Optimizing Omega-3 and Vitamin D During Pregnancy May Reduce Asthma in Your Child

optimizing vitamin d during pregnancy

Story at-a-glance -

  • Omega-3 — an essential fatty acid your body cannot make and must be obtained from food — is found in fish. Unfortunately, many species are contaminated with environmental toxins, so care in selection is important
  • Recent research demonstrates supplementation with omega-3 fatty acids in the last trimester of pregnancy may reduce the incidence of asthma and wheezing in children
  • Not all omega-3 supplements are created equally; krill oil is your best option as it is less likely to be contaminated with toxins and naturally contains phospholipids that maintain the integrity of the product

By Dr. Mercola

Omega-3 fats are essential as your body cannot make them. The only way to get them is through your food. They are important to energy storage, cell membrane function, regulation of inflammation and oxygen transport.

They are also important to the development of your baby in utero, especially eye and brain development.

Research continues to support the need for a balance of omega-3 and omega-6 fats. Omega-3s are found primarily in fish, while omega-6s are acquired from vegetable and seed oils — staples in a standard Western diet.

The ideal ratio is 1-to-1, but eating processed foods ensures you get far more omega-6 than omega-3. Animal studies have demonstrated that a lopsided ratio, common if you don't avoid processed foods and vegetable oils, can have significant health consequences.1

A recent study has also linked low levels of marine-based omega-3 fats during pregnancy with an increased risk of children developing asthma symptoms by the time they are 5.

After birth, a woman's body uses omega-3 fats to make breast milk. Generally, with each subsequent pregnancy, a woman's body becomes even further depleted in omega-3s.2

Children Develop Less Asthma When Women Supplement With Omega-3

A recent study published in The New England Journal of Medicine evaluated the results of 695 pregnant women after taking either fish oil or olive oil supplements in the last trimester of their pregnancy.3 The researchers then followed the health of the babies for the first five years of their life.

Seventeen percent of the children whose mothers took the fish oil developed asthma or persistent wheezing by the age of 5. This was a 30 percent reduction, compared to the 24 percent of the children whose mother took olive oil.4

Dr. Hans Bisgaard, lead author of the study, commented that the biggest benefit appeared to be in children born to women who had low levels of omega-3 at the outset of the study.5

Specifically, women with low levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) had children with higher risk of developing asthma.

The researchers theorized the low levels of EPA and DHA made the developing children more vulnerable to inflammation and a sensitive immune system reaction, both a factor in the development of asthma.6

However, supplementation during the third trimester did not reduce the children's risk of eczema, allergy or a severe asthma reaction.7 Low levels of EPA and DHA may be related to diet but can also be the result of a genetic variant.8 Approximately 13 percent of people in the study had that variant.

Bisgaard commented that until further studies have confirmed these results, testing blood for blood fatty acid levels and for the genetic variant could differentiate the populations of pregnant women who would benefit most from supplementation.

Omega-3 Requirements Increase During Pregnancy

There is no set recommended standard dose of omega-3 fats, but some health organizations recommend a daily dose of 250 to 500 milligrams (mg) of EPA and DHA for healthy adults.

If you're pregnant or breastfeeding, your body will likely require additional omega-3. The American Dietetic Association and Dietitians of Canada recommend pregnant and lactating women (along with all adults) consume at least 500 mg of omega-3s, including EPA and DHA, daily.

The European Commission recommends pregnant and lactating women consume a minimum of 200 mg of DHA, in particular, per day.9

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Asthma Has a Significant Public Health Impact

Although the featured study benefited women with the lowest levels of omega-3 the most, the results are an important public health discovery, as asthma has a significant community impact. The prevalence of asthma has risen dramatically in the U.S.10

According to the U.S. Centers for Disease Control and Prevention (CDC), 17.7 million adults and 6.3 million children have asthma.11 The most recently revised global estimates suggest 334 million people in the world have asthma, and the highest growing rates are in low to middle income countries.12

The medical burden in the U.S. is significant. The CDC reports 1.8 million emergency room visits, 10.5 million doctor's office visits and 1.3 million outpatient visits in 2011 were related to asthma.13

The percentage of adults and children who had asthma and reported having one or more asthma attacks in the past year was 44.7 percent. 14

More children with asthma than without were covered by Medicaid in 2014.15 Arizona had the highest rate of asthma persistent severity in children, and Alabama had the highest rate in adults.

