Intakes of PUFA are low in preschool-aged children in the Guelph Family Health Study pilot cohort

Publication: Applied Physiology, Nutrition, and Metabolism
2 September 2022


This study investigated intakes of total, n-3, and n-6 polyunsaturated fatty acids (PUFA) in 109 preschool-aged children who participated in the Guelph Family Health Study pilot. Intakes of total, n-3, and n-6 PUFA did not meet recommendations. This study highlights the need for additional monitoring and potential interventions to improve PUFA intake in preschool-aged children. Clinical Trial #NCT02223234.
Canadian preschool-aged children are not consuming enough n-3 and n-6 PUFA.


Cette étude a examiné les apports en acides gras polyinsaturés (« PUFA ») totaux, n-3 et n-6 chez 109 enfants d'âge préscolaire qui ont participé au projet pilote Guelph Family Health Study. Les apports en PUFA totaux, n-3 et n-6 n'ont pas respecté les recommandations. Cette étude met en évidence la nécessité d'une surveillance supplémentaire et d'interventions potentielles pour améliorer l'apport en PUFA chez les enfants d'âge préscolaire. Essai clinique #NCT02223234. [Traduit par la Rédaction]
Nouveauté :
Les enfants canadiens d'âge préscolaire ne consomment pas suffisamment d'acides gras polyinsaturés n-3 et n-6.


Early exposure to dietary factors, including intake of n-3 polyunsaturated fatty acids (PUFA) and n-6 PUFA are important for growth and development and inadequate intake may increase risk for developing chronic diseases later in life (De Boo and Harding 2006).
The adequate intake (AI) values for the essential n-3 PUFA, alpha-linolenic acid (ALA), are 700 and 900 mg for children aged 1–3 years and 4–8 years, respectively (Institute of Medicine 2002; Otten et al. 2006). Previous studies among young Canadian children (i.e., 1.5–8 years) have reported ALA intakes of 1.70 g/day (Innis et al. 2004) and 1.16 g/day (Madden et al. 2009), which exceed recommendations (Institute of Medicine 2002). Regarding longer chain n-3 PUFA, it is recommended that eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) contribute approximately 10% of ALA intake (i.e., 70–90 mg/day) (Otten et al. 2006). Previous studies suggest that Canadian children met these recommendations, reporting EPA plus DHA intakes ranging from 92.5 to 142 mg/day (Innis et al. 2004; Madden et al. 2009). However, some researchers have recommended that higher levels of EPA plus DHA are needed to promote optimal health, i.e., 0.3% of total energy, which correspond to 433 and 600 mg of EPA plus DHA for children aged 1–3 years and 4–8 years, respectively (Simopoulos et al. 1999).
The AIs for the essential n-6 PUFA, linoleic acid (LA), are 7 and 9 g for children aged 1–3 years and 4–8 years, respectively (Institute of Medicine 2002). There is no Dietary Reference Intake (DRI) for the longer chain n-6 PUFA, arachidonic acid (AA), although it has been recommended that young children consume 0.10%–0.25% of total energy from AA, corresponding to approximately 102–258 mg/day (Sioen et al. 2007; Forsyth et al. 2016). Little is known about intakes of n-6 PUFA in preschool-aged children, despite the critical role of these PUFA in early growth and development.
Intake of n-3 and n-6 PUFA among Canadian children is not regularly measured and the last major study that examined fatty acid intake was conducted over a decade ago (Innis et al. 2004). Therefore, this study aimed to evaluate current dietary intakes of PUFA in preschool-aged Canadian children in the Guelph Family Health Study (GFHS), with a focus on total PUFA, ALA, EPA, DHA, LA, and AA. The plasma fatty profile was also determined to confirm dietary observations.

Materials and methods

Study participants

Baseline data were collected between September 2014 and August 2016 from children participating in pilot phase 1 and phase 2 of the GFHS, a randomized controlled pilot trial of a home-based obesity prevention intervention (Haines et al. 2018). Families were eligible to participate if they had at least one child aged 18 months to 5 years, lived in the Guelph, Ontario, Canada area, and had a parent who could respond to questionnaires in English. Of the 117 child participants, 109 participants were included in this analysis. Children were excluded from analysis if they were being breastfed (n = 8).


