Review published in Advances in Nutrition finds “long-term high intake of whole grains, fruits and vegetables, and nuts significantly reduced cardiovascular mortality.”

According to the World Health Organization (WHO), cardiovascular disease is the leading cause of death and disability globally.  It accounted for 18.6 million preventable deaths in 2019, or one-third of the total number of global deaths.  Poor diet, in particular, has been identified as a key risk factor for cardiovascular mortality: the Global Burden of Disease Study 2019, for example, found that poor diet was the second leading cause of cardiovascular mortality, responsible for almost 8 million cardiovascular deaths worldwide.

Although we’ve gained a substantial understanding about the relationship between diet and cardiovascular disease mortality, this relationship is still not fully understood.  For example, only a limited number of studies have explored how long-term dietary consumption patterns affect cardiovascular mortality.  Most studies exploring cardiovascular mortality have been based on a one-time dietary measurement rather than repeated measurements over an extended period of time, which are better able to capture overall dietary habits.  Moreover, although many national dietary guidelines are based on food groups, there is limited research on the risk of consuming different food groups and cardiovascular mortality; in particular, the long-term risk of consuming different food groups and cardiovascular mortality.

In response, the authors of Long-term Consumption of Ten Food Groups and Cardiovascular Mortality: A Systematic Review and Dose Response Meta-analysis of Prospective Cohort Studies gathered and evaluated the current evidence to determine what conclusions could be drawn.  This systematic review, published in Advances in Nutrition, the international review journal of the American Society for Nutrition, worked with data from 22 studies with a total of 70,273 participants.  The length of follow-up in each study ranged from 6 years to 34 years.

According the findings, “long-term high intake of whole grains, fruits and vegetables, and nuts significantly reduced cardiovascular mortality.”  Each 10-gram increase in whole grains consumed per day, for example, was associated with a 4% reduction in the risk of cardiovascular mortality.

On the other hand, “red/processed meat consumption in the highest category was associated with an increased risk of cardiovascular mortality.”  Specifically, each 10-gram increase in red or processed meat consumed per day was associated with a 1.8% increase in the risk of cardiovascular mortality.  The authors believe that “this harmful effect may be due to saturated and trans-fat contents in red and processed meat, which are associated with increased risk of hypercholesterolemia, endothelial dysfunction, insulin resistance, and type 2 diabetes.”

Interestingly, the authors also found “long-term consumption of dairy products had no effect on cardiovascular mortality in both meta- and dose-response analysis.”  In contrast, they noted that “another systematic review reported that total dairy consumption lowered the risk of cardiovascular mortality, while high fat milk consumption was associated with a higher risk of cardiovascular mortality.”

The authors did note some limitations to their review and therefore the need to interpret their results with some caution.  In particular, all the studies under review worked with self-reported measurements to assess dietary intake which may have potentially introduced bias.

More research is needed.  Due to limited studies on the long-term effect of fish and poultry intake on cardiovascular mortality, for example, the authors were not able to establish associations with all ten food groups under investigation.  Moreover, there were not enough studies to determine whether men’s or women’s dietary long-term consumption habits had distinct effects on cardiovascular mortality.

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