Which diet lowers blood pressure more: keto or Mediterranean?

New research shows both ketogenic and Mediterranean diets help lower blood pressure and support weight loss in adults with elevated cardiovascular risk, highlighting safe, flexible options for managing hypertension.

Study: Low-Calorie, High-Protein Ketogenic Diet Versus Low-Calorie, Low-Sodium, and High-Potassium Mediterranean Diet in Overweight Patients and Patients with Obesity with High-Normal Blood Pressure or Grade I Hypertension: The Keto–Salt Pilot Study. Image Credit: 9dream studio / Shutterstock.com

A recent study published in the journal Nutrients compares the impact of a low-calorie, high-protein ketogenic diet (KD) with a Mediterranean diet on blood pressure and other cardiovascular measurements in a cohort of overweight/obese individuals.

Identifying the optimal diet for cardiovascular health

In 2022, over 2.5 billion people throughout the world were considered overweight, about one million of whom were obese. Obesity increases the risk of numerous health conditions, including metabolic dysfunction and cardiovascular disease (CVD), with these effects mediated by high blood pressure, lipid, and glucose levels.

Weight loss is crucial in obese or overweight individuals to improve metabolic function and reduce blood pressure levels. Weight loss is often achieved by restricting caloric intake under a dietitian's supervision to ensure a balanced supply of essential nutrients.

The Mediterranean diet is widely recommended for overweight and obese individuals seeking to reduce their risk of developing CVD. It is characterized by the infrequent intake of red and processed meat, sodium, and alcohol, as well as increased consumption of whole grains, vegetables, fruits, legumes, fish, and unsaturated fatty acids.

Comparatively, the KD is a high-protein, high-fat, and low-carbohydrate diet that has been shown to support weight loss and metabolic health. However, the KD is also associated with high sodium and saturated fat intake, which may not be suitable for individuals at a high risk of CVDs, particularly those with high or borderline blood pressure levels.

Study findings

The current prospective study included 26 non-diabetic adults, all of whom had central overweight or central obesity and a body mass index (BMI) of 27 kg/m2 or greater. While 15 individuals were assigned to the KD group, 11 followed the Mediterranean diet for the duration of the study period.

All study participants were diagnosed with high-normal BP, which corresponds to BP measurements of 130/85 mmHg or higher, or grade 1 hypertension, which is in the range of 140-160/90-100 mmHg.

Dietary changes were assessed at three months, with these effects based on blood sample analysis, ambulatory blood pressure monitoring (ABPM), and body composition measurements obtained from a bioelectrical impedance analysis (BIA).

At three months, both the KD and Mediterranean diet intervention groups experienced weight loss. More specifically, the KD led to a mean weight reduction from 98.6 kg at baseline to 87.3 kg, whereas the mean weight in the MD group declined from 93.8 kg to 86 kg.

Mean BP levels also decreased, irrespective of diet. The average systolic BP (SBP) over a 24-hour period declined by nine mmHg from 125 mmHg, whereas the mean diastolic BP (DBP) measurements declined from 79 mmHg to 73.7 mmHg.

Losing five kg of weight is associated with a 4.4 mmHg and 3.6 mmHg reduction in SBP and DBP, respectively. Although this observation exemplifies the vital role of weight loss in reducing CVD risk, pharmacological management is indicated if dietary changes with increased physical activity fail to control the BP.

The proportion of fat-free mass (FFM) to total body mass increased in both groups from 63.7% to 66.5%. In absolute terms, FFM decreased from 61.7 kg to 57.8 kg at three months.

Neither diet was associated with an increased risk of inflammation or renal damage, and both diets were tolerated well. Overall, both the KD and Mediterranean diet led to improvements in all assessed risk factors; however, the proportion of individuals who experienced ‘nocturnal dipping,’ a normal physiological response when blood pressure levels are lowest during the night, was greater in those following the Mediterranean diet as compared to the KD group.

Conclusions

In the current study, both the KD and Mediterranean diets led to significant weight loss, improved body composition, and decreased blood pressure levels. Both dietary approaches are considered safe, effective, and well-tolerated.

These two different popular dietary approaches may equally confer metabolic and cardiovascular benefits, emphasizing the importance of weight and FM loss.”

Future studies with larger and more diverse study cohorts, especially over extended durations, are needed to validate these findings and ensure the accuracy of dietary guidelines for the management of hypertension.