Normal and Therapeutic Nutrition

Normal and Therapeutic Nutrition 3(2+1)

Lesson 17:Old Age–Nutritional Requirement

Process of ageing

• Tissue damage by free radicals and pro-oxidant radicals like superoxide, peroxide and hydroxyl radicals is the basis for inflammatory and degenerative changes seen in variety of diseases like cancer.
• Endogenous antioxidants are superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) which act together with glutathione reductase and NADPH. With age and in diseased conditions these antioxidant defences are lowered and the vitamins A, C and E get excessively utilized and a deficiency state occurs.
• The process of ageing brings about physiological, psychological and immunological changes which influence the nutritional status. The changes associated with ageing are partly influenced by genetics, race and gender.

As part of ageing process the functioning of the organ may change which may influence the nutrient status as given in

Table: Changes in organ functioning with ageing that may influence nutrient requirements

Organ function	Changes	Effect on nutrition
Taste & Smell	Decreased taste buds & papillae on tongue	Loss of ability to detect sweet and salt
	Decreased taste, olfactory nerve endings	Decreased palatability causing poor food intake
		Decreased sensory stimulation, impairs metabolic process
Salivary glands	Decrease in salivary secretion, dry mouth, xerostomia	Difficulty in chewing and swallowing makes them avoid certain foods. crunchy, dry and sticky foods
Teeth	Loss of teeth and wearing dentures	Decreased consumption of meat and fresh fruits and vegetables. Results in inadequate intake of energy, iron and vitamin C, folate and ?-carotene.
Gastric function and emptying	Decreased secretion of HCl, intrinsic factor and pepsin	Decreased bioavailability of minerals, vitamins and proteins
	Rapid rate of emptying of fluids Above 60 years of age	Decreased absorption of protein bound vitamin B12, folate
	Increased proximal small bowel Ph and bacterial overgrowth in bowel	Increased bacterial folate synthesis, counteracts malabsorption
	Decreased calcium absorption	Poor vitamin- D status
Small intestine	Decreased secretion of lactase Constipation – prolonged recto-sigmoid transit	Risk factor for developing oesteoporosis
Liver & biliary function	Decreased size and blood flow	Decreased rate of albumin synthesis
	Minor structural and biochemical changes
	Gall bladder becomes sluggish in releasing bile	Susceptible to gall stones
	Reduced activity of drug metabolising enzymes	Drug dosage may lead to lower enzymes
Metabolic function	Impaired glucose tolerance	Need dietary modifications, exercise and oral pharmacologic agents
	Decreased metabolic rate due to change in body composition, physical activity and body proteins	Decreased energy requirements
Cardio vascular function	Blood vessels become less elastic, increase in total peripheral resistance	Prevalence of hypertension, modification of diet accordingly
Neurological function	Confusional state	Decreased synthesis of seretonine, carnitine from amino acid lysine, methionine
		Carotenoids play protective role in aging problems
Immuno competence	Declines with age	Supplementation with vitamin – E, zinc & PUFA
Psychological factors	Depression	Affects appetite, digestion, energy level, weight and well being