Salt is the most common form of sodium and is added to food during manufacturing, during home cooking, or at the table to enhance flavor or increase shelf life.
Most people have heard the advice to reduce salt. This is because high sodium intake is linked to high blood pressure, which is a major risk factor for heart disease, heart attack and stroke.
So the recent headline “Food Myths Busted: Dairy, Salt, and Steak May Be Good for You” was bound to grab attention.
In the research article this title is based on, the authors examined whether the advice to significantly reduce sodium intake was supported by strong evidence.
The premise of the article is that the current advice to limit sodium consumption to 2.3 grams per day is unacceptable in the long term for most people. And there is not good quality evidence for claims that low salt intake can reduce the risk of heart attack and stroke.
The authors suggest that current global sodium intake, which ranges from 3–5 grams per day, is associated with the lowest risk for heart attack, stroke or dying prematurely. And that heart attack and stroke only increase when the sodium intake is more or less than this.
But there is much controversy surrounding these claims, and the current advice to limit salt consumption remains in place. Let’s take a look at some of the issues associated with these claims, as well as the important research the authors missed.
Most of us can afford to cut down on salt
One teaspoon of salt weighs about 5 grams and contains 2 grams of sodium.
Australians consume about 3.6 grams of sodium per day, which is equivalent to 9.2 grams (about 2 teaspoons) of table salt.
This exceeds the suggested dietary target of 2 grams of sodium (5 grams of salt) per day and an adequate intake of 460–920 milligrams (1.3–2.6 grams of salt) a day.
Read more: Health Check: How Much Salt Is It OK to Eat?
Sodium intake in Australia is similar to that of the rest of the world. Data from 66 countries that account for three-quarters of the world’s adult population reported that the average sodium consumption is 3.95 grams per day and ranges from 2.2 to 5.5 grams per day.
Yes, it is possible to reduce salt
Changing individual behavior over the long term is challenging. But it is possible.
A 2017 systematic review of dietary salt reduction measures found that individual dietary counseling could reduce a person’s salt consumption by about 2 grams a day (equivalent to 780mg sodium), over a time period of up to five years. .
Population-wide strategies that include improving food manufactured with lower levels of salt, better labeling and mass media education were even more effective in some areas, reducing average salt intake by about 4 grams a day in Finland and Japan .
The authors of the latest paper highlight a lack of studies in populations showing they achieved dietary sodium intake of less than 2.3 grams per day.
But it fails to acknowledge the challenges in conducting such a study to test it, or to acknowledge the importance of reducing the sodium intake you typically consume.
Cutting out salt lowers the risk of heart disease
A recently published randomized trial in 600 villages in rural China suggests that reducing salt intake may reduce a person’s risk of heart disease, heart attack and stroke.
The study included more than 20,000 people with high blood pressure who either had a history of stroke or were over the age of 60. One group was randomly assigned to use salt substitutes to reduce their sodium intake. The other group continued to use regular salt. Both groups were followed over five years.
Read more: No big salt debate: We should be consuming less
The intervention resulted in a decrease in sodium excreted in the urine (a sign of complication) and a decrease in blood pressure.
The rate of any major cardiovascular event, including heart attack, was 13% lower in the salt-substitute group than in the regular salt group. The stroke rate was 14% lower.
This trial demonstrates the benefit of reducing dietary sodium intake, regardless of a specific daily target.
Is Eating Too Little Salt Risky?
Humans need sodium to maintain essential physiological processes such as fluid volume and cell stability. Sodium levels are balanced, although there is a sensitive system of hormones, chemical processes, and nerves to ensure that more sodium is excreted in the urine than needed.
There is conflicting evidence about heart health when you have too little sodium intake. Some researchers have suggested a J-shaped relationship, where both low and very high intakes increase the risk of poor outcomes (the “J” shaped end), while the lowest risk occurs at the broad midpoint of salt intake. Is. (curve in “J”).
Read more: Salt: How to cut back without losing that savory flavor
In some studies on salt and blood pressure the J-shaped curve can be explained by issues such as measurement error, random variation, other differences (in age, sex, smoking status or socioeconomic status), existing dietary patterns or other health problems, interactions. could. A major sodium deficiency, and among the body’s physiological pathways that control blood pressure.
Or it may be explained by opposite causality, where study recruits report low sodium intake because they have already been advised to follow a low-salt diet before enrolling in the trial.
While we wait for more research to explain the discrepancies related to the J-shape curve, the evidence finds a very low sodium intake, compared to a high intake, leads to a significant reduction in blood pressure.
Read more: Seven things to eat or not eat to lower your blood pressure