A new study may take some of the pleasure out of those burgers you enjoy grilling in your backyard. Researchers found that people who regularly eat meat, chicken and fish grilled, broiled or roasted at high temperatures are more likely to develop high blood pressure – although they were careful to note that they identified a trend, not a cause and effect.

Researchers based their data on long-term studies involving nearly 104,000 people taking part in long range studies of health care professionals. None of the participants had high blood pressure, diabetes, heart disease, or cancer when they enrolled, but 37,123 of them developed high blood pressure during an average follow-up of 12-16 years.

Both frequency and “doneness” affected the outcomes.

The data

Among participants who reported eating at least two servings of red meat, chicken or fish a week, the analysis revealed that the risk of developing high blood pressure was:

• 17 percent higher in those who grilled, broiled, or roasted beef, chicken or and fish more than 15 times/month, compared with less than 4 times a month.
• 15 percent higher in those who prefer their food well done, compared with those who prefer rarer meats.
• 17 percent higher in those estimated to have consumed the highest levels of heterocyclic aromatic amines (HAAs) – chemicals formed when meat protein is charred or exposed to high temperatures – compared to those with the lowest intake.

Researchers noted the relationship between cooking temperature, method, doneness and high blood pressure was independent of the amount or type of food consumed.

“The chemicals produced by cooking meats at high temperatures induce oxidative stress, inflammation and insulin resistance in animal studies, and these pathways may also lead to an elevated risk of developing high blood pressure,” said Gang Liu, Ph.D., lead author of the study and a postdoctoral research fellow in the department of nutrition at the Harvard T.H. Chan School of Public Health in Boston.

Oxidative stress, inflammation and insulin resistance affect the inner linings of blood vessels, and are associated with the development of atherosclerosis, the disease process that underlies heart disease and causes the arteries to become narrowed.

The findings are limited because data came from questionnaires that did not include certain types of meats (such as pork and lamb) and certain cooking methods (such as stewing and stir-frying). Because the participants were all health professionals and mostly Caucasian, the results may not generalize to other groups.

Reducing the risk

“Our findings suggest that it may help reduce the risk of high blood pressure if you don’t eat these foods cooked well done and avoid the use of open-flame and/or high-temperature cooking methods, including grilling/barbequing and broiling,” Liu said.

The study was presented at the American Heart Association’s Epidemiology and Prevention | Lifestyle and Cardiometabolic Health Scientific Sessions 2018, a premier global exchange of the latest advances in population based cardiovascular science for researchers and clinicians.

The study was funded by the National Heart, Lung and Blood Institute.