What are the side effects of fish oil?

Mar 19, 2025 Source: Cainiu Health

Dr. Yang Ziqi

Introduction

Oil may cause side effects such as allergic reactions, excessive vitamin supplementation, abnormal blood lipids, gastrointestinal discomfort, and increased risk of bleeding. It is best to consult a doctor or nutritionist for advice before taking fish oil and to follow the recommended dosage. At the same time, pay attention to your body's response, and if you experience any discomfort or unusual symptoms, stop taking it immediately and seek medical attention.

Generally speaking, fish oil is a common supplement that benefits heart health and brain function. However, fish oil may also cause side effects such as allergic reactions, excessive vitamin intake, abnormal blood lipids, gastrointestinal discomfort, and increased bleeding risk. A detailed analysis is as follows:

　　1. Allergic Reactions

Some individuals may experience allergic reactions to components in fish oil, presenting symptoms such as rash, itching, and difficulty breathing. These allergic reactions may affect multiple areas including the skin and respiratory system. Individuals allergic to fish or seafood should use fish oil cautiously and seek medical attention immediately if allergic reactions occur.

　　2. Excessive Vitamin Intake

Some fish oil products may contain high levels of vitamins A and D. Long-term excessive intake may lead to an overaccumulation of these vitamins. Excess vitamin A may cause symptoms such as dizziness and joint pain; excess vitamin D may lead to health problems such as hypercalcemia.

　　3. Abnormal Blood Lipids

Certain components in fish oil might interfere with lipid metabolism in specific individuals, increasing the liver's production of low-density lipoprotein (LDL) or reducing its clearance, thereby elevating LDL levels and affecting blood lipid profiles.

　　4. Gastrointestinal Discomfort

Fish oil is rich in fats and inherently oily, which can stimulate faster gastrointestinal motility, shortening the retention time of food in the intestines and potentially causing diarrhea. Additionally, its unique odor and oily nature may irritate the gastric mucosa, causing nausea, stomach pain, and other discomforts.

　　5. Increased Bleeding Risk

Fish oil has anticoagulant properties that may prolong bleeding time and thus increase the risk of bleeding. Individuals taking anticoagulant medications or other blood thinners, those with a bleeding tendency, or those about to undergo surgery should be particularly cautious when taking fish oil.

Before taking fish oil, it is best to consult a doctor or nutritionist and follow the recommended dosage. Also, monitor your body's response carefully; if any discomfort or abnormal symptoms occur, stop taking it immediately and seek medical advice.

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What are the side effects of deep-sea fish oil?

In general, deep-sea fish oil is a dietary supplement that is rich in ω-3 polyunsaturated fatty acids, which help regulate blood lipids, improve vision, and provide other benefits. Possible side effects may include gastrointestinal discomfort, bad breath and a fishy aftertaste, increased risk of bleeding, impaired blood sugar control, and increased burden on the liver. To reduce the side effects of deep-sea fish oil, it is recommended to consult a physician before taking it.

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Can I take fish oil for heart palpitations?

Patients with cardiac premature beats can take fish oil. Fish oil is rich in Omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which offer significant cardiovascular benefits. It can lower triglyceride and other harmful cholesterol levels while increasing high-density lipoprotein (HDL), helping to prevent blockages in the heart's arteries.