The increasing number of adults aged 75 years and older highlights the need for effective, low-cost interventions to preserve cardiovascular health, functional independence, and cognitive performance and to support healthy aging. Beetroot extract (BE), derived from "Beta vulgaris", contains high levels of inorganic nitrate and other bioactive compounds that may positively influence vascular and neuromuscular function. In parallel, multicomponent physical exercise is recognized as an effective strategy to improve physical and cognitive outcomes in older adults. However, evidence on the independent and combined effects of BE supplementation and structured exercise in very old adults remains limited.
This randomized controlled trial is designed to evaluate the effects of BE supplementation, alone and in combination with a multicomponent physical exercise program, on blood pressure, functional performance, and cognitive function in adults aged 75 years and older. Participants will be randomly assigned to one of four groups: BE supplementation, multicomponent exercise, combined BE supplementation and exercise, or a control condition, over a predefined intervention period. The exercise program will include strength, balance, mobility, and aerobic components specifically adapted to the abilities and safety requirements of old adults.
The primary outcomes of the study will assess changes in cardiovascular health, physical and functional performance, and cognitive function using standardized and validated assessment tools. Secondary outcomes will include additional indicators of physical capacity and health-related quality of life. This trial aims to provide clinically relevant evidence on whether BE supplementation, alone or in combination with multicomponent exercise, represents a practical and scalable intervention to improve cardiovascular, functional, and cognitive health in adults aged 75 years and older.
Adults aged 75 years and older recruited from the Geriatrics Service of the Hospital Universitario de Navarra (HUN) or primary care settings.
Ability to ambulate independently.
Ability to communicate effectively.
Ability to tolerate physical exercise.
Refusal or inability of the participant, caregiver, or legal guardian to provide written informed consent.
Advanced or severe dementia (Global Deterioration Scale [GDS] stages 6-7).
Unstable medical condition or terminal illness with a life expectancy of less than 6 months.
Ischemic heart disease or congestive heart failure.
Parallel
Beetroot Extract Supplementation
Dietary supplementParticipants receive daily supplementation with beetroot extract juice, with or without participation in a multicomponent physical exercise program, depending on group allocation. When applicable, the exercise program targets strength, balance, mobility, and aerobic capacity, and is supervised by trained professionals during the first 6 weeks and subsequently prescribed but not supervised for the following 6 weeks. This intervention aims to evaluate the independent and combined effects of beetroot extract supplementation and physical exercise on cardiovascular, functional, and cognitive outcomes in adults aged 75 years and older.
Placebo group: nitrate-depleted beetroot juice
Dietary supplementParticipants receive daily supplementation with nitrate-depleted beetroot juice, with or without participation in a multicomponent physical exercise program, according to group allocation. The placebo juice is derived from beetroot but has had its nitrate content removed, maintaining similar appearance, taste, and texture to the active supplement. When applicable, the exercise program targets strength, balance, mobility, and aerobic capacity and is supervised by trained professionals during the first 6 weeks, followed by a prescribed but unsupervised phase for the subsequent 6 weeks. This placebo-controlled intervention is designed to isolate the effects of dietary nitrate from beetroot extract and to evaluate the independent and combined effects of physical exercise on cardiovascular, functional, and cognitive outcomes in adults aged 75 years and older.
Blood Pressure
Blood pressure (systolic and diastolic) will be measured three times in a row, and the average of the three readings will be calculated.
Heart rate
Heart rate will be measured at rest, after the 6-minute walk test, and then 3 minutes after the test has finished.
Stroop Test
This test measures cognitive control and attention by asking individuals to name the color of a word rather than the word itself. It evaluates the ability to manage interference between conflicting information.
Symbol Digit Modalities Test (SDMT)
This test assesses processing speed, attention, and working memory by requiring individuals to match symbols with corresponding numbers under time pressure. Faster and more accurate performance indicates better cognitive functioning.
Continuous Glucose Monitoring
Continuous Glucose Monitoring (FreeStyle Libre 2): This system measures glucose levels continuously through a small sensor placed on the skin, providing real-time data without frequent finger pricks. It helps track glucose trends and fluctuations, supporting better diabetes management and treatment decisions.
Laboratory Parameters: Blood Nitrate and Nitric Oxide Assessment
Blood Nitrate and Nitric Oxide Assessment: This measurement evaluates nitric oxide (NO) bioavailability by analyzing changes in blood nitrate levels, a stable indirect marker of NO production, typically expressed in µmol/L. . Blood samples (10-20 mL) will be collected alongside routine clinical testing using Vacutainer tubes (EDTA, citrate, or serum tubes as appropriate). Samples will be left upright for 10 minutes and centrifuged at 3000 rpm for 15 minutes to obtain serum and plasma for analysis. Aliquots will be stored at -80°C for future specialised analyses, including flow cytometry.
Body Composition by Bioimpedance
Body Composition by Bioimpedance (BIA 101 BIVA® PRO): This method assesses body composition by measuring electrical impedance through a two-electrode system, providing estimates of body water, fat mass, and fat-free mass. It also uses bioelectrical impedance vector analysis (BIVA) to evaluate hydration status and cellular health, offering insights into nutritional and physiological condition.
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