Nutrition of the elderly

Old age is conventionally accepted as the stage of the life cycle that begins around the age of 65 and ends with death. However, chronological age is not a precise marker indicating the onset of the changes that characterize this stage. Nowadays, the longer life expectancy and the improvement in the state of health of the population reaching this age delay in many individuals the appearance of the physical limitations that reveal the onset of old age.

Aging is a complex phenomenon that encompasses morphological and physiological changes that appear as a consequence of the action of time on living beings, causing a decrease in the capacity of adaptation of each of the organs, apparatuses and systems, as well as in the capacity to react to the harmful agents that affect the individual. However, although these modifications are irreversible, the negative effects of the aging process can be lessened, at least in part, through various measures.

Factors influencing the aging process

Genetic factors (intrinsic or primary aging): these depend on the better or worse genetic load with which each subject is born. This factor affects all individuals without exception and each and every component of the organism, including those organs and systems linked to nutrition. Their action is inevitable, although they provide a narrow margin to attenuate or delay their effects, if timely and effective preventive interventions are carried out.

Environmental factors: these are the changes that have their origin in diseases, accidents, surgical mutilations and their corresponding sequelae, accumulated throughout life. These factors can reduce the longevity of the individual, or modify, to varying degrees, his or her quality of life. They can be modifiable if preventive measures are adopted, such as vaccination, adherence to healthy diets, and compliance with safety and hygiene standards, among others.

Lifestyle: among the elements that most influence this factor are the degree of physical activity maintained, the quality of the diet and the greater or lesser contact with toxic substances such as tobacco and alcohol, among many others. This group of factors is the most modifiable at a preventive level throughout life.

Although there is no doubt about the decisive influence of genetic factors, we must emphasize that the maintenance of an adequate nutritional status through diet allows us to:

• To lessen the changes related to the aging process.

• Improve the quality of life of the elderly.

• Reduce the effects of the most frequent ailments.

• Contribute to the maintenance of an independent lifestyle.

Causes that increase the risk of suffering from nutritional imbalances or deficiencies in the elderly

Changes in the digestive system.

In the mouth: The loss of teeth causes difficulties in chewing and insalivation, reducing the ability to absorb food. They can also lead to the reduction or suppression of certain food groups (nuts and lean meats) due to difficulties in chewing and crushing them, being replaced by foods that are easy to chew, without taking into account their nutritional value.

The malfunctioning of the salivary glands causes the reduction of saliva flow (xerostomia), impairing the formation of the alimentary bolus, creating swallowing difficulties.

Decreased efficiency of the taste buds, reduce sensitivity to sweet and salty tastes, which justifies the preference of the elderly for strongly seasoned, very sweet or very salty foods, and the rejection of diets with adequate levels of these ingredients.

In the stomach:

• Decreased gastric secretion, impairing the degradation of nutrients.

• Progressive reduction of motor function.

• Changes in the gastric mucosa and in the digestive glands cause a decrease in digestive functional capacity and increase the sensation of satiety with less food.

In the intestine:

• Tendency to mucosal atrophy.

• Formation of bladders or pouches (diverticula) in the bowel wall.

• Shortening of the villi of the small intestine hindering the absorption of some essential minerals and vitamins, such as iron, calcium and folic acid.

• Intestinal motility is reduced and the intestinal surface useful for absorption is reduced.

• The propulsor muscle atrophies, causing structural (diverticulosis) and functional (constipation) changes in the colon.

In the liver and pancreas:

• The liver is reduced in size and minimal functional changes occur, such as decreased blood flow, reducing its ability to detoxify the body of certain foods and drugs.

• The pancreas reduces levels of bicarbonate secretion and other enzymes, leading to intolerances and other digestive disorders.

Metabolic changes:

• There is a worse response of regulatory hormones such as insulin, glucagon, ghrelin and leptin.

• The minimum amount of energy needed to sustain life decreases by 10-20% between the ages of 30 and 75, due to a reduction in muscle mass.

• Plasma cholesterol concentration decreases progressively from the age of 70.

• Lactose intolerance may occur due to a decrease in lactase activity.

• The incidence of diabetes increases, often associated with overweight.

• The ability to increase intestinal absorption of calcium is lost, in case of calcium deficient intakes.

Changes in body composition:

• Increase in fat mass. It goes from 15% of the body weight of an adult male to 30% of an adult over 75 years of age. The distribution of fat in the body is also modified. Subcutaneous and extremity fat is reduced and fat deposited in the trunk increases. Body fat deposited in the abdomen and upper body may pose a greater health risk.

• There is a decrease in the muscle compartment, resulting in reduced strength and exercise tolerance, increasing the risk of balance and gait disturbances, which predispose to falls.

• Decreased bone mass due to bone demineralization. This is caused by endocrine disorders and insufficient intake or deficient absorption of calcium and/or vitamin D. This disorder can cause fractures, increasing the deterioration of the quality of life, due to residual disability.

• Reduction in extracellular water content, and total body water, with a reduced ability to maintain water balance, increasing the risk of dehydration.

Sensory changes:

• Visual, auditory, olfactory and gustatory deficits are manifested, favoring reduced appetite.

• There is a progressive loss of taste buds that mainly affects the anterior part of the tongue, where those responsible for preferentially detecting sweet and salty tastes are located, causing reduced attraction to certain foods.

Renal changes:

• Renal function is reduced by more than 50% between the ages of 30 and 80. This problem affects approximately 75% of the adult population and causes excessive excretion of proteins and electrolytes in the urine, altering the hydrosaline balance.

• They cause fluid accumulation in the extracellular or interstitial space (edema).

• Protein loss causes, in many cases, protein malnutrition.

Immunological changes:

• Natural defense capacity decreases, so that infectious agents can attack more easily. The natural defense barriers are weaker, being in certain situations null.

• This situation justifies the prevalence of a greater number of diseases during this stage of life.

Neurological changes: The most relevant diseases that severely condition the development of the life of the elderly at all levels are Parkinson's disease, Alzheimer's disease and senile dementia. The effects of these disorders on feeding are variable, and can range from the simple manifestation of manias or "oddities"