Sodium: A Practical Guide
Sodium is essential for life. While much is made of the risks of excess salt, if you are consuming a nutritious and minimally processed diet, your healthy appetite for sodium generally ensures you get enough. Adding ‘salt to taste’ is likely a pretty good rule of thumb.
While most people will get plenty of sodium from food, if you start to reduce the processed foods in your diet, you may need to pay more attention to your electrolyte intake, including sodium.
While you need more sodium if you are active and sweat a lot, you will likely benefit more by focusing on getting enough of the other electrolytes (potassium, magnesium and calcium) from your diet before you need to worry about adding extra sodium.
What does sodium do in your body?
Sodium is the essential ion for nerve conduction, muscle activation and cell signalling. Sodium plays a crucial function in maintaining acid/base balance, glucose utilisation, digestive and nervous system function, blood pressure and fluid balance.
Salt and hydration
Sodium also plays a vital role in keeping you hydrated.
- Consuming adequate salt will help you hold onto fluid in your cells. However, consuming too much salt can cause you to hold onto excess water.
- Your thirst will increase to help you flush excess salt from your body.
- Conversely, consuming too much water can cause you to flush too much sodium from your system.
Athletes trying to lose weight rapidly to ‘make weight’ (e.g. boxers, MMA fighters, etc.) may intentionally manipulate their sodium intake to reduce their water retention. However, this is not healthy weight loss, especially over the long term. A lack of sodium can stimulate appetite (to get more sodium) and prevent fat loss.
Sodium deficiency conditions
Signs that you may be getting too little sodium include:
- heat exhaustion,
- low blood pressure,
- rapid pulse,
- loss of appetite,
- muscle cramps,
- reduced body weight, or
Factors that increase your demand for sodium
You may need more sodium if you:
- drink a lot of coffee,
- use diuretics,
- drink too much water,
- are very active and sweat a lot, or
- consume inadequate potassium.
Sodium and the keto flu
A lack of electrolytes, including sodium, is the cause of the ‘keto flu’ that many people experience when they reduce their intake of processed carbohydrates.
Your pancreas upregulates insulin to hold onto electrolytes such as potassium in the kidneys when you’re not getting them from your diet.
Sodium vs potassium
The sodium-potassium pump is central to your energy production and the movement of that energy around your body. Potassium depletion also induces sodium retention, which is associated with hypertension, diabetes and heart disease.
In days gone by, salt was rare and highly valued, so we evolved mechanisms for protecting against the threat of low sodium levels (i.e. we crave sodium and actively seek it out). However, because potassium was plentiful, we have not developed similar mechanisms to protect us against low potassium levels.
Our Paleolithic hunter-gatherer ancestors are thought to have consumed about 11,000 milligrams (mg) of potassium a day from fruits, vegetables, leaves, flowers, roots, and other plant sources, and less than 700 mg of sodium, so our potassium:sodium ratio could have been as high as 10:1.
While we have intense cravings for salt, sodium could be a stop-gap measure when what our body wants is more potassium. You require less sodium when you get enough potassium.
If you are active, then you need at least as much potassium as sodium (i.e. 1:1 potassium ratio). However, if you are relatively sedentary, you should ideally be consuming more than twice as much potassium as sodium (i.e. 2:1 potassium:sodium ratio).
Nutrient Optimiser algorithm sets a minimum of 1:1 potassium:sodium ratio, so we will not prioritise food that contains more sodium until you are getting more potassium. We find most people need to chase more potassium in their diet before they worry about supplementing large amounts of sodium.
What sodium supplement should I use?
Most table salts come fortified with iodine these days to help with thyroid health. You can choose a natural mineral salt that has some other trace minerals, but the reality is that the quantities of these other minerals are negligible, so you can’t rely on Himalayan salt or
Celtic sea salt to give you meaningful levels of potassium, magnesium or calcium without consuming maximum quantities of sodium. If you want to keep your eye on potassium, a good option is to supplement with a lite salt which is a mixture of potassium and sodium.
Anecdotally, many people find that they can fast for longer if they supplement with some additional minerals, including sodium.
It’s worth noting though that we have a much stronger satiety response to foods with more potassium than to sodium. Foods with more sodium drive a 20% reduction in food intake, while foods and meals with more potassium tend to drive up to a 35% reduction in food intake! Potassium seems to be more important for most people because they are likely not getting enough while getting a substantial amount of sodium.
It seems that we don’t have an appetite for foods with very low sodium content (i.e. less than 2 g/2000 calories). However, we end up consuming more energy if we eat foods with moderate salt content (2 to 4 g/2000 calories). Once we get to higher sodium intakes, our appetite seems to settle down and the food likely tastes ‘too salty’ because we have had enough sodium.
The rate of sodium absorption into your body is governed by the amount of sodium already in your body. When we need more sodium, it is absorbed quickly. However, if we already have plenty of sodium in our body, sodium will hang around for longer including on our tongue, so the food will taste “saltier” if we have already had plenty of sodium on board.
How much sodium is optimal?
In the past, the official recommendation has been to consume less than 1 g per day of sodium due to worries about hypertension with high sodium intakes. However, in 2017, the Australian target intake (i.e. not minimum) was raised to 2 g per day for adults. The concerns about sodium may actually have been due to the low potassium:sodium ratio rather than the high sodium in and of itself.
The charts below from the PURE study indicate that greater than about 4 g of sodium is ideal for improving your risk of cardiovascular events or death from any cause. Unlike potassium, there is some downside to excess sodium intake (e.g. hypertension), particularly if potassium intake is also low.
The average sodium intake for Optimisers is 2.9 g per 2000 calories with an 85th percentile intake of 4.5 g per 2000 calories. There is no upper limit set for sodium given requirements are so individualised. Adding too much sodium on an empty stomach can quickly give you a ‘dose of the salts’ and leave you running to the toilet followed by guzzling water to clear the excess sodium, so in a way, it is self-limiting.
Based on the satiety analysis, we have set a target sodium intake of 5.0 g/day for men and 4.0 g/day for women. However, before jumping to these higher intakes of sodium you should ensure you are getting more potassium than sodium.
The table below shows suggested stretch targets for optimal intake compared to the average of the Optimisers, the EAR, RDI, and AI. Once you have started to get the hang of nutrient density, you could ‘level up’ by working to target these stretch targets to truly optimise your nutrition.
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Availability of sodium
The chart below shows that sodium in the diet has decreased since 1960. It’s interesting to note that this decrease in sodium in the food system has the strongest correlation with increasing obesity.
Foods containing more sodium
Foods that contain more sodium include:
- Parmesan cheese
- egg white
- cottage cheese
Sodium works synergistically with vitamins B6, D, bicarbonate, calcium, magnesium, phosphate and potassium.
The nutrient fingerprint chart below shows that we can obtain adequate sodium from a nutrient-dense diet.
Nutritious foods to naturally boost your sodium
If you are experiencing any of the symptoms of low sodium or are concerned that your current sodium intake is low, then you may be interested in our lists of sodium-rich foods and meals.
What you will get:
- Our Nutritional Optimisation Kickstart Guide,
- A list of the most popular 50 foods that contain more sodium,
- A list of 100 popular foods that contain sodium, and
- An even longer list of 150 common foods that contain more sodium to allow you to expand your nutrient-dense repertoire further.