Fibre

The current EFSA recommendation for fibre intake is 25 g/d⁽⁴⁵⁾. Fibre intakes are highly dependent on total energy (kcal) intake and it is well known that as age increases, energy requirements decrease due to changes in body composition along with a decrease in physical activity^{(Reference Roberts and Dallal83)}. The Nordic Nutrition Recommendations align fibre recommendations with energy intakes⁽⁴⁸⁾, allowing for the known variation in energy requirements.

Data from NANS indicate that up to 80 % of older adults do not meet the EFSA recommendation⁽⁴²⁾. Consideration of the variation in energy requirements due to difference in body size and activity levels among Irish adults⁽⁴²⁾ demonstrates the need for dietary fibre recommendations to be related to energy requirements; ≥3 g/MJ/d, as established by the Nordic Nutrition Recommendations⁽⁴⁸⁾.

Guidance to choose high-fibre versions of all carbohydrate foods eaten, such as wholegrain breads, pastas and cereals, fruit, salad and vegetables, will do much to ensure older adults achieve adequate fibre intakes.

Fat

Older adults are at greater risk of CVD than younger adults, with high saturated fat intakes representing one of the main risk factors for CVD. Strong evidence also exists supporting a beneficial role for the n-3 PUFAs, EPA and DHA, on cardiac health in older adults⁽⁴⁵⁾.

According to NANS⁽⁴²⁾, total dietary fat intakes among older adults, at 35 % energy, are at the top end of the EFSA reference intake range⁽⁴⁵⁾, with saturated fat contributing to 14 % of energy, exceeding the upper recommendation of 10 % energy⁽⁴⁵⁾.

While the dietary fat recommendations for older adults are the same as those for the general population, additional considerations for maintaining fat intakes within the recommended range in older adults need to be considered. In order to facilitate healthy ageing and help reduce disease risk in this age group, saturated fat intakes should be reduced by substituting with MUFAs and PUFAs, and increasing intakes of EPA and DHA^(45,84) . Guidance to use minimal amounts of oils and reduced-fat margarines rich in MUFA and PUFA and to include foods, such as reduced-fat oily fish, nuts and seeds will contribute to healthier intake of fats among older adults in Ireland. In addition, total fat intakes should be maintained at current intake levels in order to avoid the glycaemic effects of high-carbohydrate low-fat diets, with PUFAs also being linked to beneficial effects on glycaemic control⁽⁸⁴⁾.

B vitamins

Deficient folate and related B vitamin intakes and status can be common in this age group^{(Reference Hopkins, Gibney and Nugent85–Reference Laird, O'Halloran and Carey88)} and are associated with higher risk of diseases of ageing, including CVD, cognitive dysfunction and osteoporosis. Of note, lower biomarker status of folate, vitamin B₆ and riboflavin are associated with an increased risk of depression in this age group, while deficient vitamin B₆ status is associated with increased anxiety^{(Reference Moore, Hughes and Hoey86)}. The most common causes of folate and riboflavin deficiencies are low-dietary intakes, while deficient vitamin B₁₂ status is mainly caused by food-bound malabsorption as a result of atrophic gastritis (affecting up to 20 % of older adults) and the widespread use of proton pump inhibitor drugs, and low vitamin B₆ status is attributed to increased requirements in ageing^{(Reference Porter, Hoey and Hughes87)}.

In Ireland, data from NANS reported that 13 % of women have inadequate folate intakes⁽⁴²⁾, biomarker data from TUDA reported 2 % of participants having folate deficiency^{(Reference Moore, Hughes and Hoey86)}, while data from TILDA reported 15 % of participants had low or deficient folate status^{(Reference Laird, O'Halloran and Carey88)}. Studies from both TUDA^{(Reference Porter, Hoey and Hughes87)} and TILDA^{(Reference Laird, O'Halloran and Carey88)} reported that 12 % of participants had vitamin B₁₂ deficiency. There was also a 12 % deficiency rate in vitamin B₆ status reported from TUDA^{(Reference Hopkins, Gibney and Nugent85)}. Regarding riboflavin, NANS reported >50 % of older adults had suboptimal riboflavin status⁽⁴²⁾, while a similar level of 49 % was reported by TUDA^{(Reference Moore, Hughes and Hoey86)}.

Improving B vitamin status through improved diet requires separate consideration of each B vitamin, as the food sources differ for each. Natural food sources that should be included in the diet of this age group include lean meat (vitamins B₁₂ and B₆), reduced-fat (to minimise saturated fat intake) milk and dairy foods (riboflavin and vitamin B₆) and green leafy vegetables, legumes and liver (folate). Fortified breakfast cereals are also key contributors to intakes of each of the B vitamins^{(Reference Hopkins, Gibney and Nugent85,Reference Moore, Hughes and Hoey86,Reference Kehoe, Walton and Hopkins89,Reference Hoey, McNulty and Askin90)} , providing a practical and highly effective means of improving B vitamin status in this age group. In addition, consideration needs to be given to increasing the levels of fortification with vitamin B₁₂ in order to optimise status of this nutrient.

Vitamin C

Vitamin C plays an important role in immune function^{(Reference Carr and Maggini91)}. Older adults are particularly vulnerable to infections due to their reduced immune function. Thus, low vitamin C status in this group represents a potentially correctable contributing factor to morbidity and mortality^{(Reference Carr and Maggini91)}. Older adults, particularly those from lower socioeconomic status groups and those dependent on long-term residential care, are at risk of low vitamin C status. This is caused mainly by low intakes of fresh fruit and vegetables, resulting in lower body stores, along with increased needs caused by smoking, infections and diseases, such as type 2 diabetes^{(Reference Carr and Maggini91)}.

