Microencapsulated DHA in Toddler Formula Linked to Higher Blood DHA: 2025 Trial Results
A randomised controlled trial in 120 toddlers highlights the potential benefits of microencapsulation for improving DHA delivery in toddler nutrition
This article is published by Bellamy’s Organic, a certified organic producer of formula and baby food, which makes toddler milk drinks containing DHA. Bellamy’s Organic products were not tested in this study.
TL;DR
In a 2025 trial of 120 toddlers, only formula with microencapsulated high-DHA (docosahexaenoic acid) tuna oil powder raised blood DHA significantly above unfortified formula, with a blood DHA response of 2.43 vs 1.39 for wet-mixed tuna oil. The trial was industry-funded and measured blood markers only, so the results should be treated as promising but preliminary.
Trial results at a glance (Sunardi et al., 2025)
| Formula | How DHA was added | Planned DHA | Toddlers who completed | Intake vs planned | Blood DHA iAUC (mean ± SE) | Apparent DHA digestibility | Blood DHA vs control |
| Microencapsulated formula | Microencapsulated high-DHA tuna oil powder, dry-blended after spray drying | 25 mg per 40 g serving × 2 = 50 mg/day | 30 | Approximately 101% | 2.43 ± 0.36 | 99.91% | Significantly higher at weeks 6 and 8 |
| Wet-mixed formula | High-DHA tuna oil incorporated during liquid manufacturing | 16 mg per 31.65 g serving × 3 = 48 mg/day | 28 | Approximately 70% | 1.39 ± 0.26 | 99.88% | Not significantly different |
| Control formula | No added DHA | 0 mg/day | 33 | Approximately 83–90% | 0.57 ± 0.19 | Not applicable | Reference group |
Figures apply to healthy Indonesian toddlers recruited at 2–3 years of age in a single eight-week trial of commercial toddler formulas. Blood DHA iAUC is a biochemical measure and does not describe health or developmental outcomes.
Background
Docosahexaenoic acid (DHA), an omega-3 long-chain polyunsaturated fatty acid, plays an important role in early childhood nutrition and is associated with brain, retinal and cognitive development. However, dietary intake of DHA among young children can be below recommended levels, particularly where consumption of DHA-rich foods such as oily fish is limited.
A study published in September 2025 in Food Science & Nutrition investigated whether the way DHA is incorporated into toddler formula could influence its bioavailability. The study compared commercial toddler formulas containing either microencapsulated high-DHA tuna oil powder or high-DHA tuna oil incorporated through wet mixing, as well as an unfortified control formula.
Study design
The double-blind, randomised controlled trial involved 120 healthy Indonesian toddlers recruited at 2–3 years of age. Following screening, participants were randomly allocated to three groups:
- Microencapsulated formula: toddler formula containing microencapsulated high-DHA tuna oil powder, dry-blended after spray drying, providing 25 mg DHA per 40 g serving and 50 mg DHA per day as planned.
- Wet-mixed formula: toddler formula containing high-DHA tuna oil incorporated during the liquid manufacturing process, providing 16 mg DHA per 31.65 g serving and 48 mg DHA per day as planned.
- Control formula: an unfortified toddler formula without added DHA.
The intervention lasted eight weeks. Blood samples were collected as dried blood spots at baseline and at weeks 2, 4, 6 and 8 to assess fatty acid status. Faecal samples were also collected to provide additional information on fatty acid excretion and apparent DHA digestibility.
At baseline, whole-blood DHA was 1.60 ± 0.12% in the microencapsulated formula group, 1.37 ± 0.05% in the control formula group and 1.70 ± 0.12% in the wet-mixed formula group. The Omega-3 Index was 3.33 ± 0.12%, 3.02 ± 0.11% and 3.36 ± 0.13% respectively. The authors report that baseline values were comparable, and there were no significant differences between groups in weight, height, body mass index, age or sex.
