Eating fish is the best way to incorporate omega-3 fatty acids in your diet (though you can get them from other sources). Omega-3 fatty acids are polyunsaturated fats. Their molecular structure contains more than one double bond, and the 3 refers to where in the structure the double bond occurs.

They're essential fats, which means that your body doesn't naturally produce them - you have to get them from your diet, and/or supplements.

There are four main types of omega-3 fatty acids:

• alpha-linolenic acid (ALA) - found in green, leafy vegetables, chia seeds, flax seeds, walnut and canola oils.
• eicosapentaenoic acid (EPA) - found in oily fish, krill oil, and algae oil.
• docosahexaenoic acid (DHA) - found in oily fish, krill oil, and algae oil.
• eicosatetraeonic acid (ETA) - found in roe oil and green-lipped mussels.

The scientific research on the impact of omega-3 on sleep has mostly focused on children, and it suggests that omega-3 fatty acids may be able to help people sleep better.  With the known benefits of omega-3 on the brain, heart, and other organs, it's not surprising that it would also have a positive impact on sleep.

If you've already decided on supplementing your diet with omega-3 fish oil, my favorite product is from Dr. Tobias. You can find it in most stores but it is usually discounted on Amazon.

A study from the University of Oxford gave 600 mg of DHA for 16 weeks to 362 children, 40% of whom were experiencing sleep issues. The children added 58 minutes of sleep per night to their sleep times, and also had less waking episodes.

The same study included a second component that looked at the blood levels of omega-3 and omega-6 long-chain polyunsaturated fatty acids. They found that higher blood levels of DHA are significantly associated with better sleep, including less bedtime resistance, parasomnias (such as night terrors and sleepwalking), and sleep disturbances.

The lead author, Dr. Paul Montgomery, believes that lower ratios of DHA have been linked with lower levels of melatonin, which plays an important role in sleep.

Omega-3 fatty acid also regulate your levels of norepinephrine, which is a stress hormone, high levels of which will decrease REM (rapid eye movement) sleep.

Another study published in Scientific Reports found an association between regular fish consumption and high sleep quality among Chinese schoolchildren. Largely as a result of improved sleep, the children scored higher on IQ tests.

In a 2014 study from Norway, it was found that adult male participants who ate 300 g of Atlantic salmon three times per week for six months fell asleep faster.

The dietary sources that contain some of the highest concentrations of omega-3 fatty acids include fish and fish oil supplements. According to the University of California Berkeley Wellness, some of the fish that have high levels of omega-3 are:

• wild herring (Atlantic and Pacific)
• farmed Atlantic salmon
• wild King salmon
• wild Pacific and jack mackerel
• pink, sockeye, and chum canned salmon
• canned jack mackerel
• wild Atlantic and Spanish mackerel
• wild bluefin tuna
• canned sardines
• canned white albacore tuna

One drawback of eating a lot of fish is the absorption of heavy metals. The general rule is the larger and older the fish, the higher the heavy metal content.

ALA is found in plant oils such as flaxseed, soybean, and canola oils. ALA can be converted to EPA and then DHA, but only in small amounts.

Other sources of omega-3s include:

• seaweed
• lamb
• beef
• eggs
• game meat
• poultry
• walnuts
• chia seeds
• mung beans
• cauliflower
• brussel sprouts
• wild rice
• berries
• plant oils such as flax oil, soybean oil, and canola oil
• fortified foods such as yogurt, juices, milk, and soy beverages

Omega-3 fatty acids are important for the health of the brain, heart, bones, joints, and other organs. There's a long list of benefits, including prevention of heart conditions, cancer, Alzheimer's, dementia, age-related macular degeneration (a major cause of vision loss among older adults), and rheumatoid arthritis. Omega-3 is important for infant development, appears to lessen the symptoms of ADHD, childhood allergies, asthma, depression, and cystic fibrosis.

The World Health Organization recommends taking 200-500 mg of combined EPA and DHA daily. Pregnant and nursing mothers, and those with more serious issues, such as anxiety, depression, cancer, or heart issues, may use up to 4,000 mg per day.

According to the National Institutes of Health Office of Dietary Supplements, there is no official recommended daily intake levels for omega-3 fatty acids, except for ALA. Those recommended levels are:

• Birth to 12 months: .5 g
• 1-3 years: .7g
• 4-8 years: .9 g
• Boys 9-13: 1.2 g
• Girls 9-13: 1 g
• Males 14 & above: 1.6 g
• Females 14 & above: 1.1 g
• Pregnant women: 1.4 g
• Breastfeeding women: 1.3 g

The American Heart Association recommends two or more 3.5-ounce servings of fish each week.

We chose these two brands because of their reputations, sourcing, quality, and extraction process. You must be especially careful when taking a fish oil supplement because lower-quality products may carry heavy metals, PCBs, and other toxins. Though they may be at low levels, taking a contaminated supplement daily or every few days will lead to an accumulation in your system over time and can cause health issues.

Dr. Tobias - We like this brand because their omega-3 comes from wild-caught fish, so it's not a GMO (genetically modified organism). The facility where it's extracted is an FDA-registered and inspected GMP-certified facility (it follows good manufacturing practices). The product is purified with molecular distillation at low temperatures to remove heavy metals, dioxins, PCBs, and other toxins. The capsules have an enteric coating designed for better absorption as they don't break down from your stomach acid but in your intestine. The capsules also have no fishy aftertaste.

Nordic Naturals - This company also uses wild-caught fish that are non-GMO, and they follow ethical and sustainable practices. Their products all have a COA (certificate of analysis) which means that they go through third-party testing to verify what's in the product. You can actually check the product in your hand on their website by entering the lot number.

These capsules have a lemon flavor that is "burpless" with no aftertaste. Their fish oil comes in the triglyceride form, which is the form found in fish and is easily absorbed in the human body.