Unfortunately, while asthma is a long-term chronic condition, it can end in death for adults and children alike. According to the CDC, there were slightly over 3,500 deaths in 2014 attributed to asthma in children and adults combined.16 However, when separated, the number of mortalities in children amounted to less than 200.

While severe asthma attacks can increase your risk of death, asthma also triggers permanent damage to your lung tissue, increasing your risk of further health problems.

Doctors used to believe lung tissue returned to normal after an asthma attack, but today understand that your lungs change and remodel in response to inflammation during an attack.17

More Health Benefits of Animal-Based Omega-3 Fats

Researchers attribute a number of health benefits to omega-3 fats. Your cardiovascular health is a major beneficiary of omega-3 fats, including lowering your blood pressure, improving endothelial function (a major factor in the promotion of new blood vessels) and reducing triglyceride concentration. Science demonstrates omega-3s are:

  • Antiarrhythmic: counteracting or preventing cardiac arrhythmia
  • Antithrombotic: reducing your risk for thrombosis (blood clot within a blood vessel)
  • Antiatherosclerotic: preventing the formation of fatty deposits and fibrosis on the inner layer of your arteries
  • Anti-inflammatory: counteracting the inflammatory response in your body

Other health benefits of omega-3 fats include the following:

As they reduce the inflammatory response in your body, omega-3s can be helpful for those suffering with rheumatoid arthritis, reducing stiffness and pain.18

They help your body build healthy muscle mass, including people suffering from cancer who may experience cachexia.19

In one study involving patients with advanced malignancy, those taking fish oil were able to gain weight.

The length of time patients took the supplement was also a factor; the longer they took it, the better the results.

Omega-3 fats can also help improve your bone strength by improving the utilization of calcium in your body.

This may lead to a reduction in the development of osteoporosis.20

Women who suffer from menstrual pain may also experience milder pain.21,22

Improvements have been demonstrated in metabolic syndrome23 and insulin resistance.24

Reduction of your triglyceride levels may lower your risk for type 2 diabetes and cardiovascular disease.25

Demonstrated benefits have been shown for children with attention deficit hyperactivity disorder (ADHD), including reduced aggression, hyperactivity,26 impulsivity,27 oppositional behavior28 and restlessness.29

Studies have demonstrated benefits of omega-3 in reducing the symptoms of depression, heart disease, Reynaud's and lupus.30

DHA, perhaps the most important component of omega-3, is a major structural element in your eye and brain.31

Reduced risk of Parkinson's disease and Alzheimer's disease is associated with omega-3s.

In patients at high risk for schizophrenia, it may delay progression to psychosis.

Omega-3 is associated with reduced risk of death from ALL causes.

Omega-3 is associated with lowered risk for other neurological/cognitive dysfunction, including: memory loss, brain aging, learning disorders and ADHD,32 autism and dyslexia.33

Reduced risk of kidney disease has been shown with omega-3.34

Omega-3 is associated with reduced risk of Crohn's disease.

Reduced risk of colon cancer is associated with omega-3.35

Low levels of DHA may increase the risk for reduction in processing speed and poor eye hand coordination by age 4,36 age related macular degeneration37 and vascular instability.38

Improved mood regulation may also be a factor with omega-3s.

What Are the Best Sources of Omega-3?

Your optimal health depends upon receiving enough high-quality omega-3 fats from fish, such as wild-caught Alaskan salmon, sardines and anchovies, or by using a high-quality supplement, such as krill oil.

Unfortunately, much of the fish sold is severely contaminated with environmental pollutants, increasing your risk of toxic exposure to chemicals such as mercury. These chemicals are retained in the body of the animal so, generally, the closer to the bottom of the food chain your source of omega-3 fats is, the less contamination will have accumulated.

Although ALA, a helpful form of omega-3 fats, is found in plant-based foods such as chia, flaxseed, walnuts and hemp, your body requires EPA and DHA found in marine-based omega-3 sources to fight physical and mental diseases. If you don't eat a lot of high-quality fish, you can use a krill oil supplement which enjoys a number of different benefits over fish oil.

High-quality krill are harvested from the clean waters of the Antarctic and are a sustainable and earth-friendly source of supplementation, unlike fish oil, which has brought some species of fish to extinction. Krill also naturally contains astaxanthin, a powerful phospholipid that keeps the oil safe from oxidation and improves your ability to absorb the supplement.

