A growing body of research suggests that getting enough omega-3 fatty acids during pregnancy and early life can impact the development of asthma in children. The connection between omega-3 fatty acids and asthma has been studied more in recent decades, driven by a rapid increase in this disease and the role that omega-3s play in conditions underpinned by inflammation.
But first, what is asthma and why is it so dangerous for children in particular?
The incidence of asthma has more than doubled over the last several decades. The National Heart, Lung & Blood institute says of the 25 million people diagnosed with asthma, 7 million of them are children. Childhood asthma is a very serious health issue for families, especially since there is no cure. The only hope families have is managing the symptoms. Unfortunately, in some cases, asthma can be fatal.
The financial toll of asthma is also a major concern. A report put together by the Centers for Disease Control and Prevention (CDC) in collaboration with other research partners attempted to size the economic burden of asthma in the US. It showed that for the period 2008-2013, the total cost of asthma in the US was almost $82 billion. Per person, medical costs for asthma came out to about $3300 a year, half of which went to prescription medicines.
According to the American Academy of Asthma, Allergy & Immunology (AAAA&I), childhood asthma (pediatric asthma) is the most common serious chronic disease in infants and children; yet is often difficult to diagnose. It is very important to get the symptoms of asthma under control because if left unmanaged it can cause severe damage to the lungs.
The problem is sometimes asthma doesn’t even rear its ugly head in children until their first “attack.” And even then, if they are considerably young, they might not be able to explain their symptoms. In addition, most children will not be able to do a lung function test, so many pediatricians will try short-term stints on medicines and limiting exposure to “triggers” first to see if that helps.
The National Lung Association describes asthma as a condition where your airways become swollen and inflamed. Because of this, the lungs become sensitive and can be set off by triggers such as smoke, chemicals, pet dander, dust or pollen.
When this happens, the trigger can cause the lungs to swell even more, which will narrow the airways considerably and make it hard for you to breathe. As the muscles around your lungs tighten, what’s called an “attack” or “flare up” can occur. What makes asthma particularly alarming for children vs. adults is that children have much smaller airways to begin with, which makes it more dangerous for them.
Asthma is typically treated in two ways – with quick-relief medicines to stop symptoms as well as with long-term medicines that prevent symptoms.
Some of the common symptoms include:
- Wheezing (whistling sound) when breathing
- Rapid breathing
- Labored breathing
- Complaints of chest hurting
- Reduced energy
- Feeling weak or tired
Risk factors for developing childhood asthma include:
- Family history of allergies and/or asthma
- Frequent respiratory infections
- Low birth weight
- Second-hand smoke before and/or after birth
- Growing up in a low income, urban environment
The good news is most people who live with asthma today are able to get the condition under control with a variety of tactics and medicines, allowing them to live a full, active life. But what if you could prevent asthma in the first place? That is what recent omega-3 research has been trying to find out – if getting enough of these fatty acids in the womb and early in life can impact your likelihood of getting the disease during childhood.
How Omega-3s Can Help Asthma
Omega-3 fatty acids and asthma has been a focus of recent research. Some of these studies evaluated the omega-3 intake of pregnant women, while others looked at omega-3 intake in children. In all cases, it was concluded that getting enough omega-3s seems to have a preventive or controlling effect on asthma.
In one study, published in August 2018 in the Journal of Allergy and Clinical Immunology: In Practice, researchers investigated the association between omega-3s and allergic disease in 3-year-olds.
The children in the study were part of a vitamin D trial, which studied pregnant women and their offspring to see if there were any preventive effects of the vitamin on asthma.
When these children turned 3, their parents were asked what foods and how much of those foods these children ate. Meanwhile, their parents provided blood samples to establish omega-3 status alongside markers of allergy (total IgE and serum-specific IgE to common allergens).
Last but not least, parents were asked every three months until children were 3 years old about wheezing episodes, asthma medication use, and whether their child had been diagnosed with asthma by a health care provider.
As it turned out, children who had higher levels of omega-3s were less likely to have asthma or recurrent wheeze at 3 years old. Interestingly, this pattern held regardless of whether omega-3s were measured based on dietary intake or blood levels, and after the researchers adjusted for an array of possible confounding variables. Similarly, blood levels of omega-3s were associated with lower blood markers of allergy.
