Krill Oil vs. Fish Oil: Which is Better for Your Heart?

meta-analysis PMID: 32073633

Quick Summary: A recent study compared krill oil and fish oil and found that krill oil might be slightly better at lowering triglycerides (a type of fat in your blood) and raising "good" cholesterol (HDL) compared to fish oil. However, both oils had similar effects on "bad" cholesterol (LDL) and total cholesterol.

Krill Oil vs. Fish Oil: What the Research Found

This research looked at several studies to compare the effects of krill oil and fish oil on blood fats. Here's what they discovered:

Triglycerides: Krill oil was more effective at lowering triglycerides than fish oil.

HDL Cholesterol: Krill oil helped raise "good" cholesterol (HDL) more than fish oil.

LDL Cholesterol & Total Cholesterol: Both oils had similar effects on "bad" cholesterol (LDL) and total cholesterol levels.

Study Details

Who was studied: The research combined data from 11 different studies, including a total of 1,178 adults. These adults were between 20 and 70 years old and had normal or slightly high levels of fats in their blood.

How long: The studies lasted between 4 to 24 weeks (about 1 to 6 months).

What they took: Participants took either krill oil or fish oil capsules daily. Krill oil doses ranged from 2-4 grams per day, while fish oil doses varied from 1-4 grams per day.

What This Means For You

Considering your cholesterol levels? If you're looking to lower triglycerides or raise your HDL cholesterol, krill oil might be a slightly better choice than fish oil.

Already taking fish oil? Don't worry! Fish oil still offers benefits for heart health, and both oils had similar effects on LDL and total cholesterol.

Talk to your doctor: Before making any changes to your supplements, it's always a good idea to talk to your doctor. They can help you decide what's best for your individual needs.

Study Limitations

Varied studies: The studies used different doses and included people with slightly different health profiles, which could affect the results.

Smaller studies: Some of the individual studies had a limited number of participants, which can make it harder to draw firm conclusions.

Short-term: The studies only looked at the effects over a few months, so we don't know the long-term effects.

Funding: Some studies were funded by the companies that make the oils, which could potentially influence the results.

Key Findings

This 2020 network meta-analysis found that krill oil significantly reduced triglycerides (WMD: -0.29 mmol/L, 95% CI: -0.53 to -0.05) and increased high-density lipoprotein cholesterol (HDL-C) (WMD: +0.06 mmol/L, 95% CI: +0.01 to +0.11) compared to fish oil. However, no statistically significant differences were observed between krill oil and fish oil for low-density lipoprotein cholesterol (LDL-C) or total cholesterol. Krill oil also showed superior efficacy over placebo for triglycerides (-0.39 mmol/L) and HDL-C (+0.09 mmol/L).

Study Design

The study was a random-effects network meta-analysis of randomized controlled trials (RCTs) evaluating krill oil and fish oil effects on lipid profiles. Data were pooled from 11 RCTs involving 1,178 adults (age range: 20–70 years) with normal or borderline hyperlipidemia. Trials lasted 4–24 weeks, with supplements administered daily. The analysis used the Cochrane risk-of-bias tool to assess study quality and included both direct (krill oil vs. fish oil) and indirect comparisons (vs. placebo).

Dosage & Administration

Krill oil doses ranged from 2–4 g/day, providing 180–560 mg/day of combined EPA and DHA in phospholipid form. Fish oil doses varied from 1–4 g/day, delivering 180–1,680 mg/day of EPA/DHA in triglyceride form. Both supplements were administered as capsules in most trials. Intervention durations spanned 4–24 weeks, with lipid outcomes measured pre- and post-intervention.

Results & Efficacy

Triglycerides: Krill oil reduced triglycerides more than fish oil (-0.29 mmol/L, p=0.02) and placebo (-0.39 mmol/L, p=0.002).
HDL-C: Krill oil increased HDL-C compared to fish oil (+0.06 mmol/L, p=0.02) and placebo (+0.09 mmol/L, p=0.006).
LDL-C/Total Cholesterol: No significant differences between krill oil and fish oil for LDL-C (WMD: -0.01 mmol/L, p=0.94) or total cholesterol (WMD: -0.03 mmol/L, p=0.75).
Statistical Heterogeneity: Moderate heterogeneity (I²=42%) for triglycerides, low for HDL-C (I²=18%).

Limitations

Heterogeneity: Variability in study designs, doses, and populations limited pooled analysis consistency.
Small Sample Sizes: Individual trials had limited participant numbers (n=40–200), reducing robustness.
Short Duration: Most interventions lasted <12 weeks, leaving long-term effects unexamined.
Funding Bias: Several included trials received industry funding, potentially influencing results.
Publication Bias: Only published studies were analyzed, excluding gray literature.

Clinical Relevance

For individuals targeting triglyceride reduction or HDL-C improvement, krill oil may offer modest advantages over fish oil. However, both supplements appear similarly effective for LDL-C and total cholesterol management. The higher cost of krill oil should be weighed against its marginal benefits. These findings support krill oil’s potential as a lipid-modifying agent but emphasize the need for larger, longer-term RCTs to confirm effects, particularly in diverse populations (e.g., hyperlipidemic patients). Supplement users should prioritize evidence-based dosing and consult healthcare providers for personalized lipid-lowering strategies.

Note: This analysis is restricted to short-term lipid outcomes; cardiovascular event reduction or safety profiles were not assessed.