Although 120 toddlers entered the intervention, 91 completed the study: 30 in the microencapsulated formula group, 33 in the control formula group and 28 in the wet-mixed formula group. A total of 29 toddlers withdrew, including for mild discomfort such as diarrhoea and refusal to consume the formula. No allergic reactions or serious adverse events were reported.
1. Microencapsulated formula: significant improvement in blood DHA status
The microencapsulated formula contained high-DHA tuna oil powder that was dry-blended into the formula after the spray-drying process. Thirty toddlers completed the eight-week intervention. The blood DHA iAUC in this group was 2.43, compared with 0.57 for the control formula and 1.39 for the wet-mixed formula. These figures compare a blood biomarker and do not represent improvements in health or development.
Microencapsulated formula quick compare
| Feature | Detail |
| Category | Commercial toddler formula with dry-blended microencapsulated high-DHA tuna oil powder |
| Planned DHA | 25 mg per 40 g serving; 2 servings a day; 50 mg/day |
| Intake vs planned | Approximately 101% |
| Blood DHA iAUC | 2.43 ± 0.36 |
| Apparent DHA digestibility | 99.91% |
| Blood DHA vs control | Significantly higher at weeks 6 and 8 |
| Strongest evidence for | Increasing blood DHA and the Omega-3 Index over eight weeks |
Strengths and limitations
| Strengths | Limitations |
| The only formula to increase blood DHA significantly compared with the control | Industry-funded trial; two authors are employees of the ingredient supplier |
| Highest blood DHA iAUC of the three formulas | Eight-week duration; blood markers only, with no cognitive, visual or growth outcomes |
| Toddlers consumed the full planned intake | The digestibility advantage over the wet-mixed formula was 0.03 percentage points |
DHA levels in the microencapsulated formula group increased toward the end of the study, and a statistically significant difference compared with the control group was observed at weeks 6 and 8. A similar pattern was observed for the Omega-3 Index, with the microencapsulated formula group showing significant differences compared with the control group at weeks 2, 6 and 8.
Part of the advantage over the wet-mixed formula may reflect differences in intake rather than absorption alone. At approximately 101% of planned intake, toddlers in the microencapsulated formula group received approximately 50.5 mg DHA per day, compared with approximately 33.6 mg per day in the wet-mixed formula group.
Key takeaway: In this trial, the microencapsulated formula was the only formula that increased blood DHA in toddlers significantly compared with an unfortified formula.
2. Wet-mixed formula: DHA increased, but intake was lower
The wet-mixed formula contained high-DHA tuna oil incorporated during the liquid stage of manufacturing. Twenty-eight toddlers completed the eight-week intervention. Blood DHA increased in this group, but the increase was not statistically significant compared with the control group, and the blood DHA iAUC of 1.39 was significantly lower than that of the microencapsulated formula (2.43).
Wet-mixed formula quick compare
| Feature | Detail |
| Category | Commercial toddler formula with high-DHA tuna oil incorporated during liquid manufacturing |
| Planned DHA | 16 mg per 31.65 g serving; 3 servings a day; 48 mg/day |
| Intake vs planned | Approximately 70% |
| Blood DHA iAUC | 1.39 ± 0.26 |
| Apparent DHA digestibility | 99.88% |
| Blood DHA vs control | Not significantly different |
| Strongest evidence for | Showing that lower intake may limit DHA delivery |
Strengths and limitations
| Strengths | Limitations |
| Relative DHA bioavailability was significantly higher than the control formula | Parents reported that children disliked the taste, often describing it as bitter |
| Apparent DHA digestibility remained high at 99.88% | Toddlers consumed only approximately 70% of the planned intake |
| Blood DHA increased over eight weeks | Blood DHA iAUC was significantly lower than the microencapsulated formula |
An interesting finding was the difference in formula consumption between the two DHA-fortified groups. Lower intake may have limited DHA delivery in the wet-mixed formula group. Parents reported that their children disliked the formula and often described it as bitter, but the study did not directly assess sensory characteristics.
