Aluminium in table salt

Are the aluminium contents in table salt harmful?

Pawel Malczewski
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Short summary

Only a small fraction (about 1%) of the maximum daily intake of aluminium (2mg per kg of body weight) is derived from table salt. If we consider the average daily aluminium ingested, from a combination of various foods, water and kitchen utensils, then the proportion of aluminium from table salt accounts only around 10%. Aluminium contents in table salt are, therefore, negligible and do not have any impact on our health. For a quick answer click here.

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Explanation

High quantities of aluminium are toxic and their accumulation in our bodies can contribute to various health issues, such as toxicity of the nervous system, the skeletal system and the hematopoietic system. It is also associated with the Alzheimer’s disease, bone disease, such as osteomalacia, and anemia.

There is not enough evidence to suggest that aluminium is an essential or beneficial mineral for humans. (1)Lione A. The prophylactic reduction of aluminum intake. Volume 21, Issue 1, February 1983, Pages 103–109. Available here. (2)Sato K, Suzuki I, Kubota H, Furucho N, Inoue T, Yasukouchi Y, Akiyama H. Estimation of daily aluminum intake in Japan based on food consumption inspection results: impact of food additives. Food Science & Nutrition. Volume 2, Issue 4, pages 389–397, July 2014. Available here.

To determine whether the amount of aluminium contents in table salt has any impact on our health it is important to answer these two questions:

  1. Is the amount of aluminium in table salt relevant compared to the upper safe limit of aluminium intake recommended by science?
  2. Is the amount of aluminium derived from table salt relevant compared to the aluminium contents of various foods?

Some background information:
The information below relates to a normal environment and overall population and not to extreme cases where aluminium levels in the environment may be dangerously high.

