Salt is a subject that sparks a lot of recommendations for snacks in our Addison’s and adrenal insufficiency community! But why do people with Addison’s crave salty, acidic and sour foods at diagnosis, and then salt remains our “pick me up” when diagnosed? Professor Simon Pearce explains the connection between aldosterone, fludrocortisone and why you should always listen to your salt cravings. 

Overheard in Clinic

• “I could only eat very salty gravy”
• “I peeled and ate a lemon dipped in table salt”
• “I crave the juice left in the jar after the pickles are finished”
• “I found the wrappers for 3 family bags of salt & vinegar crisps under her bed. Can you tell her to eat more healthily” (mother of a teenager).
• “I was worried that I was getting worse because I started eating raw cooking apples again.”

Adrenal Glands

As well as secreting cortisol, healthy adrenal glands also make a hormone called aldosterone, which acts on your kidneys to tell them to keep salt in your body. Endocrinologists call this hormone a mineralocorticoid. In Addison’s disease, without this aldosterone your kidneys are constantly leaking sodium salt, leading to symptoms including light headedness, postural dizziness, low blood pressure, a constant washed-out or generally weak feeling, cramps and spasms including in the legs, lower back and abdominal pain. As well as these different symptoms, many people also start to crave salty foods, potato crisps, vinegar, pickles, soy sauce, olives, lemons, granny smith apples, sour sweets (‘fangtastics’ or ‘toxic waste’).

Fludrocortisone

Lack of aldosterone is compensated for by taking fludrocortisone tablets. However, many patients wonder whether the fludrocortisone is really necessary. In contrast to hydrocortisone, if you miss a dose of fludrocortisone you probably don’t notice an immediate effect on how you feel. This is because your body contains a large reservoir of salt and so most people won’t feel bad until they have missed 2 or 3 days of fludrocortisone tablets.

Furthermore, if the weather is very hot, or you are working in a hot environment or exercising vigorously, you will lose more salt from your body through sweating. This leads to the advice that you should increase your salt intake or increase your fludrocortisone doses when you go on holiday.

Young people and those who are physically very active often need to take higher fludrocortisone doses, occasionally five or six tablets daily. Whenever you have a blood test, your doctor will measure your electrolytes (aka ‘U&E’) which includes the sodium level. The normal range for blood sodium in healthy people is 135–145 and even a slight decrease (eg. 133 or less) is significant for someone with Addison’s disease, and suggests that more fludrocortisone would be beneficial. Before making any changes to your fludrocortisone dose, always speak with your Endocrinologist and have the appropriate tests.

If you feel unwell due to salt deficiency, such as light-headedness, cramps or feeling generally washed out, to feel better quickly you will need to take some salt. I often recommend soup and salty crackers (or sodium tablets, see below). This is because taking extra fludrocortisone will stop your body leaking salt, but you still need to fill up your tank to feel better. If you crave salty or sour food, this is a clear message from your body that you should take something salty. I have heard from a few people that it is also possible to dream of salty foods!

Normal dietary advice to avoid too much salt in your diet does not apply to people with primary adrenal insufficiency, and this important feeling should not be ignored. Also, be careful to eat real table salt, not ‘Lo salt’, as the low salt products contains potassium which will not help your salt (sodium) deficiency. When you think about it, the most worrying features of an adrenal crisis, that is low blood pressure, fast heart rate and feeling very faint, are the same as severe salt depletion and there is no doubt that insufficient fludrocortisone intake is a common reason for people having repeated adrenal crises.

The recommended dietary allowance (‘RDA’) for salt is 6 grams each day for healthy people, however this is too little for people with Addison’s disease. When you have an adrenal crisis and need a drip, each litre bag of saline contains 9g of salt, and it is usual to have 3 bags a day for 24 or 48hrs in this situation, meaning you receive about 30-60g of salt. This is one of the main reasons your feel better.

As well as fludrocortisone, it is sometimes necessary to prescribe salt tablets for people, known as ‘slow sodium’ tablets. However, each slow sodium tablet contains only 0.6g (600mg) of salt, meaning that to get to the basic ‘RDA’ you need to take ten per day (of course we mostly get more than the RDA from our food alone). This is a really safe and extremely cheap medication, so if you habitually find yourself feeling faint or weak following exercise or after you have been in a hot place for a while, then swigging five or ten slow sodium tablets with a couple of glasses of water is a good start. I have often had to give advice to other doctors who have recognised that someone is salt depleted and started them on two slow sodium tablets daily; this really doesn’t start to address the deficiency.

If you overdose on salt or fludrocortisone, you will notice that your feet and ankles become puffy. This is a reliable sign in most people and it may mean you need to reduce your fludrocortisone dose, although this should only be done after consulting your endocrinologist. One other thing to watch out for is liquorice, which interacts with your medications to produce salt-retention in the same way as aldosterone does. People with Addison’s need to avoid liquorice for this reason.

Lastly, why sour as well as salty foods? Sour is the taste of acidic things, but more than that is not really clear. In general, chronic deficiency of steroid hormones in your body leads to too much acid in your blood, so why people crave sour food is currently mysterious.

 

ADSHG’S Favourite Salt Snacks!

So what's your go to salty snack? Here at ADSHG HQ we're reaching for the Co-op Irresistible Sea Salt Chardonnay Wine Vinegar Crisps (we can't get enough!), adding extra soy sauce in Cup a Soup, salt sachets in lemonade and of course, snacking on the classic gherkin!

Author: Professor Simon Pearce, MD FRCP. Simon Pearce is a Professor of Endocrinology at Newcastle University and an Honorary Consultant Physician at the Royal Victoria Infirmary, Newcastle with a research interest in Addison’s disease and autoimmune thyroid disease. He trained in endocrinology at Hammersmith, London; in Boston, USA and latterly in Newcastle.  He joined the Addison's Clinical Advisory Panel in 2005 and was an ADSHG Trustee 2018-2020.  Simon is the co-author of "Living with Addison's Disease – A Guide For People With Addison's, Supporters and Professionals", which won a commendation at the 2019 British Medical Association (BMA) Patient Information Awards. He is Editor in Chief of the European Thyroid Journal and president of the British Thyroid Association (BTA).

 

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