Is Your Bottled Water Killing You?February 2007
By Dale Kiefer
Health Benefits of Magnesium Replacement
What can you expect from supplementing magnesium to optimal levels? Research over the past 20 years suggests that magnesium supplementation will accomplish several critically important goals:
Can you correct metabolic syndrome and its complications—such as insulin resistance and high blood pressure—without replacing magnesium? Of course you can, just as you can operate your car without changing the oil. However, magnesium deficiency will catch up with you, and consuming this basic supplement will help you to more easily achieve your health goals.
Strategies for Optimizing Your Magnesium Intake
According to the US Department of Health and Human Services, nearly all of us fail to achieve even the modest magnesium RDAs of 420 mg for adult males and 320 mg for adult females. Most American adults ingest about 270 mg of magnesium a day, well below the RDA and enough to generate a substantial cumulative deficiency over months and years.37
The magnesium RDA refers to elemental magnesium, defined as the amount of magnesium regardless of its source or form. Magnesium is generally available as various “salts” (not to be confused with table salt), and the amount of elemental magnesium contained in each varies depending on the salt. For example, the amount of magnesium in magnesium oxide is 60%; in magnesium carbonate, 45%; in magnesium citrate, 16%; and in magnesium chloride, 12%.38 Thus, magnesium oxide supplements tend to contain more elemental magnesium per pill than do magnesium citrate supplements.
Magnesium salts differ in absorption. Magnesium oxide, though inexpensive and widely available, is thought to be relatively less absorbed than the citrate and chloride forms.39-41
You can also increase your magnesium intake by choosing foods rich in magnesium, which are listed in the table below.42
Dietary Sources of Magnesium
Nuts, pumpkin seeds, spinach, and oat bran are particularly rich and healthy sources of magnesium.
Another strategy for boosting magnesium intake is to supplement your diet with the soluble fiber known as inulin. Like other soluble fibers, inulin may exert modest cholesterol- and triglyceride-reducing effects. However, it also enhances magnesium absorption in the intestine.43 Inulin can be taken as a supplement, and is contained in some foods (for example, the Stonyfield Farms brand of yogurt). Inulin can help increase satiety (the sense of fullness you get with eating), resulting in decreased calorie intake throughout the day.44 Inulin thus holds promise in supporting efforts to lose weight.45
One more important way to optimize your magnesium intake is to choose water that is rich in magnesium. Unfortunately, in the US, this is easier said than done. The FDA regulates bottled water and mandates that the only additives permitted are fluoride and antimicrobials to deter bacterial growth. Magnesium cannot therefore be added to water labeled spring water or mineral water.
Magnesium-rich mineral waters are not easy to find, but they are out there. By FDA definition, mineral waters must contain at least 250 parts per million (ppm) of total dissolved solids. Not all mineral water contains significant quantities of magnesium. For example, Napa Valley’s Calistoga Springs, labeled as “mineral water,” contains 0.61–0.96 mg/L of magnesium, or virtually none.
To determine the amount of magnesium contained in bottled water labeled “mineral water” but not listed above, go to the bottler’s website to determine the water’s composition.
With the exception of Florida’s Original Fountain of Youth Mineral Water, drinking an entire liter of many so-called mineral waters provides only a modest amount of magnesium. Thus, for instance, if you are currently ingesting around 250 mg a day of magnesium from your diet, drinking a liter of Gerolsteiner a day (supplying 108 mg/L of magnesium) will increase your magnesium consumption only to about 350 mg per day. However, by adding a magnesium supplement that provides as little as 100 mg of elemental magnesium, you will have more than achieved the RDA for an adult male. Since many mineral waters are expensive (around $2-3 per liter), magnesium supplements are a far less costly way to optimize your magnesium intake.
The intensification of municipal water treatment has resulted in a growing epidemic of magnesium deficiency, with most Americans failing even to achieve the modest levels set by the government-recommended RDA. Most of us have daily deficiencies in magnesium intake of only 70-200 mg a day.
The consequences of magnesium deficiency can be dramatic, including poor insulin response, migraine headaches, high blood pressure, and abnormal and even dangerous heart rhythms.
Fortunately, there are plenty of healthy choices—foods rich in magnesium, low-cost magnesium supplements, and waters rich in magnesium—that can you help reach or exceed the magnesium RDA and attain the numerous health benefits conferred by optimal magnesium intake.
Dr. William Davis is an author and cardiologist practicing in Milwaukee, WI. He is founder of the Track Your Plaque program, a heart disease prevention and reversal program that shows how CT heart scans can be used to track and control coronary plaque. He can be reached at www.TrackYourPlaque.com.
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