I often get asked why I go against the grain (so to speak) and recommend MORE salt, rather than less salt, on a lower carbohydrate diet. Salt/sodium is often used interchangeably, but actually salt (sodium chloride) is around 60% sodium and 40% chloride (one teaspoon of salt contains around 2.3g sodium). In the standard western diet, most of the salt (sodium) comes from processed food. Bread, pizza and sandwiches are listed up there with foods that taste salty, such as cured meat and cheese. While salt has become vilified as being detrimental to health, sodium is an essential micronutrient for muscle contractions, brain health adrenal health, fluid balance.
Many people do have high blood pressure (or hypertension) and in those people, reducing the amount of salt in the diet is a first-line recommendation. However, as salt intake is difficult to quantify (as we aren’t always cognizant of the salt that is in food, or the amount that we add to food during the preparation, cooking and serving of food) establishing an optimal intake is challenging at a population level. Further, there are salt-sensitive people who do benefit from salt restriction, however the state of the evidence at this time doesn’t appear to lend itself to a population wide recommendation (despite the maximum sodium level we are recommendedto consume coming in at 2000mg, or 2g a day), with cardiologists in the field suggesting that sodium restriction may reduce blood pressure but at the detriment of other health indicators.This meta-analysis, for example, found that the increase in heart rate that occurs when restricting sodium offset the benefit of reducing blood pressure. Inflammation increases and LDL cholesterol increases in people who are hypertensive, potentially due to the reduction in LDL receptor activity and reduced ability to uptake LDL from the bloodstream into the cells.In this study, a short-term low sodium diet increased uric acid and fasting insulin, both of which are physiological abnormalities which increase the risk of cardiovascular events.
Electrolytes are well controlled by the body, and it is only in disease states where we see significant changes in levels, as opposed to changes in dietary intake. Looking only at sodium intake fails to consider the role of other minerals in blood pressure control. For example, research has found that when potassium intakes are high (through the consumption of vegetables and some fruits (such as spinach, silverbeet and avocado), blood pressure remains normal. Further, reviews on the topic report that studies have often failed to show a relationship between blood pressure, sodium intake or sodium excretion, despite population based research showing a positive trend between sodium and high blood pressure. As with any population data, it can’t show cause and effect, and often those with a higher sodium diet also have a diet that is high in processed food, sugar, higher in alcohol and are less likely to be physically active and eat adequate amounts of fruits and vegetables. The last updated Cochrane Review of the literature concluded there was insufficient evidence to support population-wide reduced sodium intake. This review, 7y on, also concurs that this is the case.What is clear now in the literature is that too low and too high sodium may well be the issue, and an intake of 3-6g a day is optimal for reduced risk of mortality. For what it is worth, features of diets that successfully lower blood pressure and potential risk of cardiovascular disease are also rich in vegetables and some fruits which provide plenty of polyphenols (plant chemicals) that help vascular function. Further, they result in significant weight loss which helps lower insulin levels, uric acid and overall health risk. This includes a paleolithic diet approach and the Atkins diet.
When following a lower carbohydrate diet (which is a diet I most often recommend to people), that relies predominantly on whole foods, there is only a very small amount of sodium present (reports of less than half a teaspoon of salt each day). With that comes significant side effects that are often confused with being a side effect of a lower carbohydrate diet (and cries of ‘carbohydrate deficiency’ lol). These side effects include
This is related to a loss of sodium, not a lack of carbohydrates. Why does this occur? It’s because when carbohydrate load drops, storage carbohydrates are depleted. In the body, for every gram of carbohydrate stored, you store an additional 3-4g of water and, with that, electrolytes. Drop the carbohydrate and the storage vehicle for water, sodium (and other electrolytes) is reduced. In addition, a higher carbohydrate load raises overall insulin load. Again, drop the carbohydrate and baseline insulin drops. As insulin helps the kidney’s reabsorb sodium, the reduced insulin causes a dumping of electrolytes including sodium. This change in insulin is a really good thing, however the disruption in electrolytes is not, and results in some of those side effects above.
Actively increasing salt intake to offset these changes helps restore the imbalance created and just makes you feel better. It is 100% necessary, and it is more than you think. So many of my clients and online members struggle initially with a change in their sodium balance, and remark just what a difference it can make to do the super simple thing of increasing salt intake. Two of the ways I suggest
Not everyone experiences this disruption, however if you do this is such an easy fix to feeling better. On the lower carbohydrate approach an individual become better able to utilise fat as a fuel source and with it, spares muscle carbohydrate stores. This means that sodium isn’t so quick to be wasted. This isn’t in the first few weeks or even months, so this trick can really help restore your electrolyte balance.