Body mass index (BMI) was calculated using height and weight measurements collected at the baseline visit. Height measurements were taken to the nearest millimetre. Weight was measured to the nearest 0.01 kg. BMI Z-score was calculated using the WHO Anthro 3.2.2 software (2011). Age in months, height in centimetres (to two decimal places), and weight in kilograms (to two decimal places) were used to calculate the BMI z-score.

Dietary assessment

Dietary intake was assessed at baseline using a 3-day food record that included 2 weekdays and 1 weekend day. Parents were provided with detailed instructions on how to complete a food record. Food records were analyzed for 3-day average intakes of energy, macro- and micronutrients, total fat and fatty acids (saturated, trans, monounsaturated, total PUFA, total n-3 PUFA, ALA, EPA, DHA, total n-6 PUFA, LA, and AA) using the ESHA Food Processor Nutrition Analysis Software version 11.0.110 (ESHA Research, Salem, OR, USA).

Blood collection and plasma total fatty acid analysis

Blood collection was optional for study participants. Twenty-one children provided blood samples. Participants fasted overnight (minimum of 12 hours) prior to blood collection. Venous blood was collected by a phlebotomist at Lifelabs Medical Laboratory Services. Plasma and red blood cells were separated and stored at −80 °C.
Fatty acid composition of total plasma lipids was determined by gas−liquid chromatography. Plasma samples were thawed on ice. Fifty microlitres of plasma was combined with 3 mL of 2:1 chloroform:methanol containing 3.33 µg/mL of C19:0 FFA internal standard. Five hundred and fifty microlitres of KCl was added. Samples were spun at 1460 rpm for 10 min to separate phases. The chloroform layer was extracted and dried down under a gentle stream of nitrogen. Samples were methylated by 14% boron trifluoride in methanol at 100 °C for 1 hour. The resulting fatty acid methyl esters (FAMEs) were separated on an SP2560 column. FAME peaks were identified by comparison to reference standards. Fatty acid peak areas were determined using the Agilent EZChrome OpenLAB Chromatography Data System and used to calculate absolute concentration (μg/mL) and % total fatty acids.

Data and statistical analyses

Descriptive analyses were conducted to determine means and standard deviations for participant characteristics, fatty acid intake, and plasma fatty acid content (Tables 1–3).

Ethics approval

This study was conducted according to the guidelines laid down in the Declaration of Helsinki (WMA 2018), and all procedures involving humans were approved by the University of Guelph Research Ethics Board (REB14AP008) and registered on (NCT02223234). Parents provided written consent for themselves and their child(ren).


Participant characteristics

A total of 109 children (55 males and 54 females) from 76 families were included in the study. Mean age was 3.6 ± 1.3 years, body weight was 16.1 ± 3.6 kg, height was 99.1 ± 10.6 cm, and BMI z-score was 0.6 ± 1.0 (Table 1). The majority (89%) of participants identified as White. Household annual income ranged from $20 000 to greater than $150 000 CAD, and education levels for the primary parent ranged from some post-secondary training to post-graduate. Mean intakes of carbohydrate, fat, and protein were 54.2%, 31.9%, and 15.6% of total energy, respectively.
Table 1.
Table 1. Anthropometric and demographic characteristics of children in the Guelph Family Health Study and their families.
Among the subset of 21 children (11 males and 12 females) who provided blood samples, the mean age was 3.5 ± 1.1 years, body weight was 15.5 ± 2.7 kg, height was 97.5 ± 9.2 cm, and BMI z-score was 0.6 ± 0.7.

