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Researchers investigated whether taking prenatal DHA, a fish oil fatty acid, was able to prevent high blood pressure in children.
Childhood obesity is a growing problem all around the world. Obesity in children is a major health concern as it is often accompanied by various other illnesses such as insulin resistance, type 2 diabetes, non-alcoholic fatty liver disease, high blood pressure, high cholesterol and cardiovascular disease. These related risk factors are often grouped together into a single condition called the metabolic syndrome.
As the name suggests, metabolic syndrome indicates there is a problem with a person’s metabolism or how they process and store the energy we get from food. The exact cause for the metabolic syndrome is unknown and this is an area undergoing intense research.
Preventing childhood obesity takes more than just healthy food and exercise
It seems that childhood obesity is preventable with improvements to lifestyle such as increasing healthy food intake and physical activity. Although this advice is a great place to start, it does make it sound as if overeating were the only cause for obesity and that is an oversimplification.
Genetics has a crucial role in how our bodies process and respond to nutrients. The foundation for how our genes and therefore our bodies respond to food is laid during pregnancy. Developmental programming is a term used to describe how environmental factors that affect gene expression in a fetus can cause permanent changes to a child’s physiology.
Nutrients consumed during pregnancy has profound effects on children’s metabolism
The quality and quantity of nutrients consumed during pregnancy can have a profound effect on the risk factors associated with coronary disease and the metabolic syndrome of children. A good example of how a mother’s nutritional intake can affect her developing child is folic acid, which is a type of vitamin B. Taking folic acid or folate during pregnancy reduces the risk of a baby being born with neural tube defects, such as injuries to the spinal cord, skull and brain.
Can other supplements help prevent the risk of childhood obesity and other aspects of the metabolic syndrome?
There are numerous supplements on the market to help with various aspects of pregnancy. One compelling nutrient is a long chain fatty acid found in fish oil called docosahexaenoic acid (DHA).
Prenatal DHA is often prescribed because it reduces the risk of premature labor. DHA is also present in breast milk and is important for the development of the brain and retina within infants. What makes this fatty acid particularly interesting in the context of the metabolic syndrome is that it has been shown to prevent high blood pressure in adults. DHA is also associated with a reduction in cardiovascular disease by acting as an anti-coagulant, anti-inflammatory and it inhibits plaque buildup on vessel walls (atherosclerosis).
Can taking prenatal DHA during pregnancy prevent childhood high blood pressure?
In a recent study published in JAMA Network Open, researchers in Kansas wanted to know if taking prenatal DHA would be associated with a reduction in blood pressure in children. This phase-3, double-blinded, randomized clinical trial followed 190 pregnant women and their children for a period of 6 years. The women participating in the trial were split into two groups those that received 600 mg of prenatal DHA per day and a control group which received a placebo.
The study was originally designed to determine what effect prenatal DHA had on cognitive development in the children but had a secondary outcome to measure the effect of the supplements on childhood blood pressure. The diastolic and systolic blood pressure measurements for the children in each group, placebo or DHA treated mothers, were taken every six months along with weight and height.
The results showed that children who were overweight or obese and whose mothers had taken prenatal DHA had slightly lower blood pressure than then overweight children whose mothers were part of the placebo group. This was the case for both systolic (maximum pressure during a heartbeat) and diastolic (maximum pressure between heartbeats) blood pressure.
The blood pressure measurements presented were for children who were five years old. There was no significant difference between the two groups in children with normal weight. It is also interesting to note that a student within this research group has published a masters dissertation on the same study showing no significant difference in blood pressure between children in the placebo and prenatal DHA treatment group when they reached the age of seven and eight irrespective of the child’s weight.
Conflict of interests in the study
Both principal investigators on this study have admitted to a conflict of interests. Dr. Colombo received “non-financial support from DSM Nutritional Products outside of the submitted work”, while Dr. Carlson received “grants and other research support from DSM”. This was the same company that provided the placebo and DHA capsules for the clinical trial. The study would, therefore, benefit from additional verification from unbiased parties.
Should you include fish oil in your diet?
While it may be possible that taking prenatal DHA supplements during pregnancy may prevent high blood pressure in children who are obese, these findings require additional validation. DHA has been shown to have numerous other benefits during and after pregnancy so including fish oil in your diet or taking the supplements is still recommended by practitioners.
Written by Tarryn Bourhill MSc, PhD Candidate
- 1 Kerling, E. H. et al. Effect of Prenatal Docosahexaenoic Acid Supplementation on Blood Pressure in Children With Overweight Condition or Obesity: A Secondary Analysis of a Randomized Clinical Trial. JAMA network open 2, e190088-e190088 (2019).
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- Smithells, R. et al. Possible prevention of neural-tube defects by periconceptional vitamin supplementation. The Lancet 315, 339-340 (1980).
- Lynch, B. M. Clinical trial: Prenatal DHA prevents blood-pressure increase from obesity during childhood <https://www.eurekalert.org/pub_releases/2019-02/uok-ctp021919.php> (2019).
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