Worked example: at approximately 70% of the planned 48 mg per day, a toddler in the wet-mixed formula group received approximately 33.6 mg DHA per day, or 14.4 mg less than planned.
Key takeaway: In this trial, the formula with high-DHA tuna oil incorporated during liquid manufacturing produced a lower blood DHA response than the microencapsulated formula, and toddlers consumed approximately 30% less of it than planned.
3. Control formula: the unfortified comparison
The control formula contained no added DHA. Thirty-three toddlers completed the eight-week intervention and consumed approximately 83–90% of the planned intake. Blood DHA in this group showed a small, non-significant decline over the study period, and the blood DHA iAUC was 0.57.
Control formula quick compare
| Feature | Detail |
| Category | Commercial unfortified toddler formula |
| Planned DHA | 0 mg/day; 2 servings a day |
| Intake vs planned | Approximately 83–90% |
| Blood DHA iAUC | 0.57 ± 0.19 |
| Apparent DHA digestibility | Not applicable |
| Blood DHA vs control | Reference group |
| Strongest evidence for | Establishing blood DHA status without fortification |
Strengths and limitations
| Strengths | Limitations |
| Provides a comparison from the same population for both DHA-fortified formulas | No DHA was added, so digestibility could not be compared |
| Largest group of completers (33) | Lowest baseline blood DHA of the three groups (1.37%) |
Key takeaway: Without added DHA, blood DHA in toddlers remained stable or declined slightly over eight weeks.
How DHA bioavailability was measured
The researchers assessed DHA bioavailability using several complementary measures rather than relying solely on blood DHA concentrations.
Relative DHA bioavailability was significantly higher in both DHA-fortified groups compared with the control group. The microencapsulated formula group also demonstrated significantly greater apparent DHA digestibility and a higher blood DHA iAUC compared with the wet-mixed formula group.
The overall difference in blood DHA iAUC between groups was statistically significant (p<0.001). In pairwise comparisons, the microencapsulated formula differed significantly from the control formula (p<0.001) and from the wet-mixed formula (p=0.029).
Apparent DHA digestibility was extremely high in both intervention groups—99.91% for the microencapsulated formula and 99.88% for the wet-mixed formula. The microencapsulated formula showed a statistically significant advantage of 0.03 percentage points, the clinical significance of which is unknown. These measures are biochemical outcomes and do not demonstrate improved cognition, vision, growth or long-term health.
What the results mean for formulation choices
| If the priority is | Start with | Rationale |
| Increasing blood DHA over eight weeks | Microencapsulated formula | The only formula significantly above control at weeks 6 and 8 |
| Formula acceptance and intake | Microencapsulated formula | Approximately 101% of planned intake vs approximately 70% for the wet-mixed formula |
| Apparent DHA digestibility | Either DHA-fortified formula | 99.91% vs 99.88%; statistically significant, but a difference of 0.03 percentage points |
| Independent evidence | Neither at present | Both toddler trials to date were funded by the same ingredient supplier |
Checklist for evaluating DHA formula studies
| Check | What to look for |
| Funding and authorship | Who funded the trial, and whether authors are employed by the supplier |
| Dose | DHA per serving and per day in each group; here 50 mg/day vs 48 mg/day as planned |
| Actual intake | Whether children consumed the planned amount in every group |
| Dropout | How many enrolled children completed the study; here 91 of 120 (approximately 76%) |
| Outcome type | Blood markers (DHA, Omega-3 Index) vs functional outcomes (cognition, vision, growth) |
| Duration | Length of the intervention; this trial ran for eight weeks |
| Population | Age, country and usual diet; this trial studied Indonesian toddlers recruited at 2–3 years of age |
Limitations of the study
The study was funded by Nu-Mega Ingredients Pty Ltd. Two of the six authors, Samaneh G. Fard and Glenn Elliott, are employees of Nu-Mega Ingredients, and Samaneh G. Fard is the corresponding author. According to the paper, Nu-Mega Ingredients provided salary support and funded the study but had no role in analysing blood and faecal fatty acids.