A study in the European Journal of Nutrition demonstrated the addition of astaxanthin to fish oil will reduce susceptibility to oxidation and improve the immunomodulatory properties.39 Also, since krill are so small and eat plankton, they don't have the chance to accumulate toxins from the environment before being harvested.


It must be noted that for the majority of those eating the typical American diet, the omega-3 intake is low, and in fact includes around 10 times more dietary omega-6 fats, a very unhealthy and potentially dangerous imbalance.

Vitamin D Also Plays a Role in Prenatal Asthma Prevention

Omega-3 fat is not the only nutrient that may make a difference in your child's risk of breathing problems and asthma after birth. Bisgaard also performed a study using vitamin D supplementation in pregnant women and found a slight improvement in the number of children who developed asthma after birth. Mothers whose vitamin D levels were low and supplemented during pregnancy had children who had a slightly lower risk of developing asthma by the age of 3.40

In the video above, Dr. Max Gomez discusses how low vitamin D levels may also trigger asthma attacks in children and adults. Although Bisgaard's study showed a small reduction in numbers of children who experienced asthma by age 3, the researchers are continuing to follow the children until age 6. One theory is that vitamin D may help reduce the inflammation in the airways caused by asthma.41

Many people in the U.S. are deficient in vitamin D as your body manufacturers it in response to sun exposure. Obesity, living in northern climates and dark skin all predispose you to vitamin D insufficiency. Vitamin D may make your airway and the airways of your unborn child healthier, improving your day-to-day symptoms and decreasing your risk for an asthma attack.42

A number of other studies have linked vitamin D deficiency to a higher risk of childhood asthma, allergic diseases and severe asthma in adults.43 In a recent study of more than 25,000 people, vitamin D insufficiency increased the risk for children being diagnosed with asthma and for adults to experience recent episodes of wheezing.44 Another study is currently underway in which children with asthma are using a daily supplement of vitamin D to determine if it reduces the number of attacks or hospital visits.45

Research published in 2010 also found that asthmatic children with low blood vitamin D levels may have a greater risk of suffering severe asthma attacks. According to this study, vitamin D insufficiency itself was linked to a 50 percent increase in the risk of severe asthma attacks. According to Dr. Ronit Confino-Cohen, a senior lecturer at Meir Medical Center in Kfar Saba, Israel:46

"I think that if a patient has had good treatment for asthma and is still not controlled, maybe he should be checked for his vitamin D levels before adding on more medications. Maybe supplementation would do the job."

Vitamin D — a Simple, Inexpensive Way to Improve Your and Your Child's Health

In the video above, Glen Depke interviews Dr. Carol Wagner, a neonatologist and lead principal investigator for Protect Our Children NOW!, a public health campaign aimed at raising global awareness about the importance of optimal vitamin D levels for women's and children's health. In it, Wagner cites research done by her team showing that 4,000 international units (IUs) of vitamin D3 per day appears to be an ideal amount for pregnant women.

That said, your requirement may be higher or lower depending on your current status, so please make sure you get your vitamin D level tested — ideally before you get pregnant and routinely during pregnancy and breastfeeding — and take whatever amount of vitamin D3 you need to reach and maintain a level of 40 to 60 ng/mL. Certainly, it should be no lower than 40 ng/mL.

I strongly suggest taking this information to heart, and to share it with anyone that might benefit. Optimizing your vitamin D is one of the easiest and least expensive ways to reduce your risk of pregnancy complications and premature birth. It can also significantly reduce your child's risk of chronic health conditions such as asthma and many others.

The vitamin D test you're looking for is called 25(OH)D or 25-hydroxyvitamin D. This is the officially recognized marker of overall D status, and is most strongly associated with overall health. The other vitamin D test available, called 1,25-dihydroxyvitamin D (1,25(OH)D), is not very useful for determining vitamin D sufficiency.

While sunlight is the ideal way to optimize your vitamin D, winter and work prevent more than 90 percent of those reading this article from achieving ideal levels without supplementation. Also remember to optimize your omega-3 intake during pregnancy and breastfeeding. These two nutrients — omega-3 and vitamin D — are among the more important ones for your child's development and long-term health.

+ Sources and References