Magnesium is a mineral the body needs for blood pressure and blood sugar regulation, energy production, and many other important processes.

Omega-3 fatty acids play critical roles in regulating inflammation, maintaining heart health, and more. There are three main types of omega-3 fats: docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and alpha-linolenic acid (ALA). DHA and EPA are more associated with brain health.

Both magnesium and omega-3s affect brain health in several ways, such as regulating mood, reducing anxiety and depression, and enhancing memory.

Magnesium and omega-3s are both important for brain health. Omega-3s play a more direct role in brain development, but both are needed for proper brain function, mood regulation, and more. 

While these nutrients play different roles in brain health and function, having low levels of either can lead to cognitive issues. Having low levels of magnesium and omega-3s has been linked with depression.

Magnesium and omega-3s also regulate inflammation in the brain, which can protect against neurodegenerative diseases like dementia. This is why you should regularly consume sources of magnesium and omega-3s or take supplements. 

Magnesium supports normal brain function and helps regulate inflammation in the brain. Here are a few ways it affects brain health:

• Low levels associated with brain inflammation and disease: Magnesium deficiency is linked to chronic low-grade inflammation in the brain, which can increase the risk of neurodegenerative diseases. People with neurodegenerative diseases, such as Alzheimer’s and Parkinson’s, have been shown to have lower magnesium levels than people without these conditions.
• Influences stress and mood: Magnesium plays a role in stress response, and low levels can increase stress and negatively impact mental health. Low magnesium status is linked to mood changes, increased stress levels, anxiety, and depression.
• May ease depression and anxiety symptoms: A research review showed a significant association between low blood magnesium levels and depression severity. Another review found that magnesium supplements had a beneficial effect on subjective anxiety symptoms.
• Supports sleep: Maintaining optimal magnesium levels can promote better quality sleep, which is essential for healthy brain function.

Omega-3s are essential to brain health. Supplementing with omega-3s may protect against cognitive decline and support brain function in people, especially older adults. Here are a few ways they affect brain health:

• Support brain development: Omega-3s are necessary for fetal brain development; it’s recommended that pregnant women supplement with omega-3s to maintain optimal levels of DHA and EPA. Omega-3s are also essential for brain health throughout life, including during childhood, adulthood, and older age.
• Regulate brain inflammation: Omega-3s are essential for regulating brain inflammation, which is critical for overall brain health and reducing the risk of neurodegenerative diseases. Low levels of omega-3s are linked with several neurological conditions, including attention-deficit/ hyperactivity disorder (ADHD), autism, bipolar disorder, depression, and dementia. 
• Protect against cognitive decline: A research review found that supplementation with DHA reduced cognitive decline in people with mild cognitive impairment, and supplementation with EPA and DHA slowed cognitive aging by 2.5 years in people with healthy brains.
• Improve brain function: Studies show that omega-3 supplements can improve brain function, such as attention and memory, in older adults and children.
• May reduce depression symptoms: A review found that omega-3 supplementation had an overall beneficial effect on depressive symptoms. The researchers concluded that omega-3 formulations containing 60% or more EPA and supplements that contain 1 or more grams of EPA per day were most effective.

Magnesium is found in many foods, including whole grains, leafy greens, legumes, nuts, seeds, and dairy. Good sources of magnesium include spinach, pumpkin seeds, Swiss chard, chia seeds, black beans, and almonds.

Seafood is the main source of DHA and EPA omega-3 fatty acids. EPA and DHA are concentrated in fish and shellfish like salmon, herring, sardines, and oysters.

In addition to dietary sources, omega-3s and magnesium are available in supplement form. Omega-3 supplements usually provide 500-1,200 milligrams of combined EPA and DHA per serving.

Magnesium supplements typically contain 100-150 milligrams of magnesium per capsule or pill. There are multiple forms of magnesium, but studies show that magnesium citrate, acetyl taurate, glycinate, L-threonate, and malate are better absorbed than other forms, like magnesium oxide and sulfate.

Many people can benefit from increasing their intake of magnesium and omega-3s through diet or supplementation. If you’re concerned you don’t get enough of these nutrients in your diet, speak with your healthcare provider about taking a supplement. 

Magnesium and omega-3 supplements are considered safe and aren’t associated with many adverse side effects. 

Although higher doses can benefit some populations—such as people with inflammatory diseases—the United States Food and Drug Administration (FDA) recommends keeping your combined EPA and DHA intake to 3 grams per day, with no more than 2 grams per day coming from supplements.

Higher doses could reduce immune function and inhibit blood clotting, which can thin the blood and lead to bleeding issues. 

While taking in high levels of magnesium through food is safe, you can consume too much magnesium from supplements. The Tolerable Upper Intake Level (UL) for magnesium is 350 milligrams daily. The UL is the maximum daily intake of a nutrient unlikely to cause harm. Because magnesium from food isn’t associated with risks, the UL only applies to supplemental magnesium.

Too much supplemental magnesium can lead to side effects like diarrhea and abdominal cramps. Very high doses of supplemental magnesium can lead to magnesium toxicity, which can be fatal. However, this is rare and primarily associated with accidental overdose of antacids and laxatives containing magnesium.

Because everyone has different needs, it’s best to speak with a healthcare provider if you have questions about safe dosing for magnesium and omega-3 supplements. 

Magnesium and omega-3s play important roles in brain health. Omega-3s are essential for brain development, while both are important for brain function and regulating mood and inflammation.

If you’re concerned that your diet doesn’t provide enough magnesium and omega-3s, talk to your healthcare provider about dietary supplements.