Particularly if you are over 40 years old.
I was doing some research on feeding geriatric–uh, excuse me–senior cats, and I happened upon an article by veterinarian Andrew Sparks from Topics in Companion Animal Medicine, Volume 26, Issue 1, February 2011, Pages 37–42.
If you weren’t upset enough about spending Saturday night alone researching food for aging felines, imagine your mood after this excerpt:
Aging and Nutritional Implications in Humans
A full review of the changes associated with aging in humans is beyond the scope of this article. However, some of the important changes that may also have nutritional implications are worth highlighting , ,  and :
- •In humans, food intake diminishes with age,5 and during each decade of life after 50 years of age, the calorific requirement drops by an average of 10% (as a result of a reduced metabolic rate and loss of lean tissue mass).
- •Olfactory receptors and fibers notably decrease with age,6 resulting in a reduced sense of smell, and there is evidence too of a loss of taste associated with age. These changes can lead to loss of appetite and subsequent weight loss and malnutrition.
- •Aging is associated with loss of maxillary and mandibular bone, causing erosion of tooth sockets, gingivial recession, and potentially tooth loss.
- •There may be reduction in saliva production from some of the salivary glands (tongue, submandibular).7
- •Pharyngeal contractions associated with forming a food bolus and initiating swallowing diminish with age, which can lead to delayed swallowing or swallowing difficulties.
- •There is reduction in the lower esophageal tone, leading to a higher prevalence of gastro-esophageal reflux and “heartburn.”
- •There is a decreased elasticity of the stomach wall and a reduced ability to accommodate large meals.5
- •There is reduced gastric mucosal barrier function with reduced mucosal bicarbonate function and reduced prostaglandin synthesis, leading to an increased risk of gastric ulceration.
- •Aging in humans is associated with shorter and blunter small intestinal villi, which will significantly reduce the surface area of the small intestine and reduce absorptive capacity.
- •Lipid absorption is impaired in older humans.
- •Small intestinal bacterial populations change with age, which can contribute to bloating, pain, and reduced absorption of calcium, folate, iron, and other nutrients.
- •Large intestinal peristaltic activity declines with age, which can predispose to constipation.
- •Exocrine pancreatic function may decline with age with a reduced functional mass, causing reduced secretion of chymotrypsin and lipase.8
- •The production and flow of bile also declines with age, which may compromise fat digestion.
- •Glomerulosclerosis and loss of functioning renal mass may reduce the ability to finely regulate electrolyte and acid-base balance and may predispose to hypotension or hypertension.
- •A reduced secretion of somatotropin occurs in old age,9 leading to reduced protein synthesis and reduced lean body mass, a reduction in bone synthesis, and a decline in immune function.
- •There is an age-related reduction in thyroid hormone (T3) concentrations that may contribute to reduced metabolic rate.10
- •An age-related increase in circulating PTH concentrations occurs, which may contribute to reduced bone mineral density.11
- •An age-related reduction in aldosterone secretion is seen, resulting in a reduced ability to retain sodium, which may affect cardiovascular function.
- •There is an age-related increase in cortisol secretion10 that may contribute to reduced bone mineral density.
- •An age-related decrease in glucose tolerance and insulin sensitivity results in higher average blood glucose concentrations.12
- •Skeletal muscles atrophy and there is a decrease in lean body mass with age, which results in reduced body strength and weakness.13 In some individuals this is severe—a change referred to as sarcopenia—and is associated with loss of muscle fibers, reduced muscle fiber size, replacement of functional fibers by noncontractile fibrous tissue, less efficient mitochondrial function, reduced blood flow to major muscles, and reduced motor neurone numbers.14 The reduction in motor neurone numbers may be the major underlying cause of the sarcopenia, but this will be exacerbated by reduced concentrations of anabolic hormones (see above). The loss of lean body mass contributes significantly to the reduced metabolic rate and reduced calorific requirement in old age.
- •There is also a decreased stability and increased diversity of the intestinal microbiota with age.15