Prominent pediatrician and author Dr. William Sears says the lack of omega-3 fatty acids in the diets of American children is "one of the biggest problems facing American children today."

Research has shown that omega-3 fatty acids are essential for kids’ brain development. These "good" fats are also believed to help with mood disorders, improve eyesight and help support immune health, joint health and mobility.

The best sources for omega-3 fatty acids are oily fish (like salmon), walnuts, flax seeds, pumpkin seeds, canola oil and soy. But many parents say they have a hard time getting their children to eat these foods, or are wary of feeding their kids too much fish for fears of other environmental contaminants.

Other sources include omega-3 eggs and grass-fed beef, which is often higher in the fats than regular beef.

Fish oil supplements can be a good option, but some children may have a hard time swallowing large capsules. Some experts encourage parents to break the capsules open and drizzle the contents into oatmeal, juice, yogurt and smoothies.