Dietary intake of fatty acids

Saturated fat was the greatest contributor to total fat intake (12.0% of total energy), followed by monounsaturated fatty acid (MUFA; 7.8%) and PUFA (4.1%) (Table 2). Total n-3 PUFA intake was 0.5%, which was mainly from ALA (0.4%) with a small amount from EPA plus DHA (0.1%) (Table 2). Total n-6 PUFA intake was 2.7%, which was almost entirely from LA (2.6%) with a small amount from AA (0.1%) (Table 2). There were no significant differences in intakes of fatty acids or total fat between males and females or among BMI z-score classifications (data not shown).
Table 2.
Table 2. Total fat, n-3 polyunsaturated fatty acid (PUFA), n-6 polyunsaturated fatty acid (PUFA), and trans fat intakes of children in the Guelph Family Health Study.

Plasma fatty acid composition and content

In plasma, n-3 PUFA comprised 3.5 ± 0.8%, while n-6 PUFA comprised 40.1 ± 2.9% of total fatty acids (Table 3). Among individual PUFA, LA was the most prevalent (30.1 ± 3.6%) followed by AA (7.1 ± 1.2%), DHA (1.7 ± 0.6%), ALA (0.7 ± 0.3%), and EPA (0.5 ± 0.3%). Quantitative measurement of fatty acid content (µg/mL) mirrored relative % composition values (Table 3).
Table 3.
Table 3. Plasma fatty acid % composition and concentration (μg/mL) for a subset of children in the Guelph Family Health Study.


This study examined the dietary intake of PUFA by a sample of Canadian children aged 1.5–5 years in the GFHS. Nearly three quarters of children had ALA intakes that were below the AI and a similar proportion had EPA plus DHA intakes that were below recommended levels (Institute of Medicine 2002).
Total PUFA intake (4.1% of daily energy) was below the lower limit of the acceptable macronutrient distribution range of 5–10%, while saturated fat intake (12.0% of daily energy) exceeded the recommended 10% of energy (Institute of Medicine 2002; FAO and WHO 2010; Health Canada 2019). Furthermore, total PUFA intake was up to a third lower than two previous studies that examined PUFA intake by Canadian children between the ages of 1.5 and 8 years (Innis et al. 2004; Madden et al. 2009). This low intake of total PUFA is concerning as inadequate intakes of dietary PUFA may increase the long-term risk of chronic inflammation and chronic disease (Sanders 2021).
Mean intake of LA and AA was 4.6 and 0.2 g, which is 48.1% and 26.9% lower than previously found in Canadian children (Innis et al. 2004), respectively. Approximately 82.3% of children did not meet the AI for LA (ages 1–8 years, 7–10 g). The mean intake of ALA was 605.1 mg, and 73.4% of children had intakes lower than the AI for ALA (ages 1–8 years, 700–900 mg). Also, ALA intake was 47.9%–64.4% lower than previously reported in Canadian preschool-aged children (Innis et al. 2004; Madden et al. 2009). Mean intake of EPA plus DHA in GFHS children (117.9 mg) was comparable to previous studies (Innis et al. 2004; Madden et al. 2009). However, while the mean intake of EPA plus DHA exceeded the recommendation (Table 2), 74.3% of these children had EPA plus DHA intakes below the recommended 70–90 mg (ages 1–8 years), and 25.7% of those children consumed no EPA plus DHA. Furthermore, only 8.3% of the GFHS children met the higher suggested intake of 433–600 mg of EPA plus DHA for optimal health (Simopoulos et al. 1999).
The low intakes of LA and ALA are surprising given that LA and ALA are found in many commonly consumed oils, including corn oil, sunflower oil, canola oil, flaxseed oil, and soybean oil, as well as in processed foods containing these ingredients (Williams and Burdge 2006). A 2018 study of 20 Canadian toddlers also found low intakes of ALA with less than half of the children meeting the AI for ALA (Lacombe et al. 2018). This study also found that only 5% of children met recommended intakes for EPA and DHA (Lacombe et al. 2018). Low intake of n-3 PUFA is likely due to low intake of fish and seafood sources (Imm et al. 2007; Stark et al. 2016). The low intake of LA and ALA and corresponding low total PUFA intake observed in GFHS children may be explained by higher saturated fat intake. However, the dietary choices leading to low total PUFA, n-6 and n-3 PUFA, and higher saturated fat requires further study.
Levels of plasma n-6 and n-3 PUFA were reflective of dietary intakes. This aligns with previous studies showing that dietary PUFA are highly correlated with plasma PUFA levels (Sun et al. 2007; Patel et al. 2010).
This study has some key limitations that should be considered when interpreting results. This research is limited by its small sample size and narrow demographic, which may limit the generalizability of these results. Families in this study are highly educated and in relatively good socioeconomic standing and, as such, this sample may not reflect intakes of all Canadian children. However, this limitation may infer that PUFA intake from lower socioeconomic groups are potentially even lower. This research also used 3-day food records, which is subject to misreporting and missing periodic intake of certain foods (Jones 1992).
Overall, findings from this study show that intakes of total, n-3, and n-6 PUFA appear to be suboptimal in this sample of preschool-aged children participating in the GFHS. Future research should explore fatty acid intake among larger and more racially and socioeconomically diverse samples of children. These findings suggest a need to develop interventions to improve the consumption of healthy fats among Canadian children.


