Role of Dietary Long-Chain Polyunsaturated Fatty Acids in Infant Allergies and Respiratory Diseases

Table 1

Summary of studies on the effects of dietary PUFAs supplementation on allergic and respiratory diseases.

Study	Design		Subjects		Type of supplementation		Effects on
		Types	age (months)	𝑛=		Allergy	respiratory infections	Others
Morales et al., 2011 [47]	Cohort	Infants	0–14	580	Predominantly breastfed for 4–6 months	Protection against allergic manifestations—wheezing (adjOR = 0.53, 95% CI 0.32–0.89) and atopic eczema; (adjOR = 0.58; 95% CI 0.32–1.04) between 7 and 14 months.	Significantly lower risk of lower respiratory tract infection (LRTIs) between 7 and 14 months; (adjOR = 0.51, 95% CI 0.31–0.83) and for recurrent LRTIs (adjusted OR = 0.48, 95% CI 0.24–0.96).	(1) Reduced risk of gastroenteritis (GE) during first 6 months and recurrent GE; (2) Exposure to higher doses of AA, DHA, and total 𝑛-3 associated with reduced risk of GE.
Manley et al., 2011 [48]	Randomized controlled trial	Preterm infants less than 33 weeks gestation	0–18	657	Breast milk from mothers taking either tuna oil (high-DHA diet) or soy oil (standard-DHA) capsules	(1) Reduction in reported hay fever in all infants in the high-DHA group at either 12 or 18 months (relative risk RR = 0.41, 95% CI 0.18–0.91; 𝑃=0.03) in boys (RR = 0.15, 95% CI 0.03–0.64; 𝑃=0.01); (2) No effect on asthma, eczema, or food allergy	Reduction in bronchopulmonary dysplasia in boys; (RR = 0.67, 95% CI 0.47–0.96; 𝑃=0.03) and in all infants with a birth weight of less than 1250 grams (RR = 0.75, 95% CI 0.57–0.98; 𝑃=0.04)	No effect on duration of respiratory support, admission length, or home oxygen requirement
Sampath and Ntambi 2005 [44]	Randomized controlled trial	Children	0–36	89	DHA/AA supplemented formula (𝑛=38) versus nonsupplemented (𝑛=51) during the first year of life	DHA/AA group had significantly lower odds of having wheezing/asthma (OR = 0.31, 95% CI 0.10–0.90; 𝑃=0.03), wheezing/asthma/AD (OR = 0.29; 95% CI 0.12–0.72; 𝑃=0.008), or any allergy (OR = 0.30; 95% CI 0.12–0.73; 𝑃=0.008) during the first 3 years of life compared with the control group	(1) DHA/AA group had significantly lesser episodes of upper respiratory infections (OR = 0.32; 95% CI 0.14–0.75; 𝑃=0.008); (2) In addition, there was a tendency towards a lower number of episodes of combined nonallergic respiratory illnesses in the DHA/AA group (𝑃=0.06)	—
Grimm et al. 2002 [46]	Randomized controlled trial	Children	18–36	86	1st group—DHA 0 mg (𝑛=28); 2nd group—DHA 43 mg (𝑛=29); 3rd group—DHA 130 mg (𝑛=29)	—	Difference in respiratory illnesses detected between the groups (DHA-0 mg: 𝑛=13, 46%; DHA-43 mg: 𝑛=12, 41%; DHA-130 mg: 𝑛=5, 17%; 𝑃=0.039) with number of participants with events significantly lower in the DHA-130 mg versus DHA-0 mg group (𝑃=0.024)	Subjects consuming DHA-130 mg had significantly fewer adverse events than those consuming DHA-0 mg (𝑃=0.007)
Valledor and Ricote 2004 [45]	Randomized controlled trial	Healthy, nonbreastfed infants more than 36 weeks gestation	0–12	1342	DHA supplemented formula (𝑛=1094) and control group (𝑛=248)	—	(1) Significantly higher incidence of bronchiolitis/bronchitis observed in the control group compared to the DHA group at 5 months (13.9% versus 6.1%, 𝑃=0.0001), 7 months (10.8% versus 5.1%, 𝑃=0.01), and 9 months (11.3% versus 5.8%, 𝑃=0.01); (2) Significantly higher occurrence of rhinitis at 1 month for the control group compared with the DHA group (6.7% versus 3.0%, 𝑃=0.005); (3) Higher incidence of upper airway infection in the control group versus the DHA group at 1 month (12.1% versus 6.6%, 𝑃=0.05) and 12 months (24.2% versus 16.2%, 𝑃=0.01)	—