The Effect of Whole Milk to Improve Muscle Health in Older Women
Condition: Dairy Products; Muscle Protein Synthesis; Aging; Physical Activity
Study type: Interventional

Summary: 
      Muscle and strength begin to noticeably decline around 50 years of age, increasing an
      individual's risk for disease and disability. Although changes in muscle mass ultimately
      depend on the balance of muscle protein synthesis (MPS) and breakdown (MPB) of muscle
      proteins, the latter remains relatively constant with aging. Accordingly, interventions that
      increase rates of MPS may combat long-term decrements in skeletal muscle mass and function.
      Previous research has established that an optimal diet to maintain muscle mass in elderly
      individuals requires relatively large amounts of high-quality protein to be consumed at each
      meal of the day. While this is a seemingly simple strategy, there are some barriers to
      increasing protein feeding in elderly individuals, particularly the cost of high-quality
      protein and, sometimes, difficulty with chewing/swallowing. Moreover, older adults often do
      not wish to consume large portions of protein in one meal.

      Milk is a readily accessible, affordable and nutritious source of nutrient-dense high-quality
      protein. Consuming milk with each meal is an easy strategy to promote the maintenance of
      skeletal muscle mass with aging. There is also evidence suggesting that a higher fat content
      of milk can have a beneficial role in stimulating the MPS response to feeding, but there are
      insufficient data to recommend this strategy to elderly individuals.

      The primary aim is to measure the rates of MPS in response to controlled diets providing
      whole milk, fat-free milk, or a control supplement (almond beverage - often marketed as an
      'alternative' to milk) with each meal. All diets will provide equal amounts of energy, but
      the dairy interventions will provide more protein, reflecting the amount of protein provided
      by each beverage. The investigators hypothesize that rates of MPS will be highest in the
      whole milk group but that fat-free milk will still elicit a greater MPS than almond beverage.
      The investigators will conduct the comparison of beverages under habitual physical activity
      levels and under a brief period of increased physical activity (i.e., increased daily steps).
      Thus, the investigators will be able to determine whether MPS responses to the experimental
      beverages are increased in combination with physical activity. The results will provide
      evidence regarding the effectiveness of daily milk ingestion for the maintenance of muscle in
      the elderly, increasing the marketability of milk, and potentially whole milk.
    


Intervention name(s): Whole Milk; Skim Milk; Almond Beverage
Intervention type(s): Dietary Supplement; Dietary Supplement; Dietary Supplement
Intervention description(s): Participants will consume twice daily whole milk beverages in addition to a standardized diet.; Participants will consume twice daily skim milk beverages in addition to a standardized diet.; Participants will consume twice daily almond beverages in addition to a standardized diet.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Participants randomly assigned to one of three intervention groups (whole milk, skim milk or almond beverage)
Masking: Single (Participant)
Primary purpose: Basic Science