  • What is the current daily intake of aluminium?
    Adults in the U.S. currently consume on average between 7–9 mg of aluminum. (3)Agency for Toxic Substances and Disease Registry. Public Health Statement for Aluminum. Available here.
    The quantity of aluminium ingested depends on the measurement method, country and region. Some other sources show different ranges: 3-12mg and 6-14mg. (4)Saiyed SM, Yokel RA. Aluminium content of some foods and food products in the USA, with aluminium food additives. Food Addit Contam. 2005 Mar;22(3):234-44. Available here. (5)IPCS INCHEM. Aluminium. Available here. (6)European food safety authority. Safety of aluminium from dietary intake[1] – Scientific Opinion of the Panel on Food Additives, Flavourings, Processing Aids and Food Contact Materials (AFC). Efsa journal. November 2009. Available here.
  • What is the safe limit of aluminium daily intake?
    The safe limit of aluminium daily intake is set to 2mg per kg of body weight. (7)IPCS INCHEM. Aluminium. Available here.
    The previous limit was set to 1mg per kg of body weight. This increase was based on no visible adverse effects of the 30mg/kg per body weight which includes a safety factor. (8)Venn BJ, Green TJ. Glycemic index and glycemic load: measurement issues and their effect on diet-disease relationships. Eur J Clin Nutr. 2007 Dec;61 Suppl 1:S122-31. Available here.
    For example, a 70kg person’s safe limit is 140mg of aluminium daily.
  • What happens to the excess aluminium?
    Most of the excess aluminium that is ingested gets excreted by the body through the feces or urine. Only a small amount of the aluminium ingested gets absorbed by the body and is located in the heart, spleen and bone. (9)IPCS INCHEM. Aluminium. Available here.
  • What are the major food sources of aluminium?
    The amount of aluminium we take per day comes mainly from food ingredients, water and aluminium utensils used in the food preparation. Aluminium intake varies between countries and regions and depends on dietary patterns, aluminium containing food additives and the frequency of usage of aluminium utensils. (10)Sato K, Suzuki I, Kubota H, Furucho N, Inoue T, Yasukouchi Y, Akiyama H. Estimation of daily aluminum intake in Japan based on food consumption inspection results: impact of food additives. Food Science & Nutrition. Volume 2, Issue 4, pages 389–397, July 2014. Available here.Foods with levels of aluminium below 5mg per kg are considered to have a low concentration of aluminium. Most unprocessed foods have a low concentration of aluminium.
    On the other hand, many processed foods and some vegetables have high concentrations of aluminium, ranging between 5mg to 10mg of aluminium per kg. (11)European food safety authority. Safety of aluminium from dietary intake[1] – Scientific Opinion of the Panel on Food Additives, Flavourings, Processing Aids and Food Contact Materials (AFC). Efsa journal. November 2009. Available here.
    The highest single dietary contributor of aluminium in our diets comes from sodium aluminium phosphate used in baked products such as breads, cakes and cookies/biscuits. (12)IPCS INCHEM. Aluminium. Available here.Food and water are the main contributors to the aluminium intake by the majority of the population. Certain foods contain higher than usual amounts of aluminium and represent the major source of exposure to this metal. Here is a list of foods with a high aluminum content: (13)National Institutes of Health. Edema. Available here. (14)Venn BJ, Green TJ. Glycemic index and glycemic load: measurement issues and their effect on diet-disease relationships. Eur J Clin Nutr. 2007 Dec;61 Suppl 1:S122-31. Available here. (15)Lione A. The prophylactic reduction of aluminum intake. Volume 21, Issue 1, February 1983, Pages 103–109. Available here. (16)IPCS INCHEM. Aluminium. Available here.
    – tea leaves, herbs, cocoa and spices;
    – processed cheeses;
    – non-dairy creamer;
    – baking powders;
    – grain products;
    – dairy products;
    – cake mixes;
    – frozen doughs;
    – pancake mixes;
    – self-raising flours;
    – pickled vegetables;
    – vegetables such as mushrooms, spinach, radish, Swiss chard and lettuce.
  • Is using aluminium utensils and aluminium foil safe?
    Frequent usage of aluminium utensils and aluminium foil in food preparation is estimated to add an additional 2mg of aluminium to the western diet. However, these statistics can vary from country to country. For example, in China, where the usage of aluminium utensils is higher, the estimated aluminium intake from utensils is about 4mg per day. (17)Aluminum in Food – The Nature and Contribution of Food Additives. Available here.
    Taking into consideration the safe daily limit of 2mg of aluminium per kg of body weight, this increase shouldn’t pose health issues. (18)IPCS INCHEM. Aluminium. Available here.
  • Are some medications high in aluminium?
    There are some medications with high aluminium contents: – some antacids may raise the daily aluminium intake by 10 to 100 times; (19)IPCS INCHEM. Aluminium. Available here.
    – buffered aspirins;
    – antidiarrheal products;
    – douches and;
    – hemorrhoidal medications.
    Check the list of drugs containing aluminium-hydroxide here.
  • How much aluminium we breathe in from the air?
    Overall, the inhaled amount of aluminium is negligible in comparison with food, even from polluted air. From unpolluted air, we intake less than 2mcg (0.002mg) of aluminium per day. On the other hand, from industrial, polluted air the level of daily aluminium intake could be as high as 124 mcg (0.124 mg) per day. (20)IPCS INCHEM. Aluminium. Available here.
  • How much aluminium do we ingest from water?
    From fresh, untreated water the aluminium intake is less than 0.001-1mg per liter. However, higher amounts are found in some regions reaching 26mg per liter. Treated water contains a small amount of aluminum sulphate, which effectively removes parasites but also increases the overall amount of aluminium in water.In the U.S. the overall average of aluminium contents in water treated with aluminium sulphate is 0.16 mg per liter. The amount of aluminium varies, though, between 0.01 to 1.3 mg per liter, depending on the treatment plant. (21)WHO. Aluminium in Drinking-water. Available here.In Europe, treated water usually contains less than 0.2 mg of aluminium per liter. (22)IPCS INCHEM. Aluminium. Available here.

Aluminium in table salt

Aluminium is used as a component of the most common anticaking agent used in table salt, the “sodium aluminosilicate” known as “food additive E-554”. (23)Synthetic amorphous silica and silicates. UNEP Publications. July 2004. Available here.

Strict government regulations only allow less than 2% of this compound to be added to table salts.

How much aluminium does this compound actually contains?
The chemical formula for sodium aluminosilicate is AlNa12SO5.

Using the online molecular calculator, you can see that the aluminium content weight only 6.5% of the whole compound.

If we consider that 2% is the maximum amount of this anti-caking agent allowed in salt, then 1 gram of salt would contain 20mg of sodium aluminosilicate, which in turn contains 1.3mg of aluminium.

How much table salt do we have per day?
From current statistics we consume on average 8,500mg of salt per day. (read more..)
See also “What is the recommended daily sodium intake?”.

About 75% of this amount comes from processed foods, 12% naturally occurs in the whole foods and 13% is added at the table or while cooking. For this myth question only 13% of the 8,500mg (1,100mg=1.1g) of salt is relevant since only this portion of daily salt intake contains aluminosilicate.

Provided that you only sprinkle table salt and not a gourmet salt (which doesn’t contain this anti-caking agent) while cooking or at the table, the following formula shows how much aluminium we actually ingest through table salt per day.