In Ireland, data from NANS reported that 17 % of male older adults had inadequate intakes, while 1 % of older adults had intakes less than the UK lower reference nutrient intake of 10 mg/d^(42,92) .

Including a small glass of unsweetened orange juice as one of the five daily servings of fruit and vegetables recommended for this age group will help in achieving adequate vitamin C intakes. A vitamin C supplement, as advised by a general practitioner, may be needed in some cases where diet is poor⁽³⁹⁾.

Vitamin D

The EFSA, IOM, Nordic Nutrition Recommendations and the Scientific Advisory Committee on Nutrition have all set dietary vitamin D requirements for older adults based on specified health outcomes and the associated serum 25-hydroxyvitamin D concentration, with requirements ranging from 10 to 20 μg/d^{(45,Reference Ross, Taylor, Yaktine and Del Valle47,48,93)} . Adequate vitamin D intake is essential for bone health^{(45,Reference Ross, Taylor, Yaktine and Del Valle47,48,93)} with low vitamin D status also strongly associated with frailty in this age group^{(Reference McKenna, Freaney and Meade94,Reference O'Halloran, Laird and Feeney95)} .

In Ireland, vitamin D deficiency is common among older adults, particularly in those in long-term residential care^{(Reference Griffin, Wall and Blake96)}, and is more pronounced in winter months^{(Reference Laird, O'Halloran and Carey97–Reference McCarroll, Beirne and Casey99)}.

Vitamin D occurs naturally in few foods, such as oily fish and eggs. However, these foods do not provide adequate vitamin D for this age group. While vitamin D fortified foods (mostly breakfast cereals and milks) can significantly increase vitamin D intakes and improve status, due to the voluntary nature of food fortification practices in Ireland, these foods alone are insufficient for achieving adequate intakes. Thus, vitamin D supplementation is essential for this age group and it is recommended that all older adults take a daily 15 μg vitamin D supplement all year round^(100,101) .

Calcium

An adequate intake of calcium is needed for optimal bone health in older adults. While the IOM recommends a higher calcium intake than that of younger adults^{(Reference Ross, Taylor, Yaktine and Del Valle47)}, EFSA does not recommend higher calcium intake for older adults because their modelling analysis excluded an effect of age or sex on calcium intake requirement⁽⁴⁵⁾.

Although calcium intakes among older adults in Ireland rank among the highest when comparing adults worldwide^{(Reference Balk, Adam and Langberg102)}, very few older adults consume the recommended three portions of dairy foods daily. TUDA reported that 96 % of older adults do not consume three portions of dairy foods daily^{(Reference Laird, Casey and Ward103)}, while TILDA reported 70 %^{(Reference O'Connor, Leahy and McGarrigle104)}. Additionally, NANS reported an average intake of 1⋅98 dairy portions daily⁽⁴²⁾.

Guidance to include four portions of calcium-rich dairy food sources (e.g. milk, yogurt and cheese) in the diet every day will not only help older adults achieve the calcium goal but will also contribute to their need for higher protein intake. While calcium is obtained from plant-based foods such as cereals, pulses, nuts, seeds and dark-green leaves, these sources are generally much less bioavailable. A daily calcium supplement (500 mg) may be needed for older adults who consume less than one portion of calcium-rich dairy food sources daily⁽³⁹⁾.

Iron

Prevalence of iron deficiency increases with age, particularly among older adults who are dependent on long-term residential care^{(Reference Bach, Schruckmayer and Sam105)}. Iron deficiency in this age group can result in increased ill health and mortality, and is caused mainly by occult blood loss, poor diet, renal insufficiency and malabsorption of iron in the gut^{(Reference Bach, Schruckmayer and Sam105)}. Iron status can be readily assessed by measuring serum iron, iron-binding capacity and ferritin.

In Ireland, most older adults meet the EFSA average requirement for iron (6 mg/d)⁽⁴⁵⁾ with NANS reporting average iron intakes of 15⋅8 mg/d from all sources and 10⋅8 mg/d from food alone⁽⁴²⁾.

The inclusion of iron-containing foods, such as meat, poultry, fish, eggs and beans, in the diet of this age group along with vitamin C-containing foods (potatoes, vegetables, salads and fruit) will enhance iron absorption, particularly from plant-based foods. Iron status should be regularly monitored in this age group in order to identify those with poor iron status and, thus, avoid the development of adverse health effects⁽³⁹⁾.

Zinc

Zinc is required for many diverse functions in the body including biochemical and immunological function⁽⁴⁵⁾. Zinc deficiency is common in older adults, particularly in those dependent on residential care^{(Reference Barnett, Dao and Hamer106)}. Factors such as low socioeconomic status, poor diet, inadequate chewing of food and impaired absorption in the gut all contribute to lower zinc intakes.

In Ireland, according to NANS average zinc intake in older adults is 10⋅4 mg/d from all sources and 8⋅7 mg/d from food alone. Thus, intakes are within the EFSA average requirement ranges (6⋅2–10⋅2 mg/d for women; 7⋅5–12⋅7 mg/d for men)⁽⁴⁵⁾ but below the EFSA population reference intake of 12⋅7 mg/d for women and 16⋅3 mg/d for men^(42,45) .

High-protein foods, including ‘dark meats’, such as tuna, read meat and dark poultry meat (i.e. leg meat), cheese, eggs and nuts, also represent best sources of zinc and their consumption should be encouraged in this age group. Some older adults may also require zinc supplementation (15 mg/d) if high-protein foods are not regularly consumed⁽³⁹⁾.