Special Nutritional Needs

Information supplied by Blackmores New Zealand

Good nutrition is essential for the health of seniors, not just for minimising sickness, but to maintain an independent lifestyle for as long as is possible. The foundation of good nutrition is a diet that contains a wide variety of nutritious foods.

Ageing affects lifestyle and impacts on nutritional needs. For example with ageing, physical activity usually declines, resulting in a decrease in the amount of energy required by the body. Therefore, with lower energy demands, we eat less food; seniors therefore need to ensure that foods consumed are nutrient-dense to maintain adequate nutrient intake. It is difficult to maintain sufficient intake of nutrients without the use of supplements - a good multivitamin contains the RDI (recommended dietary intake) of most vitamins and minerals.

With age, muscle mass also declines - this is called sarcopenia. A decline in strength increases the risk of falls and susceptibility to broken bones. The decline can be slowed by ensuring an adequate intake of protein and amino acids, and by exercising for example 30 minutes of aerobic exercise daily helps maintain muscle mass.

Consumption of pharmaceutical drugs typically increases with age, and some foods can affect the absorption of drugs eg. grapefruit juice can affect liver enzymes that are involved in the metabolism of heart drugs and antihistamines, increasing blood drug levels by as much as 300%, to potentially lethal levels. The heart drug warfarin reacts with vegetables such as Brussels sprouts, cabbage, broccoli and asparagus, that contain vitamin K which hinders the drug′s clotting effect.

Substitutes for salt that are based on potassium can lead to dangerously high levels of potassium in people taking certain heart drugs. On the other hand, large amounts of liquorice can deplete potassium levels, which can be dangerous in those taking potassium-reducing diuretics.

Some herbs can also interact with prescription medicines eg. the anti-depressant herb Hypericum (St John′s Wort) stimulates certain liver enzymes which may lead to a reduction in blood level of the drugs as the body tries to eliminate them. Herbs such as ginkgo affect blood platelets aggregating and can potentiate the effects of anticoagulant drugs (such as warfarin) - even garlic and ginger can do this, so it is best to check with your healthcare professional when you are taking medicines and supplements together.

More importantly, many medicines can interfere with the absorption and metabolism of vital nutrients. For example, some antidepressants and heart drugs can cause a lack of interest in food, resulting in a reduction in protein and calorie (energy) intake. Mineral oil laxatives can inhibit absorption of the fat-soluble vitamins A, D, E and K, while drugs with a diuretic action may increase excretion of water-soluble minerals including sodium, zinc, magnesium and potassium. Corticosteroids can inhibit calcium absorption, promoting osteoporosis; they also alter sugar metabolism and affect kidney function, leading to potassium deficiency and an increase in sodium.

Ageing brings about certain physiological changes. A reduction in the secretion of stomach acid is common in older people - this decrease can lead to a decrease in the absorption of folate from foods and contribute to a deficiency in vitamin B12. Lowered blood levels of these two vitamins are associated with elevated blood levels of an amino acid called homocysteine which is a risk factor for cardiovascular disease and dementias such as Alzheimer's disease.

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