“However, the link between higher omega-3s and less asthma/wheeze was strongest in children who had higher levels of vitamin D at birth, suggesting possible synergy between these two nutrients,” researchers said, cautioning, “Studies following children over time and larger randomized trials are needed to further evaluate this safe and inexpensive potential treatment for childhood asthma and allergies.”
Another study, published in the New England Journal of Medicine in 2016, suggested that a reduced intake of omega-3s may be a contributing factor to the increasing prevalence of wheezing disorders. Researchers assessed the effect of supplementation with omega-3s in pregnant women on the risk of persistent wheeze and asthma in their offspring.
Pregnant women (736) entering their third trimester were given either 2.4 grams of omega-3s EPA and DHA as a fish oil supplement or an olive oil placebo. The children in this study eventually became part of the Copenhagen Prospective Studies on Asthma in Childhood2010 (COPSAC2010) cohort and were followed prospectively.
A total of 695 children were included in this trial, and 95.5% completed the 3-year, double-blind follow-up period. The risk of persistent wheeze or asthma in the treatment group was 17%, versus 24% in the control group, corresponding to a relative reduction of 31%.
A recent study compared omega-3 and 6 and the role they play in childhood asthma, which led researchers to conclude that they might have opposite effects on this chronic disease. The study, published online March 29th in American Journal of Respiratory and Critical Care Medicine, suggests that families and health care providers may be able to protect children from harmful effects of indoor air pollution by having them eat more foods rich in omega-3 fatty acids, such as salmon, and reducing foods rich in omega-6 fatty acids, such as soybean oil and corn oil in their diet.
Ultimately, researchers believe, policy changes in school lunches could play a role in providing these nutrients in diets.
This six-month study of 135 children from Baltimore City by Johns Hopkins Medicine researchers showed that having more omega-3 fatty acids in the diet results in fewer asthma symptoms triggered by indoor air pollution. They also found that higher amounts of dietary omega-6 fatty acids may have the opposite effect, and be associated with more severe asthma.
“Our group is working on ways to reduce the levels of indoor air pollution in Baltimore City homes,” said Emily Brigham, M.D., M.H.S, lead study author and assistant professor of medicine at the Johns Hopkins University School of Medicine. “Results are promising, but we don’t want to stop there.”
Indoor air pollution, from sources including cooking, cleaning activities (i.e., sweeping) and cigarette smoke, is a known trigger for asthma symptoms. Earlier work by the research group demonstrated that levels of indoor air pollution, specifically particles in the air in homes in Baltimore City, often exceed acceptable standards for outdoor air quality as set by the United States Environmental Protection Agency (EPA).
Brigham notes there is mounting evidence that diet, particularly omega-3 and omega-6 fatty acid levels, may play a role in lung health by changing how the body responds to and processes inflammation. Because children with asthma are already prone to inflammation and respiratory symptoms, the researchers hypothesized that omega-3 and omega-6 intake might be related to asthma severity, and how children responded to the air pollution in their homes.
The children in this study were between 5 and 12 years old. Roughly a third of the children had mild, a third moderate, and a third severe asthma. Diet, asthma symptoms (recorded daily) and inhaler use (also recorded daily) were reported by the participants and caregivers in surveys for one week each at enrollment, and again at three and six months. Researchers also collected blood samples to assess for changes in markers of inflammation each time participants filled out the surveys.
For each additional gram of omega-6 intake, children had 29% higher odds of being in a more severe asthma category. Further, more omega-6 in the diet was also associated with higher percentages of a type of white blood cell linked with inflammation, neutrophils, in response to pollution.
Conversely, with each 100 mg increase in levels of omega-3 fatty acids in the diet reported on the survey, researchers saw 3-4% lower odds of daytime asthma symptoms. Essentially, children who ate more omega-3 were less likely to have symptoms even at the same level of air pollution exposure.
The researchers say that many children in the U.S., including those in Baltimore City, where they conducted the research, consume a diet that deviates sharply from national guidelines. The diet consists of low amounts of omega-3-rich foods, and higher amounts of omega-6-rich foods, consistent with a typical American diet.
The researchers recognize and acknowledge that many places where low-income people live are food deserts that lack access to healthy options, and that foods rich in omega-3s may be more expensive. If diet proves to directly impact asthma health, eliminating these barriers will be a key step in reducing health inequalities and in combating asthma disparities in Baltimore City and elsewhere. Brigham says, “Among populations known to be disproportionately affected by asthma, we may find that improving diet and air pollution together has the greatest impact on health.”