Why take magnesium

Why aren’t Canadians getting the magnesium they need to stay healthy?


Magnesium is missing in our diets

Our diets are providing less magnesium than they used to. The composition of what we eat and the quality of our foods has drastically changed over the past hundred years, and this has made it difficult for even the most health-conscious Canadians to get enough magnesium. The 2004 Canadian Community Health Survey showed that over 34% of Canadians consumed less than the estimated average amount of required magnesium.

And those estimated average requirements are quite modest; around 350mg/day for adults. It’s thought that before industrialization, dietary intakes were closer to 475-500mg/day!

Magnesium depleted soils

Food sources we’ve traditionally relied on for our magnesium, like legumes, grains and greens, are themselves deprived of magnesium! Modern farming practices, meant to increase yields and resist pests, have left overworked farmlands depleted of essential nutrients like magnesium. Soil compaction, surface irrigation, monoculture, pesticides and chemical fertilizers have all impacted the soil’s ability to restore, retain and provide magnesium to crops. And while we are growing food in greater densities than ever before, they are all drawing from this same dwindling supply of magnesium.

The end result? We’re overfed and undernourished. Many fruits and vegetables have lost large amounts of minerals and nutrients in the past 50 years. For example, McCance and Widdowson’s epic compilation, the Composition of Foods, has tracked the nutrient composition of foods since 1940. Between 1940 and 1991, there was an average magnesium decrease of 24% in vegetables and 16% in fruits. Some foods have seen more drastic declines than others. Carrots have lost 75% of their magnesium content. You would have to eat 4 carrots today to get the same magnesium from 1 carrot in 1940!

A nation that destroys its soil destroys itself.
– Franklin D. Roosevelt

Intensive plowing eliminates protective ground cover, causing high rates of erosion. Magnesium is lost in the run-off.

Instead of traditional fertilizers made of manure and compost, today’s fertilizers are synthetic. They are rich in nitrogen, potassium and phosphorus, but low on essential minerals like magnesium.

Higher yields and more crops grown in the same area of land means fewer minerals from the soil go to each plant. This is known as the dilution effect.


Food processing removes magnesium

Food processing and refining remove large swaths of magnesium. Whole grains, a staple in the modern diet, can lose over 80% of their magnesium content simply through milling. Seeds and nuts in their raw form are rich in magnesium, but the process of refining them into oils removes nearly all of their magnesium content. Even cooking vegetables can leach magnesium.

The typical Canadian diet, laced with refined grains, oils and sugars, provides large amounts of calories with little to no magnesium.

Treated water

In some parts of the world, magnesium in drinking water accounts for 50% of the recommended dietary intake. Treating and softening tap water removes minerals like magnesium before you pour yourself a single cup! 


Magnesium is getting harder to absorb

Regardless of how much you consume, you will not get enough magnesium without good absorption. Foods containing magnesium need to be digested and broken down by enzymes and acids in our digestive tract before they can be absorbed in the small intestine. A breakdown in the digestive process will seriously impede how much magnesium can be absorbed.

Weaker stomach acid

Magnesium needs to be soluble to be absorbed by the small intestine. The strong gastric acid in the stomach provides an environment that dissolves magnesium into this soluble form. If the environment is not acidic enough, magnesium will remain insoluble and will simply be flushed through the intestinal tract. While age is the primary culprit for low stomach acid, chronic stress that is so common in modern life will also reduce acid production. The stress response diverts energy away from tasks like digestion. Overuse of antacids to reduce common symptoms like heartburn is another contributor.

Gastrointestinal conditions

Chronic functional disorders of the gastrointestinal system are becoming increasingly common. Inflammatory bowel diseases like Crohn’s and colitis result in inflammation in the intestine. The inflammation destroys intestinal mucosal cells, which impedes the absorption of key nutrients like magnesium. Other conditions such as irritable bowel syndrome (IBS) and yeast overgrowth can have similar effects on inhibiting magnesium absorption or flushing it out (through diarrhea) before it can be absorbed.

