Do kitchen herbs & spices reduce blood pressure in adults at risk of heart disease?

A recent randomised controlled trial suggests that a diet rich in herbs and spices may reduce blood pressure in people at risk of cardiovascular disease.

Official dietary guidance focusses on reducing blood pressure by reducing dietary intake of salt. While experts know about the health impacts of excess salt, little is mentioned or known about the health effects of herbs and spices. For example, the Australian Dietary Guidelines (2013)  merely states, ‘Herbs, spices, garlic, lemon juice and vinegars can also be used to season foods without adding salt’, without reference to the health benefits of these nutrients.

Some studies have shown that herbs and spices can help manage excess fats in the blood (lipaemia, recognised as a risk factor for the development of cardiovascular disease and other chronic diseases), raised blood sugar levels (hyperglycemia), oxidative stress and improve the function of the membranes that line the heart and blood vessels.

But until now there has been limited investigation of the effect of longer-term intake of mixed herbs and spices on risk factors for cardiometabolic diseases.

To examine this, researchers at Pennsylvania State University recently conducted a randomised controlled trial (RCT) investigating the effect of longer-term consumption of herbs and spices on risk factors for cardiovascular disease.

Trial participants were randomly assigned to one of three groups. Each group would eat one of three diets: a low spice diet, a moderately spiced diet, or a high spice diet. These diets included a daily intake of 0.5 grams (g), 3.3 g, and 6.6 g of herbs and spices, respectively.

The study found that a higher level of herbs and spices in food reduced 24-hour blood pressure readings:

“in the context of a suboptimal US-style diet, addition of a relatively high culinary dosage of mixed herbs and spices (6.6 g · d⁻¹ · 2100 kcal⁻¹) tended to improve 24-hour blood pressure after 4 weeks, compared with lower dosages (0.5 and 3.3 g · d⁻¹ · 2100 kcal⁻¹), in adults at elevated risk of cardiometabolic diseases.”

The study was published in the American Journal of Clinical Nutrition.

Sources:

https://academic.oup.com/ajcn/advance-article/doi/10.1093/ajcn/nqab291/6369090