HELFIMED: food hampers, cooking classes and fish oil against social groups, with 152 recruited and 85 left at six months
Adults with self-reported depression got Mediterranean diet hampers and workshops plus fish oil, or social groups. The diet group had "greater reduction in depression (t = -2.24, P = 0.03)" at three months. 95 of 152 finished three months.
Reasonable evidence with real limitations. how we score evidence
Caveat on this rating: Self-reported depression. 152 recruited, 95 with three-month data, 85 with six-month data. Diet, cooking classes and fish oil in one arm against social groups in the other, for different durations, so the diet cannot be isolated. No effect size in the abstract.
The third of the Australian diet trials, and the one that mixed a whole-diet change with a supplement, so it cannot say which one did what.
Significant findings
"Adults with self-reported depression were randomized to receive fortnightly food hampers and MedDiet cooking workshops for 3 months and fish oil supplements for 6 months, or attend social groups fortnightly for 3 months."
"n = 152 eligible adults aged 18-65 were recruited (n = 95 completed 3-month and n = 85 completed 6-month assessments)."
The diet changed as intended: at 3 months the diet group "had a higher MedDiet score (t = 3.95, P < 0.01), consumed more vegetables", fruit, nuts, legumes and wholegrains, and "less unhealthy snacks" and "red meat/chicken".
On mood: "The MedDiet group had greater reduction in depression (t = -2.24, P = 0.03) and improved mental health QoL scores (t = 2.10, P = 0.04) at 3 months. Improved diet and mental health were sustained at 6 months." Reduced depression correlated with a higher diet score (r = -0.298), nuts (r = -0.264) and vegetable diversity (r = -0.303).
The authors: "This is one of the first randomized controlled trials to show that healthy dietary changes are achievable and, supplemented with fish oil, can improve mental health in people with depression."
The other direction
Self-reported depression, not a diagnosed disorder. Of 152 recruited, 95 had three-month data and 85 had six-month data: more than a third of the sample is missing at the primary time point, and dropout that large can manufacture a result on its own if the people who left were the ones not improving. The intervention was food plus cooking classes plus fish oil for six months; the control was social groups for three. Two arms that differ in three ways and in duration cannot isolate the diet. The depression result is a t statistic at P = 0.03, with no effect size or confidence interval in the abstract.
What this does not show
It does not show what fish oil did on its own, or the diet on its own. It does not compare against any treatment. It does not tell anyone to eat or take anything, and this row does not either.
Worth asking
When a trial loses a third of its people, who left, and would the answer change if they had stayed?
Source
A Mediterranean-style dietary intervention supplemented with fish oil improves diet quality and mental health in people with depression: A randomized controlled trial (HELFIMED) — Parletta N, Zarnowiecki D, Cho J, Wilson A, Bogomolova S, Villani A, Itsiopoulos C, Niyonsenga T, Blunden S, Meyer B, Segal L, Baune BT, O'Dea K (2019)
Indexed peer-reviewed journal
Read the source: https://doi.org/10.1080/1028415X.2017.1411320
DOI: 10.1080/1028415X.2017.1411320
How this was scored
- Study design
- Randomised controlled trial
- Funding
- Funding not disclosed
- Published in
- Indexed peer-reviewed journal
- Sample size
- 152
- Preregistered
- not recorded
- Conflicts disclosed
- not recorded
- Independent of proponent
- not recorded
- Retracted
- No
Read the full scoring rubric, including what it can't tell you.
Published September 29, 2026.
Questions
How strong is the evidence behind this?
veisund rates this source "moderate evidence". Reasonable evidence with real limitations. It scores 55 out of 100 on our published rubric. One caveat travels with that badge: Self-reported depression. 152 recruited, 95 with three-month data, 85 with six-month data. Diet, cooking classes and fish oil in one arm against social groups in the other, for different durations, so the diet cannot be isolated. No effect size in the abstract. The score is calculated from recorded facts about the source — study design, funding, publication venue, sample size, preregistration — not typed in by an editor.
What is the source for this?
A Mediterranean-style dietary intervention supplemented with fish oil improves diet quality and mental health in people with depression: A randomized controlled trial (HELFIMED) — Parletta N, Zarnowiecki D, Cho J, Wilson A, Bogomolova S, Villani A, Itsiopoulos C, Niyonsenga T, Blunden S, Meyer B, Segal L, Baune BT, O'Dea K (2019). Published in: Indexed peer-reviewed journal. DOI: 10.1080/1028415X.2017.1411320. The full source is linked on this page so you can read it yourself.
Who paid for this research, and does that matter?
Study design: Randomised controlled trial. Funding: Funding not disclosed. Independence from the proponent is not recorded. Industry sponsorship is one of the most reliably measured biases in medicine, which is why funding carries real weight in the score rather than sitting in a footnote.
Is this medical advice?
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.