The Effect of Dietary Strawberry Supplementation on Older Adults

The Effect of Dietary Strawberry Supplementation on Older Adults

This study is being conducted to assess the effect of dietary strawberry supplementation on cognition and mobility in older adults. It is hypothesized that plant compounds, present in strawberries, may improve cognition and mobility by protecting against oxidative stress and inflammation.

This study is being conducted to assess the effect of dietary strawberry supplementation vs. placebo on measures of cognition and mobility in older adults. Participants will visit the HNRCA on 4 occasions. During the first visit, participants will complete a dietary assessment and familiarize themselves with some of the cognitive tests used in the study. After a period of up to 45 days participants will return for the second visit. Participants will be randomized to consume either freeze dried strawberry powder or a placebo powder that tastes like strawberry. At visits 2, 3 and 4, participants will undergo tests of cognition, memory, gait and balance. In addition, blood samples and 24-hour urine will be collected at these visits. Tests include balance and gait assessment using a treadmill instrumented with pressure sensors which will measure postural sway and a variety of spatial/temporal gait parameters. Participants will also be affixed with surface electrodes to measure the activation of muscles in their legs during these balance and gait measurements. Participants will complete a battery of cognitive tests on paper and by computer. In the time between participants' visit 2 and visit 4, participants will receive a weekly telephone call to check in with them and remind them to continue taking the study powder. At the very end of the study, when all participants are finished, participants will receive a telephone call to debrief them and notify them which group they were randomized into. An optional tissue banking protocol will be offered for collection of additional blood to be banked at visits 2-4.

Inclusion Criteria:

• Men and women are between the ages of 60 and 75 years
• Body mass index 18.5-29.9 kg/m2
• Adequate visual acuity or corrected visual acuity to read and perform computer tasks.
• Fluency in spoken and written English
• Ability to walk independently for 20 minutes
• Absence of menstruation for a minimum of 12 months or surgical menopause.

Exclusion Criteria:

• Self-reported vegetarian or vegan.
• Any condition that has resulted in cognitive deficits, including but not limited to - Alzheimer's disease or other dementias, cerebrovascular accident, or head injury
• History of any neurologic disorder resulting in permanent or relapsing/remitting neurologic impairment including but not limited to Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, peripheral neuropathy, or radiculopathy.
• History of any condition resulting in permanent muscle or mobility deficit that would interfere with walking independent of assistance for 20 minutes, including but not limited to amputation, fracture, arthritis, myopathy, or limb, hip or back surgery within the last year.
• Self-reported cognitive, memory, neurologic or functional deficits that are stated to interfere with activities of daily living or functional status.
• Any chronic condition associated with increased risk of falls such as vestibular disease, orthostatic hypotension or neuropathy.
• Falls within the last year, that occurred in the course or routine daily activities, which were not precipitated by unusual circumstances such as being pushed or falling on ice.
• Regular use (i.e. that cannot or should not be discontinued for the entire study period, as per the subject's personal physician) of medications or dietary supplements known or suspected to influence cognitive function, attention, ability to ambulate, gait, balance, or risk of falls that in the opinion of the study physician may influence study results or increase risk with participation in the study.
• Psychiatric disorders that could in the opinion of the study physician interfere with study testing, including bipolar disorder, psychosis, and major depression
• MMSE score of less than 24 at screening
• Gastrointestinal disorders that influence digestion and absorption of food
• Diabetes mellitus
• Liver dysfunction
• History of cirrhosis
• SGPT, SGOT, or total bilirubin > 2 x upper limit of normal
• Kidney disease as indicated by serum creatinine > 1.5 mg/dL at screening
• Cardiac or pulmonary conditions that limit ambulation or results in dyspnea with ambulation with walking required as part of activities of daily living.
• Reported allergy to strawberry or ingredients in the placebo.
• Ethanol use estimated to be on average > 2 servings/day of beer (12-ounces), wine (5 ounces) or liquor (1.5 ounces), or self-reported binge-drinking.
• Illicit drug use in the last 12 months.
• Cigarette smoking within the last 6 months or current use of nicotine.