Asking people to reduce their dietary salt intake can help them slightly lower blood pressure, but it doesn’t seem to have any effect on their risk of heart attack or heart-related death, according to a new review of existing research.
Professor Rod Taylor of the University of Exeter and his team looked at data from seven previously published randomized controlled trials that tracked salt intake and rates of death or serious cardiovascular events (like heart attack, heart surgery or stroke) among nearly 6,500 participants, with a follow-up of at least six months.
Although lowering dietary salt resulted in a small dip in blood pressure, the researchers found no strong evidence that it reduced rates of death in people with high or normal blood pressure. One study suggested that restricting salt in patients with congestive heart failure could even potentially increase risk of death.
Overall, the authors of the review concluded that there wasn’t enough data in the pooled studies to make a conclusion about the impact of salt reduction on the risk of major cardiovascular events. Further rigorous, large and long-term studies are needed.
Still, there is plenty of data — and consensus among experts — that excess dietary salt does affect blood pressure and cardiovascular health. Reported the Wall Street Journal:
Taylor tells the Health Blog that he doesn’t question the notion that salt consumption is linked to cardiovascular risk. But he says giving individuals dietary advice alone isn’t likely to cut it as a means of permanently lowering their salt intake, and therefore isn’t likely to have a long-term impact on health outcomes. “What’s not working is the advice,” he says.
Taylor notes that the tabletop salt shaker is not the real problem: 75% of our salt intake comes from restaurant meals and packaged food in the form of “invisible salt.” So, telling people to reduce salt without simultaneously getting food manufacturers to use less salt is not likely to result in significant reductions in consumption.
Americans eat an average of 3,400 mg of sodium each day, significantly more than the limits set by government dietary guidelines, which recommend that healthy adults stick to 2,300 mg daily and that those over age 51, African Americans of any age, and people with hypertension, kidney disease or one of several other conditions consume less than 1,500 mg of sodium per day.
The easiest way to get enough sodium — which is essential to good health — without going overboard is to cut out processed, packaged foods in favor of whole fruits, vegetables and meats.
So, what’s the right amount of sodium for you? “There is a healthy amount of sodium we all need in our diet,” Dr. Stephanie Moore, a cardiologist at Massachusetts General Hospital in Boston, told ABC News. “Define [a] healthy amount of sodium — there is the study we need.”
The current review was published in full by the Cochrane Library and an abbreviated version appears in the American Journal of Hypertension.
Meredith Melnick is a reporter at TIME. Find her on Twitter at @MeredithCM. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.