Based on the available information, it is not possible to definitively conclude that aspirin's role in heart health is irreplaceable by diet. However, the sources do provide some context that can help answer this question.

Firstly, according to the FDA-approved label for aspirin, it is used for reducing the risk of recurrent heart attacks and strokes in patients who have already experienced such events [1]. This is because aspirin has antiplatelet properties, which help prevent blood clots from forming.

Secondly, the role of diet in heart health is well-established. A study published in the Journal of the American College of Cardiology found that a diet rich in fruits, vegetables, whole grains, lean proteins, and healthy fats can significantly reduce the risk of heart disease [2]. This is because such a diet provides essential nutrients, antioxidants, and fiber that support heart health.

Lastly, a study published in the Journal of Nutrition found that a diet rich in omega-3 fatty acids, found in fish and certain plant sources, can have similar antiplatelet effects as aspirin [3]. However, it is important to note that the study did not suggest that omega-3 fatty acids can replace aspirin in patients who have already experienced heart attacks or strokes.

Therefore, while diet can certainly support heart health and potentially reduce the risk of heart disease, it may not be able to replace aspirin's role in preventing recurrent heart attacks and strokes in high-risk patients. As always, individuals should consult with their healthcare providers for personalized medical advice.

Sources:
[1] <https://www.drugpatentwatch.com/p/tradename/ASPIRIN>
[2] <https://www.sciencedirect.com/science/article/pii/S102194981500143X>
[3] <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9339570/>