Eldery

What are the main gastrointestinal changes in the elderly stomach?

Reduced pepsin levels (to 75%), reduced gastric lipase (to 15%), lowered peristalsis, higher pH gradient (6.2→2), longer transit time (~3 hr).

What happens to the small intestine with aging?

Reduced proteolytic enzymes (to 50%), reduced lipase, higher pH (6.5), longer transit time (3 hr), lowered bile, lowered peristalsis.

What are the consequences of reduced stomach acid in the elderly?

Decreased absorption of vitamin B12, folate, iron, and calcium; risk of atrophic gastritis; increased bleeding risk.

What happens to the kidney with aging and what are the consequences?

Filtration rate ↓, excretion & reabsorption ↓, vitamin D production ↓, erythropoietin ↓ → edema, accumulation of drug metabolites/uric acid, reduced vitamin D status, risk of anemia, impaired blood pressure regulation.

What are the musculoskeletal changes with aging?

Muscle mass ↓, fiber density ↓, bone density ↓ → reduced endurance, muscle force, energy expenditure, increased risk of falls and fractures.

What happens to the sensory system (taste & smell) with aging and what are the nutritional consequences?

Taste ↓, appetite ↓, salt perception threshold ↓ → increased salt intake, reduced dietary variety. Smell ↓ → risk of ingesting contaminated food, reduced food intake.

Why is decreased thirst perception in the elderly dangerous?

Reduced sensibility to thirst → risk of dehydration and increased climate vulnerability.

What are the cardiovascular changes with aging?

Heart muscle mass changes, coronary artery perfusion ↓, vessel elasticity ↓, atherosclerosis ↑ → increased blood pressure, risk of stroke, myocardial infarction, arrhythmia, edema.

What happens to the immune system with aging?

White blood cell defense capacity ↓, interferon production ↓, beneficial gut bacteria (lactobacillus, bifidobacteria) ↓ → higher risk of infection, cancer, and gastrointestinal issues.

What are the endocrine changes with aging relevant to nutrition?

Sex hormones ↓ (gonads) → muscle mass ↓, fat mass ↑; insulin resistance ↑ → diabetes risk ↑; thyroid hormone ↓ → BMR ↓, fatigue; melatonin ↓ → sleep disorders.

What happens to the CNS (central nervous system) with aging and how does it affect nutrition ?

Appetite ↓, thirst ↓, swallowing reflex ↓, number of neurons ↓ → reduced food/fluid intake, risk of aspiration pneumonia, reduced ability to purchase/prepare food.

What is the recommended daily protein intake for the elderly?

~1.2 g/kg body weight/day (e.g., 90 g/day for a 75 kg person). Higher amounts may be needed individually (optimal vs. minimal dose).

What is anabolic resistance in the elderly?

The elderly show a blunted muscle protein synthesis (MPS) response to the same protein intake compared to younger adults — they need more protein to achieve the same anabolic effect.

What is the "anabolic opportunity window" after resistance training?

Resistance training increases muscle protein synthesis for up to 48 hours, sensitizing muscle to protein feeding — protein intake during this window produces a greater MPS response.

How much protein per meal maximizes muscle protein synthesis?

~20 g of protein per meal is sufficient to maximize MPS after resistance exercise; more does not add significant benefit.

What is the optimal protein distribution throughout the day for the elderly?

Even distribution across meals (e.g., ~20–30 g per meal) is superior to loading most protein at one meal (e.g., a large dinner).

What proportion of dietary protein actually reaches the muscle?

Only ~10% of dietary protein reaches the muscle — the rest is used by splanchnic tissues (gut, liver) and other organs.

Why is leucine particularly important for the elderly?

Leucine is a key trigger for muscle protein synthesis. Elderly people have a higher leucine threshold to stimulate MPS, so high-leucine foods (e.g., meat, dairy) are especially important.

Which food groups have the highest proportion of essential amino acids (EAA)?

Dairy & eggs and meat & poultry have the highest EAA proportion; plant sources (grains, vegetables, nuts) are lower in EAA.

Does protein supplementation alone (without exercise) increase muscle mass in the elderly ?

No — protein supplementation has no significant effect on muscle mass without physical activity (resistance training).

What are the proven benefits of high-protein oral nutritional supplements in elderly patients?

Fewer hospital readmissions (OR 0.59), reduced complication rate (OR 0.68), improved grip strength (+1.76 kg). No reduction in morbidity, mortality, or hospitalization duration.

What are the key recommendations to improve protein quality and digestibility for the elderly?

Choose high-EAA-density foods; eat complementary plant proteins; favor high-leucine foods; avoid prolonged heat treatment; remove antinutrients (soak, sprout, ferment); reduce particle size for those with poor dentition.

Why do plant proteins result in lower muscle protein synthesis than animal proteins?

Plant proteins have lower EAA content and lower leucine levels, leading to a smaller plasma amino acid peak and a lower muscle FSR (fractional synthesis rate) compared to meat.

What happens to muscle mass between age 20–80?

Muscle mass decreases by ~40% total; at a rate of 0.5–1%/year from age 25–50, and 1–2%/year after age 50.

What are problematic nutrients in the elderly?

Alcohol, salt, empty calories (sugar, low-quality fat), lactose, fructose, certain fibers, and large/fatty meals.