AIM: Ischemic heart disease (IHD) is a major contributor to global mortality and disability, imposing a significant health and economic burden on patients and society. Despite existing treatment options including medications and surgeries, their effectiveness remains limited, with issues such as suboptimal treatment outcomes and high recurrence rates. This study aims to investigate the relationship between low dietary intake of ω-3 fatty acids and the burden of IHD, hoping to provide new insights into the prevention and treatment of IHD. METHOD: Using the Global Burden of Disease (GBD) 2021 dataset, we examined the impact of low ω-3 dietary intake on the burden of ischemic heart disease (IHD) between 1990 and 2021globally, regionally, temporally. The Joinpoint regression model was applied to analyze the trend of IHD burden attributed to low ω-3 dietary intake over time. RESULTS: In 2021, the global IHD-related Disability-Adjusted Life Years (DALYs) and deaths caused by a low ω-3 diet was 15,511,020(95% UI: 3,098,820 to 25,946,110) and 627,340 (95% UI: 119,540 to 1,082,740), accounting for 8.23% (95% UI: 1.64-13.52%) of all IHD-related DALYs and 6.97% (95% UI: 1.33-11.76%) of all IHD deaths, respectively. From 1990 to 2021, there was a significant upward trend in DALYs and deaths, but age-standardized DALYs and death rates showed a declining trend. Regional analysis indicated that the burden of IHD was highest in South Asia and lowest in High-Income Asia Pacific regions. At the national level, India, China, the United States, and Pakistan had a higher burden of IHD. Furthermore, as the Socio-Demographic Index (SDI) increased, the burden of IHD caused by a low ω-3 diet gradually decreased. CONCLUSION: This study untangles a significant association between a low ω-3 diet and the burden of IHD, emphasizing the importance of promoting healthy eating habits globally. Future research should further explore the impact of dietary changes on the burden of IHD and develop targeted public health policies to reduce the burden of IHD.