What exactly is fish oil?
Fish oil supplements contain oils derived from the skin and liver of fatty fish such as mackerel, tuna, sardines, and salmon. They are an excellent source of omega-3 fatty acids, and polyunsaturated fat that helps protect against heart disease and possibly other health conditions. Omega-3 fatty acids come in three varieties. One is alpha-linoleic acid (ALA), found in vegetable oils such as soybean, canola, and walnut. The other two are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), only found in fatty fish and fish-derived supplements. Though Omega-3 fatty acids are essential to humans, they cannot be produced by the body and must be consumed through diet or supplementation. Unfortunately, most Americans don’t get enough of any of these types of omega-3 fatty acids in their diets. So, many people look to fish oil supplements to gain their daily recommended value of omega-3 fatty acids and gain its heart-healthy benefits.
But what does the research say about the effect of fish oil supplements on your health? Do they lower the risk of cardiovascular diseases by lowering biomarkers such as triglycerides and LDL cholesterol while increasing HDL cholesterol? Do they reduce inflammation by lowering indicators such as C - reactive protein (CRP)? Can they maximize strength by boosting your testosterone? Below we present the highest-quality research studies and our key takeaways and recommendations. While this information is certainly valuable in itself, the best way to know the impact of fish oil supplements on your health is to regularly monitor your internal biochemistry.
Fish oil's impact on measures of heart health
Triglycerides-
Much literature suggests that a daily dosage of fish oil supplements can benefit your heart health. In a comprehensive meta-analysis of 68 studies, researchers assessed the effects of daily consumption of 3-4 grams of fish oil on triglyceride levels of more than 2,800 subjects. Even though researchers were unsure about the mechanism by which fish oil supplements exert their effects, they concluded “it is clear that practical doses of n-3 fatty acids have a significant and probably clinically important effect on serum concentrations, especially in patients.
HDL cholesterol- Cholesterol is an essential fatty molecule used to build cell membranes and hormones. It is transported by molecules called lipoproteins that come in two varieties: high-density lipoprotein (HDL) and low-density lipoprotein (LDL). Elevated HDL levels are good for your overall cardiovascular health. These cholesterol “scavengers” collect unused cholesterol and bring it to the liver to be recycled and destroyed. By doing this, they prevent the buildup of plaque in arteries and lower the risk of a variety of heart and blood vessel-related diseases. Given that fish oil supplements benefit your heart by lowering your triglycerides; can they elevate HDL as well?
LDL cholesterol- In contrast to HDL cholesterol, elevated levels of low-density lipoprotein are linked to a variety of cardiovascular illnesses. Some research studies suggest that fish oil supplements might even increase LDL cholesterol. In a 12-week, double-blind, parallel design study, researchers recruited 60 adults with elevated triglycerides and placed them into two groups. Thus, the authors concluded that “fish oil supplementation while having a substantial and highly clinically relevant beneficial impact on lowering blood TG concentrations, also has a modest adverse LDL-C increasing effect.”
C-reactive protein & inflammation- C-reactive protein, also known as CRP, is a common indicator of blood vessel inflammation in the body. Because increased levels lead to aging of cellular tissues that results in a variety of diseases, we include it with other well-known biomarkers such as Vitamin D and cortisol in our Inner Age and Ultimate panels. Athletes often take fish oil supplements to reduce inflammation—but does it affect CRP?
There isn’t much evidence suggesting that fish oil affects CRP levels in the diabetic population.
Testosterone & strength- Testosterone is known to make men stronger and more “manly.” But it is a crucial hormone in regulating the growth and development of tissues and maintenance of mental health in both men and women. Some claims circulating on the internet and social media say that fish oil supplements boost testosterone. However, not a single high-quality research study supports this finding. That being said, there is evidence that fish oil supplementation may boost strength training, at least among elderly women.
How to choose the right fish oil supplement?
There are hundreds of choices of fish oil supplements. However, not all are created equal. According to Lab door, almost half don’t contain the daily recommendation of 500 mg of omega-3 fatty acids. Additionally, some are contaminated with mercury and other toxins. So it's best to make sure whichever supplement brand you choose is third-party tested and is transparent about heavy metal testing and where exactly the fish oil is sourced. Each manufacturer provides recommended daily dosages. However, we suggest consulting with a nutrition or healthcare professional to choose a dose based on your specific biomarkers.
Keep in mind that while fish oil supplements have proven benefits, we recommend getting some of your omega-3 acids from natural sources such as fatty fish, flaxseed, chia seeds, and walnuts. These whole foods also contain many other nutrients and healthy substances that maximize the benefits of fish oil supplements. Two to three servings of fatty fish per week satisfy the weekly requirement of omega-3 fatty acids. If you do not like these foods or find them hard to fit into your diet, supplements might be most beneficial.
Vegetarians and vegans-
You can get your omega-3 fatty acids through flaxseed, walnuts, or pills containing alpha-linoleic acid (ALA). They do not contain the two kinds of omega-3 fatty acids—EPA and DHA—unique to fish oil supplements and fatty fish. However, no conclusive research to date has shown that these two sources of omega fatty acids confer unique benefits that ALA doesn’t provide.