By: Rachel Neifeld, RD, CDE, CDN

Pregnant women may be able to influence their child’s risk of being born with autism- an increasingly prevalent neurological disorder that severely impairs social, communicative and cognitive functions. The number of children with Autism Spectrum Disorder is climbing every year, with 1 in 88 children diagnosed with the disorder in the United States in 2012. Though studies aren’t conclusive, researchers at the Harvard School for Public Health found that the types of fat a woman consumes during pregnancy may influence her child’s risk of being born with Autism Spectrum Disorder.

Women in the study who consumed more linoleic acid - a type of omega-6 fatty acid found in vegetable oils, nuts, and seeds - were 34 percent less likely to birth a child with autism, while women who consumed low levels of omega-3 fatty acids - those found in fish - were 53 percent more likely to give birth to an autistic child. Once a certain level of omega-3 intake was reached, the risk of autism risk was no further reduced- so getting enough is important but more isn’t necessarily better.

The study suggests that by increasing polyunsaturated fats in pregnant women’s diets, which include both linoleic (omega 6) and linolenic (omega 3) fatty acids, the risk of a child having Autism Spectrum Disorder is decreased. Though the study needs to be replicated and the results don’t prove cause and effect, eating these types of fats while reducing the intake of saturated and trans fats is recommended regardless of their effects on autism.

For example, studies have shown the higher a woman's intake of trans fats (chemically produced fats found in foods such as french fries and donuts) during the second trimester of pregnancy, the larger her newborn. This could lead to a larger birth weight baby who may need to be delivered by C-section- a surgery that puts both mother and baby at higher risk of pregnancy complications when compared to having a vaginal delivery. Larger birth weight babies are also at increased risk of developing diabetes and heart disease later in life. Another study published in the Journal of Clinical Endocrinology and Metabolism found a connection between higher levels of omega 3 fatty acids in a mother’s plasma corresponding with lower fat mass and higher muscle mass in offspring.

Even if these additional studies don’t prove direct cause and effect, we know that consuming more unsaturated than saturated and trans fats in our diets can reduce the risk of heart disease and type 2 diabetes, as well as many other chronic diseases - so this eating style should be practiced by women throughout their lives to obtain the numerous associated health benefits.

Most women consume enough omega 6’s by eating seeds, nuts, and the oils extracted from them, as well as the refined vegetable oils such as soy oil that is used in many processed foods in the typical American diet. The key is to increase intake of unsaturated fats without increasing total fat and calorie intake by replacing them for, not eating them in addition to, saturated fats and refined carbohydrates. Examples of how to do this include switching from butter on bread to a plant-based buttery spread that contains mostly unsaturated fats such as Smart Balance, or dipping bread in olive oil instead of using butter. However, be sure to keep it to a tablespoon in order to control calories. Instead of spreading butter or cream cheese on a bagel, try natural nut butter such as almond, cashew or peanut butter. Try adding more nuts such as almonds or walnuts to yogurt rather than granola.

To get omega 3 fatty acids, a woman’s best bet is to consume cold water fish, such as salmon, herring, sardines and anchovies two to three times a week. Walnuts, flax seeds, and avocados are sources of omega-3’s as well but they provide only ALA (alpha-linolenic acid), a precursor form that the body cannot convert efficiently to the essential DHA and EPA. Therefore, taking a supplement is a good idea both before and during pregnancy if a woman doesn’t include many sources of omega-3 fatty acids in her diet.  A supplement should contain at least 300 mg of DHA, and should not smell or taste fishy as this is a sign that it may be rancid. If the recommended 12 oz of low mercury fish is consumed each week, it isn’t necessary to take an additional supplement. As with most everything else, when it comes to omega-3 fatty acids during pregnancy, more of a good thing is not always better, as the Harvard School for Public Health’s study suggests.