Zinc is a metallic element that is needed in very small amounts for human health.  Zinc regulates the activities of genes, supports blood sugar balance and metabolism, is important for the senses of taste and smell and has a key role in immune function.

 Healthy adults need around 10 mg of zinc per day; children and teens need less and the amount varies according to age and gender.  Zinc deficiency is relatively common worldwide, but is not common in Canada.  People who may have a greater than average requirement for zinc include those with chronic or recurring infections, skin conditions, ADHD or alcoholism.

Taking high doses of supplemental zinc daily for long periods of time has been implicated in doubling the risk of prostate cancer. Doses of 10-30 grams of zinc can be fatal.  People with HIV/AIDS should avoid zinc supplements unless taken under medical supervision.

If you are on any of the following medications, do not take zinc unless you have been advised to do so by your health care practitioner:

  • Amiloride (Midamor)
  • Antibiotics (Quinolone antibiotics such as ciprofloxacin (Cipro), levofloxacin (Levaquin), ofloxacin (Floxin), moxifloxacin (Avelox), gatifloxacin (Tequin) enoxacin (Penetrex), norfloxacin (Chibroxin, Noroxin), sparfloxacin (Zagam), trovafloxacin (Trovan), and grepafloxacin (Raxar))
  • Antibiotics (Tetracycline antibiotics such as demeclocycline (Declomycin), minocycline (Minocin), and tetracycline (Achromycin, Sumycin))
  • Cisplatin (Platinol-AQ)
  • Penicillamine
  • Bromelain
  • Calcium
  • Chromium
  • Copper
  • EDTA
  • Iron
  • Manganese

Also note that taking zinc sulfate with black coffee instead of water reduces zinc absorption by half and that eating fiber at the time the zinc supplement is taken can reduce its absorption.

Some of the best food sources of zinc include spinach, lamb, beef, scallops and mushrooms but all of the foods shown here are good sources.


Sulfur is a non-metallic mineral that exists as an odorless, yellow crystalline solid in its natural form. It is an essential component of the amino acids methionine, cystine, cysteine and taurine.  It is also part of the molecular structure of two vitamins: thiamine and biotin, and participates in many reactions in our bodies as sulfides and sulfates.

Sulfur’s roles in the body relate primarily to its presence in the four amino acids listed above; it is involved in protein synthesis, enzymatic reactions, the production of insulin and heparin which regulate blood sugar levels and clotting respectively, and the maintenance of hair, nails and skin.

Some of the best food sources of sulfur include eggs, garlic, onions, cabbage, cauliflower, broccoli, brussels sprouts, and turnips but it is found in many foods.  Because it is so readily available from dietary sources, deficiency and toxicity states are rarely seen.


Sodium is a metallic element.  When it is combined with chloride to form sodium chloride, we refer to it as salt.  Sodium plays important roles in the regulation of blood volume, blood pressure, pH, nerve and muscle function.

The minimum requirement for sodium is 500 mg per day.  The average North American intake is much higher than this, ten times higher or more.  Sodium deficiency manifests as generalized weakness.  Sodium excess is more of a concern and occurs much more commonly.  Excess sodium is thought to contribute to high blood pressure and premenstrual syndrome via water retention.  An appropriate adult intake for sodium is around 2000 mg – roughly the amount contained in one teaspoon of table salt.

Sodium is found in table salt and as a natural component of many foods, especially seafood and fermented soy products like soy sauce and miso.  It is used as a preservative and flavor enhancer in many processed, packaged and canned foods.


The mineral potassium is involved in many body functions including nerve signal transmission, muscle contractions, fluid balance, and various chemical reactions.  An adequate level of potassium is thought to protect against high blood pressure and stroke.

The daily requirement for adults is 40-80 mEq daily.  It is easy to get that amount from your diet.

Potassium deficiency can cause symptoms such as fatigue and weakness, muscle twitches, stiffness, aching and cramps, bloating and abdominal cramping, heart palpitations, dizziness, fainting, frequent urination and extreme thirst.  Potassium deficiency may occur with certain medications, especially diuretics (“water pills”) and drugs for high blood pressure.

Too much potassium can also create problems including stomach upset, nausea, diarrhea, vomiting, intestinal gas, feelings of burning or tingling, generalized weakness, paralysis, listlessness, dizziness, mental confusion, low blood pressure, irregular heart rhythm, and death.

Potassium can interact with many medications and some conditions:

  • If you are allergic to aspirine or tartrazine, avoid potassium supplements that contain tartrazine.
  • Medications such as ACE Inhibitors and Angiotensin receptor blockers (ARBs) can cause an increase potassium levels in the blood. ACE Inhibitors include captopril (Capoten), enalapril (Vasotec), lisinopril (Prinivil, Zestril), ramipril (Altace), and others.  ARBs include losartan (Cozaar), valsartan (Diovan), irbesartan (Avapro), candesartan (Atacand), telmisartan (Micardis), eprosartan (Teveten), and others.
  • Potassium-sparing diurectics can also cause an increase in potassium if you are taking it as a supplement.  Examples of these “water pills” include amiloride (Midamor), spironolactone (Aldactone), and triamterene (Dyrenium).

Potassium is a mineral found in foods such as fruits (especially dried fruits), cereals, beans, milk, and vegetables. A large serving of spinach salad with avocado and tomato will meet the daily requirement for most people.


Phosphorus is  a non-metallic element that is essential for life. It is a component of DNA and cell membranes, and forms part of the molecule used to transport cellular energy.  As the partner to calcium in calcium phosphate, phosphorus is also important for the health of bones and teeth.

Low blood phosphate (hypophosphatemia) can result from malnutrition, malabsorption and from metabolic conditions that increase its concentration in urine. Hypophosphatemia can result in muscle and neurological dysfunction.  Too much phosphate results in diarrhea, calcification of organs and soft tissue, and problems with the body’s ability to use other minerals such as iron, calcium, magnesium, and zinc; in extreme cases, it can lead to death.

Healthy adolescents and adults need about 700 mg of phosphorus daily.  Children need less (according to age) and pregnant or lactating women need more.

Phosphorus can interact with the following conditions, nutrients and medications:

  • kidney failure, hypoparathyroidism – can lead to excessive phosphorus in the blood and other tissues
  • calcium, Vitamin D, aluminum, potassium – can interact with phosphorus.  Check with your MD, ND or pharmacist before taking these with phosphorus.
  • potassium-sparing diuretics (water pills) taken together with a phosphate (such as aluminum phosphate antacids) may result in high blood levels of potassium (hyperkalemia).  Check with your MD, ND or pharmacist before combining these.

The best food sources for phosphorus are foods that also contain protein and/or calcium, including milk, meat, fish and soy.  Black beans, kidney beans and pumpkin seeds are also good sources of phosphorus.  Because phosphorus is widely available in foods, dietary deficiencies are rare and occur primarily under conditions of starvation.