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It is generally considered common knowledge that a diet high in salt produces numerous negative health consequences. High sodium diets may lead to an increased risk of developing type 2 diabetes and may cause inflammatory markers to increase. Reducing dietary sodium has been found to decrease all-cause mortality. A low-sodium diet may decrease blood pressure related to hypertension. However, there is some evidence that both high and low sodium intakes are associated with poorer health. Very low sodium diets are linked to cognitive decline. As such, it is important to understand how sodium influences health.

Salt vs. sodium

Although “salt” and “sodium” are used interchangeably, they are different. Sodium is considered an essential mineral in the body as it is required for normal physiological function. It is often recommended that sodium intake be below 2.3 g/day. This is equivalent to 5 g of salt, likely contributing to the confusion of sodium versus salt. There is some evidence that this level of intake is not enough to support health. Newer research now suggests that consuming between 3-5 g of sodium daily is the optimal range for health. Sodium occurs naturally in foods like meat, dairy, and seafood.

Salt, or table salt, is an ionic compound between sodium and chloride (NaCl). There is some evidence that consuming more NaCl, not sodium, is associated with health risks. Recommendations to decrease salt in the diet are the result of overconsumption and the overuse of salt as a flavor enhancer and preservative in processed foods.

Other types of salt

Unrefined sea salts are touted as healthy alternatives to table salt due to their trace mineral content. However, they may also contain toxic trace minerals, such as lead, and even microplastics, depending on how and where they are sourced. Natural sea salts are a rich source of minerals and often contain calcium, magnesium, potassium, manganese, iron, and zinc, which can be helpful for counteracting the uptake and activity of toxic metals as I discuss in another blog.

Different types of salts have different health benefits:

• Himalayan pink salt comes from the Himalayan mountains. It appears pink due to the additional minerals present in its crystals (calcium, potassium, and magnesium). Depending on the type of pink salt, it may contain up to 84 trace minerals. A small study with 17 women reported that it does not differ from table salt in terms of its effect on blood pressure.
• Black salt, also called volcanic salt or Himalayan black salt, comes from India. It tends to have a strong sulfur flavor and contains minerals such as potassium and iron, with added health benefits of calcium, iron, and magnesium. Volcanic salt seems to be rich in antioxidants and relatively lower in sodium than other salts. More research is needed on this type of salt.
• Celtic grey, or Atlantic grey, salt is largely sourced from France using traditional Celtic harvesting techniques. Because Persian blue and Atlantic grey salts are relatively high in zinc and iron, they could be used therapeutically or cautiously in individuals who either need those minerals or are trying to avoid them, respectively.

Potential issues with salt sources

There are three methods for salt harvesting: salt rock mining, brine extraction, and seawater evaporation. Evaporative harvesting is the largest source of salt, which does have some negative consequences related to health and environmental impacts. Environmental impacts include changes in topography due to digging, wildlife changes, disrupted water flow, land degradation, increased dust in the air, increased water temperatures, deforestation, air pollution, salinization of freshwater, and rainfall reduction. These consequences of salt harvesting may have severe, long-term impacts on ecosystems.

Beyond the environmental consequences, salt harvesting is potentially dangerous. Rock salt mining is considered one of the most dangerous ways to harvest salt, with a history of explosive use. What’s more, microplastics are of growing concern for consumers. They may make their way into salts due to waste mismanagement. Over time, larger plastic pieces fragment into smaller pieces and can accumulate in large bodies of water, namely oceans, where much of the world’s table salt is sourced. However, salt sourced from land (e.g., Himalayan pink salt and black salt) contains more microplastics than salt sourced from oceans, which is why it’s important to know the quality of the salt you use. Microplastics cause harm by affecting cardiovascular health, neurological health, reproduction, inflammation, gut health, brain function, and immunity. For these reasons, health- and environment-conscious consumers may want to research how and where their salts are sourced by asking the salt retailer or manufacturer about its contents, even a specification for microplastics, which is now a laboratory test being measured.

Newer findings about salt

Current findings suggest that salt has a microbiome. Table salts sourced from oceans contain archaea species from the taxa Halorubrum, Halobacterium, Hallobellus, Natronomonas, Haloplanus, Halonotius, Halomarina, and Haloarcula, Natronomonas, Halapricum, and Halobacterales. They also contain bacteria, such as Sulfitobacter sp., Bacillus, Enterococcus, and Flavobacterium. While high-salt diets are considered harmful to gut microflora, little is known about how ocean-sourced salt with microbes may affect the gut, especially in salt-sensitive individuals.

Pros of salts from a health perspective

Salt is required for health. The body uses it for electrolyte and fluid balance, nutrient transport into cells, acid-base balance, nerve impulse transmission, blood pressure regulation, and gastric acid secretion. Table salt may contain several minerals, including calcium, iron, copper, cobalt, magnesium, selenium, potassium, and zinc, depending on where it is harvested. Unrefined or “gourmet” salts may contain more minerals.

