Study Finds How Seafood, Vegetarian Diets May Help Protect Heart Health

A new study has found that primarily vegetarian diets, as well as diets containing seafood, may reduce the symptoms of hypertension-related heart disease. The beneficial effect is linked to increased levels of trimethylamine N-oxide (TMAO), which was found to reduce heart thickening and heart failure markers in rats. Higher blood plasma TMAO levels are associated with seafood and vegetarian diets versus diets with high amounts of egg and red meat.

Researchers studied TMAO's cardiovascular effects on mice that had a genetic tendency toward high blood pressure. Some rats were given regular water and others were given water that contained low doses of TMAO. Rats that received the compound were found to be in better condition at the end of the study than rats that did not receive the compound. Dosage lasted from 12 to 56 weeks.

The TMAO didn't prevent the development of high blood pressure in these rats, nor did it entirely prevent the damaging effects of the condition. The dosage was intended to increase the rats' blood plasma levels to four times more than what would otherwise be naturally produced.

This elevated plasma level didn't cause any harm to the rats' circulatory system, but was noted to decrease cardiac fibrosis and heart failure markers. Research has found that blood TMAO levels increase substantially after eating foods with high amounts of the compound, including vegetables and fish.

Diets high in both, such as the Mediterranean diet, have previously been associated with heart health, though the precise reasons for this aren't known. Increased blood plasma levels of TMAO may be a contributing factor, but additional research is necessary to determine the effect on humans. However, the findings do hint at the potential heart health benefits of adopting a vegetable- and seafood-rich diet.