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Elemental composition of human body (

The vitamins and minerals discussed on this page are considered to be the main culprits as far as deficiencies are concerned.  This does not mean that some individuals may have additional  or different deficiencies.

As background, it is useful to compare the significant elements that comprise the human body and compare that to sea-water which is where it is believed that all life began.

Elements in sea water

It is easy to see that elements such as chlorine, sodium, magnesium, sulphur, calcium and potassium are important to the human body and this is reflected in their abundance is sea water.

Vitamin D

Vitamin D deficiency is discussed on our Sunlight page.


Magnesium is important to over 300 processes in the human body including the production and use of energy within your cells.

Around 60% of your 25 grams of magnesium is stored in your bones and the rest is in your soft tissues with very little in circulation.  You need at least 0.5 grams (500mg) per day in your diet to keep magnesium levels at an adequate level.  Unfortunately, it is now almost impossible to get this amount of magnesium from food sources due to soil depletion.  However, assuming a reasonable soil, best dietary sources are: green leafy vegetables, cocoa solids (as in dark chocolate), almonds and brazil nuts.

Unless you regularly spend time swimming in sea water, you will likely need to find supplemental sources.  Magnesium is available in tablet form for oral consumption, however, it is reasonably clear that this is an ineffective method due to its poor absorption.

If you are a bather then you are much better off adding Epsom salts (a compound of magnesium and sulfate) to your bath water regularly.  If you are not a bather, then using a topical spray of magnesium chloride (often referred to as Magnesium Oil) is your best approach.

Given how important magnesium is to the production of energy within your cells, it is hardly surprising that low magnesium levels are strongly linked to the initiation and proliferation of cancer.

We highly recommend magnesium supplementation for its cancer prevention properties and its overall importance to maintaining good health.


Despite miasmic claims linking sodium consumption (as salt) with heart attacks, sodium remains critically important to your health.  Avoiding salt intake is a bad idea.

Insufficient sodium intake can result in weakness, fatigue, cramps & spasms,  personality changes, seizures, coma and death.

You are not likely to be deficient in sodium if you are eating a western-style, processed food diet as this contains high levels of salt.  If you are eating a low-carb diet based on whole foods (animals and plants), you must include additional salt in your diet to prevent deficiencies.

You should aim to add at least 2 grams  (2000mg) of salt to your meals each day and some sources have this as high as 4 grams (4000mg) per day.  As salt is readily excreted by the kidneys, it is very hard to overdo salt.


Iodine is a critically important mineral in your diet as it is essential to normal metabolic functions.  A deficiency of iodine can lead to symptoms such as:

  • nodules / enlarged thyroid – “goiter / goiterism”.
  • fatigue, weakness
  • hair loss, dry skin, brittle nails, thinning of eyebrows
  • puffy eyes, puffiness in general
  • low body temperature,  feeling the cold more than normal
  • decreased heart rate
  • memory problems, reduced mental capacity
  • heavy or irregular periods
  • fibromyalgia
  • fibroids

Lack of iodine severely affects the developing brain and mothers who are low in iodine during pregnancy and lactation can significantly impact the brain development of their infant.  Infants may be born with cretinism, developmental disorders and low IQ.

Iodine deficiency has, in numerous studies,  been linked to cancers of the breast,  ovaries,  uterus,  prostate and colon.

The recommended daily amount of iodine depends on age and other factors and ranges from 150ug(mcg) to 300ug, with pregnant or lactating mother’s having the highest requirements.   Note that these RDA amounts are based on the amount of iodine required to reduce goiter across the population and in no way reflect what might be an optimal amount for good health.

Women are 15 times more likely to be deficient due to their higher requirements.

Dietary sources of Iodine are scarce due to the depletion of soils.  Seaweed/kelp remains the best source and some fish and eggs do contain useful amounts.  Iodised salt remains the best blunt-instrument to prevent disease in the population.  In Australia, the government has mandated that bread be made using iodised salt, but that does not help low-carb eaters.

It thus appears that, unless you have a reasonable amount of seaweed,  iodine supplementation may be required for optimal health (over and above just staying overtly disease free).

Sources such as Brownstein recommend around 12.5mg of iodine per day – yes, that’s nearly 100 times the RDA.  A good discussion on how much iodine to take can be found on the Weston Price website.   It is reasonable clear that we should be taking at least ten times the RDA and maybe more.  That is a daily dose of 1.5mg to 3.0mg per day.  The only way to achieve that is to eat a lot of seaweed or to take supplements.

There are many factors that affect the requirement for iodine – such as bromides in the diet and the environment,  and fluoridation of drinking water – which would increase the requirement for iodine.  There seems to be good clinical evidence that taking high doses (100x RDA or more) is not harmful to your health.


Despite there being no Recommended Daily Allowance (RDA) for boron, this is a mineral that is critical to good health.  Boron is essential for the body to use calcium and magnesium effectively.  Boron deficiency can lead to:

  • osteoporosis,
  • hormonal imbalances (estrogen, testosterone etc)
  • arthritis,
  • brain and neurological dysfunction
  • slow wound healing

Boron deficiency has also been linked to increased risk of lung, prostate and cervical cancers.

Virtually all soils are deficient in boron and those plants (beans, nuts, grains, grapes etc) that contain useful amounts could likely be eliminated from a low-carb diet and supplementation may be required.

Like iodine, there are a range of views on how much is required for optimal health.  It certainly appears that most people, regardless of diet, would not be getting an optimal amount and that low-carb eaters may be getting significantly less.  Some advocates of boron-supplementation recommend a daily does of 30mg while the USDA has specified an upper limit of 20-25mg per day for adults.


Selenium is closely linked with iodine and boron and a lack of selenium provides the same range of symptoms.  In Australia, the RDA for selenium is around 70ug for adults with an upper limit of 400ug/day.  Some advocates of selenium recommend 200ug/day for optimal health.

Dietary sources of selenium are brazil nuts, tuna, sardines, meats, and eggs.  It should not be difficult to reach the RDA on a low-carb diet though reaching an amount for “optimal health” may be challenging without resorting to supplements.