Of the 120 toddlers enrolled, 91 completed the study, representing a dropout rate of approximately 24%.
Formula intake differed between groups. As the wet-mixed formula group consumed approximately 70% of the planned intake, the comparison between the two DHA-fortified formulas reflects both absorption and acceptance.
The formulas were commercial products that differed in more than the method of DHA delivery, including serving size and the number of servings per day. The study therefore does not prove that microencapsulation alone caused the observed differences.
The study assessed blood and faecal fatty acids over eight weeks and did not measure cognitive, visual, growth or long-term health outcomes. Eight weeks of follow-up in 91 completers cannot establish long-term safety or tolerability.
The authors note that higher DHA dosages or longer intake durations may be needed to achieve Omega-3 Index levels above 8% in populations such as this one.
Why does microencapsulation matter?
Long-chain omega-3 fatty acids such as DHA are susceptible to oxidation, which can result in undesirable flavours and odours. Microencapsulation is a technology designed to protect sensitive oils by surrounding them within a protective matrix.
In this study, the microencapsulated DHA powder was added to the formula after the spray-drying process, whereas the wet-mixed DHA oil was incorporated during the liquid manufacturing process. The researchers propose that differences in processing, protection from oxidation and the physical characteristics of the oil may contribute to the observed differences in DHA utilisation. The study did not test which of these factors was responsible.
In their discussion, the researchers also suggest that microencapsulation may help mask undesirable flavours associated with fish oils. This was not directly tested in the trial.
Key terms
| Term | Definition |
| DHA (docosahexaenoic acid) | An omega-3 long-chain polyunsaturated fatty acid found in oily fish and associated with brain and retinal development |
| Omega-3 Index | A measure based on the proportion of EPA (eicosapentaenoic acid) and DHA in blood; in adults, an index of 8% or more is associated with the lowest risk of death from coronary heart disease, and 4% or below with the highest. These thresholds are not established targets for toddlers |
| Blood DHA iAUC | Incremental area under the curve: the increase in blood DHA above baseline over the eight-week intervention |
| Apparent DHA digestibility | The proportion of ingested DHA that did not appear in the faeces |
| Relative DHA bioavailability | The extent to which DHA from each formula reached the blood, compared across groups |
Research context: the two toddler trials cited here
| Date | Study | Participants | Duration | Main finding |
| January 2020 | Ghasemi Fard et al., Nutrients (Malaysia) | 60 toddlers randomised to four groups; 48 completed | One month | Blood DHA was significantly higher with microencapsulated tuna oil powder formulas; the Omega-3 Index increased significantly after two weeks with microencapsulated powders but not with non-encapsulated oil |
| September 2025 | Sunardi et al., Food Science & Nutrition (Indonesia) | 120 toddlers randomised to three groups; 91 completed | Eight weeks | Only the microencapsulated formula increased blood DHA significantly compared with control; blood DHA iAUC and apparent DHA digestibility were significantly higher than for the wet-mixed formula |
Both trials were funded by Nu-Mega Ingredients Pty Ltd.
Key takeaway: Two industry-funded toddler trials, conducted in Malaysia in 2020 and Indonesia in 2025, both found higher blood DHA with microencapsulated tuna oil powder than with non-encapsulated tuna oil.
Do toddlers need toddler milk drinks?
This trial does not show that toddlers need toddler formula or toddler milk drinks. Pregnancy, Birth and Baby, an Australian Government-funded health information service, advises that healthy children over 12 months do not need formula and should eat a variety of foods in line with the Australian Dietary Guidelines. Toddler milk drinks are formulated supplementary foods intended to complement the diet of young children whose intake of energy and nutrients may not be adequate. Parents should speak with a doctor, dietitian or child health nurse about their child’s individual needs.
Frequently Asked Questions
What is microencapsulated DHA?
