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.


Selenium is a metallic element that acts as an essential trace mineral in human health.  Selenium plays a key role in the production of thyroid hormones and acts as an anti-oxidant.  It is incorporated into proteins by binding with certain amino acids to form compounds such as selenocysteine and selenomethionine.

 We need selenium in tiny amounts on a daily basis, ranging from 20-70 micrograms.  Healthy adults need about 55 mcg daily.

Selenium deficiency causes specific heart and joint problems along with muscle
weakness or pain, and discoloration of the hair, skin, and nail beds.  Selenium deficiency is easily treated by consuming foods that are high in selenium.

Taking high doses of supplemental selenium daily for long periods of time can be fatal.  Selenium toxicity rarely occurs unless supplements are involved.  People should avoid selenium supplements unless taken under medical supervision.

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

  • oral contraceptives
  • gold salts
  • statin medications for cholesterol
  • blood thinners

The best food sources of selenium include broccoli, lamb, halibut, tuna and garlic.


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.