We would like to thank the Study Coordinator, Angela Annis, for her work collecting and organizing the data for this study.


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Information & Authors


Published In

cover image Applied Physiology, Nutrition, and Metabolism
Applied Physiology, Nutrition, and Metabolism
Volume 47Number 9September 2022
Pages: 973 - 978


Received: 3 September 2021
Accepted: 26 April 2022
Accepted manuscript online: 1 June 2022
Version of record online: 2 September 2022

Data Availability Statement

The GFHS welcomes outside collaborators and interested investigators can contact GFHS investigators to explore this option, which preserves participant confidentiality and meets the requirements of our Research Ethics Board, to protect human subjects. Due to Research Ethics Board restrictions and participant confidentiality, we do not make participant data publicly available.

Key Words

  1. polyunsaturated fatty acids (PUFA)
  2. n-3 polyunsaturated fatty acids (n-3 PUFA)
  3. n-6 polyunsaturated fatty acids (n-6 PUFA)
  4. alpha-linolenic acid (ALA)
  5. linoleic acid (LA)
  6. eicosapentaenoic acid (EPA)
  7. docosahexaenoic acid (DHA)
  8. arachidonic acid (AA)


  1. acides gras polyinsaturés (« PUFA »)
  2. acides gras polyinsaturés n-3 (« PUFA n-3 »)
  3. acides gras polyinsaturés n-6 (« PUFA n-6 »)
  4. acide alpha-linolénique (« ALA »)
  5. acide linoléique (« LA »)
  6. acide eicosapentaénoïque (« EPA »)
  7. acide docosahexaénoïque (« DHA »)
  8. acide arachidonique (« AA »)



Jessie L. Burns
Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
Julia A. Mirotta
Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
Alison M. Duncan
Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
Gerarda Darlington
Department of Mathematics and Statistics, University of Guelph, Guelph, ON, Canada
Jess Haines
Department of Family Relations and Applied Nutrition, University of Guelph, Guelph, ON, Canada
Nitin Shivappa
Cancer Prevention and Control Program and Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA
James R. Hébert
Cancer Prevention and Control Program and Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA
Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
The Guelph Family Health Study
University of Guelph, Guelph, ON, Canada

Author Contributions

JLB: analyzed the data and wrote the manuscript
JAM: analyzed the data and contributed to the review of the manuscript
AMD: designed the research and contributed to the review of the manuscript
GD: provided statistical support and contributed to the review of the manuscript
NS: contributed to the review of the manuscript
JRH: contributed to the review of the manuscript
JH: designed the research and contributed to the review of the manuscript
DWLM: designed the research, contributed to the writing of the manuscript, and had primary responsibility for the final content.
All authors have read and approved the final manuscript.

Competing Interests

The authors have declared that no competing interests exist.

Funding Information

This work was supported by the Health for Life Initiative at the University of Guelph and by the Graduate Tuition Scholarship from the University of Guelph to Jessie L. Burns.

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