Microencapsulated DHA is DHA-rich oil surrounded by a protective matrix and dried into a powder. The matrix is designed to protect the oil from oxidation and mask undesirable fishy or bitter flavours. The powder can be dry-blended into powdered formula after spray drying.
Is microencapsulated DHA better absorbed than regular fish oil?
In the 2025 Indonesian trial, microencapsulated high-DHA tuna oil powder produced a significantly higher blood DHA response than wet-mixed high-DHA tuna oil. Apparent DHA digestibility was 99.91% compared with 99.88%, a difference of 0.03 percentage points. Toddlers also consumed more of the microencapsulated formula, and the formulas differed in other ways, so the trial does not show that microencapsulation alone explains the difference.
How much DHA did the toddlers receive in the trial?
The microencapsulated formula provided 25 mg DHA per 40 g serving, or 50 mg per day as planned. The wet-mixed formula provided 16 mg DHA per 31.65 g serving, or 48 mg per day as planned. Based on actual intake, toddlers received approximately 50.5 mg and 33.6 mg DHA per day respectively.
Why did toddlers consume less of the wet-mixed formula?
The study did not directly assess taste. Parents in the wet-mixed formula group reported that their children disliked the formula, which was often described as bitter. These toddlers consumed approximately 70% of the planned intake, compared with approximately 101% in the microencapsulated formula group.
What is a good Omega-3 Index?
In adults, an Omega-3 Index of 8% or more is associated with the lowest risk of death from coronary heart disease, and 4% or below with the highest. These thresholds are not established targets for toddlers. At baseline, the toddlers in the 2025 trial had an average Omega-3 Index of approximately 3.0–3.4%, and the authors suggest that higher DHA dosages or longer intake durations may be needed to exceed 8%.
Is tuna oil in toddler formula safe?
The 2025 trial reported no allergic reactions or serious adverse events over eight weeks. However, 29 of the 120 toddlers withdrew, including for mild discomfort such as diarrhoea and refusal to consume the formula, and an eight-week study cannot establish long-term safety. Parents of children with a fish allergy or other medical condition should consult their doctor before changing formula.
Who funded the tuna oil toddler formula study?
The 2025 trial was funded by Nu-Mega Ingredients Pty Ltd, a Brisbane-based supplier of high-DHA fish oil products. Two of the study’s authors are employees of Nu-Mega Ingredients, which the paper states had no role in analysing the blood and faecal fatty acids.
Key Takeaways
In this eight-week, double-blind randomised trial of healthy Indonesian toddlers, the commercial formula containing dry-blended microencapsulated tuna oil produced a higher blood DHA response than the wet-mixed tuna oil formula and the unfortified control formula. The microencapsulated formula supplied 25 mg DHA per serving, or 50 mg per day as planned, while the wet-mixed formula supplied 16 mg per serving, or 48 mg per day as planned.
Because intake was lower in the wet-mixed formula group and the commercial formulas differed in more than the DHA delivery method, the findings support a promising association rather than proof that microencapsulation alone caused the difference. The study measured biochemical markers, not cognition, vision, growth or long-term health, and the clinical significance of the modest changes observed remains to be established.
Related reading
References
- Sunardi, D., S. G. Fard, M. P. Ratih, A. Herawati, G. Elliott, and A. J. Sinclair. 2025. “Tuna Oil-Enriched Toddler Formula Enhances DHA Status in Indonesian Toddlers.” Food Science & Nutrition 13, no. 9: e70838. https://doi.org/10.1002/fsn3.70838
- Ghasemi Fard, S., S. P. Loh, G. M. Turchini, B. Wang, G. Elliott, and A. J. Sinclair. 2020. “Microencapsulated Tuna Oil Results in Higher Absorption of DHA in Toddlers.” Nutrients 12, no. 1: 248. https://doi.org/10.3390/nu12010248
- Pregnancy, Birth and Baby. “Feeding Your Baby with Formula.” https://www.pregnancybirthbaby.org.au/feeding-your-baby-with-formula