Hold off on that antacid.

Contrary to common belief, acid reflux or heartburn is not a symptom of too much acid in the stomach but too little.  Low stomach acid can contribute to malabsorption of carbohydrates, which in turn leads to a build-up of gasses in the stomach. This intra-abdominal pressure pushes the stomach contents, including gastric acid, up to the esophagus where it can irritate the sensitive lining. Taking an antacid can provide temporary relief, but it will decrease an already low amount of stomach acid, making the issue worse, not to mention making it harder for us to breakdown magnesium!


Foods, drugs and other substances that block absorption

If you enjoy drinking soda, you may want to find a new drink.

Some foods are not only lacking in magnesium, but can also block its absorption. For example, the phosphoric acid in many popular sodas will impair absorption by forming phosphates with magnesium ions in the digestive tract. These phosphates are insoluble and cannot be absorbed through the intestinal walls. Phytic acid, found in soybeans, the hulls of seeds or bran of grains can also form insoluble compounds. Oxalic acids in raw greens and tannins in teas do the same.

Other minerals such as calcium or iron are absorbed in the intestine the same way as magnesium. When you consume minerals together, they often compete for the same limited channels of absorption. This is the reason why practitioners recommend taking mineral supplements at different times.

It’s not limited to foods. Many drugs also bind to magnesium ions, making them insoluble. Tetracycline antibiotics, corticosteroids and diuretics are just a few examples. Even tap water, if treated with fluorine, can inhibit magnesium absorption. Fluoride binds with magnesium to form an insoluble crystalline compound that the body can’t absorb.


Magnesium is easier to lose

Our magnesium requirements have increased.

We’ve established that magnesium is involved in many processes throughout the body. Overstimulating these processes will result in an increase in our magnesium requirements. For instance, when we suffer from high stress, our body produces a hormone protein called cortisol. Producing and regulating this hormone means spending and excreting more magnesium.

Magnesium is fundamental to proper metabolism. Modern diets high in refined sugar cause more magnesium to be used in both metabolizing glucose into cellular energy, as well as activating the release of insulin. That’s why inadequate magnesium can lead to elevated insulin and glucose levels in the blood, and therefore insulin resistance. This can lead to the flushing of excess glucose in urine, which has the unfortunate side effect of flushing serum magnesium along with it.

Coffee, alcohol, diuretic drugs and birth control pills can cause our kidneys to eliminate more magnesium than they should.

Drug-Induced Nutrient Depletion

Despite being effective and even life-saving, both over-the-counter and prescription medications can have potential side effects. What most people don’t realize is that the side effects may not come from the drug itself, but rather as a result of nutritional deficiencies from prolonged use. Medications can deplete nutrients (like magnesium) through various mechanisms, like altering the way a nutrient is absorbed, converted, stored or excreted.

Some, like acid blockers, can impair the digestion of nutrients. Others may bind with nutrients, preventing absorption completely. Others, like diuretics, can increase urine output, causing a loss of water soluble vitamins and electrolytes such as potassium and magnesium.

Most at risk? Seniors.

The Canadian Institute for Health Information (CIHI) reported in 2009 that about two-thirds (63 percent) of seniors on public drug programs in six provinces were claiming the use of five or more drugs from different drug classes. Nearly a quarter (23 percent) had claims for 10 or more drug classes.

Polypharmacy, the use of five or more prescription medications, is common among seniors. It’s further compounded by the fact that seniors metabolize and eliminate drugs more slowly due to aging kidneys and liver.

Some drugs that affect magnesium levels*

  • Antacids – Calcium carbonate and sodium bicarbonate
  • Acid blockers – Ranitidine, Cimetidine, Nizatidine, Famotidine
  • Antibiotics – Tetracycline, Amoxicillin, Doxycycline, Cephalexi
  • Anti-Hypertensives – Thiazide diuretics, Loop diuretics, Hydralazine
  • Cardiac glycosides like Digoxin

*This list is by no means conclusive, but meant to give you an idea of which medication classes to watch out for.