Chinese heart-healthy diet effective for lowering BP in Chinese adults

The cuisine-based Chinese heart-healthy (CHH) diet was effective, palatable, and cost-effective in reducing blood pressure (BP) in Chinese adults with mild hypertension, findings from the DECIDE*-Diet trial suggest.

The burden of cardiovascular disease (CVD) has rapidly increased in China, partly due to the transition from traditional healthy diets to mostly unhealthy patterns today. [Circulation 2016;133:2545-2560] “[This] has become a growing concern … [hence the need for] effective dietary strategies to improve the health status of its population,” said the researchers.

“[We] conducted the trial at four** study centres across China … representing four major Chinese cuisines: Shandong, Huaiyang, Cantonese, and Szechuan,” they continued. “[Our findings] demonstrate that the BP-lowering effect of the CHH diet could be substantial and compatible with medications while palatable and affordable in Chinese adults with high BP.”

Participants did a 7-day run-in phase on a control diet that matches typical local diets tailored to suit their preference. Following which, 265 adults (mean age 56.5 years, 52 percent female, mean systolic BP [SBP] 139.4 mm Hg) were randomized 1:1 to consume either the CHH diet or the control diet provided during the run-in period. Meals were to be consumed at three mealtimes (breakfast, lunch, dinner) for the next 28 days. [Circulation 2022;146:303-315]

Compared with the components of a typical diet in urban China, the CHH diet had reduced sodium intake (from ~6,000 to 3,000 mg/day) and energy from fat (by 5–8 percent). Components that were increased were energy intake from protein (by 3.5–5.5 percent), energy from carbohydrates (by 0–5 percent), and dietary fibre (from 11 to 30 g/day) and potassium intake (from <1,700 to 3,700 mg/day).

Compared with the control arm, the CHH arm had a greater change in SBP from baseline to end of intervention (–15.0 vs –5.0 mm Hg; p<0.001). According to the researchers, the effect of the CHH diet on BP may have been driven by the adjustments in nutrient components.

The SBP reduction was greater in women vs men on subgroup analysis (–12.0 vs –7.6 mm Hg; p_interaction=0.037). “The sex differences in response to the CHH diet … might be explained by women’s better adherence to the intervention,” said the researchers.

The CHH and control arms had similar costs for food materials (average 24 vs 21 CNY/day) and food preference visual analytic score (net difference, 0.1; p=0.558). “[These suggest that] flavour preference for the CHH diet was as good as the usual local diet. [Also,] the incremental cost of the CHH diet/person/day (USD 0.6 for 10 mm Hg) was low and affordable for common people.”

Caveats

The study did not achieve the planned recruitment target owing to the COVID-19 pandemic. The intervention period was also rather short. “[Although] our weekly monitoring of morning BP showed the intervention effect increasing with the study duration, we cannot conclude if the effect size would be further increased if the intervention is prolonged,” they noted.

Like the DASH*** trial, the current study employed a meticulously controlled protocol wherein raw food materials were weighed and meals were measured pre- and post-consumption to ensure utmost precision in estimating nutrient intakes. “[However, we were not able to] separate the effect of reducing sodium intake from those caused by changes in diet by design. We believe that this is an important question that should be addressed in future studies,” they pointed out.

Scaling up warranted

“[Despite the limitations, our study showed] that the CHH diet could produce a considerable BP-lowering effect comparable with antihypertensives among patients with hypertension,” said the researchers. “Our results support the idea that ‘food is medicine’ and will give many patients with high BP the confidence to adopt a healthy diet as their lifestyle treatment.”

“Considering the already high and still increasing prevalence of hypertension in China and the size of the population affected, scaling the CHH diet up countrywide bears great significance in preventing and controlling hypertension and CVD,” they stressed.