As we age, a number of important changes occur within our body. These changes include alternations to both our preference and our metabolic requirements from the food we eat. It is important that we prioritise our nutritional needs throughout all stages of life, especially as we get older. Neglecting good dietary practices can contribute to progression of a number of chronic diseases, including type 2 diabetes, atherosclerosis, coronary heart disease and malnutrition, which can impair quality of life due to both physiological function and cognitive decline.
Nutritional deficiencies can develop in elderly populations due to a number of factors. These might include financial constraints that limit the ability to purchase nutritious food; functional limitations that limit capacity for adequate food preparation; and a decrease in appetite which fundamentally reduces the desire to consume nutritious food. A common condition associated with aging is the loss of bone density, which increases the risk of osteoporosis. Additionally, loss of muscle mass can result in sarcopenia. Environmental factors can also play a role in the aging process, increasing the formation of free radicals during normal metabolic processes. Ensuring the consumption of antioxidants, vitamins and minerals each day can help to fight off oxidative stress and delay the progression of certain diseases.
A number of nutrients are especially important for older adults. These include:
Calcium and Vitamin D - both of these nutrients play an important role in bone health. Elderly women are at a greater risk of bone loss than men (2-3% increase per year) due to the hormonal influence of menopause, reducing oestrogen production, which decreases intestinal absorption of calcium. Oestrogen deficiency can also result in decreased reabsorption of calcium within the kidneys as well as increased secretion of the parathyroid hormone and reabsorption of bone. Vitamin D deficiency also adversely affects calcium homeostasis due to reduced intestinal calcium absorption. A reduced tendency to spend time in the sun, as well as reduced dietary intake of vitamin D and reduced ability of the skin to synthesise vitamin D3 all contribute to vitamin D deficiency.
In order to obtain optimal levels of vitamin D and adequate calcium, supplementation can be important and may assist in the prevention of fractures and improve bone health. For men and women aged over 70 years of age, daily dietary intake of vitamin D should be around 800IU, which can be obtained in the form of supplements as well as vitamin D-rich foods found in egg yolks, fish (esp. salt-water origin), liver and fortified milk. The recommended daily dietary intake of calcium for men and women over 70 years of age should be 1,300 mg/day. Calcium is predominantly found in milk and milk-based products such as bony fish, legumes, nuts and fortified soy beverages and breakfast cereals. Studies have shown that supplementing with both calcium and vitamin D3 can reduce the risk of developing osteoporosis and osteopenia in older adults.
B Vitamins - Another consequence of reduction in food consumption is a decreased intake of animal food sources, be it from cultural, religious or personal choices or the increased cost of these foods. B group vitamins, particularly B6, B12 and folate are rich in animal food sources and deficiencies in these particular vitamins is associated with an increase in serum homocysteine levels which may increase the risk of developing Alzheimer’s disease and dementia. Studies suggest that increasing supplemental intake of vitamins B6, B12 and folate may assist in lowering serum homocysteine levels that may help reduce cognitive decline in patients with mild cognitive impairment. Vitamin B12 is almost exclusively derived from animal products, but can be found in fortified foods as an important alternative for vegans and vegetarians. For those who eat very little meat produce, supplementation can play an important role in assisting to optimise serum levels.
Fibre - Constipation is another condition prevalent in many older adults. The RDI of dietary fibre is between 25-30g per day which may be beneficial in relieving constipation in some individuals. Including dietary fibre in the diet can assist not only in preventing constipation but may also enhance the absorption of B12. Regular consumption of whole grains, legumes, fruits and vegetables is also an important source of water-soluble dietary fibre which has been shown to be protective against colon cancer.
Zinc - Elderly populations have reported to have lower serum zinc concentrations, which can contribute to a weakened immune system, increasing their susceptibility to infections and the risk of morbidity and mortality secondary to these infections. RDI of zinc for older men is 11mg/day and 8mg/day for older women (tolerable upper limit 25-40mg/day) from both dietary and supplemental zinc. Dietary sources of zinc can be obtained from food sources including seafood, poultry, red meat, beans, fortified breakfast cereals, whole grains, nuts and dairy products. However, it is important to note that absorption of zinc from animal protein sources is more efficient than it is from plant protein sources.
Iron - Iron deficiency is very common amongst the older population and may contribute to the development of anaemia. There may be a number of factors contributing to iron deficiency including the aging process itself, decreased food intake, certain medications, and gastrointestinal malabsorption. The bioavailability of iron is also directly affected by various constituents present in the diet. For example, tea and coffee which contain tannins and polyphenols are known to exhibit an inhibitory role in the absorption of iron, whereas foods rich in vitamin C are known to help enhance iron absorption. The RDI for iron is 8 mg/day for both men and women. Dietary intake of heme and non-heme iron sources include meat and meat products, fish (tuna, sardine), egg, fortified breakfast cereals, dry fruits, dark green vegetables, soybean, chickpea, tofu, kidney beans, and lentils.
Protein – Prevalence of sarcopenia amongst individuals over 60 sits at around 30%, whilst 50% of men and women over 80 years of age are estimated to be sarcopenic. Insufficient protein consumption is observed with decreased overall food intake. This decrease in protein intake not only contributes to chronic muscle wasting but also impacts bone health which can lead to frailty and loss of functional capacity. Spreading out protein intake throughout the day is recommended to maximise the effect of the amino acids found in protein that are known to stimulate the synthesis of skeletal muscle mass.
An increase in aerobic exercise can also have a positive effect on protein anabolism and reduce insulin resistance by increasing microvascular supply of amino acid. To help increase protein intake and reduce the risk of sarcopenia in the elderly, it is recommended to increase supplemental intake of Essential Amino Acids (EAAs), including Leucine in particular, which can be added to water and is easy to consume. Studies have shown minor improvements in muscle mass through supplementation alone, but the effects can be further enhanced when paired with exercise, as an effective means of improving muscle strength.
Sodium, cholesterol, and blood pressure - Incorporating healthy dietary intake of omega-3 fatty acids, low glycaemic index foods, lean healthy sources of protein, and vitamin-rich foods on a daily basis may assist in maintaining healthy lifestyles, and may also assist to reduce cholesterol. High sodium intake has been shown to increase blood pressure, so ensuring a reduction in sodium and sodium-containing foods, and opting for more natural foods can help to reduce sodium intake and effects on hypertension. The recommended intake for sodium in adults is between 460-920 mg/day.
Nutritional interventions can be effective in preventing adverse health outcomes in elderly populations. In many instances, supplementation may be helpful to help avoid nutrient deficiencies, especially when consumption of fresh, whole foods is not sufficient to attain target nutrient requirements.
- Australian Government. (2014). Nutrient Reference Values for Australia and New Zealand - Calcium. Ministry of Health. https://www.nrv.gov.au/nutrients/calcium
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