Salt is one of the most crucial nutrients for the human body. Our bodies need salt for essential tasks such as muscle and nerve functions, balancing fluids and minerals and maintaining a healthy blood pressure. But today, the average American is consuming several teaspoons of salt per day — well over the recommended maximum of one teaspoon (2,300 milligrams) per day for a healthy adult. So, what's the link between salt and diabetes?

Too much sodium contributes to high blood pressure, cardiovascular disease (CVD), kidney problems and other health issues. A high sodium intake can be especially harmful to those at risk of or diagnosed with type 2 diabetes because Americans with diabetes are twice as likely to have a heart attack or stroke, even if blood glucose levels are in control.

Why is salt harmful for people with diabetes?

Diabetes and heart disease often go “hand in hand” because cardiovascular disease (CVD) is the leading cause of death among people that have diabetes. While consuming salt doesn’t affect your blood glucose levels directly, it impacts pathways critical to your long-term health. 

Excessive sodium intake can lead to:

High blood pressure 
Consuming too much sodium over time will stiffen and narrow your blood vessels, making your heart work harder to get oxygen to where it’s needed, resulting in higher blood pressure. High blood pressure (also called hypertension) can make a healthy individual more susceptible to CVD, stroke and kidney disease, and diabetics are already more prone to these health conditions. A recent Cochrane review showed that dietary salt restriction, as compared with high salt intake, reduces mean arterial pressure by 0.4 mm Hg in normotensive persons and by 4 mm Hg in those with diagnosed hypertension.

Swelling in your legs and feet 
Sodium is a main mineral responsible for maintaining a normal blood volume, blood pressure and balancing the fluids in your body. Too much sodium can raise blood pressure and results in fluid retention. This can lead to swelling in your legs and feet and other health issues. 

Kidney Disease
Your kidneys filter 120 quarts of blood every day, pulling toxins and unwanted fluid from cells throughout the body, then sending them to the bladder. Eating too much salt can make it harder for your kidneys to remove fluid, which then builds up in your system and increases your blood pressure. Over time, this hypertension can stiffen and narrow the blood vessels, resulting in decreased blood and oxygen flow to key organs. So the heart tries harder to pump blood throughout the body, which further increases blood pressure. It can enlarge the heart’s left pumping chamber and weaken the heart muscle (heart failure). Unchecked hypertension can also damage the artery walls, which begin to collect fat, leading to heart disease and potentially heart attack or stroke.

Heart Disease (CVD)
The heart is responsible for circulating blood throughout your body — and when the blood vessels are less effective at their job, that increases your risk for an enlarged heart and many types of heart disease. Both diabetes and high blood pressure are risk factors for the top three types of heart disease: atherosclerosis (when blood vessels don’t pump as effectively), heart failure (when the heart muscles are too weak to pump blood properly) and arrhythmias (irregular heartbeat).

Insulin resistance
Studies have shown a link between high blood pressure and insulin resistance. When patients have both diabetes and hypertension, their risk for CVD increases even more.

Poor Sleep
Studies have indicated that a dinner high in sodium can contribute to a disturbed sleep, likely due to the increase in blood pressure and fluid retention that directly follows a salty meal. The researchers found that higher-sodium meals lead to restlessness, frequent waking up and not feeling rested in the morning. 

Weakened Immunity
Research suggests excessive salt intake may also have adverse effects independent of blood pressure, such as activation of the immune system.

How much salt should I eat if I have diabetes?

The individual effects of salt intake on blood pressure are highly variable: many people are able to consume large amounts of salt without substantial rises in arterial pressure. Furthermore, associations between very low salt intake and excess mortality have been cited as a risk. However, a recent meta-analysis published in the New England Journal of Medicine throws doubt upon those earlier low-sodium concerns, stating that related trials had “methodologic limitations, including inaccurate estimates of individual sodium intakes and reverse causation related to coexisting conditions or changes in health status.” Their conclusion: the less sodium, the better. However, you should always consult with your medical provider to determine the best nutritional plan for you.

If you have diabetes, the American Diabetes Association recommends limiting sodium intake to 2,300 milligrams (mg) per day, which is one teaspoon of table salt. However, some health professionals recommend that diabetics shouldn’t consume more than 1,500mg each day, the level for a low-sodium diet. Studies have shown that decreasing salt intake below 2,000mg can lower blood pressure and risk for CVD.

What causes salt cravings?

