Reducing salt intake can lower blood pressure

July 29, 2009

Adults who use less salt in their diet can experience a slight reduction in their blood pressure in the medium term. However, whether in the long term this can also reduce the risk of late complications in people with sustained high blood pressure, otherwise known as essential hypertension, and whether in the long term their anti-hypertensive medication can be reduced remains unresolved. This is the conclusion of a report by the German Institute for Quality and Efficiency in Health Care (IQWiG), Cologne and for which an English-language summary is now available.

This rapid report is part of a package commissioned by the Federal Joint Committee (G-BA), in which the benefit of various non-drug treatment strategies for high blood pressure are to be assessed. Stress management and more physical activity are also included, as well as giving up smoking and cutting down alcohol consumption. IQWiG has already completed a report on the effect of weight reduction on blood pressure.

Assessment was based on secondary literature

IQWiG's benefit assessments are generally based on systematic searches and analysis of clinical trials, in other words, primary literature. However, this rapid report was prepared on the basis of secondary literature. In principle, this can be done - and is included in IQWiG's General Methods - if current, high quality systematic reviews are already available on a given topic. This was the case with reducing salt intake in hypertension, as IQWiG's preliminary search revealed.

IQWiG searched for systematic reviews (these basically provide an analysis of studies in summary) that compared the following patients with hypertension: an intervention group, which was to follow a low-salt diet over a long period, versus a control group, which either did not have this target or whose salt reduction was not so great as in the intervention group. The minimum duration of the studies had to be 4 weeks. In order not to overlook any current and potentially relevant studies, IQWiG also conducted an update search of recently published primary studies.

IQWiG was able to include in its assessment 7 reviews, in which the results of between 520 and 3391 participants from a total of 62 randomized controlled trials were analysed together.

No conclusions on cardiovascular disease or mortality possible

IQWiG found that no conclusions on late complications could be drawn from the available data. The reason for this is that none of the studies had the primary goal of investigating the effects of a low-salt diet on cardiovascular disease or all-cause mortality. Moreover, most of the studies were only of a few months' duration and had low numbers of participants, which meant that possible differences in late complications might not have been detected with certainty.

Uncertainty whether the reduction in blood pressure is sustainable

However, the investigations consistently show that a reduction in salt intake can assist in lowering blood pressure: over a period of up to one year, there was a mean drop of 3.6 to 8 mmHg in systolic values and a mean drop of approximately 2 to 3 mmHg in diastolic values. This applied primarily to patients who did not take any additional anti-hypertensive drugs.

The sustainability of this effect, however, remains unclear. The authors of at least one review report that the observed advantage disappears when the analysis is restricted to studies of a longer duration (at least 6 months).

None of the reviews solely considered patients who were simultaneously taking anti-hypertensive drugs or separately analysed data for participants on concomitant medication. The additional blood pressure-lowering effect of a low-salt diet in these patients is therefore uncertain.

Basically, it is still not known whether people with essential hypertension can reduce their drug dosage through less salt intake.

Report preparation procedure

Rapid reports are intended to offer timely information on a current topic. They are not designed for G-BA guideline decisions. In order to guarantee a shorter delivery time, the report preparation procedure differs primarily in two ways from that of the other reports: working documents, report plans or preliminary reports are not published, nor is there a submission of comments procedure. Furthermore, the assessment is generally based on information already published, i.e. IQWiG is not concerned with obtaining unpublished study data from drug manufacturers, for example.

The report was produced in collaboration with external experts. A preliminary version was reviewed by a further independent research group and the final version was despatched to the G-BA on 22 June 2009.
-end-


Institute for Quality and Efficiency in Health Care

Related Blood Pressure Articles from Brightsurf:

Children who take steroids at increased risk for diabetes, high blood pressure, blood clots
Children who take oral steroids to treat asthma or autoimmune diseases have an increased risk of diabetes, high blood pressure, and blood clots, according to Rutgers researchers.

High blood pressure treatment linked to less risk for drop in blood pressure upon standing
Treatment to lower blood pressure did not increase and may decrease the risk of extreme drops in blood pressure upon standing from a sitting position.

Changes in blood pressure control over 2 decades among US adults with high blood pressure
National survey data were used to examine how blood pressure control changed overall among U.S. adults with high blood pressure between 1999-2000 and 2017-2018 and by age, race, insurance type and access to health care.

Transient increase in blood pressure promotes some blood vessel growth
Blood vessels are the body's transportation system, carrying oxygen and nutrients to cells and whisking away waste.

Effect of reducing blood pressure medications on blood pressure control in older adults
Whether the amount of blood pressure medications taken by older adults could be reduced safely and without a significant change in short-term blood pressure control was the objective of this randomized clinical trial that included 534 adults 80 and older.

Brain blood flow sensor discovery could aid treatments for high blood pressure & dementia
A study led by researchers at UCL has discovered the mechanism that allows the brain to monitor its own blood supply, a finding in rats which may help to find new treatments for human conditions including hypertension (high blood pressure) and dementia.

Here's something that will raise your blood pressure
The apelin receptor (APJ) has been presumed to play an important role in the contraction of blood vessels involved in blood pressure regulation.

New strategy for treating high blood pressure
The key to treating blood pressure might lie in people who are 'resistant' to developing high blood pressure even when they eat high salt diets, shows new research published today in Experimental Physiology.

Arm cuff blood pressure measurements may fall short for predicting heart disease risk in some people with resistant high blood pressure
A measurement of central blood pressure in people with difficult-to-treat high blood pressure could help reduce risk of heart disease better than traditional arm cuff readings for some patients, according to preliminary research presented at the American Heart Association's Hypertension 2019 Scientific Sessions.

Heating pads may lower blood pressure in people with high blood pressure when lying down
In people with supine hypertension due to autonomic failure, a condition that increases blood pressure when lying down, overnight heat therapy significantly decreased systolic blood pressure compared to a placebo.

Read More: Blood Pressure News and Blood Pressure Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.