Too Much Salt Linked to Increased Risk of Type 2 Diabetes

A person in a white shirt puts salt in a pan.
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  • People at risk for developing type 2 diabetes are usually advised to limit their sugar intake and adopt healthier lifestyle practices.
  • New research from Tulane University suggests that high salt consumption could be a risk factor for type 2 diabetes.
  • Researchers and experts advise reducing sodium intake since most people in the U.S. exceed the daily recommended amount.

The rising global prevalence of type 2 diabetes is a significant healthcare concern and a leading cause of mortality. Each year, more than 1 million deaths are attributed to diabetes.

Research published in 2020 reported that 462 million individuals were affected by type 2 diabetes in 2017, with a prevalence rate of 6,059 cases per 100,000. By 2030, type 2 diabetes is projected to increase to 7,079 cases per 100,000.

People at risk for developing the condition, such as adults over 45 and those with obesity, are often advised to limit their sugar intake, follow a balanced diet, and get regular exercise.

Now, new research from Tulane University suggests that reducing salt intake could also help prevent the onset of type 2 diabetes (T2D).

The study, published on November 1 in Mayo Clinic Proceedings, is the first to investigate a link between the behavioral marker of adding salt to foods and type 2 diabetes risk.

“We already know that limiting salt can reduce the risk of cardiovascular diseases and hypertension, but this study shows for the first time that taking the saltshaker off the table can help prevent Type 2 diabetes as well,” said lead study author Dr. Lu Qi, PhD, director of the Tulane University Obesity Research Center and professor at the School of Public Health and Tropical Medicine, in a press release.

While the researchers noted that further studies are needed to understand why high salt intake affects diabetes risk, the study did establish an association between greater salt intake and higher body mass index (BMI).

High salt intake increases diabetes risk

Tulane University researchers examined salt intake for over 400,000 adults registered in the UK Biobank for nearly 12 years.

Over 13,000 participants who regularly used salt developed type 2 diabetes, which occurs when the body no longer properly regulates blood sugar and leads to insulin resistance.

When compared to participants who “never/rarely” used salt, researchers determined that people who “sometimes,” “usually,” or “always” used salt were 13%, 20%, and 39% more likely to develop type 2 diabetes, respectively.

Kelsey Costa, a registered dietitian and nutrition consultant for the National Coalition on Healthcare, noted that high salt consumption could raise the risk of developing type 2 diabetes through its effects on: 

  • weight
  • blood pressure
  • metabolism
  • inflammation

Costa, who was not involved in the research, said excess salt intake may disrupt the balance of gut bacteria, leading to intestinal inflammation, which contributes to insulin resistance and increases the risk of developing type 2 diabetes.

“Inflammation can damage cells and tissues in the body, leading to insulin resistance and impaired glucose metabolism,” Costa told Healthline.

What’s the link between salt intake, obesity, and type 2 diabetes?

Excess salt consumption has been associated with hypertension and weight gain, which raise the risk of developing type 2 diabetes. 

“This may happen because high salt intake, especially in overweight individuals, can lead to increased calorie (and sodium) consumption,” Costa explained.

To help unpack why salt consumption could affect diabetes risk, Costa cited a new theory suggesting that fructose, a type of sugar found in many foods, could contribute to obesity by affecting cellular metabolism and increasing the desire for high-energy foods

“Fructose is not just from dietary sources but can also be produced by the body from glucose, especially when consuming high-salt, low-water diets. This increased fructose production can lead to leptin resistance, a hormone that helps regulate appetite,” she explained.

“Reduced sensitivity of body tissues to leptin can result in obesity and metabolic complications such as insulin resistance and abnormal lipid levels because it disrupts the body’s normal energy balance and metabolism,” Costa said.

Excess salt may correlate with poor dietary habits

Qi explained that people who add salt may be more likely to consume larger portions, which increases type 2 diabetes risk factors such as obesity and inflammation.

He said that adding high amounts of salt to foods may be correlated with other poor dietary factors. 

“In our analysis, we have carefully adjusted for various dietary factors; this may minimize the influence of such correlations on the findings,” Qi told Healthline.

“Our data suggest that the observed relations between adding salt to foods and diabetes risk may be partly due to high adiposity due to salt intakes. Adding salt to foods is related to high adiposity, as we have shown in our mediation analysis in this study, a certain proportion of the association between adding salt to foods and diabetes is mediated through adiposity measures,” he said.

