Salmon in Pregnancy Study (SiPS)

November 27, 2014 updated by: University Hospital Southampton NHS Foundation Trust

The Effects of Oily Fish in Pregnancy on Markers and Manifestations of Allergic Diseases in Infants at Risk of Atopy

The number of infants and children with allergic disease (dermatitis, allergies, asthma) has increased over the last several decades. This may be related to changes in diet. It is now thought that children become sensitised to allergens very early in life maybe even before they are born. Some studies show that a high omega-3 fat intake by mothers decreases risk of sensitisation in their babies. There is a biological mechanism to explain this. Omega-3 fats are found in oily fish like salmon. In the UK pregnant women are recommended to eat oily fish twice per week. However, consumption of oily fish is known to be low in pregnant women in the UK. This study sets out to identify the effects of increasing salmon intake in pregnant women. The hypothesis being investigated is that : increased consumption of oily fish during pregnancy by women at risk of having offspring who will develop atopy will increase their omega-3 fat and antioxidant status and that of their developing baby and will ameliorate the development of atopic markers and manifestations in the infants.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The prevalence of childhood atopic diseases (eczema, rhinitis [hay-fever], asthma, allergies) has increased dramatically over the last 30 years or so. This must be due to environmental changes. Dietary change is believed to be an important causative factor and three diet related hypotheses have been proposed. The first of these ("the PUFA hypothesis") is that the increase in intake of n-6 polyunsaturated fatty acids (PUFA) over the last 30 years has resulted in an absolute and relative decline in intake of n-3 PUFA, especially long chain n-3 PUFA. There is a plausible biological mechanism whereby a high n-6 to n-3 PUFA ratio would skew the immune system to favour sensitisation to allergens. The second diet hypothesis ("the antioxidant hypothesis") is that there is a lower status of antioxidant vitamins and minerals than 30 years ago and that the resulting increased oxidant stress skews the immune system to favour sensitisation to allergens. The third diet hypothesis ("the gut microflora hypothesis") is that the maturing microflora within the intestinal tract of the neonate plays a role in development of atopy through interactions with the gut immune system. Factors that influence development of neonatal gut microflora include maternal gut microflora and infant diet (e.g. breast milk composition). Since maternal diet will affect maternal gut microflora and also breast milk composition a link is suggested between modification of the maternal diet in pregnancy and development of atopy in the infant through an effect on gut microflora.

It is now recognised that sensitisation to the allergens that trigger atopic disease occurs early in life, and in many cases in utero [4]. Thus, it is most likely maternal diet during pregnancy that is important in influencing risk of atopic disease in children. There is much evidence that n-3 PUFA status is lower in plasma, erythrocytes, white cells and milk of mothers of atopic children and also in umbilical cord plasma and erythrocytes [5]. Likewise, the status of some antioxidant minerals (e.g. Se) in cord blood has been reported to be lower in children who went on to develop atopic disease than in those who did not. Finally, atopic infants have a different gut microflora than non-atopic infants. These studies suggest that maternal status of n-3 PUFA and antioxidants, and possible of certain gut microbes, is important in determining atopic outcome in children. Not surprisingly therefore, there is substantial interest in supplementation studies in pregnant women, particularly those whose babies are at risk of atopic disease (e.g. from a family history). Fish, especially oily fish like salmon, and fish oil are very good sources of long chain n-3 PUFA. A recent study investigating the effect of fish oil supplementation in pregnant women reported an alteration in the cytokine profile of umbilical cord plasma that is consistent with protection towards atopy. The study went on to demonstrate a reduced severity of atopic dermatitis and a decreased likelihood of skin-prick positivity to a variety of common allergens in the children at one year of age. Oily fish represent a unique opportunity to reduce atopy risk because they are rich sources of both n-3 PUFA and antioxidant minerals (Se). They represent a more attractive option than supplementation with fish oil capsules. Pregnant women have a low intake of fish. Current UK recommendations are that "women of reproductive age should aim to consume within the range of one to two portions of oily fish a week". The upper limit of this range is below that for the recommendations made for boys, men and women not of reproductive age. This is because of concern about contaminants in some species of oily fish (e.g. tuna). Aquaculture producing salmon with low contaminant levels is therefore an ideal solution to enable oily fish consumption by pregnant women. Consumption of tailor-made salmon by pregnant women could prevent the development of atopic disease in their children. It is important that this be assessed through a well-designed and rigorous intervention study relating maternal oily fish consumption to atopic disease in the offspring, at the same time assessing effects of maternal fish consumption on fetal growth and maternal and fetal body composition.