We’re just used to it

You might be craving salt because it’s simply ubiquitous in the American diet and, similar to sugar, your taste buds like what they’re used to. It might be surprising to hear that the highest sources of sodium intake don’t come from your salt shaker. Rather, high daily sodium levels typically derive from eating out and packaged foods, often referred to as “hidden salt.” One study showed that dining out accounts for more than 70% of our sodium intake. Packaged foods (such as marinara sauce, deli meats, oatmeal, condiments, bread and cheese) also tend to be very high in sodium. 

Poor sleep hygiene and stressful lifestyles

Similar to why we crave sugar, stress and lack of sleep impact your hormone levels: released cortisol increases, leptin (the hormone that tells you when you’re full) decreases, ghrelin (the hunger hormone) and serotonin increase. A culmination of this imbalance means you’re likely to crave comfort food and have less control over what you’re eating. 

Exercise or excessive sweating

Salt comes out of our body in two ways: through urine and perspiration. The act of sweating reduces the amount of sodium in your body and when you have lost too much sodium, your body will tell you by craving what it needs: something salty. Restoring sodium levels, through electrolytes for example, can be a good option for competitive athletes or those who exercise intensely for more than an hour.

Addison’s Disease/Adrenal Deficiency

Also known as primary adrenal insufficiency, Addison’s disease is a rare hormonal disorder that results from low production of the cortisol and and aldosterone hormones. Affecting only about one in 100,000 people (or 40-60 people for every million), symptoms can include low blood pressure (hypotension) and low blood glucose levels, along with salt cravings.

Types of salt: Are there relevant differences?

Most salts have about the same amount of sodium per teaspoon and offer no real nutritional differences. The major differences you’ll notice across salt varieties is the taste and how they mix (or stay in flakes) on your food. 

Dietary salt can come from either the earth or the ocean, and salts are typically categorized based on how they’re processed: refined and unrefined. Refined salts are ground down and might have anti-caking chemicals added to stop the granules from clumping together. These include granulated table salt, iodized salt and curing salt. Unrefined salts are typically larger, nonuniform and flakey crystals — such as coarse salt, sea salt or colored salts like Himalayan pink salt. The different hued salts — such as black, pink, unicorn — are due to very minor traces of minerals that may have a mild flavor, but no effect on your nutrition because the amount you consume is negligible.

How do I lower my salt intake?

Stay in control: make it at home

Because the majority of our sodium comes from food others prepare for us, an easy way to significantly decrease our sodium intake is to make it at home. To avoid processed or packaged foods packed with sodium, look for the canned foods labeled with “no added salt,” “low sodium” or “salt reduced.” 

Take a step-wise approach: the 10% rule

No dietary change is easy, so we recommend slowly lowering your salt intake. It might take your taste buds two to three months to adjust to the change, so be patient. Studies show that decreasing the amount of sodium in our food by about 10% is unnoticeable.

Use other flavor enhancers

Garlic, vinegar, ginger, herbs, citrus, pepper and other spices are all excellent ways of keeping your food exciting and flavorful without adding salt. 

Look at the whole label

Foods that contain 400mg or more of sodium are considered to be high in sodium. Also avoid ingredients such as “salt brine” and “monosodium glutamate.” Be aware that many low-sodium foods can be high in carbohydrates (especially sugars) and fat, so it’s important to look at all of the nutrients on the food label before selecting the lowest-sodium option. 

Foods that are labeled “no sodium” and “low sodium” can contain potassium salt substitutes in high amounts. While a recent large, cluster-randomized trial showed that persons who received a potassium-containing salt substitute (75% NaCl, 25% potassium chloride), rather than typical salt (100% NaCl), not only had lower blood pressure but also had lower rates of stroke, major cardiovascular events, and death from any cause, it’s also important to note that problems can occur when blood potassium levels are either too high or too low. Damaged kidneys allow potassium to build up in your blood, which can cause serious heart problems. If you’re worried about your potassium levels, check with your doctor about the best choices for you.

Key takeaways

Individuals with diabetes are more likely to experience cardiovascular disease, so a focus on heart health is an important part of a long-term health plan. Excessive sodium intake can lead to high blood pressure, inflammation, kidney disease and poor sleep — all factors that can contribute to the risk of heart attack and stroke. Lowering your sodium intake starts with cooking more of your own meals, using flavor enhancers beyond salt to add intrigue to your food, conscious shopping (checking the labels), and — most importantly — taking the time to slowly lower your salt intake.