8,500mg x 0.13 x 0.02 x 0.065 = 1.4 mg of aluminium.

For clarity, the following are the components of the equation:

8,500mg: the average amount of salt we consume per day;
0.13: out of all the salt consumed per day, 13% corresponds to table salt;
0.02: maximum amount of the additive sodium aluminosilicate allowed in salt;
0.065: the amount, per weight of aluminium in sodium aluminosilicate.

Considering what is stated above, we are now able to answer the questions asked in the beginning.

Conclusion

Back to top

  1. Is the amount of aluminium in table salt relevant compared to the upper safe limit of aluminium intake recommended by science?
    The upper safe limit of aluminium is 2mg per kg of bodyweight. Therefore, a safe amount of aluminum per day for a 70kg person is below 140mg. As presented below, only 1.4mg of aluminium comes from table salt which is 100 times less than the upper limit. This makes table salt with aluminosilicate completely safe.
  2. Is the amount of aluminium derived from table salt relevant comparing to the aluminium contents of various foods?
    We consume daily between 7 and 9mg of aluminium from food and water. If we use only table salt with aluminosilicate added for cooking and sprinkling on our food at the table, the amount of that salt would be around 1.1g which contains only about 1.4mg (only about 15% of overall aluminium intake from food).

The amount of aluminium contents derived from sodium aluminosilicate that is added to table salt we sprinkle on our food, is irrelevant in comparison with the safe daily upper limit and with the total amount of aluminium ingested in our diets.
If you have concerns about aluminium toxicity from your diet or the environment, locate and eliminate the major contributors of this metal. Otherwise, there is no reason of concern.

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References   [ + ]

1. Lione A. The prophylactic reduction of aluminum intake. Volume 21, Issue 1, February 1983, Pages 103–109. Available here.
2. Sato K, Suzuki I, Kubota H, Furucho N, Inoue T, Yasukouchi Y, Akiyama H. Estimation of daily aluminum intake in Japan based on food consumption inspection results: impact of food additives. Food Science & Nutrition. Volume 2, Issue 4, pages 389–397, July 2014. Available here.
3. Agency for Toxic Substances and Disease Registry. Public Health Statement for Aluminum. Available here.
4. Saiyed SM, Yokel RA. Aluminium content of some foods and food products in the USA, with aluminium food additives. Food Addit Contam. 2005 Mar;22(3):234-44. Available here.
5. IPCS INCHEM. Aluminium. Available here.
6. European food safety authority. Safety of aluminium from dietary intake[1] – Scientific Opinion of the Panel on Food Additives, Flavourings, Processing Aids and Food Contact Materials (AFC). Efsa journal. November 2009. Available here.
7. IPCS INCHEM. Aluminium. Available here.
8. Venn BJ, Green TJ. Glycemic index and glycemic load: measurement issues and their effect on diet-disease relationships. Eur J Clin Nutr. 2007 Dec;61 Suppl 1:S122-31. Available here.
9. IPCS INCHEM. Aluminium. Available here.
10. Sato K, Suzuki I, Kubota H, Furucho N, Inoue T, Yasukouchi Y, Akiyama H. Estimation of daily aluminum intake in Japan based on food consumption inspection results: impact of food additives. Food Science & Nutrition. Volume 2, Issue 4, pages 389–397, July 2014. Available here.
11. European food safety authority. Safety of aluminium from dietary intake[1] – Scientific Opinion of the Panel on Food Additives, Flavourings, Processing Aids and Food Contact Materials (AFC). Efsa journal. November 2009. Available here.
12. IPCS INCHEM. Aluminium. Available here.
13. National Institutes of Health. Edema. Available here.
14. Venn BJ, Green TJ. Glycemic index and glycemic load: measurement issues and their effect on diet-disease relationships. Eur J Clin Nutr. 2007 Dec;61 Suppl 1:S122-31. Available here.
15. Lione A. The prophylactic reduction of aluminum intake. Volume 21, Issue 1, February 1983, Pages 103–109. Available here.
16. IPCS INCHEM. Aluminium. Available here.
17. Aluminum in Food – The Nature and Contribution of Food Additives. Available here.
18. IPCS INCHEM. Aluminium. Available here.
19. IPCS INCHEM. Aluminium. Available here.
20. IPCS INCHEM. Aluminium. Available here.
21. WHO. Aluminium in Drinking-water. Available here.
22. IPCS INCHEM. Aluminium. Available here.
23. Synthetic amorphous silica and silicates. UNEP Publications. July 2004. Available here.

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