The purpose of this study is to evaluate dietary protein requirements in elderly women aged 80 years and older using the indicator amino acid oxidation technique.

Hypothesis to be tested: Protein requirement for elderly women is higher than the estimated average requirement of 0.66 g∙kg-1∙d-1 protein. The recommended protein intake for elderly women is higher than the recommended dietary allowance of 0.80 g∙kg-1∙d-1 protein.

There is currently considerable debate regarding the accuracy of the estimated average requirement (EAR) and the recommended dietary allowance (RDA) for older people. Very limited data obtained from older individuals are available to support the assumption that age does not affect protein requirement. Existing method like nitrogen balance has inherent limitations that diminish it from being considered a reference method. Indicator amino acid oxidation technique is emerging as an alternative method to measure dietary protein requirement. It is more accurate and less demanding. The current study will be the first time this technique is used with elderly adults and will provide an important foundation for geriatric nutrition research.

Inclusion Criteria:

• Female
• Age range: 80 yrs and older
• Body mass index between 22-30
• Weight stable 4.5 kg weight gain or loss within the last 6 month
• Non-smoking within the last 6 month
• Ambulatory
• Clinically normal blood profiles within 10% of clinical normalc.
• No diseases or not taking medications known to influence protein or energy metabolism,
• Willingness and ability to consume food provided and not allergic to phenylalanine
• Continent, strong bladder control

Exclusion Criteria:

• Male,
• Gained or lost more than 4.5 kg of body weight within the last 6 months,
• Non-ambulatory (i.e. bedridden, wheel-chair bound),
• Clinically abnormal blood profiles as identified by our study physician, Arthur Rosen, MD

Female Age range: 80 yrs and older Body mass index between 22-30 Weight stable 4.5 kg weight gain or loss within the last 6 month Non-smoking within the last 6 month Ambulatory Clinically normal blood profiles within 10% of clinical normalcy. No diseases or not taking medications known to influence protein or energy metabolism, Willingness and ability to consume food provided and not allergic to phenylalanine