Hypothesis:

Increased consumption of oily fish during pregnancy by women at risk of having offspring who will develop atopy will increase their n-3 PUFA and antioxidant status and that of their developing baby and will ameliorate the development of atopic markers and manifestations in the infants.

Objectives:

  1. To conduct a dietary intervention study in pregnant women using long chain n-3 PUFA-rich salmon.
  2. To determine the effects of increased consumption of oily fish during pregnancy on fetal growth and adaptations and on maternal and fetal body composition.
  3. To determine the effects of increased consumption of oily fish during pregnancy on maternal and fetal (i.e. cord blood) nutrient status
  4. To determine the effects of increased consumption of oily fish during pregnancy on maternal and fetal (i.e. cord blood) immune status
  5. To determine the effects of increased consumption of oily fish during pregnancy on predictors of atopic disease in cord blood, and on the development of atopic disease in infancy.

Study Type

Interventional

Enrollment (Actual)

124

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United Kingdom
      • Southampton, United Kingdom, SO16 6YD
        • University of Southampton

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 40 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  1. Pregnant women before 19 weeks gestation, with healthy uncomplicated singleton pregnancies, but whose babies are at risk of atopy (i.e. one or more first degree relatives affected).
  2. Not habitual consumers of oily fish (< 2 portions of oily fish per month excluding tinned tuna).
  3. Not using fish oil supplements (currently or in the last 3 months)
  4. Age 18-40 y.

Exclusion Criteria:

  1. Habitual consumer of oily fish (> 2 portions of oily fish per month excluding tinned tuna).
  2. Use of fish oil supplements within the previous 3 months.
  3. Not willing for essential identifiable information being stored for tracking purposes.
  4. Participation in another research study.
  5. Known diabetic and/or other auto-immune disease, e.g. SLE, MS, Thyroid Disease.
  6. Adults with learning disabilities.
  7. Adults who have a terminal illness.
  8. Adults with mental health problems.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Control
No change in diet
Other: Control
No change to habitual diet from week 20 of pregnancy until giving birth
Active Comparator: Oily fish
Two portions of salmon per week from week 20 of pregnancy until giving birth
Dietary supplement: Oily fish consumption
Two portions of salmon per week from week 20 of pregnancy until giving birth

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Omega-3 fatty acid status in maternal and umbilical cord plasma
Time Frame: Weeks 20, 34 and 38 of pregnancy and at birth (in cord)
Weeks 20, 34 and 38 of pregnancy and at birth (in cord)

Secondary Outcome Measures

Outcome Measure
Time Frame
Antioxidant status in maternal and umbilical cord blood
Time Frame: Weeks 20, 34 and 38 of pregnancy and at birth (in cord)
Weeks 20, 34 and 38 of pregnancy and at birth (in cord)
Allergic sensitisation of infants
Time Frame: 6 months of age
6 months of age

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University Hospital Southampton NHS Foundation Trust

Collaborators

University of Southampton

Investigators

  • Principal Investigator: Philip C Calder, PhD, University of Southampton

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

May 1, 2007

Primary Completion (Actual)

August 1, 2009

Study Completion (Actual)

March 1, 2012

Study Registration Dates

First Submitted

December 2, 2008

First Submitted That Met QC Criteria

December 2, 2008

First Posted (Estimate)

December 3, 2008

Study Record Updates

Last Update Posted (Estimate)

December 2, 2014

Last Update Submitted That Met QC Criteria

November 27, 2014

Last Verified

December 1, 2008

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RHMNUT0044

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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