As the new year kicks off, many people are thinking about ways to support their health – especially their heart health. For a start, research shows they may want to focus on eliminating extra salt from their diet.
A recent study found that the majority of adults who significantly reduced their sodium intake to about 500 mg a day — a 75% reduction from their normal salt intake — saw their systolic blood pressure drop by about 6-8 mm Hg in one week.
“It’s a dramatic effect,” said Norrina Allen, Ph.D., M.P.H., a senior author on the study and a professor of health policy, epidemiology, and pediatrics at Northwestern University’s Feinberg School of Medicine. “That’s about the effect you would see starting medication.”
Allen said the effects from this single diet change were seen across participants with varying blood pressure levels: normal, elevated, and high but controlled with medication.
Yet, as great as its benefit, drastically cutting salt intake can be difficult, said Charlotte Pratt, Ph.D., R.D., Deputy Chief of NHLBI’s Clinical Applications and Prevention branch in the Division of Cardiovascular Sciences. Most Americans consume more than 3,300 mg of sodium each day (about 1.5 teaspoons of salt), which is higher than the recommended 2,300 mg limit for adults.
One way to make the change could be a gradual shift, said Pratt. Try consuming less than 2,300 mg of sodium each day. Then aim for a lower amount, such as 2,000, 1,500, or 1,000 mg.
Alison Brown, Ph.D., R.D., a program officer in NHLBI’s Clinical Applications and Prevention branch, explains that in our food system, a trade-off for convenient or prepared foods is that they are often high in sodium. “In a clinical setting, where meals are prepared for you, it’s a lot easier to limit your sodium to 500 mg,” said Brown. “In the real world, it’s much more challenging.”
However, research has shown that when adults limited their salt intake to around 1,150 mg each day, they achieved blood pressure reductions similar to those in the study – but measured throughout a longer period of 30 days.
The key to success?
“First, and foremost, fresh is best,” said Brown.
That means eat more fresh fruits and vegetables she said, and less foods that are heavily pre-prepared, prepackaged, or come in a can. A starting point could be to eliminate or limit the “salty six,” a reference from the American Heart Association for leading sources of high-sodium foods. “That’s bread and rolls, cold cuts and processed meats, pizza, soups, and fast-food sandwiches,” said Brown.
Hidden sources of sodium can also appear in foods that seem healthful, or that may accompany fresh items. Take salad dressing. Many options come prepackaged and contain lots of salt, said Brown. Creating a homemade version — say, using olive oil, lemon, balsamic vinegar, and a little bit of honey or sugar — could be one way to curb salt intake, she suggested.
In the study, participants ate lots of fresh fruits and vegetables, but they also ate sodium-free or reduced-sodium versions of bread, chips, soup, and dinner entrées, all of which are available at many grocery stores. “Our goal was to provide something that would potentially be achievable by anyone across the population,” said Allen.
Breakfast included oatmeal made with quick oats, Greek yogurt, and grapes. This accounted for 48 mg of sodium. Lunches included a salad with oil and balsamic vinegar, reduced-sodium lentil soup, or a sandwich made with sodium-free bread. These options then paired with fresh fruit, like an apple or banana, or other vegetables, like broccoli, for a total sodium intake between 50–91 mg. Dinner featured low-sodium versions of vegetables and brown rice, vegetable lasagna or a bean burrito — all of which had less than 300 mg of sodium — and paired with a banana, orange, and milk for a total sodium count of 340–400 mg.
Altogether, participants consumed around 2,300 calories a day, which in addition to the 500 mg of sodium, included 4,500 mg of potassium and 1,000 mg of calcium.
“Even if you can’t get to 500 mg of sodium a day, if you cut out different sources of salt to reduce your daily average, that’s going to have a benefit,” said Allen. She recommends people read food labels and compare sodium across different items and brands. “It’s a little investment of time and energy up font, but it pays off in the long run.”
There are also tricks to reading food labels. “No salt added” or “unsalted” doesn’t mean a food is sodium-free, but labels that state “sodium free” or “salt free” often contain less than 5 mg of sodium per serving. Other variations fall between “very low sodium,” “low sodium,” and “reduced or less sodium.” Note that something labeled reduced or less sodium just means it contains less sodium than the product’s prior formulation.
People looking to replicate this approach could create their own mix-and-match meals – based on foods they normally consume. They could also create meals inspired by Dietary Approaches to Stop Hypertension (DASH), a long-term, flexible, heart-healthy eating plan.
With DASH, for example, breakfast might be shredded wheat cereal with fresh fruit and low-fat milk, or a low-sodium corn tortilla made with beans, vegetables, and paired with mango, orange juice, and coffee. Lunch and dinner might center around a fresh salad with a homemade vinaigrette dressing, baked fish and vegetables, or an Asian-inspired vegetable stir-fry. (Just be mindful of the sodium in soy sauce.)
As people plan heart-healthful meals, they should also make sure they get enough vitamin D, especially if they have reduced sun exposure in the winter, and iron, which is important for women and children, said Pratt. It’s also good to limit intake of saturated fats, alcoholic beverages, and added sugars found in sugar-sweetened beverages and other foods, she noted.
As a bonus, Brown mentions people could regularly check their blood pressure. Just like weight, fluctuations in blood pressure are normal, she said, so checking it weekly, bi-weekly, or monthly can help keep tabs on progress.
She added that it typically takes a few months for lifestyle changes like these to become routine. This is why she recommends people set goals that are specific, measurable, attainable, realistic, and time-bound, or SMART. That might mean pledging to eat one extra serving of fruit each day to get closer to recommendations in DASH or the Dietary Guidelines for Americans. It could also include aiming to limit sodium to 1,500 mg (less than 1 teaspoon of salt) or less each day. People with underlying conditions, like heart failure or who have very low blood pressure, should also check in with their doctor or a dietitian before making major changes to their diet.
“It’s important for people to be realistic with goals for changing their diet,” said Brown. She acknowledged New Year’s resolutions are top of mind but emphasized that “every day is a possibility for behavior and diet change.”
To learn about the study, visit https://www.nhlbi.nih.gov/news/2023/slashing-salt-intake-lowers-blood-pressure.
To learn about reducing sodium intake, visit https://www.nhlbi.nih.gov/resources/tips-reduce-salt-sodium.
For DASH-inspired meal plans, visit https://www.nhlbi.nih.gov/education/dash-eating-plan.