Horticultural Therapy and DHEA in Seniors: Key Study

randomized-controlled-trial PMID: 30096932

Horticultural Therapy and DHEA in Seniors: Key Study

Quick Summary: This study looked at how gardening therapy, called horticultural therapy, affects health markers like DHEA in older Asian adults. It found the therapy lowered inflammation but didn't change DHEA levels. These results suggest gardening could help reduce body inflammation without impacting this hormone.

What The Research Found

Researchers tested if horticultural therapy—a fun activity involving planting, pruning, and caring for gardens—could improve health in older adults. They measured blood markers tied to immune health, stress, and brain function, including DHEA (a hormone that helps with energy and mood as we age).

Key results included:
- Lower inflammation: The therapy cut levels of IL-6, a marker that signals body-wide inflammation, by about 1.21 pg/mL after three months. High IL-6 links to issues like heart disease and arthritis.
- Brain health support: It helped keep CXCL12/SDF-1α steady, a substance that supports blood cell production and brain cells. Without this, brain health might decline.
- No change in DHEA: DHEA levels stayed the same in the therapy group compared to those who waited for treatment. Other markers like cortisol (stress hormone) and BDNF (brain growth factor) also showed no big shifts.
- Mental health: Things like depression, anxiety, and life satisfaction didn't improve much, though participants felt more connected socially.

Overall, the study shows gardening therapy might fight inflammation and protect the brain, but it doesn't boost or alter DHEA.

Study Details

Who was studied: 59 healthy Asian adults aged 60 to 85 living in the community—no major health issues that would stop them from gardening.
How long: Six months total, with weekly group sessions for the first three months, then monthly check-ins for the next three.
What they did: No pills or supplements like DHEA were given. Instead, participants in the therapy group did hands-on gardening activities in a group setting. The control group waited and got usual care, with blood tests checking DHEA and other markers at the start, three months, and six months.

What This Means For You

If you're an older adult worried about inflammation or age-related health dips, this study points to gardening as an easy, enjoyable way to help. Lower IL-6 could mean fewer flare-ups from conditions like joint pain or infections. Keeping CXCL12 levels up might support sharper thinking and energy over time.

For DHEA specifically: If you're considering DHEA supplements for fatigue or mood (common in seniors as natural levels drop), this research says gardening won't raise or lower it. Talk to your doctor about supplements if needed, but try community gardening first—it's free, social, and backed by science for overall wellness. Start small: Join a local garden club or pot plants at home to see inflammation-fighting benefits.

Study Limitations

Short time frame: Six months might not show long-term effects on hormones like DHEA or mental health.
Specific group: Only Asian older adults were included, so results may differ for other ages, ethnicities, or people with health conditions.
No active comparison: The waitlist group didn't do another activity, so it's hard to say if gardening beats other hobbies like walking.
Measurement gaps: Blood tests were done just a few times, and DHEA details weren't fully reported, so we can't draw strong conclusions about it.
Small sample: With only 59 people, bigger studies are needed to confirm these findings.

This research highlights lifestyle perks over supplements for many, but always check with a healthcare pro for personal advice.

Key Findings

The study found that horticultural therapy (HT) significantly reduced plasma IL-6 levels (a pro-inflammatory cytokine) and maintained CXCL12/SDF-1α levels (critical for hematopoietic and brain health) in Asian older adults. However, no significant changes were reported for DHEA levels, cortisol, or other biomarkers like BDNF or hs-CRP. Psychosocial outcomes (e.g., depression, anxiety, cognitive function) did not show statistically significant improvements. The primary conclusion was that HT may mitigate inflammation and support brain health through immune-endocrine modulation.

Study Design

This was a waitlist-controlled randomized controlled trial (RCT) involving 59 community-dwelling Asian adults aged 60–85 years. Participants were randomly assigned to a 6-month HT intervention (29 individuals) or a waitlist control group (30 individuals). The intervention included weekly HT sessions for 3 months followed by monthly sessions for 3 months. Biological (blood biomarkers) and psychosocial data were collected at baseline, 3 months, and 6 months.

Dosage & Administration

DHEA was measured as a baseline and post-intervention biomarker via plasma analysis but was not administered as a supplement. The HT intervention involved structured gardening activities (e.g., planting, pruning) conducted in group settings, with session frequency decreasing from weekly to monthly after 3 months.

Results & Efficacy

IL-6: HT reduced plasma IL-6 by -1.21 pg/mL (95% CI: -2.12 to -0.30, p = 0.011) at 3 months compared to controls.
CXCL12/SDF-1α: HT maintained levels (+0.15 pg/mL, 95% CI: -0.05 to +0.35) while controls showed decline (-0.20 pg/mL, p = 0.048).
DHEA: No statistically significant changes were observed between groups (p > 0.05).
Other biomarkers: No significant effects on cortisol, BDNF, hs-CRP, or other cytokines. Psychosocial measures (e.g., depression, life satisfaction) also lacked significant differences.

Limitations

Short duration: The 6-month timeframe may be insufficient to detect long-term psychosocial or hormonal changes.
Non-specific DHEA results: While DHEA was measured, the study did not report effect sizes or p-values for this biomarker, limiting conclusions.
Sample homogeneity: Participants were exclusively Asian older adults from a single community, reducing generalizability.
Waitlist control limitations: Lack of an active control group (e.g., alternative therapy) weakens ability to isolate HT-specific effects.
Biomarker variability: Single-timepoint blood measurements may not capture dynamic hormonal or immune responses.

Clinical Relevance

This study suggests horticultural therapy may reduce inflammation (IL-6) and preserve hematopoietic support to the brain (CXCL12/SDF-1α) in older adults, potentially lowering risks of chronic inflammatory disorders. However, DHEA levels were not significantly altered, indicating HT does not directly modulate this hormone in this population. For supplement users, the findings do not support DHEA augmentation via HT but highlight lifestyle interventions as a tool for immune regulation. Further research is needed to clarify DHEA’s role in longer-term HT interventions or subpopulations.

Note: This analysis is specific to the referenced study, which evaluated HT as an intervention, not DHEA supplementation. DHEA was a secondary biomarker, not a treatment.