A Review of 7 Popular Diets Reveals One with Significant Benefits in Reducing Risk of Heart Attack, Stroke, and Premature Death

According to a recent comparative review published by The BMJ, Mediterranean and low-fat dietary programmes have shown promising results in reducing the chances of death and heart attack in patients who are at increased risk of cardiovascular disease.

The review, based on randomized trials of seven popular dietary programmes, also suggests that Mediterranean diets may also reduce the risk of stroke.

It’s important to note that these dietary programmes can include exercise and other health behavior support, such as smoking cessation.

While Mediterranean dietary programmes may reduce the risk of stroke, other dietary programmes have shown little to no benefit compared to minimal intervention, which could be usual diet or brief dietary advice from a health professional.

Current guidelines suggest various dietary programmes for patients at higher risk of cardiovascular disease, but the evidence has mainly come from non-randomised studies with low certainty.

While some analyses of randomised controlled trials suggest that certain diets and dietary programmes can reduce major cardiovascular events like heart attacks and strokes, it remains uncertain whether they have any beneficial impact on death.

In order to address this, researchers conducted a thorough search of databases for randomised trials examining the impact of dietary programmes on preventing death and major cardiovascular events in patients at increased risk of cardiovascular disease.

The study identified 40 eligible trials, involving 35,548 participants who were followed for an average of three years across seven different named dietary programmes. Of the seven programmes, 18 trials were low fat, 12 were Mediterranean, six were very low fat, four were modified fat, three were combined low fat and low sodium, three were Ornish, and one was Pritikin.

Some of the trials compared two different diets, such as the Mediterranean vs low fat. The researchers evaluated the methodological quality of each trial and classified 13 as being at low overall risk of bias and 27 at high risk.

The study concluded that based on moderate certainty evidence, Mediterranean dietary programmes were superior to minimal intervention in preventing all-cause mortality (17 fewer deaths per 1000 over five years), non-fatal heart attack (17 fewer per 1000), and stroke (7 fewer per 1000) for patients at intermediate risk of cardiovascular disease.

Low-fat programmes were also found to be better than minimal intervention with moderate certainty in preventing all-cause mortality (9 fewer deaths per 1000) and non-fatal heart attack (7 fewer per 1000). When comparing the Mediterranean and low-fat programmes, there were no significant differences in mortality or non-fatal heart attack.

However, the absolute effects of both dietary programmes were more pronounced in patients with a higher risk of cardiovascular disease, with those following the Mediterranean dietary programme experiencing 36 fewer all-cause deaths per 1000 and 39 fewer cardiovascular deaths per 1000 over a five-year period.

The study found that the five remaining dietary programmes generally had little to no benefit when compared with minimal intervention, based on evidence typically of low to moderate certainty.

The researchers noted several limitations, including the inability to measure adherence to the dietary programmes and the possibility that some of the benefits may have been due to other elements within the programmes, such as drug treatment or support to quit smoking.

However, the researchers emphasized that this was a comprehensive review based on a thorough literature search, rigorous assessment of study bias, and adherence to recognized GRADE methods to assess the certainty of estimates.

In conclusion, the researchers stated that Mediterranean and low-fat dietary programmes are likely to reduce the risk of mortality and non-fatal myocardial infarction in people with an increased risk of cardiovascular disease

According to them, Mediterranean diet plans are also likely to lower the risk of stroke, although other identified diet plans were often no better than minimum intervention.

Source: 10.1136/bmj-2022-072003

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