Should you avoid salt?

While high salt intake may be a risk factor for type 2 diabetes, Costa said healthy individuals shouldn’t be too concerned as long as they avoid consuming excessive amounts.

“The human body requires a small amount of sodium to maintain the right balance of fluids, send nerve signals, and help muscles contract and relax,” she said.

Costa noted that a dash of finishing salt on your meals is likely safe for most people. Still, it’s important to maintain healthy, balanced eating habits and monitor other sodium sources in your diet.

“Proactively considering low sodium alternatives to salt for seasoning can be beneficial,” Costa added. 

“This approach not only nurtures mindful eating but also enhances your meal’s nutritional value without sacrificing flavor.”

Are some salts healthier than others?

Costa explained that salt is composed of sodium and chloride ions, but the amount of sodium in different types of salt can vary depending on the source and processing methods.

“A teaspoon of table salt contains approximately 2,300 mg of sodium. Salts with larger crystal sizes, such as certain sea salts and pink salts, have less sodium content per teaspoon than table salt because the larger crystals take up more space, meaning fewer crystals — and thus less sodium — fit into the spoon,” Costa said.

Some salts, such as pink Himalayan sea salt, are marketed as “healthier” since they contain minerals like magnesium and potassium. But even “healthier” salts still contain sodium.

“These minerals are present in tiny amounts, and to gain a significant nutritional advantage from these minerals would require an excessively high intake per day, which could lead to potential adverse health effects,” Costa said. 

“By weight, all types of salt contain roughly the same amount of sodium. Ultimately, all forms of salt can contribute to high blood pressure if consumed in excess.”

How much salt is too much?

The 2020–2025 USDA Dietary Guidelines recommends that adults limit their daily sodium intake to less than 2,300 milligrams. The American Heart Association (AHA) has similar recommendations but advises adults with hypertension to reduce their salt intake to 1,500 milligrams daily.

“This includes both the salt we add during cooking and at the table, as well as the sodium naturally present in foods,” Costa said.

Still, Costa pointed out the average sodium consumption in the United States is around 3,400 milligrams per day, far exceeding the recommended levels.

“While the USDA’s guideline sets the upper limit at 2,300 milligrams of sodium per day, it must be emphasized that this is not a target but an upper boundary.

“For healthier dietary practices, individuals should aim for a lower sodium intake,” Costa said, noting that the AHA’s recommendation of 1,500 mg daily was a healthier target.

“This reduced sodium intake not only supports cardiovascular health but also contributes to better overall health outcomes. Regular monitoring and adjustment of one’s diet can ensure that this goal is met without compromising the taste and enjoyment of food,” Costa noted.

If you have questions about how your salt intake may be affecting your health, ask your doctor for more guidance.

Low sodium swaps for salt

The Tulane University researchers noted it’s a good idea to consider low sodium swaps for salt, particularly among those with a higher risk of developing type 2 diabetes. 

Costa said there are many healthy and flavorful alternatives to using salt in cooking and seasoning and shared a few examples: 

  • Herbs and spices: Using herbs and spices can enhance the flavor of dishes without adding sodium. Experiment with different combinations of herbs and spices to find your preferred flavor profiles.
  • Lemon or lime juice: The acidity of citrus fruits like lemon or lime can add a bright and tangy flavor to dishes, reducing the need for salt.
  • Garlic and onion: These aromatic vegetables can provide depth of flavor to meals. Try using fresh or dried versions in your cooking.
  • Nutritional yeast: This ingredient has a savory, cheesy taste that can be used to flavor many recipes. It also contains essential nutrients like B vitamins and protein.
  • Salt-free seasoning blends: Many companies make salt-free seasoning blends specifically designed for people looking to reduce their sodium intake. These blends often contain a variety of herbs, spices, and other flavorings to enhance the taste of dishes without adding any sodium.

“Always remember to check the ingredient list of spice blends, as many can contain added salt as a primary ingredient, defeating the purpose of choosing this option. Read labels carefully and choose options with no added salt,” Costa said.

Takeaway

New research from Tulane University suggests that reducing salt intake could also help prevent the onset of type 2 diabetes. Past studies have found that excess salt consumption has been associated with hypertension and weight gain, which raise the risk of developing type 2 diabetes. 

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