There is a “sweet spot” with salt consumption, which can be observed on a U-shaped curve. However, some studies show a linear dose-dependent association between sodium and health risks. Sodium modulates immune cell function and activity. Without it, T cells and macrophages may not function properly. Excess sodium in the diet may cause gut dysregulation, which may result in unfavorable immune responses. Nonetheless, consuming sufficient amounts of sodium in the diet is critical for health as hyponatremia is a serious problem that can result in death if not addressed.

Why and how some individuals are not affected by high-salt diets may be explained by salt sensitivity. New evidence suggests that not everyone is salt-sensitive. This finding has shifted the perception that sodium is always responsible for hypertension. Abnormalities of the renal structure, levels of uric acid, family history, body weight, and preexisting metabolic disorders may be better predictors of salt sensitivity as it relates to hypertension. For people who are salt-sensitive and have high blood pressure, there is more likelihood that they will experience insulin resistance. While the mechanism is not clear, vasoconstriction and inflammation are responsible for the coexistence of these conditions.

Cons of salts from a health perspective

Despite the requirement for sodium in the diet, there are negative consequences associated with a high-salt diet. The effect of salt intake on hypertension and cardiovascular mortality is well-established in the literature. Sodium-sensitive individuals are more at risk of developing hypertension. In addition, there is a correlation between chronic kidney disease with high blood pressure related to sodium sensitivity. The condition is worsened by fluid and sodium retention. High-salt diets may increase urinary excretion, resulting in hypercalciuria, a risk factor for osteoporosis. Body weight may also determine risk status, with higher weights associated with high blood pressure and organ damage.

Some research suggests that controlling sodium intake in the diet may be more important in already hypertensive versus normotensive individuals. This is especially true if sodium intake exceeds potassium intake. The ratio of sodium to potassium may be more of a predictor of cardiovascular health than sodium alone.

Sodium restriction may benefit kidney health. When sodium is restricted in the diet, kidney disease markers decrease. Water retention and edema may require sodium restriction. However, individuals in heart failure should use caution when decreasing sodium as this can activate the renin-angiotensin-aldosterone system, which increases mortality.

Daily salt intake recommendations

Understanding how much salt to consume will help prevent the negative health consequences associated with a high and low-salt diet. Generally, recommendations are based on age, medical conditions, and activity status.

Children’s and adolescents’ sodium intake is based on an adjusted amount from adult recommendations. Generally, it is recommended that children ages 1-6 consume 1.1-1.3 g/day and adolescents ages 7-17 consume 1.7-2 g/day. However, many children consume above the recommended amounts.

Pregnant women should consume 2 g of iodized sodium per day. Although sodium was once thought to contribute to pre-eclampsia, this has since been shown to not affect risk. Iodized salt may help supplement an otherwise low-iodine diet, which would have harmful effects on fetal development and growth.

Other factors that determine salt recommendations include race, age, and medical conditions. Individuals who are black or of advanced age should consume 1.5g/day. It is often suggested that individuals with hypertension, chronic kidney disease, diabetes, and low intakes of potassium should minimize sources of sodium in the diet.

Athletes require additional sodium, especially since sodium is lost through sweat during exercise. As sodium is depleted, athletes may experience fatigue, muscle cramping, poor performance, vomiting, dizziness, and in more serious cases, low sodium may lead to coma or death. To avoid significant losses of sodium in sweat which may translate into changes in effects on performance, and negative health outcomes, athletes should replenish with fluids that contain 300-600 mg sodium (1.7-2.9 g salt) per hour of exercise. Depending on the intensity, duration, sweat rates, and environmental conditions, athletes may need more sodium to replenish losses.

Alternative uses of salt

Are salt baths useful? At present, there is no evidence to support that salt baths are effective for many of the claims commonly cited (e.g., muscle and joint inflammation, insomnia, bruises, sprains). However, it may help as an adjunct therapy for skin conditions, such as atopic dermatitis and dry skin. Salt baths, especially those high in magnesium, may improve the skin barrier, hydration status of the skin, and inflammation. Despite the lack of evidence for other claims, individuals may enjoy the relaxing experience of soaking in salt baths.

Best practices for healthy amounts of salt

While a personalized approach is recommended, some general dietary and lifestyle support to ensure you are consuming healthy amounts of salt include:

• Emphasize more variety, especially fruits and vegetables that contain potassium, in the diet.
• Minimize the consumption of processed foods, such as precooked meats, snacks, sauces, spice mixes, and processed foods that contain high amounts of salt added as a preservative or flavor enhancer.
• Increase physical activity, reduce alcohol consumption, and seek nutritional education, as these are lifestyle factors associated with proper sodium balance.

If you have questions about salt/sodium intake and which foods can best support your health, talk to your doctor, nutritionist, dietician, or another member of your healthcare team for personal options based on your individual circumstances. Note that salt and sodium can affect medications, so consult your pharmacist if taking prescription drugs.