13) Fat, Carbohydrate, Water, Mineral, Electrolyte, and Vitamin Requirements in Adulthood and the Elderly Flashcards
What are the different age categories to define nutrient requirements in the elderly?
- Under 50
- Between 51 and 70
- Over 70
Why do distinct seniors possess different physiological and biological ages, despite having the same chronological age?
High heterogeneity of older adults in terms of diets, lifestyles and illnesses
How does the energy requirement vary in the elderly?
- The requirements are the same
- However, the elderly has decreased energy requirements due to their low muscle mass, which decreases their BMR
How does the protein requirement vary in the elderly?
- The requirements are the same (0.8 g/kg/day)
- However, recent studies have shown that this is insufficient
Why wouldn’t nitrogen balance studies produce accurate data in the elderly in terms of protein requirements?
- Does not reflect the redistribution of protein in the body
- The rate of protein turnover in muscle is relatively slow, and it is unlikely that nitrogen balance studies may detect a significant change in muscle mass
Which types of elderly individuals are less likely to benefit from protein supplementation?
Individuals with cachexia have less benefits than frail or individuals with sarcopenia
Most of the patients with (cachexia/sarcopenia) present with (cachexia/sarcopenia), but the opposite is not true.
cachexia
sarcopenia
Define cachexia.
- Complex metabolic syndrome, associated with underlying illness
- Characterized by muscle mass with or without the loss of fat mass
What are prominent clinical features of cachexia?
- Weight loss, inducing a rapid loss of muscle caused by an accelerated rate of protein breakdown
- Inflammation, increased muscle breakdown and insulin resistance
Does the ingestion of protein induce an anabolic effect in the elderly?
The response is lowered in the elderly, and the threshold is lower
Which pro-inflammatory cytokines may interfere with the hormonal control of muscle metabolism?
- IL-6 and TNF-a cause insulin resistance and reduced levels of testosterone and LH
- Increase in fat mass –> increase in pro-inflammatory cytokines
What may partially explain the lean body mass loss during aging?
The decreased ability of muscle to respond to anabolic stimuli, provided by dietary protein
Which micronutrient may affect lean body mass, acting synergistically with dietary protein?
Vitamin D
How does the carbohydrate requirement vary in the elderly?
The requirements are the same
Why are the carbohydrate requirements the same in the elderly?
- Total body glucose oxidation rate decreases with age (modestly)
- Brain mass slowly decreases with age
- The decrease in brain glucose oxidation rate is not likely to be substantially less
How does the fiber requirement vary in the elderly?
The requirements are the same (AI = 14 grams/1000 kilocalories)
How does the omega-6 requirement vary in the elderly?
Decrease with age, given the decreased energy requirements of the elderly
How does the omega-3 requirement vary in the elderly?
The requirements are the same
How does the water requirement vary in the elderly?
The requirements are the same
How are the water requirements determined in the elderly? Why?
- Based on median total water intake of young adults
- To ensure that total water intake is not limited due to a potential declining ability to consume adequate amounts of water in response to thirst
- The thirst mechanism is impaired with age
How does the sodium requirement vary in the elderly?
The requirements decrease
Why does the sodium requirement decrease in the elderly? How is the AI determined?
- The AI is extrapolated from younger adults
- The energy intakes decrease with age, and so sodium requirements decrease as well
How are the requirements for water-soluble vitamins determined in the elderly?
Based on the proportional requirements (extrapolated from young adults), as there is little evidence of increased requirements in the elderly
Why is vitamin B12 deficiency an issue in the elderly?
- 10 to 30% of mature adults lose their ability to adequately absorb protein-bound vitamin B12 in foods
- Because they are afflicted with atrophic gastritis
How does the bioavailability of crystalline vitamin B12 differ in individuals with atrophic gastritis? What is it?
- Crystalline B12 = unbound vitamin B12 (fortified foods, supplements)
- It is NOT altered in individuals with atrophic gastritis
How does the vitamin B12 requirement vary in the elderly?
- The requirements are the same
- However, the recommendation is the consumption of the majority of vitamin B12 through supplements and fortified foods (crystalline B12)
How does the vitamin D requirement vary in the elderly? Why?
- The requirements are increased
- The absorption decreases, likely due to a decreased number of vitamin D receptors
What are the dietary recommendations of vitamin D based on?
The amount of vitamin D to maintain blood levels of calcitriol associated with optimal bone health
How does the calcium requirement vary in the elderly? Why?
- The requirements are increased
- The absorption decreases
How do magnesium requirements vary with aging? Why? At what age?
- Magnesium requirements are greater in individuals over 30 years of age
- Renal status decreases after 30 years of age
What are the factors implicated in determining iron requirements in the elderly?
Only basal iron losses
